#!/usr/bin/env bash

set -euo pipefail

VALIDATION_REQUEST="/run/redbear-kde-session.validation-request"
VALIDATION_SUCCESS="/run/redbear-kde-session.validation-success"

kwin_pid=""
optional_pids=()

export DESKTOP_SESSION="${DESKTOP_SESSION:-plasmawayland}"
export DISPLAY=""
export KDE_FULL_SESSION="${KDE_FULL_SESSION:-true}"
export KDE_SESSION_VERSION="${KDE_SESSION_VERSION:-6}"
export LIBSEAT_BACKEND="${LIBSEAT_BACKEND:-seatd}"
export LOGNAME="${LOGNAME:-${USER:-root}}"
export PATH="${PATH:-/usr/bin:/bin}"
export QML2_IMPORT_PATH="${QML2_IMPORT_PATH:-/usr/qml}"
export QT_PLUGIN_PATH="${QT_PLUGIN_PATH:-/usr/plugins}"
export QT_QPA_PLATFORM="${QT_QPA_PLATFORM:-wayland}"
export QT_QPA_PLATFORM_PLUGIN_PATH="${QT_QPA_PLATFORM_PLUGIN_PATH:-/usr/plugins/platforms}"
export SEATD_SOCK="${SEATD_SOCK:-/run/seatd.sock}"
export USER="${USER:-root}"
export WAYLAND_DISPLAY="${WAYLAND_DISPLAY:-wayland-0}"
export XCURSOR_THEME="${XCURSOR_THEME:-Pop}"
export XDG_CURRENT_DESKTOP="${XDG_CURRENT_DESKTOP:-KDE}"
export XDG_SESSION_DESKTOP="${XDG_SESSION_DESKTOP:-KDE}"
export XDG_SESSION_ID="${XDG_SESSION_ID:-c1}"
export XDG_SESSION_TYPE="${XDG_SESSION_TYPE:-wayland}"
export XKB_CONFIG_ROOT="${XKB_CONFIG_ROOT:-/usr/share/X11/xkb}"

if [ -z "${XDG_RUNTIME_DIR:-}" ]; then
    export XDG_RUNTIME_DIR="/tmp/run/user/$(id -u)"
fi

mkdir -p "$XDG_RUNTIME_DIR"
chmod 700 "$XDG_RUNTIME_DIR" 2>/dev/null || true

choose_state_dir() {
    local requested="${REDBEAR_KDE_SESSION_STATE_DIR:-}"

    if [ -n "$requested" ]; then
        mkdir -p "$requested" 2>/dev/null || true
        if [ -d "$requested" ] && [ -w "$requested" ]; then
            printf '%s\n' "$requested"
            return 0
        fi
    fi

    if [ -d /run ] && [ -w /run ]; then
        printf '%s\n' "/run"
        return 0
    fi

    printf '%s\n' "$XDG_RUNTIME_DIR"
}

session_state_dir="$(choose_state_dir)"
mkdir -p "$session_state_dir"
chmod 700 "$session_state_dir" 2>/dev/null || true

session_env_file="$session_state_dir/redbear-kde-session.env"
session_ready_file="$session_state_dir/redbear-kde-session.ready"
panel_ready_file="$session_state_dir/redbear-kde-session.panel-ready"

rm -f "$session_ready_file" "$panel_ready_file"

cleanup() {
    local status=$?

    trap - EXIT INT TERM

    for pid in "${optional_pids[@]}"; do
        if kill -0 "$pid" 2>/dev/null; then
            kill "$pid" 2>/dev/null || true
            wait "$pid" 2>/dev/null || true
        fi
    done

    if [ -n "$kwin_pid" ] && kill -0 "$kwin_pid" 2>/dev/null; then
        kill "$kwin_pid" 2>/dev/null || true
        wait "$kwin_pid" 2>/dev/null || true
    fi

    exit "$status"
}

trap cleanup EXIT INT TERM

kwin_mode="virtual"

set_kwin_mode() {
    local requested="${REDBEAR_KDE_SESSION_BACKEND:-auto}"

    case "$requested" in
        drm)
            if [ -z "${KWIN_DRM_DEVICES:-}" ] && [ -e /scheme/drm/card0 ]; then
                export KWIN_DRM_DEVICES=/scheme/drm/card0
            fi
            if [ -n "${KWIN_DRM_DEVICES:-}" ]; then
                kwin_mode="drm"
            else
                kwin_mode="virtual"
            fi
            ;;
        virtual)
            kwin_mode="virtual"
            ;;
        auto|"")
            if [ -n "${KWIN_DRM_DEVICES:-}" ]; then
                kwin_mode="drm"
            elif [ -e /scheme/drm/card0 ]; then
                export KWIN_DRM_DEVICES=/scheme/drm/card0
                kwin_mode="drm"
            else
                kwin_mode="virtual"
            fi
            ;;
        *)
            kwin_mode="virtual"
            ;;
    esac
}

