// internal/frp/legacy.go
// Reload 函数适配 P0 改动

package frp

import (
	"context"
	"log"
	"os"
	"os/exec"
	"runtime"
	"strconv"
	"strings"
	"syscall"

	"frpc-console/internal/process"
)

// ================================================================
// 兼容层：保持对外接口不变
// ================================================================

func IsRunning() bool {
	pm := process.GetGlobalManager()
	if pm != nil {
		status, err := pm.Status()
		if err != nil {
			log.Printf("[WARN] ProcessManager.Status() 失败: %v，降级到 PID 文件", err)
			return isRunningLegacy()
		}
		return status.Phase == "RUNNING"
	}
	return isRunningLegacy()
}

func Start() error {
	pm := process.GetGlobalManager()
	if pm != nil {
		log.Println("[INFO] 使用 ProcessManager 启动 frpc")
		return pm.Start(context.Background())
	}
	log.Println("[WARN] ProcessManager 未初始化，使用兼容模式启动 frpc")
	return startLegacy()
}

func Stop() error {
	pm := process.GetGlobalManager()
	if pm != nil {
		log.Println("[INFO] 使用 ProcessManager 停止 frpc")
		return pm.Stop(context.Background())
	}
	log.Println("[WARN] ProcessManager 未初始化，使用兼容模式停止 frpc")
	return stopLegacy()
}

func Restart() error {
	pm := process.GetGlobalManager()
	if pm != nil {
		log.Println("[INFO] 使用 ProcessManager 重启 frpc")
		return pm.Restart(context.Background())
	}
	log.Println("[WARN] ProcessManager 未初始化，使用兼容模式重启 frpc")
	if err := stopLegacy(); err != nil {
		return err
	}
	return startLegacy()
}

func GetStatus() (map[string]interface{}, error) {
	pm := process.GetGlobalManager()
	if pm != nil {
		state, err := pm.Status()
		if err != nil {
			return nil, err
		}
		return map[string]interface{}{
			"phase":     state.Phase,
			"pid":       state.PID,
			"port":      state.Port,
			"alive":     state.Alive,
			"frp_ready": state.FRPReady,
		}, nil
	}
	running := isRunningLegacy()
	return map[string]interface{}{
		"phase":  map[bool]string{true: "RUNNING", false: "STOPPED"}[running],
		"pid":    0,
		"port":   0,
		"legacy": true,
	}, nil
}

// ================================================================
// Reload 热加载 frpc 配置（P0 核心）
// ================================================================

func Reload() error {
	pm := process.GetGlobalManager()
	if pm == nil {
		log.Println("[WARN] ProcessManager 未初始化，使用兼容模式 reload")
		return reloadLegacy()
	}

	// 使用 ProcessManager 的 ReloadConfig 方法
	// 该方法内部处理了 RELOADING 状态和 PID 归属验证
	log.Println("[INFO] 使用 ProcessManager 执行热加载")
	return pm.ReloadConfig(context.Background())
}

// ================================================================
// 旧版实现 (降级方案)
// ================================================================

func isRunningLegacy() bool {
	pidData, err := os.ReadFile("./data/frpc.pid")
	if err != nil {
		return false
	}
	pid, err := strconv.Atoi(strings.TrimSpace(string(pidData)))
	if err != nil {
		return false
	}
	if runtime.GOOS == "windows" {
		cmd := exec.Command("tasklist", "/FI", "PID eq", strconv.Itoa(pid))
		output, err := cmd.CombinedOutput()
		if err != nil {
			return false
		}
		return strings.Contains(string(output), strconv.Itoa(pid))
	}
	process, err := os.FindProcess(pid)
	if err != nil {
		return false
	}
	return process.Signal(syscall.Signal(0)) == nil
}

func startLegacy() error {
	frpcPath, err := GetFrpcPath()
	if err != nil {
		return err
	}
	if err := os.MkdirAll("./data", 0755); err != nil {
		return err
	}
	if _, err := os.Stat("./data/frpc.toml"); os.IsNotExist(err) {
		if err := GenerateConfig(); err != nil {
			return err
		}
	}
	if isRunningLegacy() {
		return nil
	}
	os.Remove("./data/frpc.pid")
	cmd := exec.Command(frpcPath, "-c", "./data/frpc.toml")
	setWindowHide(cmd)
	setSysProcAttr(cmd)
	logFile, err := os.OpenFile("./data/frpc.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
	if err != nil {
		return err
	}
	cmd.Stdout = logFile
	cmd.Stderr = logFile
	if err := cmd.Start(); err != nil {
		return err
	}
	go func() {
		if err := cmd.Wait(); err != nil {
			log.Printf("frpc 子进程退出: %v", err)
		}
		os.Remove("./data/frpc.pid")
	}()
	return os.WriteFile("./data/frpc.pid", []byte(strconv.Itoa(cmd.Process.Pid)), 0644)
}

func stopLegacy() error {
	if runtime.GOOS == "windows" {
		cmd := exec.Command("taskkill", "/F", "/IM", "frpc.exe")
		if err := cmd.Run(); err != nil && !strings.Contains(err.Error(), "not found") {
			return err
		}
		os.Remove("./data/frpc.pid")
		return nil
	}
	pidData, err := os.ReadFile("./data/frpc.pid")
	if err != nil {
		cmd := exec.Command("pkill", "-f", "frpc")
		if err := cmd.Run(); err != nil && !strings.Contains(err.Error(), "no process") {
			return err
		}
		return nil
	}
	pid, _ := strconv.Atoi(strings.TrimSpace(string(pidData)))
	process, err := os.FindProcess(pid)
	if err != nil {
		os.Remove("./data/frpc.pid")
		return nil
	}
	if err := process.Kill(); err != nil {
		return err
	}
	os.Remove("./data/frpc.pid")
	return nil
}

func reloadLegacy() error {
	if !isRunningLegacy() {
		return startLegacy()
	}
	frpcPath, err := GetFrpcPath()
	if err != nil {
		return err
	}
	cmd := exec.Command(frpcPath, "reload", "-c", "./data/frpc.toml")
	output, err := cmd.CombinedOutput()
	if err != nil {
		log.Printf("⚠️ 热加载失败 (%v)，降级为重启 frpc", err)
		log.Printf("   reload 输出: %s", string(output))
		if stopErr := stopLegacy(); stopErr != nil {
			return stopErr
		}
		return startLegacy()
	}
	log.Printf("✅ frpc 热加载成功 (兼容模式): %s", string(output))
	return nil
}