package logic

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"math"
	"strconv"
	"strings"

	"muyu-apiserver/model"
	"muyu-apiserver/rpc/inventory/pb"
)

func nullString(v string) sql.NullString {
	return sql.NullString{String: v, Valid: v != ""}
}

func nullableJSON(v string) sql.NullString {
	v = strings.TrimSpace(v)
	return sql.NullString{String: v, Valid: v != ""}
}

func parseDecimalString(v string) float64 {
	n, _ := strconv.ParseFloat(strings.TrimSpace(v), 64)
	return n
}

type yarnRatioPayload struct {
	Warp []yarnRatioItem `json:"warp"`
	Weft []yarnRatioItem `json:"weft"`
}

type yarnRatioItem struct {
	YarnID string  `json:"yarn_id"`
	YarnId string  `json:"yarnId"`
	Ratio  float64 `json:"ratio"`
}

func (i yarnRatioItem) yarnID() string {
	if i.YarnID != "" {
		return i.YarnID
	}
	return i.YarnId
}

func validateProductBatchInput(batch *pb.ProductBatchInput) error {
	if batch == nil {
		return nil
	}
	return validateYarnRatio(batch.YarnRatio)
}

func validateYarnRatio(raw string) error {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return nil
	}
	var payload yarnRatioPayload
	if err := json.Unmarshal([]byte(raw), &payload); err != nil {
		return fmt.Errorf("纱线配比格式无效")
	}
	if err := validateYarnRatioSide("经线", payload.Warp); err != nil {
		return err
	}
	return validateYarnRatioSide("纬线", payload.Weft)
}

func validateYarnRatioSide(label string, items []yarnRatioItem) error {
	if len(items) == 0 {
		return nil
	}
	total := 0
	for _, item := range items {
		if strings.TrimSpace(item.yarnID()) == "" {
			return fmt.Errorf("%s纱线不能为空", label)
		}
		if item.Ratio < 1 || item.Ratio > 10 || math.Trunc(item.Ratio) != item.Ratio {
			return fmt.Errorf("%s使用配比必须为 1-10 的整数", label)
		}
		total += int(item.Ratio)
	}
	if total != 10 {
		return fmt.Errorf("%s配比合计必须为 10，当前为 %d", label, total)
	}
	return nil
}

func batchInputToModelFields(batch *pb.ProductBatchInput, target *model.InvProductBatch) error {
	if batch == nil {
		target.ProductionProcess = nullString(defaultProcess)
		return nil
	}
	if err := validateProductBatchInput(batch); err != nil {
		return err
	}
	target.YarnRatio = nullableJSON(batch.YarnRatio)
	target.WarpWeightGM = parseDecimalString(batch.WarpWeightGM)
	target.WeftWeightGM = parseDecimalString(batch.WeftWeightGM)
	process := strings.TrimSpace(batch.ProductionProcess)
	if process == "" {
		process = defaultProcess
	}
	target.ProductionProcess = nullString(process)
	target.Remark = nullString(batch.Remark)
	return nil
}

func batchToPb(batch *model.InvProductBatch) *pb.ProductBatchInfo {
	return &pb.ProductBatchInfo{
		BatchId:           batch.BatchId,
		ProductId:         batch.ProductId,
		BatchNo:           batch.BatchNo,
		YarnRatio:         batch.YarnRatio.String,
		WarpWeightGM:      fmt.Sprintf("%.4f", batch.WarpWeightGM),
		WeftWeightGM:      fmt.Sprintf("%.4f", batch.WeftWeightGM),
		ProductionProcess: batch.ProductionProcess.String,
		Remark:            batch.Remark.String,
		Status:            batch.Status,
		CreatedAt:         batch.CreatedAt.Format("2006-01-02 15:04:05"),
		UpdatedAt:         batch.UpdatedAt.Format("2006-01-02 15:04:05"),
	}
}

func productToPb(product *model.InvProduct) *pb.ProductInfo {
	return &pb.ProductInfo{
		ProductId:   product.ProductId,
		ProductName: product.ProductName,
		ImageUrl:    product.ImageUrl,
		Spec:        product.Spec,
		Color:       product.Color,
		SalesPrice:  fmt.Sprintf("%.2f", product.SalesPrice),
		Remark:      product.Remark.String,
		Status:      product.Status,
		CreatedAt:   product.CreatedAt.Format("2006-01-02 15:04:05"),
		UpdatedAt:   product.UpdatedAt.Format("2006-01-02 15:04:05"),
		ColorNo:     product.ColorNo,
		ProductCode: product.ProductCode,
	}
}