package handlers

import (
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
	"go_blog/models"

	"gorm.io/gorm"
)

// ViewAnalyticsPage renders the admin analytics page showing article view statistics.
func ViewAnalyticsPage(db *gorm.DB) gin.HandlerFunc {
	return func(c *gin.Context) {
		tr := getTr(c)

		// Parse filters from query params
		articleTitle := c.Query("article_title")
		userIDStr := c.Query("user_id")
		ip := c.Query("ip")
		showBots := c.Query("show_bots") == "1"
		page := 1
		if p := c.Query("page"); p != "" {
			if parsed, err := strconv.Atoi(p); err == nil && parsed > 0 {
				page = parsed
			}
		}

		// Build query for view records
		query := db.Model(&models.ArticleView{}).
			Preload("Article").
			Preload("User").
			Order("created_at DESC")

		// Filter by article title (join with articles table)
		if articleTitle != "" {
			query = query.Joins("JOIN articles ON article_views.article_id = articles.id").
				Where("articles.title LIKE ?", "%"+articleTitle+"%")
		}
		if userIDStr != "" {
			query = query.Where("user_id = ?", userIDStr)
		}
		if ip != "" {
			query = query.Where("ip LIKE ?", "%"+ip+"%")
		}
		if !showBots {
			query = query.Where("is_bot = ?", false)
		}

		// Pagination
		pageSize := 50
		offset := (page - 1) * pageSize
		var views []models.ArticleView
		var totalCount int64
		query.Count(&totalCount)
		query.Limit(pageSize).Offset(offset).Find(&views)

		hasMore := int64(offset+len(views)) < totalCount

		// Calculate global statistics
		var stats struct {
			TotalViews    int64
			UniqueIPs     int64
			UniqueUsers   int64
			BotViews      int64
			HumanViews    int64
		}
		db.Model(&models.ArticleView{}).Count(&stats.TotalViews)
		db.Model(&models.ArticleView{}).Where("is_bot = ?", true).Count(&stats.BotViews)
		db.Model(&models.ArticleView{}).Where("is_bot = ?", false).Count(&stats.HumanViews)
		db.Model(&models.ArticleView{}).Distinct("ip").Count(&stats.UniqueIPs)
		db.Model(&models.ArticleView{}).Where("user_id IS NOT NULL").Distinct("user_id").Count(&stats.UniqueUsers)

		// Per-article statistics
		type ArticleStat struct {
			ArticleID  uint
			Title      string
			ViewCount  int64
			UniqueIPs  int64
			BotViews   int64
			HumanViews int64
		}
		var articleStats []ArticleStat

		db.Raw(`
			SELECT
				av.article_id,
				a.title,
				COUNT(*) as view_count,
				COUNT(DISTINCT av.ip) as unique_ips,
				SUM(CASE WHEN av.is_bot THEN 1 ELSE 0 END) as bot_views,
				SUM(CASE WHEN NOT av.is_bot THEN 1 ELSE 0 END) as human_views
			FROM article_views av
			LEFT JOIN articles a ON av.article_id = a.id
			WHERE a.deleted_at IS NULL
			GROUP BY av.article_id, a.title
			ORDER BY view_count DESC
			LIMIT 20
		`).Scan(&articleStats)

		data := DefaultData(c)
		data["Title"] = tr["analytics_views_title"]
		data["Views"] = views
		data["Stats"] = stats
		data["ArticleStats"] = articleStats
		data["Filters"] = gin.H{
			"ArticleTitle": articleTitle,
			"UserID":       userIDStr,
			"IP":           ip,
			"ShowBots":     showBots,
			"Page":         page,
		}
		data["Pagination"] = gin.H{
			"Page":     page,
			"NextPage": page + 1,
			"HasMore":  hasMore,
			"Total":    totalCount,
		}

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