/*
 * meli
 *
 * Copyright 2017-2018 Manos Pitsidianakis
 *
 * This file is part of meli.
 *
 * meli is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * meli is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with meli. If not, see <http://www.gnu.org/licenses/>.
 */

use std::process::{Command, Stdio};

use linkify::LinkFinder;
use melib::utils::xdg::query_default_app;

use super::*;
use crate::ThreadEvent;

/// Envelope view, with sticky headers, a pager for the body, and
/// subviews for more menus.
///
/// Doesn't have a concept of accounts, mailboxes or mail backends.
/// Therefore all settings it needs need to be provided through the
/// `view_settings` field of type [`ViewSettings`].
#[derive(Debug)]
pub struct EnvelopeView {
    pub pager: Pager,
    pub subview: Option<Box<dyn Component>>,
    pub dirty: bool,
    pub initialised: bool,
    pub force_draw_headers: bool,
    pub mode: ViewMode,
    pub mail: Mail,
    pub body: Box<Attachment>,
    pub display: Vec<AttachmentDisplay>,
    pub body_text: String,
    pub links: Vec<Link>,
    pub attachment_tree: String,
    pub attachment_paths: Vec<Vec<usize>>,
    pub headers_no: usize,
    pub headers_cursor: usize,
    pub force_charset: ForceCharset,
    pub view_settings: ViewSettings,
    pub cmd_buf: String,
    pub active_jobs: HashSet<JobId>,
    pub main_loop_handler: MainLoopHandler,
    pub id: ComponentId,
}

impl Clone for EnvelopeView {
    fn clone(&self) -> Self {
        Self::new(
            self.mail.clone(),
            Some(self.pager.clone()),
            None,
            Some(self.view_settings.clone()),
            self.main_loop_handler.clone(),
        )
    }
}

impl std::fmt::Display for EnvelopeView {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "view mail")
    }
}

impl EnvelopeView {
    pub fn new(
        mail: Mail,
        pager: Option<Pager>,
        subview: Option<Box<dyn Component>>,
        view_settings: Option<ViewSettings>,
        main_loop_handler: MainLoopHandler,
    ) -> Self {
        let view_settings = view_settings.unwrap_or_default();
        let body = Box::new(AttachmentBuilder::new(&mail.bytes).build());
        let mut ret = EnvelopeView {
            pager: pager.unwrap_or_default(),
            subview,
            dirty: true,
            initialised: false,
            force_draw_headers: false,
            mode: ViewMode::Normal,
            force_charset: ForceCharset::None,
            attachment_tree: String::new(),
            attachment_paths: vec![],
            body,
            display: vec![],
            links: vec![],
            body_text: String::new(),
            view_settings,
            headers_no: 5,
            headers_cursor: 0,
            mail,
            main_loop_handler,
            active_jobs: HashSet::default(),
            cmd_buf: String::with_capacity(4),
            id: ComponentId::default(),
        };

        ret.parse_attachments();

        ret
    }

    fn attachment_to_display_helper(
        a: &Attachment,
        main_loop_handler: &MainLoopHandler,
        active_jobs: &mut HashSet<JobId>,
        acc: &mut Vec<AttachmentDisplay>,
        view_settings: &ViewSettings,
        force_charset: Option<Charset>,
    ) {
        if a.content_disposition.kind.is_attachment() || a.content_type == "message/rfc822" {
            acc.push(AttachmentDisplay::Attachment {
                inner: Box::new(a.clone()),
            });
        } else if a.content_type().is_text_html() {
            let bytes = a.decode(force_charset.into());
            let filter_invocation = view_settings
                .html_filter
                .as_deref()
                .unwrap_or("w3m -I utf-8 -T text/html");
            let command_obj = Command::new("sh")
                .args(["-c", filter_invocation])
                .stdin(Stdio::piped())
                .stdout(Stdio::piped())
                .spawn()
                .and_then(|mut cmd| {
                    cmd.stdin.as_mut().unwrap().write_all(&bytes)?;
                    Ok(String::from_utf8_lossy(&cmd.wait_with_output()?.stdout).to_string())
                });
            match command_obj {
                Err(err) => {
                    main_loop_handler.send(ThreadEvent::UIEvent(UIEvent::Notification(
                        Some(format!(
                            "Failed to start html filter process: {}",
                            filter_invocation,
                        )),
                        err.to_string(),
                        Some(NotificationType::Error(melib::ErrorKind::External)),
                    )));
                    // [ref:FIXME]: add `v` configurable shortcut
                    let comment = Some(format!(
                        "Failed to start html filter process: `{}`. Press `v` to open in web \
                         browser. \n\n",
                        filter_invocation
                    ));
                    let text = String::from_utf8_lossy(&bytes).to_string();
                    acc.push(AttachmentDisplay::InlineText {
                        inner: Box::new(a.clone()),
                        comment,
                        text,
                    });
                }
                Ok(text) => {
                    // [ref:FIXME]: add `v` configurable shortcut
                    let comment = Some(format!(
                        "Text piped through `{}`. Press `v` to open in web browser. \n\n",
                        filter_invocation
                    ));
                    acc.push(AttachmentDisplay::InlineText {
                        inner: Box::new(a.clone()),
                        comment,
                        text,
                    });
                }
            }
        } else if a.is_text() {
            let bytes = a.decode(force_charset.into());
            acc.push(AttachmentDisplay::InlineText {
                inner: Box::new(a.clone()),
                comment: None,
                text: String::from_utf8_lossy(&bytes).to_string(),
            });
        } else if let ContentType::Multipart {
            ref kind,
            ref parts,
            ..
        } = a.content_type
        {
            match kind {
                MultipartType::Alternative => {
                    if parts.is_empty() {
                        return;
                    }
                    let mut display = vec![];
                    let mut chosen_attachment_idx = 0;
                    if let Some(text_attachment_pos) =
                        parts.iter().position(|a| a.content_type == "text/plain")
                    {
                        let bytes = &parts[text_attachment_pos].decode(force_charset.into());
                        if bytes.trim().is_empty()
                            && view_settings.auto_choose_multipart_alternative
                        {
                            if let Some(text_attachment_pos) =
                                parts.iter().position(|a| a.content_type == "text/html")
                            {
                                /* Select html alternative since text/plain is empty */
                                chosen_attachment_idx = text_attachment_pos;
                            }
                        } else {
                            /* Select text/plain alternative */
                            chosen_attachment_idx = text_attachment_pos;
                        }
                    }
                    for a in parts {
                        EnvelopeView::attachment_to_display_helper(
                            a,
                            main_loop_handler,
                            active_jobs,
                            &mut display,
                            view_settings,
                            force_charset,
                        );
                    }
                    acc.push(AttachmentDisplay::Alternative {
                        inner: Box::new(a.clone()),
                        shown_display: chosen_attachment_idx,
                        display,
                    });
                }
                MultipartType::Signed => {
                    #[cfg(not(feature = "gpgme"))]
                    {
                        acc.push(AttachmentDisplay::SignedUnverified {
                            inner: Box::new(a.clone()),
                            display: {
                                let mut v = vec![];
                                EnvelopeView::attachment_to_display_helper(
                                    &parts[0],
                                    main_loop_handler,
                                    active_jobs,
                                    &mut v,
                                    view_settings,
                                    force_charset,
                                );
                                v
                            },
                        });
                    }
                    #[cfg(feature = "gpgme")]
                    {
                        if view_settings.auto_verify_signatures {
                            let verify_fut = crate::mail::pgp::verify(a.clone());
                            let handle = main_loop_handler
                                .job_executor
                                .spawn_specialized("gpg::verify_sig".into(), verify_fut);
                            active_jobs.insert(handle.job_id);
                            main_loop_handler.send(ThreadEvent::UIEvent(UIEvent::StatusEvent(
                                StatusEvent::NewJob(handle.job_id),
                            )));
                            acc.push(AttachmentDisplay::SignedPending {
                                inner: Box::new(a.clone()),
                                job_id: handle.job_id,
                                display: {
                                    let mut v = vec![];
                                    EnvelopeView::attachment_to_display_helper(
                                        &parts[0],
                                        main_loop_handler,
                                        active_jobs,
                                        &mut v,
                                        view_settings,
                                        force_charset,
                                    );
                                    v
                                },
                                handle,
                            });
                        } else {
                            acc.push(AttachmentDisplay::SignedUnverified {
                                inner: Box::new(a.clone()),
                                display: {
                                    let mut v = vec![];
                                    EnvelopeView::attachment_to_display_helper(
                                        &parts[0],
                                        main_loop_handler,
                                        active_jobs,
                                        &mut v,
                                        view_settings,
                                        force_charset,
                                    );
                                    v
                                },
                            });
                        }
                    }
                }
                MultipartType::Encrypted => {
                    for a in parts {
                        if a.content_type == "application/octet-stream" {
                            #[cfg(not(feature = "gpgme"))]
                            {
                                acc.push(AttachmentDisplay::EncryptedFailed {
                                    inner: Box::new(a.clone()),
                                    error: Error::new(
                                        "Cannot decrypt: meli must be compiled with libgpgme \
                                         support.",
                                    ),
                                });
                            }
                            #[cfg(feature = "gpgme")]
                            {
                                if view_settings.auto_decrypt {
                                    let decrypt_fut = crate::mail::pgp::decrypt(a.raw().to_vec());
                                    let handle = main_loop_handler
                                        .job_executor
                                        .spawn_specialized("gpg::decrypt".into(), decrypt_fut);
                                    active_jobs.insert(handle.job_id);
                                    main_loop_handler.send(ThreadEvent::UIEvent(
                                        UIEvent::StatusEvent(StatusEvent::NewJob(handle.job_id)),
                                    ));
                                    acc.push(AttachmentDisplay::EncryptedPending {
                                        inner: Box::new(a.clone()),
                                        handle,
                                    });
                                } else {
                                    acc.push(AttachmentDisplay::EncryptedFailed {
                                        inner: Box::new(a.clone()),
                                        error: Error::new("Undecrypted."),
                                    });
                                }
                            }
                        }
                    }
                }
                _ => {
                    for a in parts {
                        EnvelopeView::attachment_to_display_helper(
                            a,
                            main_loop_handler,
                            active_jobs,
                            acc,
                            view_settings,
                            force_charset,
                        );
                    }
                }
            }
        }
    }

