package service

import (
	"regexp"
	"strings"
	"unicode"

	"github.com/ShukeBta/MediaStationGo/internal/model"
)

var (
	seriesPackRE = regexp.MustCompile(`(?i)(complete|batch|合集|全集|全\s*\d+\s*[集话話期]|整季|全季|s\d{1,2}\s*(?:complete|batch|pack)|season\s*\d{1,2}\s*(?:complete|batch|pack)|s\d{1,2}e\d{1,3}\s*[-~–—]\s*(?:s\d{1,2})?e?\d{1,3}|第\s*\d+\s*[-~–—]\s*\d+\s*[集话話期])`)
	seasonOnlyRE = regexp.MustCompile(`(?i)(?:^|[\s._-])(?:s|season)\s*\d{1,2}(?:[\s._-]|$)|第\s*\d+\s*季`)
)

// defaultExcludeWords 是默认过滤的「垃圾版本」排除清单，对所有订阅生效。
// 拉丁词在 containsAnyExcludeToken 里按词边界匹配以避免子串误伤。
const defaultExcludeWords = "cam,ts,tc,telesync,telecine,hdcam,hdts,枪版,抢先,抢鲜,预告,trailer,sample"

// defaultCompatibilityExcludeWords 是面向自动订阅的兼容性默认排除清单。
// 仅在用户未真正自定义排除词时启用，避免默认命中 DoVi/H.265/10bit/杜比音轨等版本。
const defaultCompatibilityExcludeWords = "dovi,dv,dolby vision,dolby,杜比视界,杜比,h265,h.265,h-265,h_265,h 265,hevc,x265,10bit,10-bit,10 bit,hi10p,atmos,truehd,ddp,dd+,eac3"

const legacyFrontendExcludeWords = "cam,ts,tc,枪版"

func matchesSubscriptionRules(sub *model.Subscription, title string) bool {
	titleFold := strings.ToLower(title)
	if containsAnyExcludeToken(titleFold, defaultExcludeWords) {
		return false
	}
	if sub == nil {
		return true
	}
	if shouldApplyDefaultCompatibilityExcludes(sub.ExcludeWords) && containsAnyExcludeToken(titleFold, defaultCompatibilityExcludeWords) {
		return false
	}
	if sub.ExcludeWords != "" && containsAnyExcludeToken(titleFold, sub.ExcludeWords) {
		return false
	}
	if sub.ReleaseGroups != "" && !containsAnyToken(titleFold, sub.ReleaseGroups) {
		return false
	}
	if sub.Resolution != "" && sub.Resolution != "best" && !titleMatchesResolution(titleFold, sub.Resolution) {
		return false
	}
	if sub.Quality != "" && sub.Quality != "best" && !titleMatchesQuality(titleFold, sub.Quality) {
		return false
	}
	if sub.Effects != "" && !containsAnyEffect(titleFold, sub.Effects) {
		return false
	}
	return true
}

func shouldApplyDefaultCompatibilityExcludes(excludeWords string) bool {
	normalized := normalizeExcludeWords(excludeWords)
	return normalized == "" || normalized == normalizeExcludeWords(legacyFrontendExcludeWords)
}

func normalizeExcludeWords(csv string) string {
	parts := make([]string, 0)
	for _, token := range strings.FieldsFunc(strings.ToLower(csv), func(r rune) bool {
		return r == ',' || r == '/' || r == '|' || r == ';' || r == '，'
	}) {
		token = strings.TrimSpace(token)
		if token != "" {
			parts = append(parts, token)
		}
	}
	return strings.Join(parts, ",")
}

func subscriptionCandidateScore(sub *model.Subscription, item SearchResult) int {
	title := strings.ToLower(subscriptionSearchResultText(item))
	score := item.Seeders
	if sub == nil || !sub.WashEnabled {
		if item.Free {
			score += 25
		}
		return score
	}
	resolutionScore := detectResolutionScore(title)
	qualityScore := detectQualityScore(title)
	effectScore := detectEffectScore(title)

	priority := "balanced"
	if sub != nil && strings.TrimSpace(sub.WashPriority) != "" {
		priority = strings.ToLower(strings.TrimSpace(sub.WashPriority))
	}
	switch priority {
	case "resolution":
		score += resolutionScore*1000 + qualityScore*100 + effectScore*50
	case "quality":
		score += qualityScore*1000 + resolutionScore*200 + effectScore*50
	case "effects":
		score += effectScore*1000 + resolutionScore*200 + qualityScore*100
	case "seeders":
		score += qualityScore*3 + resolutionScore*2 + effectScore
	default:
		score += resolutionScore*500 + qualityScore*300 + effectScore*150
	}
	if item.Free {
		score += 25
	}
	return score
}

func containsAnyToken(titleFold, csv string) bool {
	for _, token := range strings.FieldsFunc(strings.ToLower(csv), func(r rune) bool {
		return r == ',' || r == '/' || r == '|' || r == ';' || r == '，'
	}) {
		token = strings.TrimSpace(token)
		if token != "" && strings.Contains(titleFold, token) {
			return true
		}
	}
	return false
}

