package handler

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

	"bj_power_wms/ent"
	"bj_power_wms/ent/zone"
	"bj_power_wms/internal/svc"
)

// zoneLocationReq 区域下的一个货位（货架号 / 第几层 / 位置号，均可手填）。
// 区域维护按「区域编码」分组展示：一个区域编码 + 名称只登记一次，货位可以有多条。
type zoneLocationReq struct {
	ID         int    `json:"id"`
	ShelfNo    string `json:"shelfNo"`
	LayerNo    string `json:"layerNo"`
	PositionNo string `json:"positionNo"`
}

// normLoc 归一货位三级输入（去首尾空格），与 DB 组合唯一索引 COALESCE 归一空值的口径保持一致
func normLoc(loc *zoneLocationReq) {
	loc.ShelfNo = strings.TrimSpace(loc.ShelfNo)
	loc.LayerNo = strings.TrimSpace(loc.LayerNo)
	loc.PositionNo = strings.TrimSpace(loc.PositionNo)
}

// locComboKey 货位三级组合的比较键（同区域内判重用）
func locComboKey(shelfNo, layerNo, positionNo string) string {
	return shelfNo + "\x00" + layerNo + "\x00" + positionNo
}

// createZoneHandler 新建区域（一次可登记多个货位）
func createZoneHandler(ctx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var req struct {
			ZoneCode    string            `json:"zoneCode"`
			ZoneName    string            `json:"zoneName"`
			Description string            `json:"description"`
			Locations   []zoneLocationReq `json:"locations"`
			// 兼容旧版单货位入参
			ShelfNo    string `json:"shelfNo"`
			LayerNo    string `json:"layerNo"`
			PositionNo string `json:"positionNo"`
		}
		if err := parseJSON(r, &req); err != nil {
			fail(w, http.StatusBadRequest, "参数错误")
			return
		}
		req.ZoneCode = strings.ToUpper(strings.TrimSpace(req.ZoneCode))
		req.ZoneName = strings.TrimSpace(req.ZoneName)
		if req.ZoneCode == "" || req.ZoneName == "" {
			fail(w, http.StatusBadRequest, "区域编码和区域名称必填")
			return
		}
		if req.Locations == nil {
			req.Locations = []zoneLocationReq{{ShelfNo: req.ShelfNo, LayerNo: req.LayerNo, PositionNo: req.PositionNo}}
		}
		if len(req.Locations) == 0 {
			fail(w, http.StatusBadRequest, "至少填写一个货位")
			return
		}

		// 区域编码已存在：区域维护按区域编码分组，同一区域应通过「编辑」继续添加货位
		sameZone, err := ctx.EntClient.Zone.Query().
			Where(zone.ZoneCodeEQ(req.ZoneCode)).
			All(ctx0())
		if err != nil {
			fail(w, http.StatusInternalServerError, err.Error())
			return
		}
		if len(sameZone) > 0 {
			fail(w, http.StatusConflict, "区域编码已存在："+req.ZoneCode+"，请在列表中编辑该区域添加货位")
			return
		}

		// 货位唯一性（U18）：请求内按四级组合判重，与 DB 组合唯一索引 ux_zones_location 一致
		seen := map[string]bool{}
		for i := range req.Locations {
			normLoc(&req.Locations[i])
			key := locComboKey(req.Locations[i].ShelfNo, req.Locations[i].LayerNo, req.Locations[i].PositionNo)
			if seen[key] {
				fail(w, http.StatusConflict, locDupMsg(req.ZoneCode, req.Locations[i].ShelfNo, req.Locations[i].LayerNo, req.Locations[i].PositionNo))
				return
			}
			seen[key] = true
		}

		created := make([]*ent.Zone, 0, len(req.Locations))
		for _, loc := range req.Locations {
			z, err := ctx.EntClient.Zone.Create().
				SetZoneCode(req.ZoneCode).
				SetZoneName(req.ZoneName).
				SetNillableDescription(strPtr(strings.TrimSpace(req.Description))).
				SetNillableShelfNo(strPtr(loc.ShelfNo)).
				SetNillableLayerNo(strPtr(loc.LayerNo)).
				SetNillablePositionNo(strPtr(loc.PositionNo)).
				SetStatus("启用").
				Save(ctx0())
			if err != nil {
				fail(w, http.StatusInternalServerError, err.Error())
				return
			}
			created = append(created, z)
		}
		ctx.EventLog.Write(ctx0(), "zone.create", r.Header.Get("X-Username"), "zone", req.ZoneCode,
			"新建区域 "+req.ZoneName+"（"+strconv.Itoa(len(created))+" 个货位）", nil)
		ok(w, created)
	}
}