    pub fn parse_attachments(&mut self) {
        let mut display = vec![];
        Self::attachment_to_display_helper(
            &self.body,
            &self.main_loop_handler,
            &mut self.active_jobs,
            &mut display,
            &self.view_settings,
            (&self.force_charset).into(),
        );
        let (attachment_paths, attachment_tree) = self.attachment_displays_to_tree(&display);
        self.display = display;
        self.attachment_tree = attachment_tree;
        self.attachment_paths = attachment_paths;
        self.regenerate_body_text();
    }

    pub fn regenerate_body_text(&mut self) {
        self.body_text = Self::attachment_displays_to_text(&self.display, true);
    }

    pub fn attachment_displays_to_text(
        displays: &[AttachmentDisplay],
        show_comments: bool,
    ) -> String {
        let mut acc = String::new();
        for d in displays {
            use AttachmentDisplay::*;
            match d {
                Alternative {
                    inner: _,
                    shown_display,
                    display,
                } => {
                    acc.push_str(&Self::attachment_displays_to_text(
                        &display[*shown_display..(*shown_display + 1)],
                        show_comments,
                    ));
                }
                InlineText {
                    inner: _,
                    text,
                    comment: Some(comment),
                } if show_comments => {
                    acc.push_str(comment);
                    if !acc.ends_with("\n\n") {
                        acc.push_str("\n\n");
                    }
                    acc.push_str(text);
                }
                InlineText {
                    inner: _,
                    text,
                    comment: _,
                } => acc.push_str(text),
                InlineOther { inner } => {
                    if !acc.ends_with("\n\n") {
                        acc.push_str("\n\n");
                    }
                    acc.push_str(&inner.to_string());
                    if !acc.ends_with("\n\n") {
                        acc.push_str("\n\n");
                    }
                }
                Attachment { inner: _ } => {}
                SignedPending {
                    inner: _,
                    display,
                    handle: _,
                    job_id: _,
                } => {
                    if show_comments {
                        acc.push_str("Waiting for signature verification.\n\n");
                    }
                    acc.push_str(&Self::attachment_displays_to_text(display, show_comments));
                }
                SignedUnverified { inner: _, display } => {
                    if show_comments {
                        acc.push_str("Unverified signature.\n\n");
                    }
                    acc.push_str(&Self::attachment_displays_to_text(display, show_comments))
                }
                SignedFailed {
                    inner: _,
                    display,
                    error,
                } => {
                    if show_comments {
                        let _ = writeln!(acc, "Failed to verify signature: {}.\n", error);
                    }
                    acc.push_str(&Self::attachment_displays_to_text(display, show_comments));
                }
                SignedVerified {
                    inner: _,
                    display,
                    description,
                } => {
                    if show_comments {
                        if description.is_empty() {
                            acc.push_str("Verified signature.\n\n");
                        } else {
                            acc.push_str(description);
                            acc.push_str("\n\n");
                        }
                    }
                    acc.push_str(&Self::attachment_displays_to_text(display, show_comments));
                }
                EncryptedPending { .. } => acc.push_str("Waiting for decryption result."),
                EncryptedFailed { inner: _, error } => {
                    let _ = write!(acc, "Decryption failed: {}.", &error);
                }
                EncryptedSuccess {
                    inner: _,
                    plaintext: _,
                    plaintext_display,
                    description,
                } => {
                    if show_comments {
                        if description.is_empty() {
                            acc.push_str("Succesfully decrypted.\n\n");
                        } else {
                            acc.push_str(description);
                            acc.push_str("\n\n");
                        }
                    }
                    acc.push_str(&Self::attachment_displays_to_text(
                        plaintext_display,
                        show_comments,
                    ));
                }
            }
        }
        acc
    }

    fn attachment_displays_to_tree(
        &self,
        displays: &[AttachmentDisplay],
    ) -> (Vec<Vec<usize>>, String) {
        let mut acc = String::new();
        let mut branches = SmallVec::new();
        let mut paths = Vec::with_capacity(displays.len());
        let mut cur_path = vec![];
        let mut idx = 0;

