ChineseSubFinder/internal/logic/sub_parser/srt/srt.go

package srt

import (
	"github.com/allanpk716/ChineseSubFinder/internal/common"
	"github.com/allanpk716/ChineseSubFinder/internal/pkg/language"
	"github.com/allanpk716/ChineseSubFinder/internal/types/subparser"
	"io/ioutil"
	"path/filepath"
	"regexp"
	"strings"
)

type Parser struct {
}

func NewParser() *Parser {
	return &Parser{}
}

func (p Parser) GetParserName() string {
	return "srt"
}

/*
	DetermineFileTypeFromFile 确定字幕文件的类型，是双语字幕或者某一种语言等等信息
	当 error 是 common.DetermineFileTypeFromFileExtNotFitSRT
	需要额外的处理逻辑，比如不用报错，而是跳过后续的逻辑
*/
func (p Parser) DetermineFileTypeFromFile(filePath string) (*subparser.FileInfo, error) {
	nowExt := filepath.Ext(filePath)
	if strings.ToLower(nowExt) != common.SubExtSRT {
		return nil, common.DetermineFileTypeFromFileExtNotFitSRT
	}
	fBytes, err := ioutil.ReadFile(filePath)
	if err != nil {
		return nil, err
	}
	inBytes, err := language.ChangeFileCoding2UTF8(fBytes)
	if err != nil {
		return nil, err
	}
	return p.DetermineFileTypeFromBytes(inBytes, nowExt)
}

// DetermineFileTypeFromBytes 确定字幕文件的类型，是双语字幕或者某一种语言等等信息
func (p Parser) DetermineFileTypeFromBytes(inBytes []byte, nowExt string) (*subparser.FileInfo, error) {

	allString := string(inBytes)
	// 注意，需要替换掉 \r 不然正则表达式会有问题
	allString = strings.ReplaceAll(allString, "\r", "")
	re := regexp.MustCompile(regString)
	// 找到 start end text
	matched := re.FindAllStringSubmatch(allString, -1)
	if len(matched) < 1 {
		return nil, nil
	}
	subFileInfo := subparser.FileInfo{}
	subFileInfo.Ext = nowExt
	subFileInfo.Dialogues = make([]subparser.OneDialogue, 0)
	// 这里需要统计一共有几个 \N，以及这个数量在整体行数中的比例，这样就知道是不是双语字幕了
	countLineFeed := 0
	for _, oneDial := range matched {
		startTime := oneDial[2]
		endTime := oneDial[3]
		nowText := oneDial[4]
		odl := subparser.OneDialogue{
			StartTime: startTime,
			EndTime:   endTime,
		}
		odl.Lines = make([]string, 0)
		nowText = strings.TrimRight(nowText, "\n")
		texts := strings.Split(nowText, "\n")
		for i, text := range texts {
			if i == 1 {
				// 这样说明有两行字幕，也就是双语啦
				countLineFeed++
			}
			odl.Lines = append(odl.Lines, text)
		}
		subFileInfo.Dialogues = append(subFileInfo.Dialogues, odl)
	}
	// 再分析
	// 需要判断每一个 Line 是啥语言，[语言的code]次数
	var langDict map[int]int
	langDict = make(map[int]int)
	var chLines = make([]string, 0)
	for _, dialogue := range subFileInfo.Dialogues {
		language.DetectSubLangAndStatistics(dialogue.Lines, langDict, &chLines)
	}
	// 从统计出来的字典，找出 Top 1 或者 2 的出来，然后计算出是什么语言的字幕
	detectLang := language.SubLangStatistics2SubLangType(float32(countLineFeed), float32(len(matched)), langDict, chLines)
	subFileInfo.Lang = detectLang
	subFileInfo.Data = inBytes
	return &subFileInfo, nil
}

const regString = `(\d+)\n([\d:,]+)\s+-{2}\>\s+([\d:,]+)\n([\s\S]*?(\n{2}|$))`