package order

import (
	"enaklo-pos-be/internal/common/logger"
	"enaklo-pos-be/internal/common/mycontext"
	"enaklo-pos-be/internal/entity"
	"fmt"

	"github.com/pkg/errors"
	"go.uber.org/zap"
)

func (s *orderSvc) PartialRefundRequest(ctx mycontext.Context, partnerID, orderID int64, reason string, items []entity.PartialRefundItem) error {
	order, err := s.repo.FindByIDAndPartnerID(ctx, orderID, partnerID)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to find order for partial refund", zap.Error(err))
		return err
	}

	if order.Status != "PAID" && order.Status != "PARTIAL" {
		return errors.New("only paid order can be partially refunded")
	}

	refundedAmount := 0.0
	orderItemMap := make(map[int64]*entity.OrderItem)

	for _, item := range order.OrderItems {
		orderItemMap[item.ID] = &item
	}

	for _, refundItem := range items {
		orderItem, exists := orderItemMap[refundItem.OrderItemID]
		if !exists {
			return errors.New(fmt.Sprintf("order item %d not found", refundItem.OrderItemID))
		}

		if refundItem.Quantity > orderItem.Quantity {
			return errors.New(fmt.Sprintf("refund quantity %d exceeds available quantity %d for item %d",
				refundItem.Quantity, orderItem.Quantity, refundItem.OrderItemID))
		}

		refundedAmount += orderItem.Price * float64(refundItem.Quantity)
	}

	for _, refundItem := range items {
		orderItem := orderItemMap[refundItem.OrderItemID]
		newQuantity := orderItem.Quantity - refundItem.Quantity

		if newQuantity == 0 {
			err = s.repo.UpdateOrderItem(ctx, refundItem.OrderItemID, 0)
		} else {
			err = s.repo.UpdateOrderItem(ctx, refundItem.OrderItemID, newQuantity)
		}

		if err != nil {
			logger.ContextLogger(ctx).Error("failed to update order item", zap.Error(err))
			return err
		}
	}

	remainingAmount := order.Amount - refundedAmount
	remainingTax := (remainingAmount / order.Amount) * order.Tax
	remainingTotal := remainingAmount + remainingTax

	err = s.repo.UpdateOrderTotals(ctx, orderID, remainingAmount, remainingTax, remainingTotal)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to update order totals", zap.Error(err))
		return err
	}

	newStatus := "PARTIAL"
	if remainingAmount <= 0 {
		newStatus = "REFUNDED"
	}

	err = s.repo.UpdateOrder(ctx, orderID, newStatus, reason)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to update order status", zap.Error(err))
		return err
	}

	refundTransaction, err := s.createRefundTransaction(ctx, order, reason)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to create refund transaction", zap.Error(err))
		return err
	}

	refundTransaction.Amount = -refundedAmount
	_, err = s.transaction.Create(ctx, refundTransaction)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to update refund transaction", zap.Error(err))
		return err
	}

	logger.ContextLogger(ctx).Info("partial refund processed successfully",
		zap.Int64("orderID", orderID),
		zap.String("reason", reason),
		zap.Float64("refundedAmount", refundedAmount),
		zap.String("refundTransactionID", refundTransaction.ID))

	return nil
}

// VoidOrderRequest handles voiding orders (for ongoing orders) or specific items
func (s *orderSvc) VoidOrderRequest(ctx mycontext.Context, partnerID, orderID int64, reason string, voidType string, items []entity.VoidItem) error {
	order, err := s.repo.FindByIDAndPartnerID(ctx, orderID, partnerID)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to find order for void", zap.Error(err))
		return err
	}

	if order.Status != "NEW" && order.Status != "PENDING" {
		return errors.New("only new or pending orders can be voided")
	}

	if voidType == "ALL" {
		// Void all items - create new VOIDED items for all existing items
		for _, orderItem := range order.OrderItems {
			if orderItem.Status == "ACTIVE" && orderItem.Quantity > 0 {
				// Create new VOIDED order item with the voided quantity
				voidedItem := &entity.OrderItem{
					OrderID:   orderID,
					ItemID:    orderItem.ItemID,
					ItemType:  orderItem.ItemType,
					Price:     orderItem.Price,
					Quantity:  orderItem.Quantity, // Void the full quantity
					Status:    "VOIDED",
					CreatedBy: orderItem.CreatedBy,
					ItemName:  orderItem.ItemName,
					Notes:     reason, // Use the reason as notes for tracking
				}

				err = s.repo.CreateOrderItem(ctx, orderID, voidedItem)
				if err != nil {
					logger.ContextLogger(ctx).Error("failed to create voided order item", zap.Error(err))
					return err
				}