set_kwin_mode

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

write_session_environment() {
    {
        printf 'DBUS_SESSION_BUS_ADDRESS=%s\n' "${DBUS_SESSION_BUS_ADDRESS:-}"
        printf 'DESKTOP_SESSION=%s\n' "$DESKTOP_SESSION"
        printf 'KDE_FULL_SESSION=%s\n' "$KDE_FULL_SESSION"
        printf 'KDE_SESSION_VERSION=%s\n' "$KDE_SESSION_VERSION"
        printf 'KWIN_DRM_DEVICES=%s\n' "${KWIN_DRM_DEVICES:-}"
        printf 'KWIN_MODE=%s\n' "$kwin_mode"
        printf 'QML2_IMPORT_PATH=%s\n' "$QML2_IMPORT_PATH"
        printf 'QT_PLUGIN_PATH=%s\n' "$QT_PLUGIN_PATH"
        printf 'QT_QPA_PLATFORM=%s\n' "$QT_QPA_PLATFORM"
        printf 'QT_QPA_PLATFORM_PLUGIN_PATH=%s\n' "$QT_QPA_PLATFORM_PLUGIN_PATH"
        printf 'SEATD_SOCK=%s\n' "$SEATD_SOCK"
        printf 'SESSION_STATE_DIR=%s\n' "$session_state_dir"
        printf 'WAYLAND_DISPLAY=%s\n' "$WAYLAND_DISPLAY"
        printf 'XDG_CURRENT_DESKTOP=%s\n' "$XDG_CURRENT_DESKTOP"
        printf 'XDG_RUNTIME_DIR=%s\n' "$XDG_RUNTIME_DIR"
        printf 'XDG_SESSION_DESKTOP=%s\n' "$XDG_SESSION_DESKTOP"
        printf 'XDG_SESSION_ID=%s\n' "$XDG_SESSION_ID"
        printf 'XDG_SESSION_TYPE=%s\n' "$XDG_SESSION_TYPE"
        printf 'XKB_CONFIG_ROOT=%s\n' "$XKB_CONFIG_ROOT"
    } > "$session_env_file"
    chmod 600 "$session_env_file" 2>/dev/null || true
}

write_session_environment

if command -v dbus-update-activation-environment >/dev/null 2>&1; then
    dbus-update-activation-environment \
        DBUS_SESSION_BUS_ADDRESS \
        DBUS_SESSION_BUS_PID \
        DESKTOP_SESSION \
        KDE_FULL_SESSION \
        KDE_SESSION_VERSION \
        KWIN_DRM_DEVICES \
        QML2_IMPORT_PATH \
        QT_PLUGIN_PATH \
        QT_QPA_PLATFORM \
        QT_QPA_PLATFORM_PLUGIN_PATH \
        WAYLAND_DISPLAY \
        XDG_CURRENT_DESKTOP \
        XDG_RUNTIME_DIR \
        XDG_SESSION_DESKTOP \
        XDG_SESSION_ID \
        XDG_SESSION_TYPE \
        XKB_CONFIG_ROOT \
        XCURSOR_THEME
fi

wait_for_wayland_socket() {
    local socket_path="$XDG_RUNTIME_DIR/$WAYLAND_DISPLAY"
    local attempts=0

    while [ "$attempts" -lt 40 ]; do
        if [ -S "$socket_path" ] || [ -e "$socket_path" ]; then
            return 0
        fi
        if [ -n "$kwin_pid" ] && ! kill -0 "$kwin_pid" 2>/dev/null; then
            return 1
        fi
        attempts=$((attempts + 1))
        sleep 1
    done

    return 1
}

mark_validation_success() {
    if [ -e "$VALIDATION_REQUEST" ]; then
        : > "$VALIDATION_SUCCESS" 2>/dev/null || true
    fi
}

launch_optional_component() {
    local program="$1"
    local ready_marker="$2"

    if ! command -v "$program" >/dev/null 2>&1; then
        return 0
    fi

    "$program" &
    local pid=$!
    optional_pids+=("$pid")

    if [ -n "$ready_marker" ]; then
        sleep 1
        if kill -0 "$pid" 2>/dev/null; then
            : > "$ready_marker"
        fi
    fi
}

kwin_args=()
if [ "$kwin_mode" = "drm" ]; then
    kwin_args+=(--drm)
else
    kwin_args+=(--virtual)
fi

kwin_wayland_wrapper "${kwin_args[@]}" &
kwin_pid=$!

if ! wait_for_wayland_socket; then
    printf '%s\n' "redbear-kde-session: kwin_wayland_wrapper failed to expose $XDG_RUNTIME_DIR/$WAYLAND_DISPLAY" >&2
    exit 1
fi

: > "$session_ready_file"
mark_validation_success
launch_optional_component kded6 ""
launch_optional_component plasmashell "$panel_ready_file"

wait "$kwin_pid"