        fn append_entry(
            (idx, (depth, att_display)): (&mut usize, (usize, &AttachmentDisplay)),
            branches: &mut SmallVec<[bool; 8]>,
            paths: &mut Vec<Vec<usize>>,
            cur_path: &mut Vec<usize>,
            has_sibling: bool,
            s: &mut String,
        ) {
            use AttachmentDisplay::*;
            let mut default_alternative: Option<usize> = None;
            let (att, sub_att_display_vec) = match att_display {
                Alternative {
                    inner,
                    shown_display,
                    display,
                } => {
                    default_alternative = Some(*shown_display);
                    (inner, display.as_slice())
                }
                InlineText {
                    inner,
                    text: _,
                    comment: _,
                }
                | InlineOther { inner }
                | Attachment { inner }
                | EncryptedPending { inner, handle: _ }
                | EncryptedFailed { inner, error: _ } => (inner, &[][..]),
                SignedPending {
                    inner,
                    display,
                    handle: _,
                    job_id: _,
                }
                | SignedUnverified { inner, display }
                | SignedFailed {
                    inner,
                    display,
                    error: _,
                }
                | SignedVerified {
                    inner,
                    display,
                    description: _,
                }
                | EncryptedSuccess {
                    inner: _,
                    plaintext: inner,
                    plaintext_display: display,
                    description: _,
                } => (inner, display.as_slice()),
            };
            s.extend(format!("\n[{}]", idx).chars());
            for &b in branches.iter() {
                if b {
                    s.push('|');
                } else {
                    s.push(' ');
                }
                s.push(' ');
            }
            if depth > 0 {
                if has_sibling {
                    s.push('|');
                } else {
                    s.push(' ');
                }
                s.push_str("\\_ ");
            } else {
                s.push(' ');
                s.push(' ');
            }

            s.push_str(&att.to_string());
            paths.push(cur_path.clone());
            if matches!(att.content_type, ContentType::Multipart { .. }) {
                let mut iter = (0..sub_att_display_vec.len()).peekable();
                if has_sibling {
                    branches.push(true);
                } else {
                    branches.push(false);
                }
                while let Some(i) = iter.next() {
                    *idx += 1;
                    cur_path.push(i);
                    append_entry(
                        (idx, (depth + 1, &sub_att_display_vec[i])),
                        branches,
                        paths,
                        cur_path,
                        iter.peek().is_some(),
                        s,
                    );
                    if Some(i) == default_alternative {
                        s.push_str(" (displayed by default)");
                    }
                    cur_path.pop();
                }
                branches.pop();
            }
        }

        for (i, d) in displays.iter().enumerate() {
            cur_path.push(i);
            append_entry(
                (&mut idx, (0, d)),
                &mut branches,
                &mut paths,
                &mut cur_path,
                i + 1 < displays.len(),
                &mut acc,
            );
            cur_path.pop();
            idx += 1;
        }
        (paths, acc)
    }

    fn open_attachment(
        &'_ self,
        lidx: usize,
        context: &mut Context,
    ) -> Option<&'_ melib::Attachment> {
        if let Some(path) = self.attachment_paths.get(lidx).and_then(|path| {
            if !path.is_empty() {
                Some(path)
            } else {
                None
            }
        }) {
            let first = path[0];
            use AttachmentDisplay::*;
            let root_attachment = match &self.display[first] {
                Alternative {
                    inner,
                    shown_display: _,
                    display: _,
                }
                | InlineText {
                    inner,
                    text: _,
                    comment: _,
                }
                | InlineOther { inner }
                | Attachment { inner }
                | SignedPending {
                    inner,
                    display: _,
                    handle: _,
                    job_id: _,
                }
                | SignedFailed {
                    inner,
                    display: _,
                    error: _,
                }
                | SignedVerified {
                    inner,
                    display: _,
                    description: _,
                }
                | SignedUnverified { inner, display: _ }
                | EncryptedPending { inner, handle: _ }
                | EncryptedFailed { inner, error: _ }
                | EncryptedSuccess {
                    inner: _,
                    plaintext: inner,
                    plaintext_display: _,
                    description: _,
                } => inner,
            };
            fn find_attachment<'a>(
                a: &'a melib::Attachment,
                path: &[usize],
            ) -> Option<&'a melib::Attachment> {
                if path.is_empty() {
                    return Some(a);
                }
                if let ContentType::Multipart { ref parts, .. } = a.content_type {
                    let first = path[0];
                    if first < parts.len() {
                        return find_attachment(&parts[first], &path[1..]);
                    }
                }
                None
            }

            let ret = find_attachment(root_attachment, &path[1..]);
            if lidx == 0 {
                return ret.and_then(|a| {
                    if a.content_disposition.kind.is_attachment()
                        || a.content_type == "message/rfc822"
                    {
                        Some(a)
                    } else {
                        None
                    }
                });
            } else {
                return ret;
            }
        }
        context
            .replies
            .push_back(UIEvent::StatusEvent(StatusEvent::DisplayMessage(format!(
                "Attachment `{}` not found.",
                lidx
            ))));
        None
    }
}

impl Component for EnvelopeView {
    fn draw(&mut self, grid: &mut CellBuffer, area: Area, context: &mut Context) {
        self.view_settings.theme_default = crate::conf::value(context, "theme_default");

        let hdr_theme = crate::conf::value(context, "mail.view.headers");
        let hdr_name_theme = crate::conf::value(context, "mail.view.headers_names");
        let hdr_area_theme = crate::conf::value(context, "mail.view.headers_area");

        let y: usize = {
            if self.mode.is_source() {
                grid.clear_area(area, self.view_settings.theme_default);
                context.dirty_areas.push_back(area);
                0
            } else {
                let envelope = &self.mail;
                let height_p = self.pager.size().1;

                let height = area
                    .height()
                    .saturating_sub(self.headers_no)
                    .saturating_sub(1);

