package handler

import (
	"net/http"
	"strconv"

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

	"github.com/wangjia/jiu/backend/internal/middleware"
	"github.com/wangjia/jiu/backend/internal/model"
)

type InventoryHandler struct {
	db *gorm.DB
}

func NewInventoryHandler(db *gorm.DB) *InventoryHandler {
	return &InventoryHandler{db: db}
}

// List GET /api/v1/inventory
func (h *InventoryHandler) List(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	query := h.db.Model(&model.Inventory{}).Where("shop_id = ?", shopID)

	if warehouseID := c.Query("warehouse_id"); warehouseID != "" {
		query = query.Where("warehouse_id = ?", warehouseID)
	}
	if productID := c.Query("product_id"); productID != "" {
		query = query.Where("product_id = ?", productID)
	}
	if c.Query("in_stock") == "1" {
		query = query.Where("quantity > 0")
	}

	var total int64
	query.Count(&total)

	var inventory []model.Inventory
	query.Preload("Product").Preload("Warehouse").
		Offset((page - 1) * pageSize).Limit(pageSize).
		Find(&inventory)

	c.JSON(http.StatusOK, gin.H{"data": inventory, "total": total, "page": page, "page_size": pageSize})
}

// Logs GET /api/v1/inventory/logs
func (h *InventoryHandler) Logs(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	query := h.db.Model(&model.InventoryLog{}).Where("shop_id = ?", shopID)

	if productID := c.Query("product_id"); productID != "" {
		query = query.Where("product_id = ?", productID)
	}

	var total int64
	query.Count(&total)

	var logs []model.InventoryLog
	query.Offset((page - 1) * pageSize).Limit(pageSize).Order("id DESC").Find(&logs)

	c.JSON(http.StatusOK, gin.H{"data": logs, "total": total, "page": page, "page_size": pageSize})
}

// CreateCheck POST /api/v1/inventory/checks
func (h *InventoryHandler) CreateCheck(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	operatorID := middleware.GetUserID(c)

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

	req.ShopID = shopID
	req.OperatorID = operatorID
	req.Status = "draft"

	// 自动填入系统库存数量
	for i := range req.Items {
		req.Items[i].ShopID = shopID
		var inv model.Inventory
		if err := h.db.Where("shop_id = ? AND warehouse_id = ? AND product_id = ?",
			shopID, req.WarehouseID, req.Items[i].ProductID).First(&inv).Error; err == nil {
			req.Items[i].SystemQty = inv.Quantity
		}
	}

	if err := h.db.Create(&req).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusCreated, gin.H{"data": req})
}

// GetCheck GET /api/v1/inventory/checks/:id
func (h *InventoryHandler) GetCheck(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	var check model.InventoryCheck
	if err := h.db.Preload("Items.Product").
		Where("id = ? AND shop_id = ?", c.Param("id"), shopID).
		First(&check).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"data": check})
}