package logic

import (
	"context"
	"database/sql"
	"strconv"
	"time"

	"math"

	"muyu-apiserver/model"
	"muyu-apiserver/pkg/metrics"
	"muyu-apiserver/pkg/tenantctx"
	"muyu-apiserver/pkg/uid"
	"muyu-apiserver/rpc/inventory/internal/svc"
	"muyu-apiserver/rpc/inventory/pb"

	"github.com/zeromicro/go-zero/core/logx"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type CreateStockAdjustLogic struct {
	ctx    context.Context
	svcCtx *svc.ServiceContext
	logx.Logger
}

func NewCreateStockAdjustLogic(ctx context.Context, svcCtx *svc.ServiceContext) *CreateStockAdjustLogic {
	return &CreateStockAdjustLogic{
		ctx:    ctx,
		svcCtx: svcCtx,
		Logger: logx.WithContext(ctx),
	}
}

// currentQty returns the total bolt length (meters) for a product.
func (l *CreateStockAdjustLogic) currentQty(productId string) float64 {
	bolts, err := l.svcCtx.BoltModel.FindByProductId(l.ctx, productId)
	if err != nil {
		return 0
	}
	var total float64
	for _, b := range bolts {
		total += b.LengthM
	}
	return total
}

func (l *CreateStockAdjustLogic) CreateStockAdjust(in *pb.CreateStockAdjustReq) (*pb.IdResp, error) {
	adjustId := uid.Generate()
	adjustNo := generateNo("TZ")

	adjustDate, err := time.Parse("2006-01-02", in.AdjustDate)
	if err != nil {
		return nil, status.Error(codes.InvalidArgument, "invalid adjust_date format, expected YYYY-MM-DD")
	}

	adjust := &model.InvStockAdjust{
		AdjustId:     adjustId,
		AdjustNo:     adjustNo,
		AdjustDate:   adjustDate,
		AdjustReason: in.AdjustReason,
		Operator:     in.Operator,
		Status:       0,
		Remark:       sql.NullString{String: in.Remark, Valid: in.Remark != ""},
	}

	_, err = l.svcCtx.StockAdjustModel.Insert(l.ctx, adjust)
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	details := make([]*model.InvStockAdjustDetail, 0, len(in.Details))
	for _, d := range in.Details {
		_, err := l.svcCtx.ProductModel.FindOneByProductId(l.ctx, d.ProductId)
		if err != nil {
			return nil, status.Errorf(codes.NotFound, "product %s not found", d.ProductId)
		}

		beforeQty := l.currentQty(d.ProductId)
		adjustQty, _ := strconv.ParseFloat(d.AdjustQuantity, 64)
		afterQty := beforeQty + adjustQty

		details = append(details, &model.InvStockAdjustDetail{
			DetailId:       uid.Generate(),
			AdjustId:       adjustId,
			ProductId:      d.ProductId,
			BeforeQuantity: beforeQty,
			AdjustQuantity: adjustQty,
			AfterQuantity:  afterQty,
			Remark:         sql.NullString{String: d.Remark, Valid: d.Remark != ""},
		})
	}

	err = l.svcCtx.AdjustDetailModel.BatchInsert(l.ctx, details)
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	tenantId := tenantctx.ExtractTenantId(l.ctx)
	metrics.StockAdjustCreatedTotal.WithLabelValues(tenantId, in.AdjustReason).Inc()
	for _, d := range details {
		if d.AdjustQuantity >= 0 {
			metrics.StockAdjustQuantityMeters.WithLabelValues(tenantId, "increase").Add(d.AdjustQuantity)
		} else {
			metrics.StockAdjustQuantityMeters.WithLabelValues(tenantId, "decrease").Add(math.Abs(d.AdjustQuantity))
		}
	}

	return &pb.IdResp{Id: adjustId}, nil
}