                self.headers_no = 0;
                let mut skip_header_ctr = self.headers_cursor;
                let sticky = self.view_settings.sticky_headers || height_p < height;
                let mut y = 0;
                macro_rules! print_header {
                    ($(($header:path, $string:expr)),*$(,)?) => {
                        $({
                            if sticky || skip_header_ctr == 0 {
                                if y <= area.height() {
                                    grid.clear_area(
                                        area.skip_rows(y),
                                        hdr_area_theme,
                                    );
                                    let (_x, _y) =
                                        grid.write_string(
                                        &format!("{}:", $header),
                                        hdr_name_theme.fg,
                                        hdr_name_theme.bg,
                                        hdr_name_theme.attrs,
                                        area.skip_rows(y),
                                        Some(0),
                                    );
                                    let (__x, __y) =
                                        grid.write_string(
                                        &$string,
                                        hdr_theme.fg,
                                        hdr_theme.bg,
                                        hdr_theme.attrs,
                                        area.skip(_x+1, y+ _y),
                                        Some(0),
                                    );
                                    y += _y +__y + 1;
                                }
                            } else {
                                skip_header_ctr = skip_header_ctr.saturating_sub(1);
                            }
                            self.headers_no += 1;
                        })+
                    };
                }
                let find_offset = |s: &str| -> (bool, (i64, i64)) {
                    let mut diff = (true, (0, 0));
                    if let Some(pos) = s.as_bytes().iter().position(|b| *b == b'+' || *b == b'-') {
                        let offset = &s[pos..];
                        diff.0 = offset.starts_with('+');
                        if let (Ok(hr_offset), Ok(min_offset)) =
                            (offset[1..3].parse::<i64>(), offset[3..5].parse::<i64>())
                        {
                            diff.1 .0 = hr_offset;
                            diff.1 .1 = min_offset;
                        }
                    }
                    diff
                };
                let orig_date = envelope.date_as_str();
                let date_str: std::borrow::Cow<str> = if self.view_settings.show_date_in_my_timezone
                {
                    let local_date = datetime::timestamp_to_string(
                        envelope.timestamp,
                        Some(datetime::formats::RFC822_DATE),
                        false,
                    );
                    let orig_offset = find_offset(orig_date);
                    let local_offset = find_offset(&local_date);
                    if orig_offset == local_offset {
                        orig_date.into()
                    } else {
                        format!(
                            "{} [actual timezone: {}{:02}{:02}]",
                            local_date,
                            if orig_offset.0 { '+' } else { '-' },
                            orig_offset.1 .0,
                            orig_offset.1 .1
                        )
                        .into()
                    }
                } else {
                    orig_date.into()
                };
                print_header!(
                    (HeaderName::DATE, date_str),
                    (HeaderName::FROM, envelope.field_from_to_string()),
                    (HeaderName::TO, envelope.field_to_to_string()),
                );
                if envelope.other_headers().contains_key(HeaderName::CC)
                    && !envelope.other_headers()[HeaderName::CC].is_empty()
                {
                    print_header!((HeaderName::CC, envelope.field_cc_to_string()));
                }
                print_header!(
                    (HeaderName::SUBJECT, envelope.subject()),
                    (
                        HeaderName::MESSAGE_ID,
                        format!("<{}>", envelope.message_id_raw())
                    )
                );
                if self.view_settings.expand_headers {
                    if let Some(val) = envelope.in_reply_to_display() {
                        print_header!(
                            (HeaderName::IN_REPLY_TO, val),
                            (
                                HeaderName::REFERENCES,
                                envelope
                                    .references()
                                    .iter()
                                    .map(std::string::ToString::to_string)
                                    .collect::<Vec<String>>()
                                    .join(", ")
                            )
                        );
                    }
                }
                for hdr in &self.view_settings.show_extra_headers {
                    if let Some((val, hdr)) = HeaderName::try_from(hdr)
                        .ok()
                        .and_then(|hdr| Some((envelope.other_headers().get(&hdr)?, hdr)))
                    {
                        print_header!((hdr, val));
                    }
                }
                if let Some(list_management::ListActions {
                    ref id,
                    ref archive,
                    ref post,
                    ref unsubscribe,
                }) = list_management::ListActions::detect(envelope)
                {
                    let mut x = 0;
                    if let Some(id) = id {
                        if sticky || skip_header_ctr == 0 {
                            grid.clear_area(area.nth_row(y), hdr_area_theme);
                            let (_x, _) = grid.write_string(
                                "List-ID: ",
                                hdr_name_theme.fg,
                                hdr_name_theme.bg,
                                hdr_name_theme.attrs,
                                area.nth_row(y),
                                None,
                            );
                            x = _x;
                            let (_x, _y) = grid.write_string(
                                id,
                                hdr_theme.fg,
                                hdr_theme.bg,
                                hdr_theme.attrs,
                                area.nth_row(y).skip_cols(_x),
                                None,
                            );
                            x += _x;
                            if _y != 0 {
                                x = 0;
                            }
                            y += _y;
                        }
                        self.headers_no += 1;
                    }
                    if sticky || skip_header_ctr == 0 {
                        if archive.is_some() || post.is_some() || unsubscribe.is_some() {
                            let (_x, _y) = grid.write_string(
                                " Available actions: [ ",
                                hdr_name_theme.fg,
                                hdr_name_theme.bg,
                                hdr_name_theme.attrs,
                                area.skip(x, y),
                                Some(0),
                            );
                            x += _x;
                            y += _y;
                        }
                        if archive.is_some() {
                            let (_x, _y) = grid.write_string(
                                "list-archive, ",
                                hdr_theme.fg,
                                hdr_theme.bg,
                                hdr_theme.attrs,
                                area.skip(x, y),
                                Some(0),
                            );
                            x += _x;
                            y += _y;
                        }
                        if post.is_some() {
                            let (_x, _y) = grid.write_string(
                                "list-post, ",
                                hdr_theme.fg,
                                hdr_theme.bg,
                                hdr_theme.attrs,
                                area.skip(x, y),
                                Some(0),
                            );
                            x += _x;
                            y += _y;
                        }
                        if unsubscribe.is_some() {
                            let (_x, _y) = grid.write_string(
                                "list-unsubscribe, ",
                                hdr_theme.fg,
                                hdr_theme.bg,
                                hdr_theme.attrs,
                                area.skip(x, y),
                                Some(0),
                            );
                            x += _x;
                            y += _y;
                        }
                        if archive.is_some() || post.is_some() || unsubscribe.is_some() {
                            if x >= 2 {
                                for c in grid.row_iter(area, (x - 2)..(x - 1), y) {
                                    grid[c].set_ch(' ');
                                }
                            }
                            if x > 0 {
                                for c in grid.row_iter(area, (x - 1)..x, y) {
                                    grid[c]
                                        .set_ch(']')
                                        .set_fg(hdr_name_theme.fg)
                                        .set_bg(hdr_name_theme.bg)
                                        .set_attrs(hdr_name_theme.attrs);
                                }
                            }
                        }
                        for c in grid.row_iter(area, (x + 1)..area.width(), y) {
                            grid[c]
                                .set_ch(' ')
                                .set_fg(hdr_area_theme.fg)
                                .set_bg(hdr_area_theme.bg);
                        }
                        y += 1;
                    }
                }

                self.force_draw_headers = false;

                grid.clear_area(area.nth_row(y), hdr_area_theme);
                context.dirty_areas.push_back(area.take_rows(y + 3));
                if !self.view_settings.sticky_headers {
                    let height_p = self.pager.size().1;

                    let height = area.height().saturating_sub(y).saturating_sub(1);
                    if self.pager.cursor_pos() >= self.headers_no {
                        0
                    } else if (height_p > height && self.headers_cursor < self.headers_no + 1)
                        || self.headers_cursor == 0
                        || height_p < height
                    {
                        y + 1
                    } else {
                        0
                    }
                } else {
                    y + 1
                }
            }
        };

