package service

import (
	"database/sql"

	"github.com/shopspring/decimal"
	"github.com/wmms/wmms/internal/model"
	"github.com/wmms/wmms/internal/repository"
)

type StockService struct {
	stockRepo *repository.StockRepo
}

func NewStockService() *StockService {
	return &StockService{
		stockRepo: repository.NewStockRepo(),
	}
}

func (s *StockService) GetAllStock(search string, limit, offset int) ([]model.Stock, int64, error) {
	return s.stockRepo.GetAllStock(search, limit, offset)
}

func (s *StockService) GetByMaterialID(materialID int64) (*model.Stock, error) {
	return s.stockRepo.GetByMaterialID(materialID)
}

func (s *StockService) GetWarningStock(limit, offset int) ([]model.Stock, int64, error) {
	return s.stockRepo.GetWarningStock(limit, offset)
}

func (s *StockService) UpdateWarningStock(materialID int64, minimumAvailable decimal.Decimal) error {
	return s.stockRepo.UpdateWarningStock(materialID, minimumAvailable)
}

func (s *StockService) GetLogsByMaterialID(materialID int64, limit, offset int) ([]model.StockLogResponse, int64, error) {
	logs, total, err := s.stockRepo.GetLogsByMaterialID(materialID, limit, offset)
	if err != nil {
		return nil, 0, err
	}

	var responses []model.StockLogResponse
	balance := decimal.Zero
	for _, log := range logs {
		quantity := decimal.NewFromInt(int64(log.Quantity))
		if log.Type == "in" {
			balance = balance.Add(quantity)
		} else {
			balance = balance.Sub(quantity)
		}

		changeType := "outbound"
		if log.Type == "in" {
			changeType = "inbound"
		}

		beforeQuantity := balance.Sub(quantity)
		if log.Type != "in" {
			beforeQuantity = balance.Add(quantity)
		}

		responses = append(responses, model.StockLogResponse{
			ID:             log.ID,
			MaterialID:     log.MaterialID,
			ChangeType:     changeType,
			ChangeQuantity: quantity,
			BeforeQuantity: beforeQuantity,
			AfterQuantity:  balance,
			ReferenceID:    log.RelatedOrderID,
			ReferenceType:  log.RelatedOrderType,
			CreatedAt:      log.CreatedAt,
		})
	}
	return responses, total, nil
}

func (s *StockService) GetAllLogs(limit, offset int) ([]model.StockLogResponse, int64, error) {
	logs, total, err := s.stockRepo.GetAllLogsWithBalance(limit, offset)
	if err != nil {
		return nil, 0, err
	}

	var responses []model.StockLogResponse
	for _, log := range logs {
		changeType := "outbound"
		if log.Type == "in" {
			changeType = "inbound"
		}

		quantity := decimal.NewFromInt(int64(log.Quantity))
		beforeQuantity := log.RunningBalance.Sub(quantity)
		if log.Type != "in" {
			beforeQuantity = log.RunningBalance.Add(quantity)
		}

		// inbound=+quantity, outbound=-quantity
		changeQuantity := quantity
		if log.Type != "in" {
			changeQuantity = quantity.Neg()
		}

		responses = append(responses, model.StockLogResponse{
			ID:             log.ID,
			MaterialID:     log.MaterialID,
			ChangeType:     changeType,
			ChangeQuantity: changeQuantity,
			BeforeQuantity: beforeQuantity,
			AfterQuantity:  log.RunningBalance,
			ReferenceID:    log.RelatedOrderID,
			ReferenceType:  log.RelatedOrderType,
			CreatedAt:      log.CreatedAt,
		})
	}
	return responses, total, nil
}

func (s *StockService) MaterialExists(materialID int64) (bool, error) {
	_, err := s.stockRepo.GetByMaterialID(materialID)
	if err == sql.ErrNoRows {
		return false, nil
	}
	if err != nil {
		return false, err
	}
	return true, nil
}

func (s *StockService) GetInventoryBalanceDetails(materialID int64) ([]model.InventoryBalanceDetail, error) {
	return s.stockRepo.GetInventoryBalanceDetails(materialID)
}