package handler

import (
	"net/http"
	"strings"

	"bj_power_wms/ent/inbounddetail"
	"bj_power_wms/ent/inboundorder"
	"bj_power_wms/ent/inventory"
	"bj_power_wms/internal/svc"
)

// voidInboundHandler 入库单作废（客户诉求 2026-09-19）：
// 填写作废原因 → 回滚本入库单对应的库存 → 单据标记作废（保留记录供追溯）。
//
// 回滚口径（绝不混淆）：
//   - 结构件（按批次）：按"本单明细"的批次号扣减对应批次库存数量，扣到 0 删除该库存行。
//   - 电气件（按 SN）：按"本单明细"的 SN 精确删除对应 SN 库存行——只回滚本单的 SN，
//     不会波及其它入库单/物料的 SN（SN 全局唯一，一码一物）。
//
// 安全门禁：目标库存已被锁定（lockedQty>0，已被出库预留）或数量不足/已出库，
// 一律拒绝作废并提示先处理，避免把已消耗库存回滚成负数或误删他单库存。
func voidInboundHandler(ctx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var req struct {
			InboundNo string `json:"inboundNo"`
			Reason    string `json:"reason"`
		}
		if err := parseJSON(r, &req); err != nil {
			fail(w, http.StatusBadRequest, "参数错误")
			return
		}
		req.InboundNo = strings.TrimSpace(req.InboundNo)
		req.Reason = strings.TrimSpace(req.Reason)
		if req.InboundNo == "" {
			fail(w, http.StatusBadRequest, "入库单号必填")
			return
		}
		if req.Reason == "" {
			fail(w, http.StatusBadRequest, "作废原因必填")
			return
		}

		ib, err := ctx.EntClient.InboundOrder.Query().
			Where(inboundorder.InboundNoEQ(req.InboundNo)).Only(ctx0())
		if err != nil {
			fail(w, http.StatusNotFound, "入库单不存在："+req.InboundNo)
			return
		}
		if ib.Voided {
			fail(w, http.StatusConflict, "该入库单已作废，请勿重复操作")
			return
		}

		tx, err := ctx.EntClient.Tx(ctx0())
		if err != nil {
			fail(w, http.StatusInternalServerError, "开启事务失败: "+err.Error())
			return
		}
		committed := false
		defer func() {
			if !committed {
				_ = tx.Rollback()
			}
		}()

		details, err := tx.InboundDetail.Query().
			Where(inbounddetail.InboundNoEQ(req.InboundNo)).All(ctx0())
		if err != nil {
			fail(w, http.StatusInternalServerError, err.Error())
			return
		}
		if len(details) == 0 {
			fail(w, http.StatusConflict, "该入库单无明细，无法回滚库存")
			return
		}

		rolledSN := 0
		rolledQty := 0
		if ib.ManageMode == 2 {
			// 电气件：逐个 SN 精确回滚（只删本单 SN 的库存行）
			for _, d := range details {
				if d.SnCode == "" {
					continue
				}
				inv, e := tx.Inventory.Query().Where(inventory.SnCodeEQ(d.SnCode)).Only(ctx0())
				if e != nil {
					fail(w, http.StatusConflict, "SN 库存行不存在，无法作废："+d.SnCode)
					return
				}
				if inv.LockedQty > 0 {
					fail(w, http.StatusConflict, "SN "+d.SnCode+" 已被出库锁定，请先取消出库再作废")
					return
				}
				if inv.Status == "出库" {
					fail(w, http.StatusConflict, "SN "+d.SnCode+" 已出库，无法作废（请走退库）")
					return
				}
				if err := tx.Inventory.DeleteOneID(inv.ID).Exec(ctx0()); err != nil {
					fail(w, http.StatusInternalServerError, "回滚 SN 库存失败: "+err.Error())
					return
				}
				rolledSN++
			}
		} else {
			// 结构件：按批次扣减本单数量
			for _, d := range details {
				if d.BatchNo == "" {
					continue
				}
				inv, e := tx.Inventory.Query().
					Where(inventory.ManageModeEQ(1), inventory.BatchNoEQ(d.BatchNo)).Only(ctx0())
				if e != nil {
					fail(w, http.StatusConflict, "批次库存行不存在，无法作废："+d.BatchNo)
					return
				}
				if inv.LockedQty > 0 {
					fail(w, http.StatusConflict, "批次 "+d.BatchNo+" 存在锁定库存，请先取消出库再作废")
					return
				}
				if inv.Quantity < d.Quantity {
					fail(w, http.StatusConflict, "批次 "+d.BatchNo+" 在库数量不足（已被出库消耗），无法作废")
					return
				}
				newQty := inv.Quantity - d.Quantity
				if newQty <= 0 {
					if err := tx.Inventory.DeleteOneID(inv.ID).Exec(ctx0()); err != nil {
						fail(w, http.StatusInternalServerError, "回滚批次库存失败: "+err.Error())
						return
					}
				} else if _, err := tx.Inventory.UpdateOneID(inv.ID).SetQuantity(newQty).Save(ctx0()); err != nil {
					fail(w, http.StatusInternalServerError, "回滚批次库存失败: "+err.Error())
					return
				}
				rolledQty += d.Quantity
			}
		}

		if _, err := tx.InboundOrder.UpdateOneID(ib.ID).
			SetVoided(true).SetVoidReason(req.Reason).
			SetNillableVoidedBy(strPtr(r.Header.Get("X-Username"))).
			SetVoidedAt(timeNow().Unix()).
			Save(ctx0()); err != nil {
			fail(w, http.StatusInternalServerError, "标记作废失败: "+err.Error())
			return
		}

		if err := tx.Commit(); err != nil {
			fail(w, http.StatusInternalServerError, "提交事务失败: "+err.Error())
			return
		}
		committed = true

		ctx.EventLog.Write(ctx0(), "inbound.void", r.Header.Get("X-Username"), "inbound", req.InboundNo,
			"作废入库单 "+req.InboundNo+"，原因："+req.Reason, map[string]any{
				"rolledSN": rolledSN, "rolledQty": rolledQty})
		ok(w, map[string]any{
			"inboundNo": req.InboundNo,
			"rolledSN":  rolledSN,
			"rolledQty": rolledQty,
		})
	}
}