package main

import (
	"bytes"
	"errors"
	"fmt"
	"github.com/spf13/viper"
	"golang.org/x/sync/errgroup"
	"image"
	_ "image/jpeg"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"unicode"
)

type Crawler struct {
	avPath     string
	outputPath string
	config     *viper.Viper
}

func NewCrawler(avPath, outputPath string) *Crawler {
	config := viper.New()
	config.SetConfigName("config")
	config.AddConfigPath(".")
	config.SetConfigType("yaml")

	if err := config.ReadInConfig(); err != nil {
		fmt.Printf("读取配置文件发生错误, %s", err)
	}

	return &Crawler{
		avPath:     avPath,
		outputPath: outputPath,
		config:     config,
	}
}

// 检查文件是否是视频文件
func (c *Crawler) isVideoFile(fileName string) bool {
	videoExtensions := c.config.GetStringSlice("crawler.video")
	ext := strings.ToLower(filepath.Ext(fileName))
	for _, videoExt := range videoExtensions {
		if ext == videoExt {
			return true
		}
	}
	return false
}

// 获取文件信息，包括大小和修改时间
func (c *Crawler) getFileInfo(filePath string) (int64, string, error) {
	info, err := os.Stat(filePath)
	if err != nil {
		return 0, "", err
	}
	return info.Size(), info.ModTime().String(), nil
}

// 获取代码数字
func (c *Crawler) getCodeNum(s string) int {
	runes := []rune(s)
	if len(runes) < 3 {
		return 0
	}

	for i := 0; i < 3; i++ {
		if !unicode.IsDigit(runes[i]) {
			return 0
		}
	}

	num, _ := strconv.Atoi(string(runes[:3]))
	return num
}

// 获取封面代码列表
func (c *Crawler) getCoverCodeList(files []string) (coverList []string) {
	for _, file := range files {
		// 去除域名部分
		if strings.IndexRune(file, '@') > 0 {
			file = strings.Split(file, "@")[1]
		}

		nameSlice := strings.Split(file, "-")
		if len(nameSlice) < 2 || len(nameSlice[0]) > 5 {
			continue
		}

		num := c.getCodeNum(nameSlice[1])
		if num == 0 {
			continue
		}

		format := "%s%05d"
		if len(nameSlice[0]) > 4 {
			format = "1%s%05d"
		}

		coverList = append(coverList, fmt.Sprintf(format, strings.ToLower(nameSlice[0]), num))
	}
	return coverList
}

// 获取封面图片
func (c *Crawler) fetchCoverImg(code string) error {
	imgUrl := strings.ReplaceAll(c.config.GetString("crawler.url"), `*`, code)
	suffix := filepath.Ext(imgUrl)
	nameSlice := strings.Split(code, "00")

	if len(nameSlice) < 2 {
		return nil
	}

	if len(nameSlice[0]) > 4 {
		nameSlice[0] = nameSlice[0][1:]
	}

	fileName := filepath.Join(c.outputPath, fmt.Sprintf("%s-%s%s",
		strings.ToUpper(nameSlice[0]),
		nameSlice[1],
		suffix,
	))

	req, err := http.NewRequest("GET", imgUrl, nil)
	if err != nil {
		return fmt.Errorf("创建请求失败: %w", err)
	}

	// 模拟浏览器请求
	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return fmt.Errorf("请求失败: %w", err)
	}
	defer resp.Body.Close()

	// 检查 HTTP 状态码
	if resp.StatusCode != http.StatusOK {
		return nil
	}

	// 先完整读取 HTTP Body
	imgData, err := io.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("读取图片数据失败: %w", err)
	}

	// 使用内存数据解码图片
	img, _, err := image.DecodeConfig(bytes.NewReader(imgData))
	if err != nil {
		return fmt.Errorf("图片解码失败: %w", err)
	}

	// 图片高度未到达配置最低值则抛弃
	if img.Height < c.config.GetInt("crawler.minHeight") {
		return nil
	}

	// 将内存数据写入文件
	if err := os.WriteFile(fileName, imgData, 0644); err != nil {
		return fmt.Errorf("文件写入失败: %w", err)
	}

	return nil
}

func (c *Crawler) Handle() error {
	if c.avPath == "未选择" || c.outputPath == "未选择" {
		return errors.New("请选择作品存放目录或输出目录")
	}

	// 用于去重的集合
	uniqueFiles := make(map[string]struct{})
	var videoFiles []string

	if err := filepath.Walk(c.avPath, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return fmt.Errorf("访问路径 %s 失败: %w", path, err)
		}

		// 仅处理视频文件
		if !c.isVideoFile(info.Name()) {
			return nil
		}

		baseName := strings.TrimSuffix(info.Name(), filepath.Ext(info.Name()))

		// 获取文件大小和修改时间
		fileSize, modTime, err := c.getFileInfo(path)
		if err != nil {
			return fmt.Errorf("获取文件信息失败 %s: %w", baseName, err)
		}

		// 根据文件的大小和修改时间生成唯一的文件标识
		uniqueID := fmt.Sprintf("%d-%s", fileSize, modTime)
		if _, exists := uniqueFiles[uniqueID]; !exists {
			uniqueFiles[uniqueID] = struct{}{}
			videoFiles = append(videoFiles, baseName)
		}
		return nil
	}); err != nil {
		return fmt.Errorf("目录遍历失败: %w", err)
	}

	coverList := c.getCoverCodeList(videoFiles)

	var g errgroup.Group
	for _, cover := range coverList {
		g.Go(func() error {
			if err := c.fetchCoverImg(cover); err != nil {
				return err
			}

			return nil
		})
	}

	return g.Wait()
}