#!/bin/sh
# Supervise the app and keep yt-dlp fresh.
#
# yt-dlp breaks frequently against site changes, so we check PyPI once a day
# for a newer release. The app imports yt_dlp at startup, so a new version
# only takes effect on (re)start -- we therefore restart the app *only* when
# an update was actually installed. If the app exits on its own, we propagate
# its exit status so Docker's restart policy can handle it.
set -e

CHECK_INTERVAL=86400   # check for a new yt-dlp once per day
POLL=60                # how often to check on the app

# Upgrade yt-dlp only if PyPI has a newer version.
# Returns 0 if an update was installed, 1 otherwise (incl. errors / up to date).
check_and_update() {
    current=$(python -c "import yt_dlp; print(yt_dlp.version.__version__)" 2>/dev/null) || return 1
    latest=$(python -c "import json,urllib.request; print(json.load(urllib.request.urlopen('https://pypi.org/pypi/yt-dlp/json', timeout=30))['info']['version'])" 2>/dev/null) || {
        echo "Could not reach PyPI to check for yt-dlp updates; will retry."
        return 1
    }

    if [ "$current" = "$latest" ]; then
        echo "yt-dlp is up to date ($current)."
        return 1
    fi

    echo "New yt-dlp available: $current -> $latest. Updating..."
    if pip install --upgrade --quiet --root-user-action=ignore yt-dlp; then
        return 0
    fi
    echo "yt-dlp update failed; continuing with the installed version."
    return 1
}

# Forward termination to the app so the container stops cleanly.
trap 'kill "$APP_PID" 2>/dev/null; exit 0' TERM INT

while true; do
    # Make sure we launch with the latest available yt-dlp.
    check_and_update || true

    "$@" &
    APP_PID=$!

    # Periodically check for updates; restart the app only when one is applied.
    while true; do
        waited=0
        while [ "$waited" -lt "$CHECK_INTERVAL" ] && kill -0 "$APP_PID" 2>/dev/null; do
            sleep "$POLL"
            waited=$((waited + POLL))
        done

        if ! kill -0 "$APP_PID" 2>/dev/null; then
            wait "$APP_PID"
            status=$?
            echo "App exited with status $status"
            exit "$status"
        fi

        if check_and_update; then
            echo "Restarting app to apply yt-dlp update..."
            kill "$APP_PID" 2>/dev/null || true
            wait "$APP_PID" 2>/dev/null || true
            break   # outer loop relaunches the app
        fi
    done
done