        if !self.initialised {
            self.initialised = true;
            let body = self.mail.body();
            match self.mode {
                ViewMode::Attachment(aidx) if body.attachments()[aidx].is_html() => {
                    let attachment = &body.attachments()[aidx];
                    self.subview = Some(Box::new(HtmlView::new(attachment, context)));
                }
                ViewMode::Attachment(aidx) => {
                    let mut text = format!(
                        "Viewing attachment. Press {} to return \n",
                        self.shortcuts(context)
                            .get(Shortcuts::ENVELOPE_VIEW)
                            .and_then(|m| m.get("return_to_normal_view"))
                            .unwrap_or(
                                &context
                                    .settings
                                    .shortcuts
                                    .envelope_view
                                    .return_to_normal_view
                            )
                    );
                    let attachment = &body.attachments()[aidx];
                    text.push_str(&attachment.text());
                    self.pager = Pager::from_string(
                        text,
                        Some(context),
                        Some(0),
                        None,
                        self.view_settings.theme_default,
                    );
                    if let Some(ref filter) = self.view_settings.pager_filter {
                        self.pager.filter(filter);
                    }
                    self.subview = None;
                }
                ViewMode::Normal if body.is_html() => {
                    self.subview = Some(Box::new(HtmlView::new(&body, context)));
                    self.mode = ViewMode::Subview;
                }
                ViewMode::Normal
                    if self.view_settings.auto_choose_multipart_alternative
                        && match body.content_type {
                            ContentType::Multipart {
                                kind: MultipartType::Alternative,
                                ref parts,
                                ..
                            } => parts.iter().all(|p| {
                                p.is_html() || (p.is_text() && p.body().trim().is_empty())
                            }),
                            _ => false,
                        } =>
                {
                    let subview = Box::new(HtmlView::new(
                        body.content_type
                            .parts()
                            .unwrap()
                            .iter()
                            .find(|a| a.is_html())
                            .unwrap_or(&body),
                        context,
                    ));
                    self.subview = Some(subview);
                    self.mode = ViewMode::Subview;
                }
                ViewMode::Subview => {}
                ViewMode::Source(Source::Raw) => {
                    let text = String::from_utf8_lossy(self.mail.bytes()).into_owned();
                    self.view_settings.body_theme = crate::conf::value(context, "mail.view.body");
                    self.pager = Pager::from_string(
                        text,
                        Some(context),
                        None,
                        None,
                        self.view_settings.body_theme,
                    );
                    if let Some(ref filter) = self.view_settings.pager_filter {
                        self.pager.filter(filter);
                    }
                }
                ViewMode::Source(Source::Decoded) => {
                    let text = {
                        /* Decode each header value */
                        let mut ret = String::new();
                        match melib::email::parser::headers::headers(self.mail.bytes())
                            .map(|(_, v)| v)
                        {
                            Ok(headers) => {
                                for (h, v) in headers {
                                    _ = match melib::email::parser::encodings::phrase(v, true) {
                                        Ok((_, v)) => ret.write_fmt(format_args!(
                                            "{h}: {}\n",
                                            String::from_utf8_lossy(&v)
                                        )),
                                        Err(err) => ret.write_fmt(format_args!("{h}: {err}\n")),
                                    };
                                }
                            }
                            Err(err) => {
                                _ = write!(&mut ret, "{err}");
                            }
                        }
                        if !ret.ends_with("\n\n") {
                            if ret.ends_with('\n') {
                                ret.pop();
                            }
                            ret.push_str("\n\n");
                        }
                        ret.push_str(&self.body_text);
                        if !ret.ends_with("\n\n") {
                            if ret.ends_with('\n') {
                                ret.pop();
                            }
                            ret.push_str("\n\n");
                        }
                        // ret.push_str(&self.attachment_tree);
                        ret
                    };
                    self.view_settings.body_theme = crate::conf::value(context, "mail.view.body");
                    self.pager = Pager::from_string(
                        text,
                        Some(context),
                        None,
                        None,
                        self.view_settings.body_theme,
                    );
                    if let Some(ref filter) = self.view_settings.pager_filter {
                        self.pager.filter(filter);
                    }
                }
                ViewMode::Url => {
                    let mut text = self.body_text.clone();
                    if self.links.is_empty() {
                        let finder = LinkFinder::new();
                        self.links = finder
                            .links(&text)
                            .filter_map(|l| {
                                if *l.kind() == linkify::LinkKind::Url {
                                    Some(Link {
                                        start: l.start(),
                                        end: l.end(),
                                        kind: LinkKind::Url,
                                    })
                                } else if *l.kind() == linkify::LinkKind::Email {
                                    Some(Link {
                                        start: l.start(),
                                        end: l.end(),
                                        kind: LinkKind::Email,
                                    })
                                } else {
                                    None
                                }
                            })
                            .collect::<Vec<Link>>();
                    }
                    for (lidx, l) in self.links.iter().enumerate().rev() {
                        text.insert_str(l.start, &format!("[{}]", lidx));
                    }
                    if !text.ends_with("\n\n") {
                        text.push_str("\n\n");
                    }
                    text.push_str(&self.attachment_tree);

                    let cursor_pos = self.pager.cursor_pos();
                    self.view_settings.body_theme = crate::conf::value(context, "mail.view.body");
                    self.pager = Pager::from_string(
                        text,
                        Some(context),
                        Some(cursor_pos),
                        None,
                        self.view_settings.body_theme,
                    );
                    if let Some(ref filter) = self.view_settings.pager_filter {
                        self.pager.filter(filter);
                    }
                    self.subview = None;
                }
                _ => {
                    let mut text = self.body_text.clone();
                    if !text.ends_with("\n\n") {
                        text.push_str("\n\n");
                    }
                    text.push_str(&self.attachment_tree);
                    let cursor_pos = if self.mode.is_attachment() {
                        0
                    } else {
                        self.pager.cursor_pos()
                    };
                    self.view_settings.body_theme = crate::conf::value(context, "mail.view.body");
                    self.pager = Pager::from_string(
                        text,
                        Some(context),
                        Some(cursor_pos),
                        None,
                        self.view_settings.body_theme,
                    );
                    if let Some(ref filter) = self.view_settings.pager_filter {
                        self.pager.filter(filter);
                    }
                    self.subview = None;
                }
            };
            self.dirty = false;
        }

        match self.mode {
            ViewMode::Subview if self.subview.is_some() => {
                if let Some(s) = self.subview.as_mut() {
                    if !s.is_dirty() {
                        s.set_dirty(true);
                    }
                    s.draw(grid, area.skip_rows(y), context);
                }
            }
            _ => {
                self.pager.draw(grid, area.skip_rows(y), context);
            }
        }
        if let ForceCharset::Dialog(ref mut s) = self.force_charset {
            s.draw(grid, area, context);
        }

        // Draw number command buffer at the bottom right corner:

        let l = area.nth_row(area.height());
        if self.cmd_buf.is_empty() {
            grid.clear_area(l.skip_cols_from_end(8), self.view_settings.theme_default);
        } else {
            let s = self.cmd_buf.to_string();
            grid.write_string(
                &s,
                self.view_settings.theme_default.fg,
                self.view_settings.theme_default.bg,
                self.view_settings.theme_default.attrs,
                l.skip_cols_from_end(8),
                None,
            );
        }

        self.dirty = false;
    }

    fn process_event(&mut self, event: &mut UIEvent, context: &mut Context) -> bool {
        match (&mut self.force_charset, &event) {
            (ForceCharset::Dialog(selector), UIEvent::FinishedUIDialog(id, results))
                if *id == selector.id() =>
            {
                if let Some(results) = results.downcast_ref::<Vec<Option<Charset>>>() {
                    if results.len() != 1 {
                        self.force_charset = ForceCharset::None;
                        self.set_dirty(true);
                        return true;
                    }
                    if let Some(charset) = results[0] {
                        self.force_charset = ForceCharset::Forced(charset);
                    } else {
                        self.force_charset = ForceCharset::None;
                    }
                } else {
                    self.force_charset = ForceCharset::None;
                }
                self.set_dirty(true);
                return true;
            }
            (ForceCharset::Dialog(selector), _) => {
                if selector.process_event(event, context) {
                    return true;
                }
            }
            _ => {}
        }