				// Update original item quantity to 0
				err = s.repo.UpdateOrderItem(ctx, orderItem.ID, 0)
				if err != nil {
					logger.ContextLogger(ctx).Error("failed to update original order item", zap.Error(err))
					return err
				}
			}
		}

		// Update order status to VOIDED
		err = s.repo.UpdateOrder(ctx, orderID, "VOIDED", reason)
		if err != nil {
			logger.ContextLogger(ctx).Error("failed to void order", zap.Error(err))
			return err
		}

		// Recalculate order totals (should be 0 for voided order)
		err = s.repo.UpdateOrderTotals(ctx, orderID, 0, 0, 0)
		if err != nil {
			logger.ContextLogger(ctx).Error("failed to update order totals", zap.Error(err))
			return err
		}

	} else if voidType == "ITEM" {
		// Void specific items
		orderItemMap := make(map[int64]*entity.OrderItem)
		for i := range order.OrderItems {
			orderItemMap[order.OrderItems[i].ID] = &order.OrderItems[i]
		}

		for _, voidItem := range items {
			orderItem, exists := orderItemMap[voidItem.OrderItemID]
			if !exists {
				return errors.New(fmt.Sprintf("order item %d not found", voidItem.OrderItemID))
			}

			if orderItem.Status != "ACTIVE" {
				return errors.New(fmt.Sprintf("order item %d is not active", voidItem.OrderItemID))
			}

			if voidItem.Quantity > orderItem.Quantity {
				return errors.New(fmt.Sprintf("void quantity %d exceeds available quantity %d for item %d",
					voidItem.Quantity, orderItem.Quantity, voidItem.OrderItemID))
			}
		}

		for _, voidItem := range items {
			orderItem := orderItemMap[voidItem.OrderItemID]

			// Create new VOIDED order item with the voided quantity
			voidedItem := &entity.OrderItem{
				OrderID:   orderID,
				ItemID:    orderItem.ItemID,
				ItemType:  orderItem.ItemType,
				Price:     orderItem.Price,
				Quantity:  voidItem.Quantity, // Void the requested quantity
				Status:    "VOIDED",
				CreatedBy: orderItem.CreatedBy,
				ItemName:  orderItem.ItemName,
				Notes:     reason, // Use the reason as notes for tracking
			}

			err = s.repo.CreateOrderItem(ctx, orderID, voidedItem)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to create voided order item", zap.Error(err))
				return err
			}

			// Update original item quantity
			newQuantity := orderItem.Quantity - voidItem.Quantity
			err = s.repo.UpdateOrderItem(ctx, voidItem.OrderItemID, newQuantity)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to update order item", zap.Error(err))
				return err
			}
		}

		updatedOrder, err := s.repo.FindByIDAndPartnerID(ctx, orderID, partnerID)
		if err != nil {
			logger.ContextLogger(ctx).Error("failed to fetch updated order for recalculation", zap.Error(err))
			return err
		}

		var activeItems []entity.OrderItemRequest
		for _, item := range updatedOrder.OrderItems {
			if item.Status == "ACTIVE" && item.Quantity > 0 {
				activeItems = append(activeItems, entity.OrderItemRequest{
					ProductID: item.ItemID,
					Quantity:  item.Quantity,
					Notes:     item.Notes,
				})
			}
		}

		if len(activeItems) > 0 {
			productIDs, _, err := s.ValidateOrderItems(ctx, activeItems)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to validate order items for recalculation", zap.Error(err))
				return err
			}

			productDetails, err := s.product.GetProductDetails(ctx, productIDs, partnerID)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to get product details for recalculation", zap.Error(err))
				return err
			}

			orderCalculation, err := s.CalculateOrderTotals(ctx, activeItems, productDetails, order.Source, partnerID)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to calculate order totals", zap.Error(err))
				return err
			}

