#!/usr/bin/env bash

set -euo pipefail

export DISPLAY=""
export WAYLAND_DISPLAY="${WAYLAND_DISPLAY:-wayland-0}"
export XDG_SESSION_TYPE=wayland
export LIBSEAT_BACKEND=seatd
export SEATD_SOCK=/run/seatd.sock
export QT_PLUGIN_PATH="${QT_PLUGIN_PATH:-/usr/plugins}"
export QT_QPA_PLATFORM_PLUGIN_PATH="${QT_QPA_PLATFORM_PLUGIN_PATH:-/usr/plugins/platforms}"
export QML2_IMPORT_PATH="${QML2_IMPORT_PATH:-/usr/qml}"
export QT_WAYLAND_SHELL_INTEGRATION="${QT_WAYLAND_SHELL_INTEGRATION:-xdg-shell}"
export XCURSOR_THEME="${XCURSOR_THEME:-Pop}"
export XKB_CONFIG_ROOT="${XKB_CONFIG_ROOT:-/usr/share/X11/xkb}"

if [ -z "${XDG_RUNTIME_DIR:-}" ]; then
    export XDG_RUNTIME_DIR="/tmp/run/redbear-greeter"
fi

mkdir -p "$XDG_RUNTIME_DIR"

parse_drm_devices() {
    local devices="${1:-}"
    local part=""

    IFS=':' read -r -a parts <<< "$devices"
    for part in "${parts[@]}"; do
        if [ -n "$part" ]; then
            printf '%s\n' "$part"
        fi
    done
}

drm_devices_ready() {
    local devices="${1:-}"
    local device=""

    while IFS= read -r device; do
        if [ ! -e "$device" ]; then
            return 1
        fi
    done < <(parse_drm_devices "$devices")

    return 0
}

wait_for_drm_devices() {
    local devices="${1:-}"
    local wait_seconds="${REDBEAR_DRM_WAIT_SECONDS:-10}"
    local attempts=0

    if [ -z "$devices" ]; then
        return 1
    fi

    if [ "$wait_seconds" -le 0 ] 2>/dev/null; then
        drm_devices_ready "$devices"
        return $?
    fi

    attempts=$((wait_seconds * 2))

    if ! drm_devices_ready "$devices"; then
        echo "redbear-greeter-compositor: waiting up to ${wait_seconds}s for DRM device(s): ${devices}" >&2
    fi

    while [ "$attempts" -gt 0 ]; do
        if drm_devices_ready "$devices"; then
            return 0
        fi

        sleep 0.5
        attempts=$((attempts - 1))
    done

    drm_devices_ready "$devices"
}

if [ -z "${DBUS_SESSION_BUS_ADDRESS:-}" ] && command -v dbus-launch >/dev/null 2>&1; then
    eval "$(dbus-launch --sh-syntax)"
fi

if ! command -v redbear-compositor >/dev/null 2>&1; then
    # Fall back to redbear-compositor (simpler Rust compositor)
    if command -v /usr/bin/redbear-compositor >/dev/null 2>&1 || command -v redbear-compositor >/dev/null 2>&1; then
        echo "redbear-greeter-compositor: redbear-compositor not found, using redbear-compositor" >&2
        exec /usr/bin/redbear-compositor
    fi
    echo "redbear-greeter-compositor: redbear-compositor not found, and redbear-compositor not found either" >&2
    exit 1
fi

# pcid-spawner is intentionally async in Red Bear OS, so service ordering only guarantees that
# spawning has started. The compositor wrapper still has to wait for the actual DRM node.
desired_drm_devices="${KWIN_DRM_DEVICES:-/scheme/drm/card0}"

if wait_for_drm_devices "$desired_drm_devices"; then
    export KWIN_DRM_DEVICES="$desired_drm_devices"
    echo "redbear-greeter-compositor: using DRM compositor backend (KWIN_DRM_DEVICES=${KWIN_DRM_DEVICES})" >&2
    exec redbear-compositor --drm
else
    unset KWIN_DRM_DEVICES
    echo "redbear-greeter-compositor: DRM device not ready after wait, using virtual compositor backend" >&2
    exec redbear-compositor --virtual
fi