        if let Some(ref mut sub) = self.subview {
            if sub.process_event(event, context) {
                return true;
            }
        } else {
            if !self.view_settings.sticky_headers {
                let shortcuts = self.pager.shortcuts(context);
                match event {
                    UIEvent::Input(ref key)
                        if shortcut!(key == shortcuts[Shortcuts::PAGER]["scroll_up"])
                            && self.pager.cursor_pos() == 0
                            && self.headers_cursor > 0 =>
                    {
                        self.headers_cursor -= 1;
                        self.set_dirty(true);
                        return true;
                    }
                    UIEvent::Input(ref key)
                        if shortcut!(key == shortcuts[Shortcuts::PAGER]["scroll_down"])
                            && self.headers_cursor < self.headers_no =>
                    {
                        self.headers_cursor += 1;
                        self.set_dirty(true);
                        return true;
                    }

                    _ => {}
                }
            }

            if self.pager.process_event(event, context) {
                return true;
            }
        }

        let shortcuts = &self.shortcuts(context);

        match *event {
            UIEvent::Resize | UIEvent::VisibilityChange(true) => {
                self.set_dirty(true);
            }
            UIEvent::Input(Key::Esc) | UIEvent::Input(Key::Alt('')) if !self.cmd_buf.is_empty() => {
                self.cmd_buf.clear();
                context
                    .replies
                    .push_back(UIEvent::StatusEvent(StatusEvent::BufClear));
                return true;
            }
            UIEvent::Input(Key::Char(c)) if c.is_ascii_digit() => {
                if self.cmd_buf.len() < 9 {
                    self.cmd_buf.push(c);
                    self.set_dirty(true);
                }
                return true;
            }
            UIEvent::Input(ref key)
                if matches!(
                    self.mode,
                    ViewMode::Normal
                        | ViewMode::Subview
                        | ViewMode::Source(Source::Decoded)
                        | ViewMode::Source(Source::Raw)
                ) && shortcut!(
                    key == shortcuts[Shortcuts::ENVELOPE_VIEW]["view_raw_source"]
                ) =>
            {
                self.mode = match self.mode {
                    ViewMode::Source(Source::Decoded) => ViewMode::Source(Source::Raw),
                    _ => ViewMode::Source(Source::Decoded),
                };
                self.set_dirty(true);
                self.initialised = false;
                return true;
            }
            UIEvent::Input(ref key)
                if matches!(
                    self.mode,
                    ViewMode::Attachment(_)
                        | ViewMode::Subview
                        | ViewMode::Url
                        | ViewMode::Source(Source::Decoded)
                        | ViewMode::Source(Source::Raw)
                ) && shortcut!(
                    key == shortcuts[Shortcuts::ENVELOPE_VIEW]["return_to_normal_view"]
                ) =>
            {
                self.mode = ViewMode::Normal;
                self.set_dirty(true);
                self.initialised = false;
                return true;
            }
            UIEvent::Input(ref key)
                if (self.mode == ViewMode::Normal || self.mode == ViewMode::Subview)
                    && !self.cmd_buf.is_empty()
                    && shortcut!(key == shortcuts[Shortcuts::ENVELOPE_VIEW]["open_mailcap"]) =>
            {
                let lidx = self.cmd_buf.parse::<usize>().unwrap();
                self.cmd_buf.clear();
                context
                    .replies
                    .push_back(UIEvent::StatusEvent(StatusEvent::BufClear));
                if let Some(attachment) = self.open_attachment(lidx, context) {
                    if let Ok(()) = crate::mailcap::MailcapEntry::execute(attachment, context) {
                        self.set_dirty(true);
                    } else {
                        context.replies.push_back(UIEvent::StatusEvent(
                            StatusEvent::DisplayMessage(format!(
                                "no mailcap entry found for {}",
                                attachment.content_type()
                            )),
                        ));
                    }
                }
                return true;
            }
            UIEvent::Action(View(ViewAction::ExportMail(ref path))) => {
                // Save entire message as eml
                let mut path = std::path::Path::new(path).to_path_buf();

                if path.is_dir() {
                    path.push(format!("{}.eml", self.mail.message_id_raw()));
                }
                if path.is_relative() {
                    path = context.current_dir().join(&path);
                }
                match save_attachment(&path, &self.mail.bytes) {
                    Err(err) => {
                        context.replies.push_back(UIEvent::Notification(
                            Some(format!("Failed to create file at {}", path.display())),
                            err.to_string(),
                            Some(NotificationType::Error(melib::ErrorKind::External)),
                        ));
                        log::error!("Failed to create file at {}: {err}", path.display());
                        return true;
                    }
                    Ok(()) => {
                        context.replies.push_back(UIEvent::Notification(
                            None,
                            format!("Saved at {}", &path.display()),
                            Some(NotificationType::Info),
                        ));
                    }
                }

                return true;
            }
            UIEvent::Action(View(ViewAction::SaveAttachment(a_i, ref path))) => {
                let mut path = std::path::Path::new(path).to_path_buf();

                if let Some(u) = self.open_attachment(a_i, context) {
                    if path.is_dir() {
                        if let Some(filename) = u.filename() {
                            path.push(filename);
                        } else {
                            path.push(format!(
                                "meli_attachment_{a_i}_{}",
                                Uuid::new_v4().as_simple()
                            ));
                        }
                    }
                    if path.is_relative() {
                        path = context.current_dir().join(&path);
                    }
                    match save_attachment(&path, &u.decode(Default::default())) {
                        Err(err) => {
                            context.replies.push_back(UIEvent::Notification(
                                Some(format!("Failed to create file at {}", path.display())),
                                err.to_string(),
                                Some(NotificationType::Error(melib::ErrorKind::External)),
                            ));
                            log::error!("Failed to create file at {}: {err}", path.display());
                        }
                        Ok(()) => {
                            context.replies.push_back(UIEvent::Notification(
                                None,
                                format!("Saved at {}", path.display()),
                                Some(NotificationType::Info),
                            ));
                        }
                    }
                } else if a_i == 0 {
                    // Save entire message as eml
                    if path.is_dir() {
                        path.push(format!("{}.eml", self.mail.message_id_raw()));
                    }
                    if path.is_relative() {
                        path = context.current_dir().join(&path);
                    }
                    match save_attachment(&path, &self.mail.bytes) {
                        Err(err) => {
                            context.replies.push_back(UIEvent::Notification(
                                Some(format!("Failed to create file at {}", path.display())),
                                err.to_string(),
                                Some(NotificationType::Error(melib::ErrorKind::External)),
                            ));
                            log::error!("Failed to create file at {}: {err}", path.display());
                            return true;
                        }
                        Ok(()) => {
                            context.replies.push_back(UIEvent::Notification(
                                None,
                                format!("Saved at {}", &path.display()),
                                Some(NotificationType::Info),
                            ));
                        }
                    }