// updateZoneHandler 编辑区域（区域信息 + 该区域下的货位一次性同步）
func updateZoneHandler(ctx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var req struct {
			ID          int               `json:"id"`
			ZoneCode    string            `json:"zoneCode"`
			ZoneName    string            `json:"zoneName"`
			Description string            `json:"description"`
			Status      string            `json:"status"`
			Locations   []zoneLocationReq `json:"locations"`
		}
		if err := parseJSON(r, &req); err != nil {
			fail(w, http.StatusBadRequest, "参数错误")
			return
		}
		req.ZoneName = strings.TrimSpace(req.ZoneName)
		if req.ZoneName == "" {
			fail(w, http.StatusBadRequest, "区域名称必填")
			return
		}
		// 兼容旧版：仅传 id 时先反查区域编码
		if req.ZoneCode == "" && req.ID > 0 {
			cur, err := ctx.EntClient.Zone.Get(ctx0(), req.ID)
			if err != nil {
				fail(w, http.StatusNotFound, "区域不存在")
				return
			}
			req.ZoneCode = cur.ZoneCode
		}
		req.ZoneCode = strings.ToUpper(strings.TrimSpace(req.ZoneCode))
		if req.ZoneCode == "" {
			fail(w, http.StatusBadRequest, "区域编码必填")
			return
		}
		status := req.Status
		if status == "" {
			status = "启用"
		}
		if status != "启用" && status != "停用" {
			fail(w, http.StatusBadRequest, "状态取值非法")
			return
		}

		rows, err := ctx.EntClient.Zone.Query().Where(zone.ZoneCodeEQ(req.ZoneCode)).All(ctx0())
		if err != nil {
			fail(w, http.StatusInternalServerError, err.Error())
			return
		}
		if len(rows) == 0 {
			fail(w, http.StatusNotFound, "区域不存在："+req.ZoneCode)
			return
		}

		// locations 为 nil（未传）时只改区域信息，不动货位；传了就按提交结果整体同步
		var toCreate []zoneLocationReq
		keepIDs := make([]int, 0, len(req.Locations))
		if req.Locations != nil {
			if len(req.Locations) == 0 {
				fail(w, http.StatusBadRequest, "至少保留一个货位")
				return
			}
			exist := make(map[int]bool, len(rows))
			for _, z := range rows {
				exist[z.ID] = true
			}
			seen := map[string]bool{}
			for i := range req.Locations {
				normLoc(&req.Locations[i])
				loc := req.Locations[i]
				key := locComboKey(loc.ShelfNo, loc.LayerNo, loc.PositionNo)
				if seen[key] {
					fail(w, http.StatusConflict, locDupMsg(req.ZoneCode, loc.ShelfNo, loc.LayerNo, loc.PositionNo))
					return
				}
				seen[key] = true
				if loc.ID > 0 {
					if !exist[loc.ID] {
						fail(w, http.StatusBadRequest, "货位不存在或不属于该区域")
						return
					}
					keepIDs = append(keepIDs, loc.ID)
				} else {
					toCreate = append(toCreate, loc)
				}
			}
		}

		// 区域信息（名称/说明/状态）在该区域所有货位行上统一更新
		if _, err := ctx.EntClient.Zone.Update().Where(zone.ZoneCodeEQ(req.ZoneCode)).
			SetZoneName(req.ZoneName).
			SetNillableDescription(strPtr(strings.TrimSpace(req.Description))).
			SetStatus(status).
			Save(ctx0()); err != nil {
			fail(w, http.StatusInternalServerError, "更新区域失败: "+err.Error())
			return
		}

		if req.Locations != nil {
			// 先删后增：避免与 DB 组合唯一索引 ux_zones_location 冲突
			del := ctx.EntClient.Zone.Delete().Where(zone.ZoneCodeEQ(req.ZoneCode))
			if len(keepIDs) > 0 {
				del = del.Where(zone.IDNotIn(keepIDs...))
			}
			if _, err := del.Exec(ctx0()); err != nil {
				fail(w, http.StatusInternalServerError, "删除货位失败: "+err.Error())
				return
			}
			for _, loc := range req.Locations {
				if loc.ID <= 0 {
					continue
				}
				if _, err := ctx.EntClient.Zone.UpdateOneID(loc.ID).
					SetZoneName(req.ZoneName).
					SetNillableShelfNo(strPtr(loc.ShelfNo)).
					SetNillableLayerNo(strPtr(loc.LayerNo)).
					SetNillablePositionNo(strPtr(loc.PositionNo)).
					SetStatus(status).
					Save(ctx0()); err != nil {
					fail(w, http.StatusInternalServerError, "更新货位失败: "+err.Error())
					return
				}
			}
			for _, loc := range toCreate {
				if _, err := ctx.EntClient.Zone.Create().
					SetZoneCode(req.ZoneCode).
					SetZoneName(req.ZoneName).
					SetNillableDescription(strPtr(strings.TrimSpace(req.Description))).
					SetNillableShelfNo(strPtr(loc.ShelfNo)).
					SetNillableLayerNo(strPtr(loc.LayerNo)).
					SetNillablePositionNo(strPtr(loc.PositionNo)).
					SetStatus(status).
					Save(ctx0()); err != nil {
					fail(w, http.StatusInternalServerError, "新增货位失败: "+err.Error())
					return
				}
			}
		}
		ctx.EventLog.Write(ctx0(), "zone.update", r.Header.Get("X-Username"), "zone", req.ZoneCode,
			"编辑区域 "+req.ZoneName, nil)
		ok(w, map[string]any{"zoneCode": req.ZoneCode, "zoneName": req.ZoneName})
	}
}

