#!/bin/bash

set -euo pipefail

SCRIPT_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
SERVICE_NAME="clash-for-linux"

resolve_clash_home() {
	local candidates
	if [ -n "${CLASH_HOME:-}" ] && [ -d "$CLASH_HOME" ]; then
		echo "$CLASH_HOME"
		return 0
	fi
	if [ -f "/etc/default/${SERVICE_NAME}" ]; then
		candidates=$(awk -F= '/^CLASH_HOME=/{print $2}' "/etc/default/${SERVICE_NAME}" | tr -d '"')
		if [ -n "$candidates" ] && [ -d "$candidates" ]; then
			echo "$candidates"
			return 0
		fi
	fi
	if [ -f "$SCRIPT_DIR/.env" ]; then
		echo "$SCRIPT_DIR"
		return 0
	fi
	if [ -f "/opt/clash-for-linux/.env" ]; then
		echo "/opt/clash-for-linux"
		return 0
	fi
	echo "$SCRIPT_DIR"
}

CLASH_HOME=$(resolve_clash_home)
ENV_FILE="$CLASH_HOME/.env"
PID_FILE="$CLASH_HOME/temp/clash.pid"

use_systemd() {
	command -v systemctl >/dev/null 2>&1
}

action_with_systemd() {
	local action="$1"
	if use_systemd; then
		if systemctl "$action" "${SERVICE_NAME}.service" >/dev/null 2>&1; then
			return 0
		fi
	fi
	return 1
}

print_usage() {
	cat <<USAGE
Usage: clashctl <command> [args]

Commands:
  start                 Start Clash service
  stop                  Stop Clash service
  restart               Restart Clash service
  status                Show Clash service status
  update                Refresh subscription config
  set-url <url>          Update CLASH_URL in .env

Environment:
  CLASH_HOME             Override Clash installation directory
USAGE
}

set_url() {
	local url="$1"
	if [ -z "$url" ]; then
		echo "[ERROR] 请提供订阅地址" >&2
		exit 1
	fi
	if [ ! -f "$ENV_FILE" ]; then
		echo "[ERROR] 未找到 .env 文件: $ENV_FILE" >&2
		exit 1
	fi
	local escaped
	escaped=$(printf "%s" "$url" | sed "s/'/'\"'\"'/g")
	if grep -q '^export CLASH_URL=' "$ENV_FILE"; then
		sed -i "s@^export CLASH_URL=.*@export CLASH_URL='${escaped}'@" "$ENV_FILE"
	else
		echo "export CLASH_URL='${escaped}'" >> "$ENV_FILE"
	fi
	echo "[OK] 已更新 CLASH_URL"
}

status_fallback() {
	if [ -f "$PID_FILE" ]; then
		local pid
		pid=$(cat "$PID_FILE")
		if [ -n "$pid" ] && kill -0 "$pid" >/dev/null 2>&1; then
			echo "[OK] Clash 进程运行中 (PID: $pid)"
			return 0
		fi
	fi
	if pgrep -f "clash-linux-" >/dev/null 2>&1; then
		echo "[OK] Clash 进程运行中"
		return 0
	fi
	echo "[WARN] 未检测到 Clash 进程"
	return 1
}

run_script() {
	local script="$1"
	if [ ! -x "$CLASH_HOME/$script" ]; then
		echo "[ERROR] 未找到脚本: $CLASH_HOME/$script" >&2
		exit 1
	fi
	( cd "$CLASH_HOME" && bash "$CLASH_HOME/$script" )
}

command=${1:-}
case "$command" in
	start)
		action_with_systemd start || run_script start.sh
		;;
	stop)
		action_with_systemd stop || run_script shutdown.sh
		;;
	restart)
		action_with_systemd restart || run_script restart.sh
		;;
	status)
		if use_systemd; then
			if systemctl status "${SERVICE_NAME}.service" --no-pager; then
				exit 0
			fi
		fi
		status_fallback
		;;
	update)
		run_script update.sh
		;;
	set-url)
		set_url "${2:-}"
		;;
	-h|--help|help|'')
		print_usage
		;;
	*)
		echo "[ERROR] 未知命令: $command" >&2
		print_usage
		exit 1
		;;
esac