#!/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="$CLASH_HOME/temp/clash.pid"
SUBSCRIPTION_FILE="$CLASH_HOME/conf/subscriptions.list"

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
  sub add <name> <url> [headers]   Add subscription entry
  sub del <name>                   Delete subscription entry
  sub use <name>                   Activate subscription entry
  sub update [name]                Update subscription config by entry
  sub list                         List subscriptions
  sub log                          Show subscription update logs

Environment:
  CLASH_HOME             Override Clash installation directory
USAGE
}

set_env_var() {
	local key="$1"
	local value="${2:-}"
	if [ ! -f "$ENV_FILE" ]; then
		echo "[ERROR] 未找到 .env 文件: $ENV_FILE" >&2
		exit 1
	fi
	local escaped
	escaped=$(printf "%s" "$value" | sed "s/'/'\"'\"'/g")
	if grep -q "^export ${key}=" "$ENV_FILE"; then
		sed -i "s@^export ${key}=.*@export ${key}='${escaped}'@" "$ENV_FILE"
	else
		echo "export ${key}='${escaped}'" >> "$ENV_FILE"
	fi
}

set_url() {
	local url="$1"
	if [ -z "$url" ]; then
		echo "[ERROR] 请提供订阅地址" >&2
		exit 1
	fi
	set_env_var "CLASH_URL" "$url"
	set_env_var "CLASH_SUBSCRIPTION" ""
	echo "[OK] 已更新 CLASH_URL"
}

ensure_subscription_file() {
	mkdir -p "$(dirname "$SUBSCRIPTION_FILE")"
	if [ ! -f "$SUBSCRIPTION_FILE" ]; then
		touch "$SUBSCRIPTION_FILE"
	fi
}

subscription_lookup() {
	local name="$1"
	awk -F'|' -v target="$name" '$1 == target {print; exit}' "$SUBSCRIPTION_FILE"
}

subscription_add() {
	local name="$1"
	local url="$2"
	local headers="${3:-}"
	if [ -z "$name" ] || [ -z "$url" ]; then
		echo "[ERROR] 用法: clashctl sub add <name> <url> [headers]" >&2
		exit 1
	fi
	ensure_subscription_file
	if subscription_lookup "$name" >/dev/null; then
		echo "[ERROR] 订阅已存在: $name" >&2
		exit 1
	fi
	printf "%s|%s|%s|-\n" "$name" "$url" "$headers" >> "$SUBSCRIPTION_FILE"
	echo "[OK] 已添加订阅: $name"
}

subscription_del() {
	local name="$1"
	if [ -z "$name" ]; then
		echo "[ERROR] 用法: clashctl sub del <name>" >&2
		exit 1
	fi
	ensure_subscription_file
	if ! subscription_lookup "$name" >/dev/null; then
		echo "[ERROR] 未找到订阅: $name" >&2
		exit 1
	fi
	awk -F'|' -v target="$name" 'BEGIN{OFS=FS} $1 != target {print}' "$SUBSCRIPTION_FILE" > "${SUBSCRIPTION_FILE}.tmp"
	mv "${SUBSCRIPTION_FILE}.tmp" "$SUBSCRIPTION_FILE"
	echo "[OK] 已删除订阅: $name"
}

subscription_use() {
	local name="$1"
	if [ -z "$name" ]; then
		echo "[ERROR] 用法: clashctl sub use <name>" >&2
		exit 1
	fi
	ensure_subscription_file
	local line
	line=$(subscription_lookup "$name")
	if [ -z "$line" ]; then
		echo "[ERROR] 未找到订阅: $name" >&2
		exit 1
	fi
	local url headers
	url=$(echo "$line" | awk -F'|' '{print $2}')
	headers=$(echo "$line" | awk -F'|' '{print $3}')
	set_env_var "CLASH_URL" "$url"
	set_env_var "CLASH_HEADERS" "$headers"
	set_env_var "CLASH_SUBSCRIPTION" "$name"
	echo "[OK] 已切换订阅: $name"
}

subscription_touch() {
	local name="$1"
	local timestamp
	timestamp=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
	awk -F'|' -v target="$name" -v ts="$timestamp" 'BEGIN{OFS=FS} {if ($1==target) {$4=ts} print}' "$SUBSCRIPTION_FILE" > "${SUBSCRIPTION_FILE}.tmp"
	mv "${SUBSCRIPTION_FILE}.tmp" "$SUBSCRIPTION_FILE"
}

subscription_update() {
	local name="${1:-}"
	if [ -z "$name" ]; then
		name=$(awk -F= '/^export CLASH_SUBSCRIPTION=/{print $2}' "$ENV_FILE" | tr -d "'" | tr -d '"')
	fi
	if [ -z "$name" ]; then
		echo "[ERROR] 未指定订阅名称，且 CLASH_SUBSCRIPTION 未设置" >&2
		exit 1
	fi
	subscription_use "$name"
	run_script update.sh
	subscription_touch "$name"
	echo "[OK] 订阅已更新: $name"
}

subscription_list() {
	ensure_subscription_file
	local active
	active=$(awk -F= '/^export CLASH_SUBSCRIPTION=/{print $2}' "$ENV_FILE" | tr -d "'" | tr -d '"')
	printf "%-20s %-6s %s\n" "NAME" "ACTIVE" "URL"
	while IFS='|' read -r name url headers updated; do
		[ -z "$name" ] && continue
		if [ "$name" = "$active" ]; then
			printf "%-20s %-6s %s\n" "$name" "yes" "$url"
		else
			printf "%-20s %-6s %s\n" "$name" "no" "$url"
		fi
	done < "$SUBSCRIPTION_FILE"
}

subscription_log() {
	ensure_subscription_file
	printf "%-20s %s\n" "NAME" "LAST_UPDATE"
	while IFS='|' read -r name url headers updated; do
		[ -z "$name" ] && continue
		printf "%-20s %s\n" "$name" "${updated:--}"
	done < "$SUBSCRIPTION_FILE"
}

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:-}"
		;;
	sub)
		subcommand="${2:-}"
		case "$subcommand" in
			add)
				subscription_add "${3:-}" "${4:-}" "${5:-}"
				;;
			del|delete|rm|remove)
				subscription_del "${3:-}"
				;;
			use)
				subscription_use "${3:-}"
				;;
			update)
				subscription_update "${3:-}"
				;;
			list|ls)
				subscription_list
				;;
			log)
				subscription_log
				;;
			*)
				echo "[ERROR] 未知订阅命令: $subcommand" >&2
				print_usage
				exit 1
				;;
		esac
		;;
	-h|--help|help|'')
		print_usage
		;;
	*)
		echo "[ERROR] 未知命令: $command" >&2
		print_usage
		exit 1
		;;
esac