// listZonesGroupedHandler 区域列表（按区域编码分组：一个区域一行，货位作为子项返回）
// 优化点（小周问题记录 L6）：原先每行 = 一个货位，同一区域编码/名称在列表里大量重复；
// 现按区域编码聚合，货位放在 locations 子数组里，分页按「区域」计数。
func listZonesGroupedHandler(ctx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		page := atoi(r.URL.Query().Get("page"), 1)
		pageSize := atoi(r.URL.Query().Get("pageSize"), 20)
		if page <= 0 {
			page = 1
		}
		if pageSize <= 0 {
			pageSize = 20
		}
		zoneCode := r.URL.Query().Get("zoneCode")
		zoneName := r.URL.Query().Get("zoneName")
		status := r.URL.Query().Get("status")
		startDate := r.URL.Query().Get("startDate")
		endDate := r.URL.Query().Get("endDate")

		q := ctx.EntClient.Zone.Query()
		if zoneCode != "" {
			// 区域编码搜索大小写不敏感
			q = q.Where(zone.ZoneCodeContainsFold(zoneCode))
		}
		if zoneName != "" {
			q = q.Where(zone.ZoneNameContainsFold(zoneName))
		}
		if status != "" {
			q = q.Where(zone.StatusEQ(status))
		}
		if startDate != "" {
			if t, err := time.ParseInLocation("2006-01-02", startDate, time.Local); err == nil {
				q = q.Where(zone.CreatedAtGTE(t.Unix()))
			}
		}
		if endDate != "" {
			if t, err := time.ParseInLocation("2006-01-02", endDate, time.Local); err == nil {
				q = q.Where(zone.CreatedAtLTE(t.Add(24 * time.Hour).Unix()))
			}
		}
		rows, err := q.Order(ent.Asc("zone_code"), ent.Asc("id")).All(ctx0())
		if err != nil {
			fail(w, http.StatusInternalServerError, err.Error())
			return
		}

		type zoneGroup struct {
			ZoneCode      string           `json:"zoneCode"`
			ZoneName      string           `json:"zoneName"`
			Description   string           `json:"description"`
			Status        string           `json:"status"`
			CreatedAt     int64            `json:"createdAt"`
			LocationCount int              `json:"locationCount"`
			Locations     []map[string]any `json:"locations"`
		}
		order := make([]string, 0)
		groups := map[string]*zoneGroup{}
		for _, z := range rows {
			g, found := groups[z.ZoneCode]
			if !found {
				g = &zoneGroup{
					ZoneCode: z.ZoneCode, ZoneName: z.ZoneName, Description: z.Description,
					Status: z.Status, CreatedAt: z.CreatedAt,
					Locations: make([]map[string]any, 0, 4),
				}
				groups[z.ZoneCode] = g
				order = append(order, z.ZoneCode)
			}
			g.Locations = append(g.Locations, map[string]any{
				"id": z.ID, "shelfNo": z.ShelfNo, "layerNo": z.LayerNo, "positionNo": z.PositionNo,
			})
			g.LocationCount++
		}

		total := len(order)
		start := (page - 1) * pageSize
		if start > total {
			start = total
		}
		end := start + pageSize
		if end > total {
			end = total
		}
		list := make([]*zoneGroup, 0, end-start)
		for _, code := range order[start:end] {
			list = append(list, groups[code])
		}
		ok(w, map[string]any{
			"total":    total,
			"list":     list,
			"page":     page,
			"pageSize": pageSize,
		})
	}
}

// listZonesForPicker 区域下拉列表（不分页，仅启用）
func listZonesForPicker(ctx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		list, err := ctx.EntClient.Zone.Query().
			Where(zone.StatusEQ("启用")).
			Order(ent.Asc("id")).
			All(ctx0())
		if err != nil {
			fail(w, http.StatusInternalServerError, err.Error())
			return
		}
		ok(w, list)
	}
}

// locDupMsg 货位重复登记的统一提示（复用 locLabel 拼四级货位串，U18）。
func locDupMsg(zoneCode, shelfNo, layerNo, positionNo string) string {
	return "该货位已存在：" + locLabel(zoneCode, shelfNo, layerNo, positionNo)
}