// Copyright 2026 tamakyi. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package user

import (
	stdctx "context"
	"encoding/json"
	"strconv"
	"strings"
	"time"

	"github.com/flamego/cache"
	"github.com/sirupsen/logrus"

	"github.com/tamakyi/TamaBox/internal/context"
	"github.com/tamakyi/TamaBox/internal/db"
	"github.com/tamakyi/TamaBox/internal/dbutil"
	"github.com/tamakyi/TamaBox/internal/i18n"
)

// hotVotesCacheKey 探索页热门投票缓存 key（缓存 60s，避免每次 COUNT 聚合）。
// v2：改用独立 DTO 缓存，修复 db.Vote.LinkToken 因 json:"-" 在 Redis 序列化时丢失、
// 导致热门投票链接退化为 /vote/ 的问题。
// v3：额外保留 UserID，用于按箱主的投票功能开关过滤。
const hotVotesCacheKey = "explore:hot_votes:v3"

// hotVoteCacheItem 热门投票缓存条目：独立 DTO，显式保留 LinkToken（db.Vote 的
// LinkToken 带 json:"-" 标签，直接 Marshal Vote 会丢失，缓存命中后链接失效）。
type hotVoteCacheItem struct {
	ID        uint      `json:"id"`
	UserID    uint      `json:"user_id"`
	Title     string    `json:"title"`
	Type      string    `json:"type"`
	LinkToken string    `json:"link_token"`
	CreatedAt time.Time `json:"created_at"`
}

var tagColors = []string{
	"uk-label-success",
	"uk-label-warning",
	"uk-label-danger",
	"uk-label-primary",
	"uk-label-secondary",
}

type exploreUser struct {
	*db.User
	TagList   []string
	TagColors []string
}

// getHotVotesCached 读取探索页热门投票，带 Redis 缓存（60s）。
// 存储格式为 JSON []byte，避免 gob 序列化对模型类型注册的依赖。
func getHotVotesCached(ctx context.Context, c cache.Cache) ([]*db.Vote, error) {
	if v, err := c.Get(stdctx.Background(), hotVotesCacheKey); err == nil {
		if data, ok := v.([]byte); ok {
			var items []*hotVoteCacheItem
			if json.Unmarshal(data, &items) == nil && len(items) > 0 {
				votes := make([]*db.Vote, 0, len(items))
				for _, it := range items {
					votes = append(votes, &db.Vote{
						Model:     dbutil.Model{ID: it.ID, CreatedAt: it.CreatedAt},
						UserID:    it.UserID,
						Title:     it.Title,
						Type:      it.Type,
						LinkToken: it.LinkToken,
					})
				}
				return votes, nil
			}
		}
	}

	votes, err := db.Votes.GetHot(ctx.Request().Context(), 6)
	if err != nil {
		return nil, err
	}
	items := make([]*hotVoteCacheItem, 0, len(votes))
	for _, v := range votes {
		items = append(items, &hotVoteCacheItem{
			ID:        v.ID,
			UserID:    v.UserID,
			Title:     v.Title,
			Type:      v.Type,
			LinkToken: v.LinkToken,
			CreatedAt: v.CreatedAt,
		})
	}
	if data, err := json.Marshal(items); err == nil {
		_ = c.Set(stdctx.Background(), hotVotesCacheKey, data, 60*time.Second)
	}
	return votes, nil
}

// filterVotesByOwnerFeature 过滤掉箱主已关闭投票功能的投票（开关 / 定时 / 定量收集），
// 避免探索页出现点了打不开的死链。功能配置批量加载，避免逐条查询造成 N+1；
// 加载失败时按原样返回，依赖表抖动不应导致探索页空白。
func filterVotesByOwnerFeature(ctx context.Context, votes []*db.Vote) []*db.Vote {
	if len(votes) == 0 {
		return votes
	}

	ownerIDs := make([]uint, 0, len(votes))
	seen := make(map[uint]bool, len(votes))
	for _, v := range votes {
		if !seen[v.UserID] {
			seen[v.UserID] = true
			ownerIDs = append(ownerIDs, v.UserID)
		}
	}

	controls, err := db.FeatureControls.ListByUserIDs(ctx.Request().Context(), ownerIDs, db.FeatureVote)
	if err != nil {
		logrus.WithContext(ctx.Request().Context()).WithError(err).Warn("Failed to batch load vote feature controls")
		return votes
	}

	now := time.Now()
	out := make([]*db.Vote, 0, len(votes))
	for _, v := range votes {
		fc, ok := controls[v.UserID]
		if !ok {
			fc = db.DefaultFeatureControl(v.UserID, db.FeatureVote)
		}
		if fc.Evaluate(now).Open {
			out = append(out, v)
		}
	}
	return out
}

// Explore 显示用户列表，支持分页和排序
func Explore(ctx context.Context, c cache.Cache) {
	keyword := ctx.Query("q")
	sort := ctx.Query("sort")
	// 白名单校验排序方式
	if sort != "latest" && sort != "oldest" {
		sort = "latest"
	}

	pageStr := ctx.Query("page")
	page := 1
	if pageStr != "" {
		if p, err := strconv.Atoi(pageStr); err == nil && p > 0 {
			page = p
		}
	}
	pageSize := 20

	var users []*db.User
	var total int64
	var err error

	if keyword != "" {
		users, total, err = db.Users.GetByTag(ctx.Request().Context(), keyword, page, pageSize, sort)
	} else {
		users, total, err = db.Users.GetShowInHome(ctx.Request().Context(), page, pageSize, sort)
	}
	if err != nil {
		logrus.WithContext(ctx.Request().Context()).WithError(err).Error("Failed to get users for explore")
		ctx.SetInternalError() // 设置内部错误并渲染页面
		ctx.Success("user/explore")
		return
	}

