#!/bin/bash

set -e

COMPOSITOR=""
COMPOSITOR_CONFIG=""
DMS_PATH="dms-greeter"
CACHE_DIR="/var/cache/dms-greeter"
REMEMBER_LAST_SESSION=""
REMEMBER_LAST_USER=""
DEBUG_MODE=0

show_help() {
    cat << EOF
dms-greeter - DankMaterialShell greeter launcher

Usage: dms-greeter --command COMPOSITOR [OPTIONS]

Required:
    --command COMPOSITOR    Compositor to use (niri, hyprland, sway, scroll, miracle, mango, or labwc)

Options:
    -C, --config PATH       Custom compositor config file
    -p, --path PATH         DMS path (config name or absolute path)
                           (default: dms-greeter)
    --cache-dir PATH        Cache directory for greeter data
                           (default: /var/cache/dms-greeter)
    --remember-last-session BOOL
                           Persist selected session to greeter memory
                           (BOOL: true/false, default: from settings.json)
    --remember-last-user BOOL
                           Persist last successful username to greeter memory
                           (BOOL: true/false, default: from settings.json)
    --no-save-session      Alias for --remember-last-session false
    --no-save-username     Alias for --remember-last-user false
    --debug                Enable verbose startup logging to stderr
    -h, --help             Show this help message

Examples:
    dms-greeter --command niri
    dms-greeter --command hyprland -C /etc/greetd/custom-hypr.conf
    dms-greeter --command sway -p /home/user/.config/quickshell/custom-dms
    dms-greeter --command scroll -p /home/user/.config/quickshell/custom-dms
    dms-greeter --command niri --cache-dir /tmp/dmsgreeter
    dms-greeter --command niri --no-save-session --no-save-username
    dms-greeter --command mango
    dms-greeter --command labwc
EOF
}

require_command() {
    local cmd="$1"
    if ! command -v "$cmd" >/dev/null 2>&1; then
        echo "Error: required command '$cmd' was not found in PATH" >&2
        exit 1
    fi
}

normalize_bool_flag() {
    local flag_name="$1"
    local value="$2"
    local normalized="${value,,}"

    case "$normalized" in
        1|true|yes|on)
            echo "1"
            ;;
        0|false|no|off)
            echo "0"
            ;;
        *)
            echo "Error: $flag_name must be true/false (or 1/0, yes/no, on/off)" >&2
            exit 1
            ;;
    esac
}

exec_compositor() {
    local log_tag="$1"
    shift

    if [[ "$DEBUG_MODE" == "1" ]]; then
        exec "$@"
    fi

    if command -v systemd-cat >/dev/null 2>&1; then
        exec "$@" > >(systemd-cat -t "dms-greeter/$log_tag" -p info) 2>&1
    fi

    exec "$@"
}

while [[ $# -gt 0 ]]; do
    case $1 in
        --command)
            COMPOSITOR="$2"
            shift 2
            ;;
        -C|--config)
            COMPOSITOR_CONFIG="$2"
            shift 2
            ;;
        -p|--path)
            DMS_PATH="$2"
            shift 2
            ;;
        --cache-dir)
            CACHE_DIR="$2"
            shift 2
            ;;
        --remember-last-session)
            REMEMBER_LAST_SESSION="$2"
            shift 2
            ;;
        --remember-last-user)
            REMEMBER_LAST_USER="$2"
            shift 2
            ;;
        --no-save-session)
            REMEMBER_LAST_SESSION="0"
            shift
            ;;
        --no-save-username)
            REMEMBER_LAST_USER="0"
            shift
            ;;
        --debug)
            DEBUG_MODE=1
            shift
            ;;
        -h|--help)
            show_help
            exit 0
            ;;
        *)
            echo "Unknown option: $1" >&2
            show_help
            exit 1
            ;;
    esac
done

if [[ -z "$COMPOSITOR" ]]; then
    echo "Error: --command COMPOSITOR is required" >&2
    show_help
    exit 1
fi

locate_dms_config() {
    local config_name="$1"
    local search_paths=()

    local config_home="${XDG_CONFIG_HOME:-$HOME/.config}"
    search_paths+=("$config_home/quickshell/$config_name")

    search_paths+=("/usr/share/quickshell/$config_name")

    local config_dirs="${XDG_CONFIG_DIRS:-/etc/xdg}"
    IFS=':' read -ra dirs <<< "$config_dirs"
    for dir in "${dirs[@]}"; do
        if [[ -n "$dir" ]]; then
            search_paths+=("$dir/quickshell/$config_name")
        fi
    done

    for path in "${search_paths[@]}"; do
        if [[ -f "$path/shell.qml" ]]; then
            echo "$path"
            return 0
        fi
    done