                    return true;
                } else {
                    context
                        .replies
                        .push_back(UIEvent::StatusEvent(StatusEvent::DisplayMessage(format!(
                            "Attachment `{}` not found.",
                            a_i
                        ))));
                }
                return true;
            }
            UIEvent::Input(ref key)
                if shortcut!(key == shortcuts[Shortcuts::ENVELOPE_VIEW]["open_attachment"])
                    && !self.cmd_buf.is_empty()
                    && (self.mode == ViewMode::Normal || self.mode == ViewMode::Subview) =>
            {
                let lidx = self.cmd_buf.parse::<usize>().unwrap();
                self.cmd_buf.clear();
                context
                    .replies
                    .push_back(UIEvent::StatusEvent(StatusEvent::BufClear));
                if let Some(attachment) = self.open_attachment(lidx, context) {
                    match attachment.content_type() {
                        ContentType::MessageRfc822 => {
                            match Mail::new(attachment.body().to_vec(), Some(Flag::SEEN)) {
                                Ok(wrapper) => {
                                    self.mode = ViewMode::Subview;
                                    self.subview = Some(Box::new(EnvelopeView::new(
                                        wrapper,
                                        None,
                                        None,
                                        Some(self.view_settings.clone()),
                                        context.main_loop_handler.clone(),
                                    )));
                                    self.set_dirty(true);
                                }
                                Err(e) => {
                                    context.replies.push_back(UIEvent::StatusEvent(
                                        StatusEvent::DisplayMessage(format!("{}", e)),
                                    ));
                                }
                            }
                        }
                        ContentType::Text { .. }
                        | ContentType::PGPSignature
                        | ContentType::CMSSignature => {
                            self.mode = ViewMode::Attachment(lidx);
                            self.initialised = false;
                            self.dirty = true;
                        }
                        ContentType::Multipart { .. } => {
                            context.replies.push_back(UIEvent::StatusEvent(
                                StatusEvent::DisplayMessage(
                                    "Multipart attachments are not supported yet.".to_string(),
                                ),
                            ));
                        }
                        ContentType::Other { .. } => {
                            let attachment_type = attachment.mime_type();
                            let filename = attachment.filename();
                            if let Ok(command) = query_default_app(&attachment_type) {
                                match File::create_temp_file(
                                    &attachment.decode(Default::default()),
                                    filename.as_deref(),
                                    None,
                                    None,
                                    true,
                                )
                                .and_then(|p| {
                                    let exec_cmd = desktop_exec_to_command(
                                        &command,
                                        p.path().display().to_string(),
                                        false,
                                    );
                                    Ok((
                                        p,
                                        Command::new("sh")
                                            .args(["-c", &exec_cmd])
                                            .stdin(Stdio::piped())
                                            .stdout(Stdio::piped())
                                            .spawn()?,
                                    ))
                                }) {
                                    Ok((p, child)) => {
                                        context.temp_files.push(p);
                                        context.children.push(child);
                                    }
                                    Err(err) => {
                                        context.replies.push_back(UIEvent::StatusEvent(
                                            StatusEvent::DisplayMessage(format!(
                                                "Failed to execute command: {err}"
                                            )),
                                        ));
                                    }
                                }
                            } else {
                                context.replies.push_back(UIEvent::StatusEvent(
                                    StatusEvent::DisplayMessage(
                                        if let Some(filename) = filename.as_ref() {
                                            format!(
                                                "Couldn't find a default application for file {} \
                                                 (type {})",
                                                filename, attachment_type
                                            )
                                        } else {
                                            format!(
                                                "Couldn't find a default application for type {}",
                                                attachment_type
                                            )
                                        },
                                    ),
                                ));
                            }
                        }
                        ContentType::OctetStream {
                            ref name,
                            parameters: _,
                        } => {
                            context.replies.push_back(UIEvent::StatusEvent(
                                StatusEvent::DisplayMessage(format!(
                                    "Failed to open {}. application/octet-stream isn't supported \
                                     yet",
                                    name.as_ref().map(|n| n.as_str()).unwrap_or("file")
                                )),
                            ));
                        }
                    }
                }
                return true;
            }
            UIEvent::Input(ref key)
                if (self.mode == ViewMode::Normal || self.mode == ViewMode::Url)
                    && shortcut!(
                        key == shortcuts[Shortcuts::ENVELOPE_VIEW]["toggle_expand_headers"]
                    ) =>
            {
                self.view_settings.expand_headers = !self.view_settings.expand_headers;
                self.set_dirty(true);
                return true;
            }
            UIEvent::Input(ref key)
                if !self.cmd_buf.is_empty()
                    && self.mode == ViewMode::Url
                    && shortcut!(key == shortcuts[Shortcuts::ENVELOPE_VIEW]["go_to_url"]) =>
            {
                let lidx = self.cmd_buf.parse::<usize>().unwrap();
                self.cmd_buf.clear();
                context
                    .replies
                    .push_back(UIEvent::StatusEvent(StatusEvent::BufClear));
                let body_text = &self.body_text;
                let links = &self.links;
                let (_kind, url) = {
                    if let Some(l) = links
                        .get(lidx)
                        .and_then(|l| Some((l.kind, body_text.get(l.start..l.end)?)))
                    {
                        l
                    } else {
                        context.replies.push_back(UIEvent::StatusEvent(
                            StatusEvent::DisplayMessage(format!("Link `{}` not found.", lidx)),
                        ));
                        return true;
                    }
                };

