package procctl

import (
	"bytes"
	"fmt"
	"io"
	"os/exec"
	"strconv"
	"strings"
	"time"
)

// SystemCtlController 使用 systemctl 管理 Media Server
type SystemCtlController struct {
	serviceName string
}

// NewSystemCtlController 创建 systemctl 控制器
func NewSystemCtlController(serviceName string) *SystemCtlController {
	return &SystemCtlController{
		serviceName: serviceName,
	}
}

func (s *SystemCtlController) Enabled() bool { return s != nil }

func (s *SystemCtlController) Status() (Status, error) {
	// 检查服务是否运行
	cmd := exec.Command("systemctl", "is-active", "--quiet", s.serviceName)
	err := cmd.Run()
	
	if err != nil {
		// 服务未运行
		return Status{Running: false}, nil
	}
	
	// 获取 PID
	pidCmd := exec.Command("systemctl", "show", "--property=MainPID", "--value", s.serviceName)
	out, err := pidCmd.Output()
	if err != nil {
		return Status{Running: true}, nil // 运行但无法获取 PID
	}
	
	pid, _ := strconv.Atoi(strings.TrimSpace(string(out)))
	if pid <= 0 {
		return Status{Running: true}, nil
	}
	
	return Status{
		Running:    true,
		Pid:        pid,
		ConfigPath: "/opt/rk3588-media-server/etc/media-server.json",
	}, nil
}

func (s *SystemCtlController) Version() (string, error) {
	// 直接执行 media-server --version
	cmd := exec.Command("/opt/rk3588-media-server/bin/media-server", "--version")
	out, err := cmd.Output()
	if err != nil {
		return "", fmt.Errorf("get version failed: %w", err)
	}
	return strings.TrimSpace(string(out)), nil
}

func (s *SystemCtlController) Start(configName string) (Status, error) {
	// 使用 systemctl start
	cmd := exec.Command("systemctl", "start", s.serviceName)
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	
	if err := cmd.Run(); err != nil {
		return Status{}, fmt.Errorf("start failed: %w, stderr: %s", err, stderr.String())
	}
	
	// 等待服务启动
	time.Sleep(500 * time.Millisecond)
	return s.Status()
}

func (s *SystemCtlController) Stop() (Status, error) {
	cmd := exec.Command("systemctl", "stop", s.serviceName)
	if err := cmd.Run(); err != nil {
		return Status{}, fmt.Errorf("stop failed: %w", err)
	}
	return Status{Running: false}, nil
}

func (s *SystemCtlController) Restart(configName string) (Status, error) {
	cmd := exec.Command("systemctl", "restart", s.serviceName)
	if err := cmd.Run(); err != nil {
		return Status{}, fmt.Errorf("restart failed: %w", err)
	}
	time.Sleep(500 * time.Millisecond)
	return s.Status()
}

// 二进制更新相关功能在 systemctl 模式下不支持
func (s *SystemCtlController) BinaryInfo() (BinaryUpdateResult, error) {
	return BinaryUpdateResult{}, ErrNotSupported
}

func (s *SystemCtlController) UpdateBinary(r io.Reader, contentLength int64, expectedSha256 string) (BinaryUpdateResult, error) {
	return BinaryUpdateResult{}, ErrNotSupported
}

func (s *SystemCtlController) RollbackBinary(backupPath string) (BinaryUpdateResult, error) {
	return BinaryUpdateResult{}, ErrNotSupported
}