package handlers

import (
	"net/http"
	"strconv"
	"strings"
	"time"

	"goblog/database"
	"goblog/models"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

// 文章列表请求参数
type PostListQuery struct {
	Page       int    `form:"page,default=1"`
	PageSize   int    `form:"page_size,default=10"`
	CategoryID uint   `form:"category_id"`
	TagID      uint   `form:"tag_id"`
	Status     string `form:"status"`
	Keyword    string `form:"keyword"`
}

// 创建文章请求
type CreatePostRequest struct {
	Title      string   `json:"title" binding:"required"`
	Content    string   `json:"content" binding:"required"`
	Summary    string   `json:"summary"`
	Cover      string   `json:"cover"`
	CategoryID uint     `json:"category_id" binding:"required"`
	Tags       []string `json:"tags"`
	Status     string   `json:"status"`
	IsTop      bool     `json:"is_top"`
}

// 更新文章请求
type UpdatePostRequest struct {
	Title      string   `json:"title"`
	Content    string   `json:"content"`
	Summary    string   `json:"summary"`
	Cover      string   `json:"cover"`
	CategoryID uint     `json:"category_id"`
	Tags       []string `json:"tags"`
	Status     string   `json:"status"`
	IsTop      bool     `json:"is_top"`
}

// 生成 slug
func generateSlug(title string) string {
	slug := strings.ToLower(title)
	slug = strings.ReplaceAll(slug, " ", "-")
	slug = strings.ReplaceAll(slug, "_", "-")
	// 简化处理，实际项目中可能需要更完善的 slug 生成
	return slug
}

// 获取文章列表
func GetPosts(c *gin.Context) {
	var query PostListQuery
	if err := c.ShouldBindQuery(&query); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	db := database.DB.Model(&models.Post{}).Preload("Category").Preload("Tags").Preload("Author")

	// 前端只显示已发布的文章
	if !isAdmin(c) {
		db = db.Where("status = ?", "published")
	} else if query.Status != "" {
		db = db.Where("status = ?", query.Status)
	}

	if query.CategoryID > 0 {
		db = db.Where("category_id = ?", query.CategoryID)
	}

	if query.TagID > 0 {
		db = db.Joins("JOIN post_tags ON post_tags.post_id = posts.id").
			Where("post_tags.tag_id = ?", query.TagID)
	}

	if query.Keyword != "" {
		db = db.Where("title LIKE ? OR content LIKE ?", "%"+query.Keyword+"%", "%"+query.Keyword+"%")
	}

	var total int64
	db.Count(&total)

	var posts []models.Post
	offset := (query.Page - 1) * query.PageSize
	db.Order("is_top DESC, published_at DESC, created_at DESC").
		Offset(offset).Limit(query.PageSize).Find(&posts)

	c.JSON(http.StatusOK, gin.H{
		"data":  posts,
		"total": total,
		"page":  query.Page,
		"size":  query.PageSize,
	})
}

// 获取单篇文章
func GetPost(c *gin.Context) {
	id := c.Param("id")

	var post models.Post
	query := database.DB.Preload("Category").Preload("Tags").Preload("Author").Preload("Comments", func(db *gorm.DB) *gorm.DB {
		return db.Where("status = ? AND parent_id IS NULL", "approved").Preload("Children", func(db *gorm.DB) *gorm.DB {
			return db.Where("status = ?", "approved")
		})
	})

	// 尝试按 ID 或 slug 查找
	if _, err := strconv.Atoi(id); err == nil {
		query = query.Where("id = ?", id)
	} else {
		query = query.Where("slug = ?", id)
	}

	// 非管理员只能查看已发布文章
	if !isAdmin(c) {
		query = query.Where("status = ?", "published")
	}

	if err := query.First(&post).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "文章不存在"})
		return
	}

	// 增加浏览量
	database.DB.Model(&post).UpdateColumn("views", gorm.Expr("views + 1"))

	c.JSON(http.StatusOK, gin.H{"data": post})
}

// 创建文章
func CreatePost(c *gin.Context) {
	var req CreatePostRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	userID, _ := c.Get("userID")

	post := models.Post{
		Title:      req.Title,
		Slug:       generateSlug(req.Title),
		Content:    req.Content,
		Summary:    req.Summary,
		Cover:      req.Cover,
		AuthorID:   userID.(uint),
		CategoryID: req.CategoryID,
		Status:     req.Status,
		IsTop:      req.IsTop,
	}

	if req.Status == "published" {
		now := time.Now()
		post.PublishedAt = &now
	}

	// 处理标签
	if len(req.Tags) > 0 {
		var tags []models.Tag
		for _, tagName := range req.Tags {
			var tag models.Tag
			database.DB.FirstOrCreate(&tag, models.Tag{
				Name: tagName,
				Slug: generateSlug(tagName),
			})
			tags = append(tags, tag)
		}
		post.Tags = tags
	}

	if err := database.DB.Create(&post).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "创建文章失败"})
		return
	}

	c.JSON(http.StatusCreated, gin.H{"data": post})
}

// 更新文章
func UpdatePost(c *gin.Context) {
	id := c.Param("id")

	var post models.Post
	if err := database.DB.First(&post, id).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "文章不存在"})
		return
	}

	var req UpdatePostRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	updates := map[string]interface{}{}
	if req.Title != "" {
		updates["title"] = req.Title
		updates["slug"] = generateSlug(req.Title)
	}
	if req.Content != "" {
		updates["content"] = req.Content
	}
	if req.Summary != "" {
		updates["summary"] = req.Summary
	}
	if req.Cover != "" {
		updates["cover"] = req.Cover
	}
	if req.CategoryID > 0 {
		updates["category_id"] = req.CategoryID
	}
	if req.Status != "" {
		updates["status"] = req.Status
		if req.Status == "published" && post.Status != "published" {
			now := time.Now()
			updates["published_at"] = &now
		}
	}
	updates["is_top"] = req.IsTop

	// 处理标签
	if len(req.Tags) > 0 {
		var tags []models.Tag
		for _, tagName := range req.Tags {
			var tag models.Tag
			database.DB.FirstOrCreate(&tag, models.Tag{
				Name: tagName,
				Slug: generateSlug(tagName),
			})
			tags = append(tags, tag)
		}
		database.DB.Model(&post).Association("Tags").Replace(tags)
	}

	if err := database.DB.Model(&post).Updates(updates).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "更新文章失败"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"data": post})
}

// 删除文章
func DeletePost(c *gin.Context) {
	id := c.Param("id")

	var post models.Post
	if err := database.DB.First(&post, id).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "文章不存在"})
		return
	}

	if err := database.DB.Delete(&post).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "删除文章失败"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "删除成功"})
}

// 判断是否为管理员
func isAdmin(c *gin.Context) bool {
	role, exists := c.Get("role")
	return exists && role == "admin"
}