#!/usr/bin/env bash
#
# Behavior
#   Userscript for qutebrowser which casts the url passed in $1 to the default
#   ChromeCast device in the network using the program `castnow`
#
# Usage
#   You can launch the script from qutebrowser as follows:
#       spawn --userscript ${PATH_TO_FILE} {url}
#
#   Then, you can control the chromecast by launching the simple command
#   `castnow` in a shell which will connect to the running castnow instance.
#
#   For stopping the script, issue the command `pkill -f castnow` which would
#   then let the rest of the userscript execute for cleaning temporary file.
#
# Thanks
#   This userscript borrows Thorsten Wißmann's javascript code from his `mpv`
#   userscript.
#
# Dependencies
#   - castnow, https://github.com/xat/castnow
#   - youtube-dl (https://youtube-dl.org/) or a drop-in replacement such as
#     yt-dlp (https://github.com/yt-dlp/yt-dlp).
#
# Configuration:
#   This script looks at the optional QUTE_CAST_YTDL_PROGRAM environment
#   variable (if it exists) to decide which program to use for downloading
#   videos. If specified, this should be youtube-dl or a drop-in replacement
#   for it.
#
# Author
#   Simon Désaulniers <sim.desaulniers@gmail.com>

if [ -z "$QUTE_FIFO" ] ; then
    cat 1>&2 <<EOF
Error: $0 can not be run as a standalone script.

It is a qutebrowser userscript. In order to use it, call it using
'spawn --userscript' as described in qute://help/userscripts.html
EOF
    exit 1
fi

msg() {
    local cmd="$1"
    shift
    local msg="$*"
    if [ -z "$QUTE_FIFO" ] ; then
        echo "$cmd: $msg" >&2
    else
        echo "message-$cmd '${msg//\'/\\\'}'" >> "$QUTE_FIFO"
    fi
}

js() {
cat <<EOF

    function descendantOfTagName(child, ancestorTagName) {
        // tells whether child has some (proper) ancestor
        // with the tag name ancestorTagName
        while (child.parentNode != null) {
            child = child.parentNode;
            if (typeof child.tagName === 'undefined') break;
            if (child.tagName.toUpperCase() == ancestorTagName.toUpperCase()) {
                return true;
            }
        }
        return false;
    }

    var App = {};

    var all_videos = [];
    all_videos.push.apply(all_videos, document.getElementsByTagName("video"));
    all_videos.push.apply(all_videos, document.getElementsByTagName("object"));
    all_videos.push.apply(all_videos, document.getElementsByTagName("embed"));
    App.backup_videos = Array();
    App.all_replacements = Array();
    for (i = 0; i < all_videos.length; i++) {
        var video = all_videos[i];
        if (descendantOfTagName(video, "object")) {
            // skip tags that are contained in an object, because we hide
            // the object anyway.
            continue;
        }
        var replacement = document.createElement("div");
        replacement.innerHTML = "
            <p style=\\"margin-bottom: 0.5em\\">
            The video is being cast on your ChromeCast device.
            </p>
            <p>
            In order to restore this particular video
            <a style=\\"font-weight: bold;
                        color: white;
                        background: transparent;
                     \\"
               onClick=\\"restore_video(this, " + i + ");\\"
               href=\\"javascript: restore_video(this, " + i + ")\\"
              >click here</a>.
            </p>
        ";
        replacement.style.position = "relative";
        replacement.style.zIndex = "100003000000";
        replacement.style.fontSize = "1rem";
        replacement.style.textAlign = "center";
        replacement.style.verticalAlign = "middle";
        replacement.style.height = "100%";
        replacement.style.background = "#101010";
        replacement.style.color = "white";
        replacement.style.border = "4px dashed #545454";
        replacement.style.padding = "2em";
        replacement.style.margin = "auto";
        App.all_replacements[i] = replacement;
        App.backup_videos[i] = video;
        video.parentNode.replaceChild(replacement, video);
    }

    function restore_video(obj, index) {
        obj = App.all_replacements[index];
        video = App.backup_videos[index];
        console.log(video);
        obj.parentNode.replaceChild(video, obj);
    }

    /** force repainting the video, thanks to:
     * http://web.archive.org/web/20151029064649/https://martinwolf.org/2014/06/10/force-repaint-of-an-element-with-javascript/
     */
    var siteHeader = document.getElementById('header');
    siteHeader.style.display='none';
    siteHeader.offsetHeight; // no need to store this anywhere, the reference is enough
    siteHeader.style.display='block';

EOF
}

printjs() {
    js | sed 's,//.*$,,' | tr '\n' ' '
}
echo "jseval -q $(printjs)" >> "$QUTE_FIFO"

tmpdir=$(mktemp -d)
file_to_cast=${tmpdir}/qutecast
cast_program=$(command -v castnow)

# pick a ytdl program
for p in "$QUTE_CAST_YTDL_PROGRAM" yt-dlp youtube-dl; do
    ytdl_program=$(command -v -- "$p")
    [ "$ytdl_program" == "" ] || break
done

if [[ "${cast_program}" == "" ]]; then
    msg error "castnow can't be found"
    exit 1
fi
if [[ "${ytdl_program}" == "" ]]; then
    msg error "youtube-dl or a drop-in replacement can't be found in PATH, and no installed program " \
        "specified in QUTE_CAST_YTDL_PROGRAM (currently \"$QUTE_CAST_YTDL_PROGRAM\")"
    exit 1
fi

# kill any running instance of castnow
pkill -f -- "${cast_program}"

# start youtube download in stream mode (-o -) into temporary file
"${ytdl_program}" -qo - "$1" > "${file_to_cast}" &
ytdl_pid=$!

msg info "Casting $1" >> "$QUTE_FIFO"
# start castnow in stream mode to cast on ChromeCast
tail -F "${file_to_cast}" | ${cast_program} -

# cleanup remaining background process and file on disk
kill ${ytdl_pid}
rm -rf "${tmpdir}"