package handler

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

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

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

func timeNow() *time.Time {
	t := time.Now()
	return &t
}

type StockInHandler struct {
	db       *gorm.DB
	stockSvc *service.StockService
}

func NewStockInHandler(db *gorm.DB, svc *service.StockService) *StockInHandler {
	return &StockInHandler{db: db, stockSvc: svc}
}

// List GET /api/v1/stock-in/orders
func (h *StockInHandler) List(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
	pageSize = util.ValidatePageSize(pageSize, 20, 200)

	query := h.db.Model(&model.StockInOrder{}).
		Where("shop_id = ? AND deleted_at IS NULL", shopID)

	if status := c.Query("status"); status != "" {
		query = query.Where("status IN ?", strings.Split(status, ","))
	}
	if startDate := c.Query("start_date"); startDate != "" {
		query = query.Where("order_date >= ?", startDate)
	}
	if endDate := c.Query("end_date"); endDate != "" {
		query = query.Where("order_date <= ?", endDate)
	}
	if kw := strings.TrimSpace(c.Query("keyword")); kw != "" {
		like := "%" + kw + "%"
		// keyword 命中：单号 / 酒名（含全拼+首字母）/ 商品编码 —— 反查含该明细的单据。
		// （不含往来单位；供应商/客户改由工具栏下拉筛选。）
		// 酒名「product 主数据名 OR 明细快照名」任一命中——不能用 COALESCE 二选一：历史导入单的
		// 明细 product_id 统一指向占位商品「历史导入占位」（p.name 非空），COALESCE 会被占位名劫持，
		// 永远取不到真实快照 product_name，导致导入单按真实酒名搜不到。拼音只在 products 上（快照无拼音列）。
		// 编码同理「主数据 p.code OR 快照 it.product_code」双匹配，与页面显示口径（主数据优先）对齐。
		query = query.Where(
			"order_no LIKE ?"+
				" OR id IN (SELECT it.order_id FROM stock_in_items it"+
				"   LEFT JOIN products p ON p.id = it.product_id AND p.shop_id = it.shop_id"+
				"   WHERE it.shop_id = ? AND it.deleted_at IS NULL"+
				"     AND (p.name LIKE ? OR it.product_name LIKE ? OR it.product_code LIKE ?"+
				"          OR p.code LIKE ? OR p.name_pinyin LIKE ? OR p.name_initials LIKE ?))",
			like, shopID, like, like, like, like, like, like,
		)
	}
	// 详细搜索多字段（各参数独立可选、组合为 AND）
	query = applyStockOrderDetailFilters(query, shopID, c, "stock_in_items")

	var total int64
	query.Count(&total)

	orders := make([]model.StockInOrder, 0)
	query.Preload("Warehouse", "shop_id = ?", shopID).
		Preload("Partner", "shop_id = ?", shopID).
		Preload("Operator", "shop_id = ?", shopID).
		Preload("Reviewer", "shop_id = ?", shopID).
		Offset((page - 1) * pageSize).Limit(pageSize).
		Order("order_date DESC, id DESC").Find(&orders)

