//go:build windows

// Package task 实现 Windows Agent 的 PowerShell 任务执行能力。 // Logan.Li
package task

import (
	"bytes"
	"context"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"time"
)

type Executor struct {
	logger *log.Logger
}

func New(logger *log.Logger) *Executor {
	return &Executor{logger: logger}
}

func (e *Executor) ExecuteTask(ctx context.Context, t Task) Result {
	res := Result{TaskID: t.TaskID}
	execCtx, cancel := e.withTimeout(ctx, t.Timeout)
	defer cancel()

	var cmd *exec.Cmd
	var cleanup func()
	switch t.Type {
	case TypeCommand:
		cmd = exec.CommandContext(execCtx, "powershell.exe", "-NoProfile", "-ExecutionPolicy", "Bypass", "-Command", t.Command)
	case TypeScript:
		path, err := writeTempPowerShell(t.Command)
		if err != nil {
			res.ExitCode = -1
			res.Status = "failed"
			res.Result = "写入临时 PowerShell 脚本失败: " + err.Error()
			return res
		}
		cleanup = func() { _ = os.Remove(path) }
		cmd = exec.CommandContext(execCtx, "powershell.exe", "-NoProfile", "-ExecutionPolicy", "Bypass", "-File", path)
	default:
		res.ExitCode = -1
		res.Status = "failed"
		res.Result = fmt.Sprintf("未知的任务类型: %q", t.Type)
		return res
	}
	if cleanup != nil {
		defer cleanup()
	}

	var buf bytes.Buffer
	cmd.Stdout = &buf
	cmd.Stderr = &buf
	start := time.Now()
	err := cmd.Run()
	elapsed := time.Since(start)
	if execCtx.Err() == context.DeadlineExceeded {
		res.ExitCode = -1
		res.Status = "timeout"
		res.Result = fmt.Sprintf("任务执行超时（%ds），已输出:\n%s", t.Timeout, buf.String())
		e.logger.Printf("任务 %s 执行超时（%ds）", t.TaskID, t.Timeout)
		return res
	}
	res.ExitCode = exitCode(err)
	res.Result = buf.String()
	if res.ExitCode == 0 {
		res.Status = "success"
		e.logger.Printf("任务 %s 执行成功 exit=0 耗时=%s 输出=%dB", t.TaskID, elapsed, buf.Len())
	} else {
		res.Status = "failed"
		e.logger.Printf("任务 %s 执行失败 exit=%d 耗时=%s 输出=%dB", t.TaskID, res.ExitCode, elapsed, buf.Len())
	}
	return res
}

func (e *Executor) withTimeout(parent context.Context, timeout int) (context.Context, context.CancelFunc) {
	if timeout <= 0 {
		return parent, func() {}
	}
	return context.WithTimeout(parent, time.Duration(timeout)*time.Second)
}

func exitCode(err error) int {
	if err == nil {
		return 0
	}
	if exitErr, ok := err.(*exec.ExitError); ok {
		return exitErr.ExitCode()
	}
	return -1
}

func writeTempPowerShell(script string) (string, error) {
	path := filepath.Join(os.TempDir(), fmt.Sprintf("aiops-agent-task-%d.ps1", time.Now().UnixNano()))
	if err := os.WriteFile(path, []byte(script), 0600); err != nil {
		return "", err
	}
	return path, nil
}