package service

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/cloudprint/cloudprint-backend/internal/model"
	"github.com/cloudprint/cloudprint-backend/internal/repository"
	"github.com/google/uuid"
)

type OrderService struct {
	orderRepo     *repository.OrderRepository
	orderItemRepo *repository.OrderItemRepository
	fileRepo      *repository.FileRepository
	priceRepo     *repository.PriceRepository
	userRepo      *repository.UserRepository
	printerRepo   *repository.PrinterRepository
	printJobRepo  *repository.PrintJobRepository
}

func NewOrderService(
	orderRepo *repository.OrderRepository,
	orderItemRepo *repository.OrderItemRepository,
	fileRepo *repository.FileRepository,
	priceRepo *repository.PriceRepository,
	userRepo *repository.UserRepository,
	printerRepo *repository.PrinterRepository,
	printJobRepo *repository.PrintJobRepository,
) *OrderService {
	return &OrderService{
		orderRepo:     orderRepo,
		orderItemRepo: orderItemRepo,
		fileRepo:      fileRepo,
		priceRepo:     priceRepo,
		userRepo:      userRepo,
		printerRepo:   printerRepo,
		printJobRepo:  printJobRepo,
	}
}

type CreateOrderItem struct {
	FileID    int32
	PrinterID int32
	Copies    int
	Color     bool
	Duplex    bool
	PageRange string
}

func (s *OrderService) CreateOrder(ctx context.Context, userID int32, items []*CreateOrderItem, remark string) (*model.Order, error) {
	if len(items) == 0 {
		return nil, errors.New("order must have at least one item")
	}

	// Generate order number
	orderNo := generateOrderNo()

	// Calculate total amount
	var totalAmount float64
	orderItems := make([]*model.OrderItem, 0, len(items))

	for _, item := range items {
		// Verify file exists
		file, err := s.fileRepo.GetByID(ctx, item.FileID)
		if err != nil || file == nil {
			return nil, fmt.Errorf("file not found: %d", item.FileID)
		}

		// Calculate price
		price, err := s.calculatePrice(ctx, item)
		if err != nil {
			return nil, err
		}

		orderItem := &model.OrderItem{
			FileID:    item.FileID,
			PrinterID: intPtr(item.PrinterID),
			Copies:    item.Copies,
			Color:     item.Color,
			Duplex:    item.Duplex,
			PageRange: item.PageRange,
			Price:     price,
		}
		orderItems = append(orderItems, orderItem)
		totalAmount += price
	}

	// Create order
	order := &model.Order{
		OrderNo:     orderNo,
		UserID:      userID,
		Status:      model.OrderStatusPending,
		TotalAmount: totalAmount,
		Remark:      remark,
		Items:       orderItems,
	}

	// Save order with items
	if err := s.orderRepo.CreateWithItems(ctx, order, orderItems); err != nil {
		return nil, fmt.Errorf("failed to create order: %w", err)
	}

	return order, nil
}

func (s *OrderService) calculatePrice(ctx context.Context, item *CreateOrderItem) (float64, error) {
	// Get price list
	prices, err := s.priceRepo.GetAllActive(ctx)
	if err != nil {
		return 0, err
	}

	// Default price calculation (A4 B&W per page)
	defaultPrice := 0.10
	colorMultiplier := 3.0
	duplexDiscount := 0.8

	// Calculate based on file type and settings
	// For simplicity, using default values
	// In production, look up from price list based on file type

	pageCount := 1 // Default, should get actual page count from file
	if item.Copies <= 0 {
		item.Copies = 1
	}

	price := float64(pageCount) * defaultPrice * float64(item.Copies)

	if item.Color {
		price *= colorMultiplier
	}

	if item.Duplex {
		price *= duplexDiscount
	}

	return price, nil
}

func generateOrderNo() string {
	now := time.Now()
	return fmt.Sprintf("CP%d%s", now.UnixNano()/1000000, uuid.New().String()[:8])
}

func intPtr(i int32) *int32 {
	return &i
}

func (s *OrderService) GetOrder(ctx context.Context, orderNo string) (*model.Order, error) {
	return s.orderRepo.GetByOrderNo(ctx, orderNo)
}

func (s *OrderService) GetOrderList(ctx context.Context, userID int32, status int8, page, pageSize int) ([]*model.Order, int64, error) {
	return s.orderRepo.GetListByUserID(ctx, userID, status, page, pageSize)
}

func (s *OrderService) UpdateOrderStatus(ctx context.Context, orderNo string, status int8) error {
	return s.orderRepo.UpdateStatus(ctx, orderNo, status)
}

func (s *OrderService) CancelOrder(ctx context.Context, orderNo string) error {
	order, err := s.orderRepo.GetByOrderNo(ctx, orderNo)
	if err != nil || order == nil {
		return errors.New("order not found")
	}

	if order.Status != model.OrderStatusPending {
		return errors.New("only pending orders can be cancelled")
	}

	return s.orderRepo.UpdateStatus(ctx, orderNo, model.OrderStatusCancelled)
}

// PayOrder handles payment for an order
func (s *OrderService) PayOrder(ctx context.Context, orderNo string, payType string) error {
	order, err := s.orderRepo.GetByOrderNo(ctx, orderNo)
	if err != nil || order == nil {
		return errors.New("order not found")
	}

	if order.Status != model.OrderStatusPending {
		return errors.New("order is not pending")
	}

	// Update order status to paid
	if err := s.orderRepo.UpdateStatus(ctx, orderNo, model.OrderStatusPaid); err != nil {
		return err
	}

	// Create print jobs for each order item
	for _, item := range order.Items {
		if item.PrinterID != nil {
			jobNo := generateJobNo()
			job := &model.PrintJob{
				JobNo:       jobNo,
				PrinterID:   *item.PrinterID,
				OrderItemID: item.ID,
				Status:      model.PrintJobStatusPending,
				Progress:    0,
			}
			if err := s.printJobRepo.Create(ctx, job); err != nil {
				// Log error but don't fail
				continue
			}
		}
	}

	// Update order status to printing
	return s.orderRepo.UpdateStatus(ctx, orderNo, model.OrderStatusPrinting)
}

func generateJobNo() string {
	now := time.Now()
	return fmt.Sprintf("PJ%d%s", now.UnixNano()/1000000, uuid.New().String()[:8])
}