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

// applyStockOrderDetailFilters 详细搜索多字段过滤（出入库共用，itemsTable 传 stock_in_items / stock_out_items，
// 为硬编码常量非用户输入，无注入风险）。各参数独立可选：单据表字段直接过滤，明细字段走子查询 IN。
func applyStockOrderDetailFilters(q *gorm.DB, shopID uint64, c *gin.Context, itemsTable string) *gorm.DB {
	if v := strings.TrimSpace(c.Query("order_no")); v != "" {
		q = q.Where("order_no LIKE ?", "%"+v+"%")
	}
	if v := c.Query("partner_id"); v != "" {
		q = q.Where("partner_id = ?", v)
	}
	if v := c.Query("operator_id"); v != "" {
		q = q.Where("operator_id = ?", v)
	}
	if v := c.Query("reviewer_id"); v != "" {
		q = q.Where("reviewer_id = ?", v)
	}
	// 退单状态（none/partial/full；单据表直接过滤，供「部分退单/已退单」筛选）
	if v := c.Query("return_state"); v != "" {
		q = q.Where("return_state = ?", v)
	}
	// 明细/商品级条件合并为「一条」子查询：命中要求**同一条明细**同时满足全部条件
	// （product/编码/系列/规格/批次/分类），而非「各条件各自由不同明细凑齐」。
	// 一次扫描 items（走 idx_order_id 回连单据），语义更准、比多条 id IN 更省。
	var itemConds []string
	var itemArgs []interface{}
	if v := strings.TrimSpace(c.Query("product")); v != "" {
		like := "%" + v + "%"
		itemConds = append(itemConds,
			"(p.name LIKE ? OR it.product_name LIKE ? OR it.product_code LIKE ?"+
				" OR p.code LIKE ? OR p.name_pinyin LIKE ? OR p.name_initials LIKE ?)")
		itemArgs = append(itemArgs, like, like, like, like, like, like)
	}
	// 编码「主数据 OR 快照」双匹配：存量出库明细快照有空串，只查快照会漏单
	if v := strings.TrimSpace(c.Query("product_code")); v != "" {
		like := "%" + v + "%"
		itemConds = append(itemConds, "(it.product_code LIKE ? OR p.code LIKE ?)")
		itemArgs = append(itemArgs, like, like)
	}
	if v := strings.TrimSpace(c.Query("series")); v != "" {
		itemConds = append(itemConds, "it.series = ?")
		itemArgs = append(itemArgs, v)
	}
	if v := strings.TrimSpace(c.Query("spec")); v != "" {
		itemConds = append(itemConds, "it.spec = ?")
		itemArgs = append(itemArgs, v)
	}
	if v := strings.TrimSpace(c.Query("batch")); v != "" {
		itemConds = append(itemConds, "it.batch_no LIKE ?")
		itemArgs = append(itemArgs, "%"+v+"%")
	}
	if v := c.Query("category_id"); v != "" {
		itemConds = append(itemConds, "p.category_id = ?")
		itemArgs = append(itemArgs, v)
	}
	if len(itemConds) > 0 {
		sub := "id IN (SELECT it.order_id FROM " + itemsTable + " it" +
			" LEFT JOIN products p ON p.id = it.product_id AND p.shop_id = it.shop_id" +
			" WHERE it.shop_id = ? AND it.deleted_at IS NULL AND " +
			strings.Join(itemConds, " AND ") + ")"
		args := append([]interface{}{shopID}, itemArgs...)
		q = q.Where(sub, args...)
	}
	return q
}

// stockSummary 出/入库 KPI 汇总（本月 + 上月同期供环比 + 待审核）。
type stockSummary struct {
	MonthCount      int64   `json:"month_count"`
	MonthAmount     float64 `json:"month_amount"`
	PendingCount    int64   `json:"pending_count"`
	DraftCount      int64   `json:"draft_count"`
	LastMonthCount  int64   `json:"last_month_count"`
	LastMonthAmount float64 `json:"last_month_amount"`
}

// monthBounds 本月起 / 下月起 / 上月起（YYYY-MM-DD 串，日期串比较跨 MySQL/SQLite 可移植）。
func monthBounds(now time.Time) (mStart, next, prev string) {
	s := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, now.Location())
	const f = "2006-01-02"
	return s.Format(f), s.AddDate(0, 1, 0).Format(f), s.AddDate(0, -1, 0).Format(f)
}