			// Update order totals
			err = s.repo.UpdateOrderTotals(ctx, orderID, orderCalculation.Subtotal, orderCalculation.Tax, orderCalculation.Total)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to update order totals", zap.Error(err))
				return err
			}

			// Update order status based on remaining amount
			newStatus := "PENDING"
			if orderCalculation.Subtotal <= 0 {
				newStatus = "CANCELED"
			}

			err = s.repo.UpdateOrder(ctx, orderID, newStatus, reason)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to update order status", zap.Error(err))
				return err
			}
		} else {
			// No active items left, cancel the order
			err = s.repo.UpdateOrderTotals(ctx, orderID, 0, 0, 0)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to update order totals", zap.Error(err))
				return err
			}

			err = s.repo.UpdateOrder(ctx, orderID, "CANCELED", reason)
			if err != nil {
				logger.ContextLogger(ctx).Error("failed to update order status", zap.Error(err))
				return err
			}
		}
	}

	logger.ContextLogger(ctx).Info("order voided successfully",
		zap.Int64("orderID", orderID),
		zap.String("reason", reason),
		zap.String("voidType", voidType))

	return nil
}

func (s *orderSvc) SplitBillRequest(ctx mycontext.Context, partnerID, orderID int64, splitType string, items []entity.SplitBillItem, amount float64) (*entity.Order, error) {
	order, err := s.repo.FindByIDAndPartnerID(ctx, orderID, partnerID)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to find order for split bill", zap.Error(err))
		return nil, err
	}

	if order.Status != "NEW" && order.Status != "PENDING" {
		return nil, errors.New("only new or pending orders can be split")
	}

	var splitOrder *entity.Order

	if splitType == "ITEM" {
		splitOrder, err = s.splitByItems(ctx, order, items)
	} else if splitType == "AMOUNT" {
		splitOrder, err = s.splitByAmount(ctx, order, amount)
	}

	if err != nil {
		logger.ContextLogger(ctx).Error("failed to split bill", zap.Error(err))
		return nil, err
	}

	logger.ContextLogger(ctx).Info("bill split successfully",
		zap.Int64("orderID", orderID),
		zap.String("splitType", splitType),
		zap.Int64("splitOrderID", splitOrder.ID))

	return splitOrder, nil
}

func (s *orderSvc) splitByItems(ctx mycontext.Context, originalOrder *entity.Order, items []entity.SplitBillItem) (*entity.Order, error) {
	var splitOrderItems []entity.OrderItem
	orderItemMap := make(map[int64]*entity.OrderItem)

	for i := range originalOrder.OrderItems {
		orderItemMap[originalOrder.OrderItems[i].ID] = &originalOrder.OrderItems[i]
	}

	assignedItems := make(map[int64]bool)

	for _, item := range items {
		orderItem, exists := orderItemMap[item.OrderItemID]
		if !exists {
			return nil, errors.New(fmt.Sprintf("order item %d not found", item.OrderItemID))
		}

		if item.Quantity > orderItem.Quantity {
			return nil, errors.New(fmt.Sprintf("split quantity %d exceeds available quantity %d for item %d",
				item.Quantity, orderItem.Quantity, item.OrderItemID))
		}

		if assignedItems[item.OrderItemID] {
			return nil, errors.New(fmt.Sprintf("order item %d is already assigned to another split", item.OrderItemID))
		}

		assignedItems[item.OrderItemID] = true

		splitOrderItems = append(splitOrderItems, entity.OrderItem{
			ItemID:    orderItem.ItemID,
			ItemType:  orderItem.ItemType,
			Price:     orderItem.Price,
			ItemName:  orderItem.ItemName,
			Quantity:  item.Quantity,
			CreatedBy: originalOrder.CreatedBy,
			Product:   orderItem.Product,
			Notes:     orderItem.Notes,
		})
	}

	splitAmount := 0.0
	for _, item := range splitOrderItems {
		splitAmount += item.Price * float64(item.Quantity)
	}

	splitTax := (splitAmount / originalOrder.Amount) * originalOrder.Tax
	splitTotal := splitAmount + splitTax

