package sitemap

import (
	"context"
	"strings"
	"sync"
	"time"
	"videoweb/pub/common/utils"
	"videoweb/pub/models/playletcategorymod"
	"videoweb/pub/models/playletmod"
	"videoweb/pub/models/playlettagmod"
	"videoweb/pub/models/playletthememod"

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

type idWithTime struct {
	Id      int64
	Slug    string
	LastMod time.Time
}

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:        utils.JoinUrlPathKeepSlash(webAddr, entry.path),
			LastMod:    now,
			ChangeFreq: entry.changeFreq,
			Priority:   entry.priority,
		})
	}
	return urls
}

func entityPath(prefix, slug string, id int64) string {
	if segment := utils.PathSegment(slug, id); segment != "" {
		return strings.TrimSuffix(prefix, "/") + "/" + segment + "/"
	}
	if strings.HasSuffix(prefix, "/") {
		return prefix
	}
	return prefix + "/"
}

func hgdjStaticPages() []staticPageEntry {
	return []staticPageEntry{
		{path: "/", changeFreq: "daily", priority: 1.0},
		{path: "/list/ai-short-play/", changeFreq: "daily", priority: 0.9},
		{path: "/list/ai-short-play/popular/", changeFreq: "daily", priority: 0.8},
		{path: "/list/ai-short-play/original/", changeFreq: "daily", priority: 0.8},
		{path: "/series/", changeFreq: "daily", priority: 0.9},
		{path: "/series/popular/", changeFreq: "daily", priority: 0.8},
		{path: "/series/original/", changeFreq: "daily", priority: 0.8},
		{path: "/rank/", changeFreq: "daily", priority: 0.8},
		{path: "/today-update/", changeFreq: "daily", priority: 0.8},
		{path: "/topic/", changeFreq: "daily", priority: 0.8},
		{path: "/application/", changeFreq: "weekly", priority: 0.6},
		{path: "/home-road/", changeFreq: "weekly", priority: 0.6},
		{path: "/download-app/", changeFreq: "monthly", priority: 0.5},
		{path: "/nav/", changeFreq: "monthly", priority: 0.5},
		{path: "/about-us/", changeFreq: "yearly", priority: 0.3},
		{path: "/help-center/", changeFreq: "yearly", priority: 0.3},
	}
}

// getURL 并发拉取短剧数据并写入 sitemap 分片，URL 规则对齐 jha-1043-hgdj-web。
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
		categoryItems []idWithTime
	)

	wg.Add(4)
	go func() {
		defer wg.Done()
		listed = getPlayletList(ctx)
	}()
	go func() {
		defer wg.Done()
		themeItems = getThemeList(ctx)
	}()
	go func() {
		defer wg.Done()
		tagItems = getTagList(ctx)
	}()
	go func() {
		defer wg.Done()
		categoryItems = getCategoryList(ctx)
	}()
	wg.Wait()

	// 专题/标签没有上架短剧时不写入，避免空列表页被收录。
	// 分类页无绑定短剧时会回退展示全部上架短剧，因此启用分类都写入。
	themeItems = keepWithListedPlaylets(themeItems, listed.themeIDs)
	tagItems = keepWithListedPlaylets(tagItems, listed.tagIDs)

	pageURLs := buildStaticURLs(webAddr, hgdjStaticPages())
	for _, item := range themeItems {
		pageURLs = append(pageURLs, URL{
			Loc:        utils.JoinUrlPathKeepSlash(webAddr, entityPath("/topic", item.Slug, item.Id)),
			LastMod:    formatLastMod(item.LastMod),
			ChangeFreq: "daily",
			Priority:   0.8,
		})
	}
	for _, item := range categoryItems {
		pageURLs = append(pageURLs, URL{
			Loc:        utils.JoinUrlPathKeepSlash(webAddr, entityPath("/category", item.Slug, item.Id)),
			LastMod:    formatLastMod(item.LastMod),
			ChangeFreq: "daily",
			Priority:   0.8,
		})
	}
	for _, item := range tagItems {
		pageURLs = append(pageURLs, URL{
			Loc:        utils.JoinUrlPathKeepSlash(webAddr, entityPath("/tag", item.Slug, item.Id)),
			LastMod:    formatLastMod(item.LastMod),
			ChangeFreq: "weekly",
			Priority:   0.6,
		})
	}
	if len(pageURLs) > 0 {
		_ = sg.writeSitemapFile("sitemap-pages.xml", pageURLs)
	}

	if urls := buildPlayletPathURLs(webAddr, listed.items, "/detail", "weekly", 0.7); len(urls) > 0 {
		_ = sg.writeSitemapFiles("sitemap-playletdetail", urls)
	}
	if urls := buildPlayletPathURLs(webAddr, listed.items, "/play", "weekly", 0.6); len(urls) > 0 {
		_ = sg.writeSitemapFiles("sitemap-playletplay", urls)
	}
}

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

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, prefix string, changeFreq string, priority float32) []URL {
	urls := make([]URL, 0, len(items))
	for _, item := range items {
		lastMod := formatLastMod(item.LastMod)
		if lastMod == "" {
			lastMod = time.Now().Format(time.DateOnly)
		}
		urls = append(urls, URL{
			Loc:        utils.JoinUrlPathKeepSlash(webAddr, entityPath(prefix, item.Slug, item.Id)),
			LastMod:    lastMod,
			ChangeFreq: changeFreq,
			Priority:   priority,
		})
	}
	return urls
}

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{}),
		categoryIDs: 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.UpdatedAt:   1,
				playletmod.FN.Playlet.OnlineAt:    1,
				playletmod.FN.Playlet.ThemeIds:    1,
				playletmod.FN.Playlet.TagIds:      1,
				playletmod.FN.Playlet.CategoryIds: 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})
			addListedIDs(result.themeIDs, info.ThemeIds)
			addListedIDs(result.tagIDs, info.TagIds)
			addListedIDs(result.categoryIDs, info.CategoryIds)
		}
		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
}

func getCategoryList(ctx context.Context) []idWithTime {
	filter := bson.M{
		playletcategorymod.FN.PlayletCategory.Status: true,
	}
	pageSize := int64(1000)
	items := make([]idWithTime, 0)
	for i := int64(0); i < 100; i++ {
		skip := i * pageSize
		list, _ := playletcategorymod.FindManyPlayletCategory(ctx, filter, options.Find().
			SetSort(bson.M{playletcategorymod.FN.PlayletCategory.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
}