// summaryBounds 依 ?window= 选统计口径：
//   - rolling30：近 30 天滚动窗 [今-29d, 明)，对照窗为再往前 30 天——出入库列表
//     KPI 用（月初自然月全 0 的观感问题，用户拍板改滚动窗）；
//   - 默认：自然月 + 上月（原型/财务屏口径）。
//
// 返回 YYYY-MM-DD 串，日期串比较跨 MySQL/SQLite 可移植。
func summaryBounds(c *gin.Context, now time.Time) (curFrom, curTo, prevFrom, prevTo string) {
	const f = "2006-01-02"
	if c.Query("window") == "rolling30" {
		d := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
		return d.AddDate(0, 0, -29).Format(f), d.AddDate(0, 0, 1).Format(f),
			d.AddDate(0, 0, -59).Format(f), d.AddDate(0, 0, -29).Format(f)
	}
	mStart, next, prev := monthBounds(now)
	return mStart, next, prev, mStart
}

// Summary GET /api/v1/stock-in/summary —— 全店入库 KPI（守多租户；?window=rolling30 见 summaryBounds）
func (h *StockInHandler) Summary(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	curFrom, curTo, prevFrom, prevTo := summaryBounds(c, time.Now())
	agg := func(from, to string) (int64, float64) {
		var r struct {
			Cnt int64
			Amt float64
		}
		h.db.Model(&model.StockInOrder{}).
			Where("shop_id = ? AND deleted_at IS NULL AND order_date >= ? AND order_date < ?", shopID, from, to).
			Select("COUNT(*) AS cnt, COALESCE(SUM(cost_total),0) AS amt").Scan(&r)
		return r.Cnt, r.Amt
	}
	var s stockSummary
	s.MonthCount, s.MonthAmount = agg(curFrom, curTo)
	s.LastMonthCount, s.LastMonthAmount = agg(prevFrom, prevTo)
	h.db.Model(&model.StockInOrder{}).
		Where("shop_id = ? AND status = ? AND deleted_at IS NULL", shopID, "pending").Count(&s.PendingCount)
	h.db.Model(&model.StockInOrder{}).
		Where("shop_id = ? AND status = ? AND deleted_at IS NULL", shopID, "draft").Count(&s.DraftCount)
	c.JSON(http.StatusOK, s)
}

// Get GET /api/v1/stock-in/orders/:id
func (h *StockInHandler) Get(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	var order model.StockInOrder
	if err := h.db.Preload("Items.Product", "shop_id = ?", shopID).Preload("Items.Product.Origin").
		Preload("Items.Product.ShelfLife").Preload("Items.Product.Storage").
		Preload("Warehouse", "shop_id = ?", shopID).Preload("Partner", "shop_id = ?", shopID).
		Preload("Operator", "shop_id = ?", shopID).Preload("Reviewer", "shop_id = ?", shopID).
		Where("id = ? AND shop_id = ? AND deleted_at IS NULL", c.Param("id"), shopID).
		First(&order).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
		return
	}
	util.RespondSuccess(c, order)
}

// Create POST /api/v1/stock-in/orders
func (h *StockInHandler) Create(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	operatorID := middleware.GetUserID(c)

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

	// SEC-001：外键必须属于当前店（防跨租户引用泄露）
	if err := ensureShopRef(h.db, "warehouses", req.WarehouseID, shopID); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if err := ensureShopRefOpt(h.db, "partners", req.PartnerID, shopID); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	req.ShopID = shopID
	req.OperatorID = operatorID
	req.Status = "draft"

	// 生成单号
	orderNo, err := h.stockSvc.GenerateOrderNo(shopID, "stock_in")
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	req.OrderNo = orderNo

	// 事务内：每条明细新建一个独立产品（特有产品/序列号，不按名称复用），回填 product_id，再建单。
	err = h.db.Transaction(func(tx *gorm.DB) error {
		var total float64
		for i := range req.Items {
			it := &req.Items[i]
			it.ShopID = shopID
			// 兼容旧客户端(≤1.0.87)：unit_price 回落为 cost_price（新 key 优先）
			if it.CostPrice == 0 && it.LegacyUnitPrice != nil {
				it.CostPrice = *it.LegacyUnitPrice
			}
			if it.BatchNo == "" {
				it.BatchNo = fmt.Sprintf("%s-%02d", req.OrderNo, i+1)
			}
			prod, e := createIndependentProduct(tx, shopID, it.ProductName, it.Series, it.Spec, it.BatchNo, it.ProductionDate, it.CostPrice, it.SalePrice)
			if e != nil {
				return e
			}
			it.ProductID = prod.ID
			it.ProductCode = prod.Code // 保留快照,兼容现有查询(瘦身阶段再去)
			it.CostAmount = it.Quantity * it.CostPrice
			total += it.CostAmount
		}
		req.CostTotal = total
		return tx.Create(&req).Error
	})
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	util.RespondCreated(c, req)
}