                let url_launcher = self.view_settings.url_launcher.as_deref().unwrap_or(
                    #[cfg(target_os = "macos")]
                    {
                        "open"
                    },
                    #[cfg(not(target_os = "macos"))]
                    {
                        "xdg-open"
                    },
                );
                match Command::new(url_launcher)
                    .arg(url)
                    .stdin(Stdio::piped())
                    .stdout(Stdio::piped())
                    .spawn()
                {
                    Ok(child) => {
                        context.children.push(child);
                    }
                    Err(err) => {
                        context.replies.push_back(UIEvent::Notification(
                            Some(format!("Failed to launch {:?}", url_launcher)),
                            err.to_string(),
                            Some(NotificationType::Error(melib::ErrorKind::External)),
                        ));
                    }
                }
                return true;
            }
            UIEvent::Input(ref key)
                if (self.mode == ViewMode::Normal || self.mode == ViewMode::Url)
                    && shortcut!(key == shortcuts[Shortcuts::ENVELOPE_VIEW]["toggle_url_mode"]) =>
            {
                match self.mode {
                    ViewMode::Normal => self.mode = ViewMode::Url,
                    ViewMode::Url => self.mode = ViewMode::Normal,
                    _ => {}
                }
                self.initialised = false;
                self.dirty = true;
                return true;
            }
            UIEvent::Input(ref key)
                if shortcut!(key == shortcuts[Shortcuts::ENVELOPE_VIEW]["change_charset"]) =>
            {
                let entries = vec![
                    (None, "default".to_string()),
                    (Some(Charset::Ascii), Charset::Ascii.to_string()),
                    (Some(Charset::UTF8), Charset::UTF8.to_string()),
                    (Some(Charset::UTF16), Charset::UTF16.to_string()),
                    (Some(Charset::ISO8859_1), Charset::ISO8859_1.to_string()),
                    (Some(Charset::ISO8859_2), Charset::ISO8859_2.to_string()),
                    (Some(Charset::ISO8859_3), Charset::ISO8859_3.to_string()),
                    (Some(Charset::ISO8859_4), Charset::ISO8859_4.to_string()),
                    (Some(Charset::ISO8859_5), Charset::ISO8859_5.to_string()),
                    (Some(Charset::ISO8859_6), Charset::ISO8859_6.to_string()),
                    (Some(Charset::ISO8859_7), Charset::ISO8859_7.to_string()),
                    (Some(Charset::ISO8859_8), Charset::ISO8859_8.to_string()),
                    (Some(Charset::ISO8859_10), Charset::ISO8859_10.to_string()),
                    (Some(Charset::ISO8859_13), Charset::ISO8859_13.to_string()),
                    (Some(Charset::ISO8859_14), Charset::ISO8859_14.to_string()),
                    (Some(Charset::ISO8859_15), Charset::ISO8859_15.to_string()),
                    (Some(Charset::ISO8859_16), Charset::ISO8859_16.to_string()),
                    (Some(Charset::Windows1250), Charset::Windows1250.to_string()),
                    (Some(Charset::Windows1251), Charset::Windows1251.to_string()),
                    (Some(Charset::Windows1252), Charset::Windows1252.to_string()),
                    (Some(Charset::Windows1253), Charset::Windows1253.to_string()),
                    (Some(Charset::GBK), Charset::GBK.to_string()),
                    (Some(Charset::GB2312), Charset::GB2312.to_string()),
                    (Some(Charset::GB18030), Charset::GB18030.to_string()),
                    (Some(Charset::BIG5), Charset::BIG5.to_string()),
                    (Some(Charset::ISO2022JP), Charset::ISO2022JP.to_string()),
                    (Some(Charset::EUCJP), Charset::EUCJP.to_string()),
                    (Some(Charset::KOI8R), Charset::KOI8R.to_string()),
                    (Some(Charset::KOI8U), Charset::KOI8U.to_string()),
                ];
                self.force_charset = ForceCharset::Dialog(Box::new(Selector::new(
                    "select charset to force",
                    entries,
                    true,
                    Some(Box::new(
                        move |id: ComponentId, results: &[Option<Charset>]| {
                            Some(UIEvent::FinishedUIDialog(id, Box::new(results.to_vec())))
                        },
                    )),
                    context,
                )));
                self.dirty = true;
                return true;
            }
            UIEvent::StatusEvent(StatusEvent::JobFinished(ref job_id))
                if self.active_jobs.contains(job_id) =>
            {
                let mut caught = false;
                for d in self.display.iter_mut() {
                    match d {
                        AttachmentDisplay::SignedPending {
                            ref mut inner,
                            handle,
                            display,
                            job_id: our_job_id,
                        } if *our_job_id == *job_id => {
                            caught = true;
                            match handle.chan.try_recv() {
                                Err(_) => { /* Job was canceled */ }
                                Ok(None) => { /* something happened,
                                      * perhaps a worker thread
                                      * panicked */
                                }
                                Ok(Some(Ok(()))) => {
                                    *d = AttachmentDisplay::SignedVerified {
                                        inner: std::mem::replace(
                                            inner,
                                            Box::new(AttachmentBuilder::new(&[]).build()),
                                        ),
                                        display: std::mem::take(display),
                                        description: String::new(),
                                    };
                                }
                                Ok(Some(Err(error))) => {
                                    *d = AttachmentDisplay::SignedFailed {
                                        inner: std::mem::replace(
                                            inner,
                                            Box::new(AttachmentBuilder::new(&[]).build()),
                                        ),
                                        display: std::mem::take(display),
                                        error,
                                    };
                                }
                            }
                        }
                        AttachmentDisplay::EncryptedPending {
                            ref mut inner,
                            handle,
                        } if handle.job_id == *job_id => {
                            caught = true;
                            match handle.chan.try_recv() {
                                Err(_) => { /* Job was canceled */ }
                                Ok(None) => { /* something happened,
                                      * perhaps a worker thread
                                      * panicked */
                                }
                                Ok(Some(Ok((metadata, decrypted_bytes)))) => {
                                    let plaintext =
                                        Box::new(AttachmentBuilder::new(&decrypted_bytes).build());
                                    let mut plaintext_display = vec![];
                                    Self::attachment_to_display_helper(
                                        &plaintext,
                                        &self.main_loop_handler,
                                        &mut self.active_jobs,
                                        &mut plaintext_display,
                                        &self.view_settings,
                                        (&self.force_charset).into(),
                                    );
                                    *d = AttachmentDisplay::EncryptedSuccess {
                                        inner: std::mem::replace(
                                            inner,
                                            Box::new(AttachmentBuilder::new(&[]).build()),
                                        ),
                                        plaintext,
                                        plaintext_display,
                                        description: format!("{:?}", metadata),
                                    };
                                }
                                Ok(Some(Err(error))) => {
                                    *d = AttachmentDisplay::EncryptedFailed {
                                        inner: std::mem::replace(
                                            inner,
                                            Box::new(AttachmentBuilder::new(&[]).build()),
                                        ),
                                        error,
                                    };
                                }
                            }
                        }
                        _ => {}
                    }
                }
                if caught {
                    self.links.clear();
                    self.regenerate_body_text();
                    self.initialised = false;
                    self.set_dirty(true);
                }

                self.active_jobs.remove(job_id);
            }
            _ => {}
        }
        false
    }

    fn shortcuts(&self, context: &Context) -> ShortcutMaps {
        let mut map = if let Some(ref sbv) = self.subview {
            sbv.shortcuts(context)
        } else {
            self.pager.shortcuts(context)
        };

        let mut our_map = self.view_settings.env_view_shortcuts.clone();

        if !(self.mode.is_attachment()
            || self.mode == ViewMode::Subview
            || self.mode == ViewMode::Source(Source::Decoded)
            || self.mode == ViewMode::Source(Source::Raw)
            || self.mode == ViewMode::Url)
        {
            our_map.remove("return_to_normal_view");
        }
        if self.mode != ViewMode::Url {
            our_map.remove("go_to_url");
        }
        if !(self.mode == ViewMode::Normal || self.mode == ViewMode::Url) {
            our_map.remove("toggle_url_mode");
        }
        map.insert(Shortcuts::ENVELOPE_VIEW, our_map);

        map
    }

    fn is_dirty(&self) -> bool {
        self.dirty
            || self.pager.is_dirty()
            || self.subview.as_ref().map(|p| p.is_dirty()).unwrap_or(false)
            || matches!(self.force_charset, ForceCharset::Dialog(ref s) if s.is_dirty())
    }

    fn set_dirty(&mut self, value: bool) {
        self.dirty = value;
        self.pager.set_dirty(value);
        if let Some(ref mut s) = self.subview {
            s.set_dirty(value);
        }
        if let ForceCharset::Dialog(ref mut s) = self.force_charset {
            s.set_dirty(value);
        }
    }

    fn id(&self) -> ComponentId {
        self.id
    }

    fn kill(&mut self, id: ComponentId, context: &mut Context) {
        debug_assert!(self.id == id);
        context
            .replies
            .push_back(UIEvent::Action(Tab(Kill(self.id))));
    }
}