    return 1
}

export XDG_SESSION_TYPE=wayland
export QT_QPA_PLATFORM=wayland
export QT_WAYLAND_DISABLE_WINDOWDECORATION=1
export EGL_PLATFORM=gbm
export DMS_RUN_GREETER=1

if [[ ! -d "$CACHE_DIR" ]]; then
    echo "Error: cache directory '$CACHE_DIR' does not exist." >&2
    echo "  Run 'dms greeter sync' to initialize it, or pass --cache-dir to an existing directory." >&2
    exit 1
fi

export DMS_GREET_CFG_DIR="$CACHE_DIR"

if [[ -n "$REMEMBER_LAST_SESSION" ]]; then
    DMS_GREET_REMEMBER_LAST_SESSION=$(normalize_bool_flag "--remember-last-session" "$REMEMBER_LAST_SESSION")
    export DMS_GREET_REMEMBER_LAST_SESSION
    if [[ "$DMS_GREET_REMEMBER_LAST_SESSION" == "1" ]]; then
        DMS_SAVE_SESSION=true
    else
        DMS_SAVE_SESSION=false
    fi
    export DMS_SAVE_SESSION
fi

if [[ -n "$REMEMBER_LAST_USER" ]]; then
    DMS_GREET_REMEMBER_LAST_USER=$(normalize_bool_flag "--remember-last-user" "$REMEMBER_LAST_USER")
    export DMS_GREET_REMEMBER_LAST_USER
    if [[ "$DMS_GREET_REMEMBER_LAST_USER" == "1" ]]; then
        DMS_SAVE_USERNAME=true
    else
        DMS_SAVE_USERNAME=false
    fi
    export DMS_SAVE_USERNAME
fi

export HOME="$CACHE_DIR"
export XDG_STATE_HOME="$CACHE_DIR/.local/state"
export XDG_DATA_HOME="$CACHE_DIR/.local/share"
export XDG_CACHE_HOME="$CACHE_DIR/.cache"


# Keep greeter VT clean by default; callers can override via env or --debug.
if [[ -z "${RUST_LOG:-}" ]]; then
    export RUST_LOG=warn
fi
if [[ -z "${NIRI_LOG:-}" ]]; then
    export NIRI_LOG=warn
fi

if command -v qs >/dev/null 2>&1; then
    QS_BIN="qs"
elif command -v quickshell >/dev/null 2>&1; then
    QS_BIN="quickshell"
else
    echo "Error: neither 'qs' nor 'quickshell' was found in PATH" >&2
    exit 1
fi

QS_CMD="$QS_BIN"
if [[ "$DMS_PATH" == /* ]]; then
    QS_CMD="$QS_BIN -p $DMS_PATH"
else
    RESOLVED_PATH=$(locate_dms_config "$DMS_PATH")
    if [[ $? -eq 0 && -n "$RESOLVED_PATH" ]]; then
        if [[ "$DEBUG_MODE" == "1" ]]; then
            echo "Located DMS config at: $RESOLVED_PATH" >&2
        fi
        QS_CMD="$QS_BIN -p $RESOLVED_PATH"
    else
        echo "Error: Could not find DMS config '$DMS_PATH' (shell.qml) in any valid config path" >&2
        exit 1
    fi
fi

case "$COMPOSITOR" in
    niri)
        require_command "niri"
        if [[ -z "$COMPOSITOR_CONFIG" ]]; then
            TEMP_CONFIG=$(mktemp)
			# base/default config
            cat > "$TEMP_CONFIG" << NIRI_EOF
hotkey-overlay {
    skip-at-startup
}

environment {
    DMS_RUN_GREETER "1"
}

debug {
  keep-max-bpc-unchanged
}

gestures {
   hot-corners {
     off
   }
}

layout {
  background-color "#000000"
}
NIRI_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        else
            TEMP_CONFIG=$(mktemp)
            cat "$COMPOSITOR_CONFIG" > "$TEMP_CONFIG"
        fi
		# Append includes if override_files exist
		OVERRIDE_FILES=(
			/usr/share/greetd/niri_overrides.kdl # for building into a system image
			/etc/greetd/niri_overrides.kdl # for local overrides
			)
		for override_file in "${OVERRIDE_FILES[@]}"; do
			if [[ -e "$override_file" ]]; then
		# TODO: maybe move to optional=true when Niri Next drops, so we can avoid these checks ;-)
				cat >> "$TEMP_CONFIG" << NIRI_EOF

include "$override_file"
NIRI_EOF
			fi
		done
		# Append spawn command
            cat >> "$TEMP_CONFIG" << NIRI_EOF

