package sitemap

import (
	"context"
	"strings"
	"sync"
	"time"
	"videoweb/pub/models/playletchaptermod"
	"videoweb/pub/models/playletmod"
	"videoweb/pub/models/playlettagmod"
	"videoweb/pub/models/playletthememod"
	"videoweb/pub/seo/h5path"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo/options"
)

type idWithTime struct {
	Id              int64
	Slug            string
	LastMod         time.Time
	IsOriginal      bool
	ChapterID       int64
	SkipPlaySitemap bool
}

type staticPageEntry struct {
	path       string
	changeFreq string
	priority   float32
}

func buildStaticURLs(webAddr string, entries []staticPageEntry) []URL {
	urls := make([]URL, 0, len(entries))
	now := time.Now().Format(time.DateOnly)
	for _, entry := range entries {
		urls = append(urls, URL{
			Loc:        h5path.SitemapAbs(webAddr, entry.path),
			LastMod:    now,
			ChangeFreq: entry.changeFreq,
			Priority:   entry.priority,
		})
	}
	return urls
}

func entityPath(prefix, slug string, id int64) string {
	return h5path.Entity(prefix, slug, id)
}

// jgdjStaticPages 固定页面，对齐 jgdj1.net 上可收录的地址。
// /topics 专题列表、/config 首页配置、充值和反馈为 noindex；/rank 会规范到 /rank/hot。
func jgdjStaticPages() []staticPageEntry {
	return []staticPageEntry{
		{path: "/", changeFreq: "daily", priority: 1.0},
		{path: "/shorts", changeFreq: "daily", priority: 0.9},
		{path: "/rank/hot", changeFreq: "daily", priority: 0.8},
		{path: "/rank/new", changeFreq: "daily", priority: 0.7},
		{path: "/rank/follow", changeFreq: "daily", priority: 0.7},
		{path: "/info/about-us", changeFreq: "yearly", priority: 0.3},
		{path: "/info/user-agreement", changeFreq: "yearly", priority: 0.3},
		{path: "/info/privacy-policy", changeFreq: "yearly", priority: 0.3},
		{path: "/info/help-center", changeFreq: "yearly", priority: 0.3},
		{path: "/info/2257", changeFreq: "yearly", priority: 0.3},
		{path: "/info/dmca", changeFreq: "yearly", priority: 0.3},
	}
}

func contentPath(prefix, slug string, id int64) string {
	if h5path.Segment(slug, id) == "" {
		return ""
	}
	return h5path.Entity(prefix, slug, id)
}

// getURL 并发拉取短剧数据并写入 sitemap 分片。
// 分片对齐 jgdj1.net：sitemap-pages、sitemap-playletdetail。
func getURL(sg *SitemapGenerator) {
	webAddr := strings.TrimSpace(sg.WebAddr)
	if webAddr == "" {
		return
	}

	ctx := context.Background()
	var (
		wg         sync.WaitGroup
		listed     listedPlaylets
		themeItems []idWithTime
		tagItems   []idWithTime
	)

	wg.Add(3)
	go func() {
		defer wg.Done()
		listed = getPlayletList(ctx)
	}()
	go func() {
		defer wg.Done()
		themeItems = getThemeList(ctx)
	}()
	go func() {
		defer wg.Done()
		tagItems = getTagList(ctx)
	}()
	wg.Wait()

	// 题材/标签没有上架短剧时不写入，避免空列表页被收录。
	themeItems = keepWithListedPlaylets(themeItems, listed.themeIDs)
	tagItems = keepWithListedPlaylets(tagItems, listed.tagIDs)

	pageURLs := buildStaticURLs(webAddr, jgdjStaticPages())
	for _, item := range themeItems {
		if path := contentPath("/topics", item.Slug, item.Id); path != "" {
			pageURLs = append(pageURLs, newURL(webAddr, path, item.LastMod, "daily", 0.8))
		}
	}
	for _, item := range tagItems {
		if path := contentPath("/tag", item.Slug, item.Id); path != "" {
			pageURLs = append(pageURLs, newURL(webAddr, path, item.LastMod, "weekly", 0.6))
		}
	}
	if len(pageURLs) > 0 {
		_ = sg.writeSitemapFile("sitemap-pages.xml", pageURLs)
	}