	splitOrder := &entity.Order{
		PartnerID:        originalOrder.PartnerID,
		CustomerID:       originalOrder.CustomerID,
		CustomerName:     originalOrder.CustomerName,
		Status:           "PAID",
		Amount:           splitAmount,
		Tax:              splitTax,
		Total:            splitTotal,
		Source:           originalOrder.Source,
		CreatedBy:        originalOrder.CreatedBy,
		OrderItems:       splitOrderItems,
		OrderType:        originalOrder.OrderType,
		TableNumber:      originalOrder.TableNumber,
		CashierSessionID: originalOrder.CashierSessionID,
	}

	createdOrder, err := s.repo.Create(ctx, splitOrder)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to create split order", zap.Error(err))
		return nil, err
	}

	for _, item := range items {
		orderItem := orderItemMap[item.OrderItemID]
		newQuantity := orderItem.Quantity - item.Quantity

		if newQuantity == 0 {
			err = s.repo.UpdateOrderItem(ctx, item.OrderItemID, 0)
		} else {
			err = s.repo.UpdateOrderItem(ctx, item.OrderItemID, newQuantity)
		}

		if err != nil {
			logger.ContextLogger(ctx).Error("failed to update original order item", zap.Error(err))
			return nil, err
		}
	}

	remainingAmount := originalOrder.Amount - splitAmount
	remainingTax := (remainingAmount / originalOrder.Amount) * originalOrder.Tax
	remainingTotal := remainingAmount + remainingTax

	err = s.repo.UpdateOrderTotals(ctx, originalOrder.ID, remainingAmount, remainingTax, remainingTotal)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to update original order totals", zap.Error(err))
		return nil, err
	}

	return createdOrder, nil
}

// splitByAmount splits the order by assigning specific amounts to each split
func (s *orderSvc) splitByAmount(ctx mycontext.Context, originalOrder *entity.Order, amount float64) (*entity.Order, error) {
	// Validate that split amount is less than original order total
	if amount >= originalOrder.Total {
		return nil, errors.New(fmt.Sprintf("split amount %.2f must be less than order total %.2f",
			amount, originalOrder.Total))
	}

	// For amount-based split, we create a new order with all items
	var splitOrderItems []entity.OrderItem

	for _, item := range originalOrder.OrderItems {
		splitOrderItems = append(splitOrderItems, entity.OrderItem{
			ItemID:    item.ItemID,
			ItemType:  item.ItemType,
			Price:     item.Price,
			ItemName:  item.ItemName,
			Quantity:  item.Quantity,
			CreatedBy: originalOrder.CreatedBy,
			Product:   item.Product,
			Notes:     item.Notes,
		})
	}

	splitAmount := amount
	splitTax := (splitAmount / originalOrder.Amount) * originalOrder.Tax
	splitTotal := splitAmount + splitTax

	splitOrder := &entity.Order{
		PartnerID:        originalOrder.PartnerID,
		CustomerID:       originalOrder.CustomerID,
		CustomerName:     originalOrder.CustomerName,
		Status:           "PAID",
		Amount:           splitAmount,
		Tax:              splitTax,
		Total:            splitTotal,
		Source:           originalOrder.Source,
		CreatedBy:        originalOrder.CreatedBy,
		OrderItems:       splitOrderItems,
		OrderType:        originalOrder.OrderType,
		TableNumber:      originalOrder.TableNumber,
		CashierSessionID: originalOrder.CashierSessionID,
	}

	createdOrder, err := s.repo.Create(ctx, splitOrder)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to create split order", zap.Error(err))
		return nil, err
	}

	// Adjust original order amount
	remainingAmount := originalOrder.Amount - splitAmount
	remainingTax := (remainingAmount / originalOrder.Amount) * originalOrder.Tax
	remainingTotal := remainingAmount + remainingTax

	// Update original order totals
	err = s.repo.UpdateOrderTotals(ctx, originalOrder.ID, remainingAmount, remainingTax, remainingTotal)
	if err != nil {
		logger.ContextLogger(ctx).Error("failed to update original order totals", zap.Error(err))
		return nil, err
	}

	return createdOrder, nil
}