spawn-at-startup "sh" "-c" "$QS_CMD; niri msg action quit --skip-confirmation"
NIRI_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        exec_compositor "niri" niri -c "$COMPOSITOR_CONFIG"
        ;;

    hyprland)
        if ! command -v start-hyprland >/dev/null 2>&1 && ! command -v Hyprland >/dev/null 2>&1; then
            echo "Error: neither 'start-hyprland' nor 'Hyprland' was found in PATH" >&2
            exit 1
        fi
        if [[ -z "$COMPOSITOR_CONFIG" ]]; then
            TEMP_CONFIG=$(mktemp)
            cat > "$TEMP_CONFIG" << HYPRLAND_EOF
env = DMS_RUN_GREETER,1

misc {
    disable_hyprland_logo = true
}

exec-once = sh -c "$QS_CMD; hyprctl dispatch exit"
HYPRLAND_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        else
            TEMP_CONFIG=$(mktemp)
            cat "$COMPOSITOR_CONFIG" > "$TEMP_CONFIG"
            cat >> "$TEMP_CONFIG" << HYPRLAND_EOF

exec-once = sh -c "$QS_CMD; hyprctl dispatch exit"
HYPRLAND_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        fi
        if command -v start-hyprland >/dev/null 2>&1; then
            exec_compositor "hyprland" start-hyprland -- --config "$COMPOSITOR_CONFIG"
        else
            exec_compositor "hyprland" Hyprland -c "$COMPOSITOR_CONFIG"
        fi
        ;;

    sway)
        require_command "sway"
        if [[ -z "$COMPOSITOR_CONFIG" ]]; then
            TEMP_CONFIG=$(mktemp)
            cat > "$TEMP_CONFIG" << SWAY_EOF
exec "$QS_CMD; swaymsg exit"
SWAY_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        else
            TEMP_CONFIG=$(mktemp)
            cat "$COMPOSITOR_CONFIG" > "$TEMP_CONFIG"
            cat >> "$TEMP_CONFIG" << SWAY_EOF

exec "$QS_CMD; swaymsg exit"
SWAY_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        fi
        exec_compositor "sway" sway --unsupported-gpu -c "$COMPOSITOR_CONFIG"
        ;;

    scroll)
        require_command "scroll"
        if [[ -z "$COMPOSITOR_CONFIG" ]]; then
            TEMP_CONFIG=$(mktemp)
            cat > "$TEMP_CONFIG" << SCROLL_EOF
exec "$QS_CMD; scrollmsg exit"
SCROLL_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        else
            TEMP_CONFIG=$(mktemp)
            cat "$COMPOSITOR_CONFIG" > "$TEMP_CONFIG"
            cat >> "$TEMP_CONFIG" << SCROLL_EOF

exec "$QS_CMD; scrollmsg exit"
SCROLL_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        fi
        exec_compositor "scroll" scroll -c "$COMPOSITOR_CONFIG"
        ;;

    miracle|miracle-wm)
        require_command "miracle-wm"
        if [[ -z "$COMPOSITOR_CONFIG" ]]; then
            TEMP_CONFIG=$(mktemp)
            cat > "$TEMP_CONFIG" << MIRACLE_EOF
exec "$QS_CMD; miraclemsg exit"
MIRACLE_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        else
            TEMP_CONFIG=$(mktemp)
            cat "$COMPOSITOR_CONFIG" > "$TEMP_CONFIG"
            cat >> "$TEMP_CONFIG" << MIRACLE_EOF

exec "$QS_CMD; miraclemsg exit"
MIRACLE_EOF
            COMPOSITOR_CONFIG="$TEMP_CONFIG"
        fi
        exec_compositor "miracle" miracle-wm -c "$COMPOSITOR_CONFIG"
        ;;

    labwc)
        require_command "labwc"
        if [[ -n "$COMPOSITOR_CONFIG" ]]; then
            exec_compositor "labwc" labwc --config "$COMPOSITOR_CONFIG" --session "$QS_CMD"
        else
            exec_compositor "labwc" labwc --session "$QS_CMD"
        fi
        ;;

    mango|mangowc)
        require_command "mango"
        if [[ -n "$COMPOSITOR_CONFIG" ]]; then
            exec_compositor "mango" mango -c "$COMPOSITOR_CONFIG" -s "$QS_CMD && mmsg -d quit"
        else
            exec_compositor "mango" mango -s "$QS_CMD && mmsg -d quit"
        fi
        ;;

    *)
        echo "Error: Unsupported compositor: $COMPOSITOR" >&2
        echo "Supported compositors: niri, hyprland, sway, scroll, miracle, mango, labwc" >&2
        exit 1
        ;;
esac