package handler

import (
	"net/http"
	"strconv"

	"spider/internal/model"

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

// MerchantHandler handles merchant queries.
type MerchantHandler struct {
	db *gorm.DB
}

// Stats returns aggregate statistics for merchants.
// GET /merchants/stats
func (h *MerchantHandler) Stats(c *gin.Context) {
	type countRow struct {
		Key   string `json:"key"`
		Count int64  `json:"count"`
	}

	var rawTotal int64
	h.db.Model(&model.MerchantRaw{}).Count(&rawTotal)

	var cleanTotal int64
	h.db.Model(&model.MerchantClean{}).Count(&cleanTotal)

	// Count by status in clean table.
	statusCounts := map[string]int64{}
	var statusRows []struct {
		Status string
		Cnt    int64
	}
	h.db.Model(&model.MerchantClean{}).
		Select("status, count(*) as cnt").
		Group("status").
		Scan(&statusRows)
	for _, r := range statusRows {
		statusCounts[r.Status] = r.Cnt
	}

	// Count by source_type in raw table.
	var sourceRows []struct {
		SourceType string
		Cnt        int64
	}
	h.db.Model(&model.MerchantRaw{}).
		Select("source_type, count(*) as cnt").
		Group("source_type").
		Scan(&sourceRows)
	bySource := map[string]int64{}
	for _, r := range sourceRows {
		bySource[r.SourceType] = r.Cnt
	}

	// Count by industry in clean table.
	var industryRows []struct {
		Industry string
		Cnt      int64
	}
	h.db.Model(&model.MerchantClean{}).
		Select("industry, count(*) as cnt").
		Group("industry").
		Scan(&industryRows)
	byIndustry := map[string]int64{}
	for _, r := range industryRows {
		byIndustry[r.Industry] = r.Cnt
	}

	OK(c, gin.H{
		"raw_total":   rawTotal,
		"clean_total": cleanTotal,
		"valid":       statusCounts["valid"],
		"invalid":     statusCounts["invalid"],
		"bot":         statusCounts["bot"],
		"duplicate":   statusCounts["duplicate"],
		"group":       statusCounts["group"],
		"by_source":   bySource,
		"by_industry": byIndustry,
	})
}

// ListRaw returns raw merchants with filters and pagination.
// GET /merchants/raw?status=&source_type=&page=&page_size=
func (h *MerchantHandler) ListRaw(c *gin.Context) {
	page, pageSize, offset := parsePage(c)

	query := h.db.Model(&model.MerchantRaw{})
	if status := c.Query("status"); status != "" {
		query = query.Where("status = ?", status)
	}
	if sourceType := c.Query("source_type"); sourceType != "" {
		query = query.Where("source_type = ?", sourceType)
	}

	var total int64
	if err := query.Count(&total).Error; err != nil {
		Fail(c, 500, err.Error())
		return
	}

	var items []model.MerchantRaw
	if err := query.Order("created_at DESC").Limit(pageSize).Offset(offset).Find(&items).Error; err != nil {
		Fail(c, 500, err.Error())
		return
	}

	PageOK(c, items, total, page, pageSize)
}

// ListClean returns clean merchants with filters and pagination.
// GET /merchants/clean?status=&industry=&min_score=&sort=quality_score&order=desc&page=&page_size=
func (h *MerchantHandler) ListClean(c *gin.Context) {
	page, pageSize, offset := parsePage(c)

	query := h.db.Model(&model.MerchantClean{})
	if status := c.Query("status"); status != "" {
		query = query.Where("status = ?", status)
	}
	if industry := c.Query("industry"); industry != "" {
		query = query.Where("industry = ?", industry)
	}
	if minScore := c.Query("min_score"); minScore != "" {
		if score, err := strconv.ParseFloat(minScore, 64); err == nil {
			query = query.Where("quality_score >= ?", score)
		}
	}

	sortField := c.DefaultQuery("sort", "quality_score")
	// whitelist sort fields to prevent SQL injection
	allowedSort := map[string]bool{
		"quality_score": true,
		"created_at":    true,
		"updated_at":    true,
		"member_count":  true,
	}
	if !allowedSort[sortField] {
		sortField = "quality_score"
	}
	order := c.DefaultQuery("order", "desc")
	if order != "asc" && order != "desc" {
		order = "desc"
	}

	var total int64
	if err := query.Count(&total).Error; err != nil {
		Fail(c, 500, err.Error())
		return
	}

	var items []model.MerchantClean
	if err := query.Order(sortField + " " + order).Limit(pageSize).Offset(offset).Find(&items).Error; err != nil {
		Fail(c, 500, err.Error())
		return
	}

	PageOK(c, items, total, page, pageSize)
}

// GetByID fetches a merchant by ID, checking clean table first then raw.
// GET /merchants/:id
func (h *MerchantHandler) GetByID(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		Fail(c, http.StatusBadRequest, "invalid id")
		return
	}

	var clean model.MerchantClean
	if err := h.db.First(&clean, id).Error; err == nil {
		OK(c, gin.H{"source": "clean", "data": clean})
		return
	}

	var raw model.MerchantRaw
	if err := h.db.First(&raw, id).Error; err == nil {
		OK(c, gin.H{"source": "raw", "data": raw})
		return
	}

	Fail(c, 404, "merchant not found")
}