// containsAnyExcludeToken 用于排除词匹配：纯 ASCII 字母数字的词按词边界匹配（避免 "ts"
// 误伤 "tsukihime"、"cam" 误伤 "camp" 之类的子串误判），含 CJK/符号的词仍按子串匹配。
func containsAnyExcludeToken(titleFold, csv string) bool {
	for _, token := range strings.FieldsFunc(strings.ToLower(csv), func(r rune) bool {
		return r == ',' || r == '/' || r == '|' || r == ';' || r == '，'
	}) {
		token = strings.TrimSpace(token)
		if token == "" {
			continue
		}
		if isASCIIWordToken(token) {
			if matchesWordBoundary(titleFold, token) {
				return true
			}
			continue
		}
		if strings.Contains(titleFold, token) {
			return true
		}
	}
	return false
}

func isASCIIWordToken(token string) bool {
	for _, r := range token {
		if r > unicode.MaxASCII || !(unicode.IsLetter(r) || unicode.IsDigit(r)) {
			return false
		}
	}
	return token != ""
}

// matchesWordBoundary 判断 token 是否作为独立词出现在 title 中，词边界为「非字母数字」。
func matchesWordBoundary(titleFold, token string) bool {
	isWordRune := func(r rune) bool {
		return unicode.IsLetter(r) || unicode.IsDigit(r)
	}
	from := 0
	for {
		idx := strings.Index(titleFold[from:], token)
		if idx < 0 {
			return false
		}
		start := from + idx
		end := start + len(token)
		leftOK := start == 0 || !isWordRune(rune(titleFold[start-1]))
		rightOK := end >= len(titleFold) || !isWordRune(rune(titleFold[end]))
		if leftOK && rightOK {
			return true
		}
		from = start + 1
		if from >= len(titleFold) {
			return false
		}
	}
}

func containsAnyEffect(titleFold, csv string) bool {
	for _, token := range strings.FieldsFunc(strings.ToLower(csv), func(r rune) bool {
		return r == ',' || r == '/' || r == '|' || r == ';' || r == '，'
	}) {
		token = strings.TrimSpace(token)
		if token == "" {
			continue
		}
		switch token {
		case "dolby-vision", "dolby vision", "dv":
			if strings.Contains(titleFold, "dolby vision") || strings.Contains(titleFold, "dovi") || regexp.MustCompile(`\bdv\b`).MatchString(titleFold) {
				return true
			}
		default:
			if strings.Contains(titleFold, token) {
				return true
			}
		}
	}
	return false
}

func titleMatchesResolution(titleFold, resolution string) bool {
	switch strings.ToLower(strings.TrimSpace(resolution)) {
	case "2160p", "4k", "uhd":
		return strings.Contains(titleFold, "2160p") || strings.Contains(titleFold, "4k") || strings.Contains(titleFold, "uhd")
	case "1080p":
		return strings.Contains(titleFold, "1080p") || strings.Contains(titleFold, "fhd")
	case "720p":
		return strings.Contains(titleFold, "720p")
	default:
		return strings.Contains(titleFold, strings.ToLower(strings.TrimSpace(resolution)))
	}
}

func titleMatchesQuality(titleFold, quality string) bool {
	switch strings.ToLower(strings.TrimSpace(quality)) {
	case "webdl", "web-dl":
		return strings.Contains(titleFold, "web-dl") || strings.Contains(titleFold, "webdl")
	case "bluray", "blu-ray":
		return strings.Contains(titleFold, "bluray") || strings.Contains(titleFold, "blu-ray") || strings.Contains(titleFold, "bdrip")
	case "remux":
		return strings.Contains(titleFold, "remux")
	case "hdtv":
		return strings.Contains(titleFold, "hdtv")
	default:
		return strings.Contains(titleFold, strings.ToLower(strings.TrimSpace(quality)))
	}
}

func detectResolutionScore(titleFold string) int {
	switch {
	case titleMatchesResolution(titleFold, "2160p"):
		return 4
	case titleMatchesResolution(titleFold, "1080p"):
		return 3
	case titleMatchesResolution(titleFold, "720p"):
		return 2
	default:
		return 1
	}
}

func detectQualityScore(titleFold string) int {
	switch {
	case titleMatchesQuality(titleFold, "remux"):
		return 5
	case titleMatchesQuality(titleFold, "bluray"):
		return 4
	case titleMatchesQuality(titleFold, "web-dl"):
		return 3
	case titleMatchesQuality(titleFold, "hdtv"):
		return 2
	default:
		return 1
	}
}

func detectEffectScore(titleFold string) int {
	score := 0
	if containsAnyEffect(titleFold, "dolby-vision") {
		score += 4
	}
	if strings.Contains(titleFold, "hdr10+") {
		score += 3
	} else if strings.Contains(titleFold, "hdr") {
		score += 2
	}
	if strings.Contains(titleFold, "atmos") {
		score += 2
	}
	return score
}

func isSubscriptionSeriesType(mediaType string) bool {
	switch normalizeMediaType(mediaType, "", "") {
	case "tv", "anime", "variety":
		return true
	default:
		return false
	}
}

func isSeriesPackTitle(title string) bool {
	title = strings.TrimSpace(title)
	if title == "" {
		return false
	}
	if seriesPackRE.MatchString(title) {
		return true
	}
	_, episode := ParseEpisode(title)
	return episode == 0 && seasonOnlyRE.MatchString(title)
}