	// 分集页不进 sitemap，只保留 /detail/{slug}。
	// 原创且第一集无水印的详情不进 sitemap，避免空壳页被提交。
	populateFirstChapters(ctx, listed.items)
	if urls := buildPlayletPathURLs(webAddr, listed.items, "weekly", 0.7); len(urls) > 0 {
		_ = sg.writeSitemapFiles("sitemap-playletdetail", urls)
	}
}

type listedPlaylets struct {
	items    []idWithTime
	themeIDs map[int64]struct{}
	tagIDs   map[int64]struct{}
}

func newURL(webAddr, path string, lastMod time.Time, changeFreq string, priority float32) URL {
	mod := formatLastMod(lastMod)
	if mod == "" {
		mod = time.Now().Format(time.DateOnly)
	}
	return URL{
		Loc:        h5path.SitemapAbs(webAddr, path),
		LastMod:    mod,
		ChangeFreq: changeFreq,
		Priority:   priority,
	}
}

func keepWithListedPlaylets(items []idWithTime, listed map[int64]struct{}) []idWithTime {
	if len(items) == 0 || len(listed) == 0 {
		return nil
	}
	out := make([]idWithTime, 0, len(items))
	for _, item := range items {
		if _, ok := listed[item.Id]; ok {
			out = append(out, item)
		}
	}
	return out
}

func addListedIDs(dst map[int64]struct{}, ids []int64) {
	for _, id := range ids {
		if id > 0 {
			dst[id] = struct{}{}
		}
	}
}

func buildPlayletPathURLs(webAddr string, items []idWithTime, changeFreq string, priority float32) []URL {
	urls := make([]URL, 0, len(items))
	for _, item := range items {
		if item.SkipPlaySitemap {
			continue
		}
		path := contentPath("/detail", item.Slug, item.Id)
		if path == "" {
			continue
		}
		urls = append(urls, newURL(webAddr, path, item.LastMod, changeFreq, priority))
	}
	return urls
}

func playletIDs(items []idWithTime) []int64 {
	ids := make([]int64, 0, len(items))
	for _, item := range items {
		if item.Id > 0 {
			ids = append(ids, item.Id)
		}
	}
	return ids
}

func skipOriginalChapterWithoutWatermark(isOriginal bool, watermarkURL string) bool {
	return isOriginal && strings.TrimSpace(watermarkURL) == ""
}

// populateFirstChapters 每剧只看第一集；原创且无水印则不写播放 URL。
func populateFirstChapters(ctx context.Context, items []idWithTime) {
	for start := 0; start < len(items); start += 500 {
		end := start + 500
		if end > len(items) {
			end = len(items)
		}
		ids := make([]int64, 0, end-start)
		byID := make(map[int64]*idWithTime, end-start)
		for i := start; i < end; i++ {
			if items[i].Id <= 0 {
				continue
			}
			ids = append(ids, items[i].Id)
			byID[items[i].Id] = &items[i]
		}
		if len(ids) == 0 {
			continue
		}
		chapters, err := playletchaptermod.FindManyPlayletChapter(ctx, bson.M{
			playletchaptermod.FN.PlayletChapter.PlayletId: bson.M{"$in": ids},
		}, options.Find().
			SetSort(bson.D{
				{Key: playletchaptermod.FN.PlayletChapter.CurrentEpisode, Value: 1},
				{Key: playletchaptermod.FN.PlayletChapter.Id, Value: 1},
			}).
			SetProjection(bson.M{
				playletchaptermod.FN.PlayletChapter.Id:                1,
				playletchaptermod.FN.PlayletChapter.PlayletId:         1,
				playletchaptermod.FN.PlayletChapter.WatermarkVideoUrl: 1,
			}))
		if err != nil {
			return
		}
		seenFirst := make(map[int64]struct{}, len(ids))
		for _, ch := range chapters {
			if ch == nil || ch.Id <= 0 {
				continue
			}
			item := byID[ch.PlayletId]
			if item == nil {
				continue
			}
			if _, ok := seenFirst[ch.PlayletId]; ok {
				continue
			}
			seenFirst[ch.PlayletId] = struct{}{}
			if skipOriginalChapterWithoutWatermark(item.IsOriginal, ch.WatermarkVideoUrl) {
				item.SkipPlaySitemap = true
				continue
			}
			item.ChapterID = ch.Id
		}
	}
}

