package util

import (
	"context"
	"fmt"
	"log"
	"os"
	"time"

	"github.com/chromedp/cdproto/emulation"
	"github.com/chromedp/cdproto/network"
	"github.com/chromedp/cdproto/page"
	"github.com/chromedp/chromedp"
)

// ScreenshotURL 截图函数：传入网址、输出路径、宽高、四个边距和等待的元素 ID
func ScreenshotURL(url, output string, width, height int, marginTop, marginRight, marginBottom, marginLeft int, waitClass string) error {
	// 创建一个上下文，连接到 Docker 中运行的 headless-shell 实例
	remoteAllocatorCtx, cancel := chromedp.NewRemoteAllocator(
		context.Background(), "ws://127.0.0.1:9222/json/ws",
	)
	defer cancel()

	ctx, cancel := chromedp.NewContext(remoteAllocatorCtx)
	defer cancel()

	// 设置超时时间，避免长时间无响应
	ctx, cancel = context.WithTimeout(ctx, 60*time.Second)
	defer cancel()

	// 设置页面的宽高和缩放
	if err := chromedp.Run(ctx, setViewportAndUserAgent(width, height, "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:131.0) Gecko/20100101 Firefox/131.0")); err != nil {
		return fmt.Errorf("设置页面大小失败: %w", err)
	}

	// 启用网络请求拦截
	if err := chromedp.Run(ctx, enableRequestInterception()); err != nil {
		return fmt.Errorf("启用请求拦截失败: %w", err)
	}

	// 用于存储截图的变量
	var screenshot []byte

	queryAction := chromedp.WaitVisible(fmt.Sprintf(".%s", waitClass), chromedp.ByQuery)
	if waitClass == "" {
		queryAction = chromedp.WaitVisible(`body`, chromedp.ByQuery)
	}

	// 执行任务：打开网页并截图
	err := chromedp.Run(ctx,
		chromedp.Navigate(url),    // 打开网页
		ignoreErrors(queryAction), // 等待指定元素
		chromedp.ActionFunc(func(ctx context.Context) error { // 自定义截图逻辑
			// 计算调整后的截图区域
			clip := &page.Viewport{
				X:      float64(marginLeft),
				Y:      float64(marginTop),
				Width:  float64(width - marginLeft - marginRight),
				Height: float64(height - marginTop - marginBottom),
				Scale:  1.0,
			}
			var err error
			screenshot, err = page.CaptureScreenshot().WithClip(clip).Do(ctx)
			return err
		}),
	)
	if err != nil {
		return fmt.Errorf("截图失败: %w", err)
	}

	// 保存截图到本地
	if err := os.WriteFile(output, screenshot, 0644); err != nil {
		return fmt.Errorf("保存图片失败: %w", err)
	}

	return nil
}

func setViewportAndUserAgent(width, height int, userAgent string) chromedp.Tasks {
	return chromedp.Tasks{
		emulation.SetDeviceMetricsOverride(int64(width), int64(height), 1.0, false).
			WithScreenOrientation(&emulation.ScreenOrientation{
				Type:  emulation.OrientationTypePortraitPrimary,
				Angle: 0,
			}),
		emulation.SetUserAgentOverride(userAgent),
	}
}

// enableRequestInterception 启用网络请求拦截，忽略不必要的资源加载（如广告、图片等）
func enableRequestInterception() chromedp.Tasks {
	return chromedp.Tasks{
		chromedp.ActionFunc(func(ctx context.Context) error {
			return network.Enable().Do(ctx)
		}),
		network.SetBlockedURLS([]string{
			"pagead2.googlesyndication.com",
			"optimizationguide-pa.googleapis.com",
		}),
	}
}

// ignoreErrors 包裹 chromedp 任务，忽略执行过程中出现的错误
func ignoreErrors(task chromedp.Action) chromedp.ActionFunc {
	return chromedp.ActionFunc(func(ctx context.Context) error {
		err := task.Do(ctx)
		if err != nil {
			log.Printf("忽略错误: %v", err)
		}
		return nil
	})
}