// Update PUT /api/v1/stock-in/orders/:id （只允许草稿状态）
func (h *StockInHandler) Update(c *gin.Context) {
	shopID := middleware.GetShopID(c)

	var order model.StockInOrder
	if err := h.db.Where("id = ? AND shop_id = ? AND status = 'draft' AND deleted_at IS NULL", c.Param("id"), shopID).
		First(&order).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "入库单不存在或不可修改"})
		return
	}

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

	// SEC-001：外键必须属于当前店（防跨租户引用泄露）
	if err := ensureShopRef(h.db, "warehouses", req.WarehouseID, shopID); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if err := ensureShopRefOpt(h.db, "partners", req.PartnerID, shopID); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	err := h.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("order_id = ?", order.ID).Delete(&model.StockInItem{}).Error; err != nil {
			return err
		}
		var total float64
		for i := range req.Items {
			it := &req.Items[i]
			it.ShopID = shopID
			it.OrderID = order.ID
			if it.CostPrice == 0 && it.LegacyUnitPrice != nil {
				it.CostPrice = *it.LegacyUnitPrice
			}
			if it.BatchNo == "" {
				it.BatchNo = fmt.Sprintf("%s-%02d", order.OrderNo, i+1)
			}
			// 编辑草稿:旧明细已删,每条按新模型重建独立产品（旧草稿 product 无库存,暂留待后续清理）
			prod, e := createIndependentProduct(tx, shopID, it.ProductName, it.Series, it.Spec, it.BatchNo, it.ProductionDate, it.CostPrice, it.SalePrice)
			if e != nil {
				return e
			}
			it.ProductID = prod.ID
			it.ProductCode = prod.Code
			it.CostAmount = it.Quantity * it.CostPrice
			total += it.CostAmount
		}
		updates := map[string]interface{}{
			"warehouse_id": req.WarehouseID,
			"partner_id":   req.PartnerID,
			"order_date":   req.OrderDate,
			"remark":       req.Remark,
			"cost_total": total,
		}
		if err := tx.Model(&order).Updates(updates).Error; err != nil {
			return err
		}
		if len(req.Items) > 0 {
			if err := tx.Create(&req.Items).Error; err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "updated"})
}

// Delete DELETE /api/v1/stock-in/orders/:id （只允许草稿状态）
func (h *StockInHandler) Delete(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	now := timeNow()
	result := h.db.Model(&model.StockInOrder{}).
		Where("id = ? AND shop_id = ? AND status = 'draft' AND deleted_at IS NULL", c.Param("id"), shopID).
		Update("deleted_at", now)
	if result.RowsAffected == 0 {
		c.JSON(http.StatusNotFound, gin.H{"error": "入库单不存在或不可删除"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "deleted"})
}

// Submit PUT /api/v1/stock-in/orders/:id/submit （草稿→待审核）
func (h *StockInHandler) Submit(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	result := h.db.Model(&model.StockInOrder{}).
		Where("id = ? AND shop_id = ? AND status = 'draft'", c.Param("id"), shopID).
		Update("status", "pending")
	if result.RowsAffected == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "order not found or not in draft status"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "submitted"})
}

// Approve PUT /api/v1/stock-in/orders/:id/approve
func (h *StockInHandler) Approve(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	reviewerID := middleware.GetUserID(c)

	id, _ := strconv.ParseUint(c.Param("id"), 10, 64)
	if err := h.stockSvc.ApproveStockIn(shopID, id, reviewerID); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "approved"})
}