func formatLastMod(t time.Time) string {
	if t.IsZero() {
		return ""
	}
	return t.Format(time.DateOnly)
}

func getPlayletList(ctx context.Context) listedPlaylets {
	result := listedPlaylets{
		items:    make([]idWithTime, 0),
		themeIDs: make(map[int64]struct{}),
		tagIDs:   make(map[int64]struct{}),
	}
	filter := bson.M{
		playletmod.FN.Playlet.Status: playletmod.StatusUp,
	}
	pageSize := int64(1000)
	for i := int64(0); i < 500; i++ {
		skip := i * pageSize
		list, _ := playletmod.FindManyPlaylet(ctx, filter, options.Find().
			SetSort(bson.M{playletmod.FN.Playlet.Id: -1}).
			SetSkip(skip).
			SetLimit(pageSize).
			SetProjection(bson.M{
				playletmod.FN.Playlet.Id:         1,
				playletmod.FN.Playlet.Slug:       1,
				playletmod.FN.Playlet.IsOriginal: 1,
				playletmod.FN.Playlet.UpdatedAt:  1,
				playletmod.FN.Playlet.OnlineAt:   1,
				playletmod.FN.Playlet.ThemeIds:   1,
				playletmod.FN.Playlet.TagIds:     1,
			}))
		for _, info := range list {
			if info == nil || info.Id <= 0 {
				continue
			}
			lastMod := info.UpdatedAt
			if lastMod.IsZero() {
				lastMod = info.OnlineAt
			}
			result.items = append(result.items, idWithTime{Id: info.Id, Slug: info.Slug, LastMod: lastMod, IsOriginal: info.IsOriginal})
			addListedIDs(result.themeIDs, info.ThemeIds)
			addListedIDs(result.tagIDs, info.TagIds)
		}
		if len(list) < int(pageSize) {
			break
		}
	}
	return result
}

func getThemeList(ctx context.Context) []idWithTime {
	filter := bson.M{
		playletthememod.FN.PlayletTheme.Status: true,
	}
	pageSize := int64(1000)
	items := make([]idWithTime, 0)
	for i := int64(0); i < 100; i++ {
		skip := i * pageSize
		list, _ := playletthememod.FindManyPlayletTheme(ctx, filter, options.Find().
			SetSort(bson.M{playletthememod.FN.PlayletTheme.Rank: -1}).
			SetSkip(skip).
			SetLimit(pageSize))
		for _, info := range list {
			if info == nil || info.Id <= 0 || strings.TrimSpace(info.Name) == "" {
				continue
			}
			items = append(items, idWithTime{Id: info.Id, Slug: info.Slug, LastMod: info.UpdatedAt})
		}
		if len(list) < int(pageSize) {
			break
		}
	}
	return items
}

func getTagList(ctx context.Context) []idWithTime {
	filter := bson.M{
		playlettagmod.FN.PlayletTag.Status: true,
	}
	pageSize := int64(1000)
	items := make([]idWithTime, 0)
	for i := int64(0); i < 100; i++ {
		skip := i * pageSize
		list, _ := playlettagmod.FindManyPlayletTag(ctx, filter, options.Find().
			SetSort(bson.M{playlettagmod.FN.PlayletTag.Rank: -1}).
			SetSkip(skip).
			SetLimit(pageSize))
		for _, info := range list {
			if info == nil || info.Id <= 0 || strings.TrimSpace(info.Name) == "" {
				continue
			}
			items = append(items, idWithTime{Id: info.Id, Slug: info.Slug, LastMod: info.UpdatedAt})
		}
		if len(list) < int(pageSize) {
			break
		}
	}
	return items
}