package handlers

import (
	"html/template"
	"math"
	"net/http"
	"strconv"
	"time"

	"goblog/config"
	"goblog/database"
	"goblog/models"

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

func templateFuncs() template.FuncMap {
	return template.FuncMap{
		"add": func(a, b int) int {
			return a + b
		},
		"sub": func(a, b int) int {
			return a - b
		},
		"html": func(s string) template.HTML {
			return template.HTML(s)
		},
	}
}

// 首页
type IndexData struct {
	Title       string
	SiteName    string
	SiteDesc    string
	Description string
	Posts       []models.Post
	Pages       []models.Page
	CurrentPage int
	TotalPages  int
	Year        int
}

func IndexView(c *gin.Context) {
	cfg := config.Load()
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	if page < 1 {
		page = 1
	}
	pageSize := 10

	categoryID, _ := strconv.Atoi(c.Query("category"))
	tagID, _ := strconv.Atoi(c.Query("tag"))

	db := database.DB.Model(&models.Post{}).Preload("Category").Preload("Tags").Preload("Author").
		Where("status = ?", "published")

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

	var total int64
	db.Count(&total)

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

	// 获取页面
	var pages []models.Page
	database.DB.Where("status = ?", "published").Order("`order` ASC").Find(&pages)

	totalPages := int(math.Ceil(float64(total) / float64(pageSize)))

	data := IndexData{
		Title:       "首页",
		SiteName:    cfg.App.Name,
		SiteDesc:    cfg.App.Description,
		Description: cfg.App.Description,
		Posts:       posts,
		Pages:       pages,
		CurrentPage: page,
		TotalPages:  totalPages,
		Year:        time.Now().Year(),
	}

	c.HTML(http.StatusOK, "index", data)
}

// 文章详情页
type PostDetailData struct {
	Title        string
	SiteName     string
	SiteDesc     string
	Description  string
	Post         models.Post
	Pages        []models.Page
	Comments     []models.Comment
	CommentCount int64
	Year         int
	PrevPost     *models.Post // 上一篇
	NextPost     *models.Post // 下一篇
}

func PostView(c *gin.Context) {
	cfg := config.Load()
	slug := c.Param("slug")

	var post models.Post
	err := 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")
			})
		}).
		Where("slug = ? AND status = ?", slug, "published").
		First(&post).Error

	if err != nil {
		c.HTML(http.StatusNotFound, "index", gin.H{
			"Title":    "404 - 页面不存在",
			"SiteName": cfg.App.Name,
			"Year":     time.Now().Year(),
		})
		return
	}

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

	// 获取页面
	var pages []models.Page
	database.DB.Where("status = ?", "published").Order("`order` ASC").Find(&pages)

	// 统计评论数
	var commentCount int64
	database.DB.Model(&models.Comment{}).Where("post_id = ? AND status = ?", post.ID, "approved").Count(&commentCount)

	// 获取上一篇（发布时间更早的文章）
	var prevPost models.Post
	prevErr := database.DB.Where("status = ? AND published_at < ?", "published", post.PublishedAt).
		Order("published_at DESC").First(&prevPost).Error

	// 获取下一篇（发布时间更晚的文章）
	var nextPost models.Post
	nextErr := database.DB.Where("status = ? AND published_at > ?", "published", post.PublishedAt).
		Order("published_at ASC").First(&nextPost).Error

	data := PostDetailData{
		Title:        post.Title,
		SiteName:     cfg.App.Name,
		SiteDesc:     cfg.App.Description,
		Description:  post.Summary,
		Post:         post,
		Pages:        pages,
		Comments:     post.Comments,
		CommentCount: commentCount,
		Year:         time.Now().Year(),
	}

	// 只有当查询成功时才赋值
	if prevErr == nil {
		data.PrevPost = &prevPost
	}
	if nextErr == nil {
		data.NextPost = &nextPost
	}

	c.HTML(http.StatusOK, "post", data)
}

// 独立页面
type PageDetailData struct {
	Title       string
	SiteName    string
	SiteDesc    string
	Description string
	Page        models.Page
	Pages       []models.Page
	Year        int
}

func PageView(c *gin.Context) {
	cfg := config.Load()
	slug := c.Param("slug")

	var page models.Page
	err := database.DB.Where("slug = ? AND status = ?", slug, "published").First(&page).Error
	if err != nil {
		c.HTML(http.StatusNotFound, "index", gin.H{
			"Title":    "404 - 页面不存在",
			"SiteName": cfg.App.Name,
			"Year":     time.Now().Year(),
		})
		return
	}

	// 获取所有页面
	var pages []models.Page
	database.DB.Where("status = ?", "published").Order("`order` ASC").Find(&pages)

	data := PageDetailData{
		Title:       page.Title,
		SiteName:    cfg.App.Name,
		SiteDesc:    cfg.App.Description,
		Description: "",
		Page:        page,
		Pages:       pages,
		Year:        time.Now().Year(),
	}

	c.HTML(http.StatusOK, "page", data)
}

// 提交评论（表单提交）
func SubmitComment(c *gin.Context) {
	postID, _ := strconv.Atoi(c.PostForm("post_id"))
	author := c.PostForm("author")
	email := c.PostForm("email")
	website := c.PostForm("website")
	content := c.PostForm("content")

	// 检查文章是否存在
	var post models.Post
	if err := database.DB.First(&post, postID).Error; err != nil {
		c.String(http.StatusBadRequest, "文章不存在")
		return
	}

	comment := models.Comment{
		PostID:  uint(postID),
		Author:  author,
		Email:   email,
		Website: website,
		Content: content,
		Status:  "pending",
	}

	if err := database.DB.Create(&comment).Error; err != nil {
		c.String(http.StatusInternalServerError, "提交失败")
		return
	}

	c.Redirect(http.StatusFound, "/post/"+post.Slug)
}