// Reject PUT /api/v1/stock-in/orders/:id/reject
func (h *StockInHandler) Reject(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	reviewerID := middleware.GetUserID(c)
	now := timeNow()

	result := h.db.Model(&model.StockInOrder{}).
		Where("id = ? AND shop_id = ? AND status = 'pending'", c.Param("id"), shopID).
		Updates(map[string]interface{}{
			"status":      "rejected",
			"reviewer_id": reviewerID,
			"reviewed_at": now,
		})
	if result.RowsAffected == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "order not found or not in pending status"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "rejected"})
}

// Withdraw PUT /api/v1/stock-in/orders/:id/withdraw
// 审核中(pending)撤回为草稿(draft)，修改后可重新提交。仅 pending 可撤回；
// 已审核(approved)单据只读、库存已变动，不可撤回。
// 权限：管理员/超管可撤回任意单；普通操作员只能撤回本人提交的单（operator_id 为本人）。
func (h *StockInHandler) Withdraw(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	userID := middleware.GetUserID(c)
	role := middleware.GetRole(c)

	var order model.StockInOrder
	if err := h.db.Where("id = ? AND shop_id = ? AND status = 'pending'", c.Param("id"), shopID).
		First(&order).Error; err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "order not found or not in pending status"})
		return
	}

	isAdmin := role == "admin" || role == "superadmin"
	if !isAdmin && order.OperatorID != userID {
		c.JSON(http.StatusForbidden, gin.H{"error": "只能撤回本人提交的单据"})
		return
	}

	h.db.Model(&model.StockInOrder{}).
		Where("id = ? AND shop_id = ?", order.ID, shopID).
		Update("status", "draft")
	c.JSON(http.StatusOK, gin.H{"message": "withdrawn"})
}

// Return POST /api/v1/stock-in/orders/:id/return
// 入库退单：退掉指定明细，对应库存从库存删除、冲减应付。仅 approved 单、管理员/超管。
func (h *StockInHandler) Return(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	userID := middleware.GetUserID(c)
	role := middleware.GetRole(c)
	id, _ := strconv.ParseUint(c.Param("id"), 10, 64)

	var req struct {
		ItemIDs []uint64 `json:"item_ids"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if len(req.ItemIDs) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "未选择退单明细"})
		return
	}
	if err := h.stockSvc.ReturnStockIn(shopID, id, userID, role, req.ItemIDs); err != nil {
		if errors.Is(err, service.ErrForbidden) {
			c.JSON(http.StatusForbidden, gin.H{"error": "无权退单"})
			return
		}
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "returned"})
}

// ConfirmCost POST /api/v1/stock-in/orders/:id/confirm-cost
// 确认进价：调货等以 0 价（暂估）入库并已审核后，价格确定时补填真实进价。
// 前向补偿（更新库存成本、回填已出库成本快照、补应付差额），不反审核。
// 仅 approved 单、管理员/超管（service 内判权）。
func (h *StockInHandler) ConfirmCost(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	userID := middleware.GetUserID(c)
	role := middleware.GetRole(c)
	id, _ := strconv.ParseUint(c.Param("id"), 10, 64)

	var req struct {
		Items []service.CostConfirmItem `json:"items"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if len(req.Items) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "未提供要确认的明细"})
		return
	}
	for _, it := range req.Items {
		if it.UnitPrice <= 0 {
			c.JSON(http.StatusBadRequest, gin.H{"error": "进价必须大于 0"})
			return
		}
	}
	if err := h.stockSvc.ConfirmStockInCost(shopID, id, userID, role, req.Items); err != nil {
		if errors.Is(err, service.ErrForbidden) {
			c.JSON(http.StatusForbidden, gin.H{"error": "无权确认进价"})
			return
		}
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "cost confirmed"})
}