	// 热门投票板块（Redis 缓存 60s）
	hotVotes, err := getHotVotesCached(ctx, c)
	if err != nil {
		logrus.WithContext(ctx.Request().Context()).WithError(err).Warn("Failed to get hot votes")
		hotVotes = []*db.Vote{}
	}
	ctx.Data["HotVotes"] = filterVotesByOwnerFeature(ctx, hotVotes)

	allVotes, err := db.Votes.ListPublishedPublic(ctx.Request().Context(), 30)
	if err != nil {
		logrus.WithContext(ctx.Request().Context()).WithError(err).Warn("Failed to get public votes for explore")
		allVotes = []*db.Vote{}
	}
	ctx.Data["AllVotes"] = filterVotesByOwnerFeature(ctx, allVotes)

	// 计算总页数（向上取整）
	totalPages := (int(total) + pageSize - 1) / pageSize

	// 页面越界保护
	if page > totalPages && totalPages > 0 {
		page = totalPages
	}

	// 构建带有标签颜色的用户列表
	exploreUsers := make([]*exploreUser, 0, len(users))
	for _, u := range users {
		var tags []string
		if u.Tags != "" {
			tags = strings.Split(u.Tags, ",")
		}
		tagColorsList := make([]string, len(tags))
		for i := range tags {
			tagColorsList[i] = tagColors[i%len(tagColors)]
		}
		exploreUsers = append(exploreUsers, &exploreUser{
			User:      u,
			TagList:   tags,
			TagColors: tagColorsList,
		})
	}

	ctx.Data["Users"] = exploreUsers
	ctx.Data["Keyword"] = keyword
	ctx.Data["Sort"] = sort
	ctx.Data["Page"] = page
	ctx.Data["TotalPages"] = totalPages
	ctx.Data["PrevPage"] = page - 1
	ctx.Data["NextPage"] = page + 1

	// 热门标签榜：统计展示在首页用户的高频标签
	hotTags, err := db.Users.GetHotTags(ctx.Request().Context(), 12)
	if err != nil {
		logrus.WithContext(ctx.Request().Context()).WithError(err).Warn("Failed to get hot tags")
		hotTags = []string{}
	}
	ctx.Data["HotTags"] = hotTags

	// 服务端直接获取随机推荐，避免前端 AJAX 往返导致"加载中"等待
	randomUsers, err := db.Users.GetRandom(ctx.Request().Context(), 6)
	if err != nil {
		logrus.WithContext(ctx.Request().Context()).WithError(err).Warn("Failed to get random users for sidebar")
	}
	recommendUsers := make([]*exploreUser, 0, len(randomUsers))
	for _, u := range randomUsers {
		var tags []string
		if u.Tags != "" {
			tags = strings.Split(u.Tags, ",")
		}
		tagColorsList := make([]string, len(tags))
		for i := range tags {
			tagColorsList[i] = tagColors[i%len(tagColors)]
		}
		recommendUsers = append(recommendUsers, &exploreUser{
			User:      u,
			TagList:   tags,
			TagColors: tagColorsList,
		})
	}
	ctx.Data["RecommendUsers"] = recommendUsers

	lang := i18n.Default
	if l, ok := ctx.Data["Lang"].(string); ok && l != "" {
		lang = l
	}
	ctx.SetTitle(i18n.T(lang, "nav.explore") + " - " + i18n.T(lang, "site.title"))
	ctx.Success("user/explore")
}

// RandomRecommend 返回6个随机推荐用户（JSON格式）
// 前端期望的响应格式：{ "code": 0, "data": [...] }
func RandomRecommend(ctx context.Context) {
	users, err := db.Users.GetRandomFresh(ctx.Request().Context(), 6)
	if err != nil {
		logrus.WithContext(ctx.Request().Context()).WithError(err).Error("Failed to get random users")
		ctx.JSONError(50000, i18n.T(ctx.Lang(), "explore.errRandomUser"))
		return
	}

	type recommendUser struct {
		ID       uint     `json:"id"`
		Name     string   `json:"name"`
		Domain   string   `json:"domain"`
		Avatar   string   `json:"avatar"`
		Intro    string   `json:"intro"`
		TagList  []string `json:"tag_list"`
		TagColor []string `json:"tag_color"`
	}

	result := make([]recommendUser, 0, len(users))
	for _, u := range users {
		var tags []string
		if u.Tags != "" {
			tags = strings.Split(u.Tags, ",")
		}
		tagColorsList := make([]string, len(tags))
		for i := range tags {
			tagColorsList[i] = tagColors[i%len(tagColors)]
		}
		result = append(result, recommendUser{
			ID:       u.ID,
			Name:     u.Name,
			Domain:   u.Domain,
			Avatar:   u.Avatar,
			Intro:    u.Intro,
			TagList:  tags,
			TagColor: tagColorsList,
		})
	}

	// Context.JSON 已统一包装 code/data/message，这里只传业务数据，避免嵌套响应。
	ctx.JSON(result)
}