package processor

import (
	"context"
	"fmt"

	"github.com/google/uuid"

	"apskel-pos-be/internal/models"
	"apskel-pos-be/internal/repository"
)

const (
	customerOrdersPageLimit = 20
	customerOrdersMaxLimit  = 100
)

type orderEarnedReader interface {
	EarnedByOrders(ctx context.Context, orderIDs []uuid.UUID) (map[uuid.UUID]OrderEarned, error)
}

// CustomerOrderProcessor serves the customer app's order history: the customer's own
// orders only, without costs or staff details.
type CustomerOrderProcessor struct {
	repo   repository.CustomerOrderRepository
	earned orderEarnedReader
}

func NewCustomerOrderProcessor(repo repository.CustomerOrderRepository, earned orderEarnedReader) *CustomerOrderProcessor {
	return &CustomerOrderProcessor{repo: repo, earned: earned}
}

// List is GET /customer/orders: the customer's orders across all outlets, newest first.
func (p *CustomerOrderProcessor) List(ctx context.Context, customerID uuid.UUID, query models.ListCustomerOrdersQuery) (*models.PaginatedResponse[models.CustomerOrderSummary], error) {
	page, limit := query.Page, query.Limit
	if page == 0 {
		page = 1
	}
	if limit == 0 {
		limit = customerOrdersPageLimit
	}
	if page < 1 || limit < 1 || limit > customerOrdersMaxLimit {
		return nil, fmt.Errorf("%w: page must be at least 1 and limit between 1 and %d", ErrInvalidWalletQuery, customerOrdersMaxLimit)
	}

	rows, total, err := p.repo.ListOrders(ctx, customerID, (page-1)*limit, limit)
	if err != nil {
		return nil, err
	}
	ids := make([]uuid.UUID, 0, len(rows))
	for _, r := range rows {
		ids = append(ids, r.ID)
	}
	earned, err := p.earned.EarnedByOrders(ctx, ids)
	if err != nil {
		return nil, err
	}
	data := make([]models.CustomerOrderSummary, 0, len(rows))
	for _, r := range rows {
		data = append(data, customerOrderSummary(r, earned[r.ID]))
	}
	return &models.PaginatedResponse[models.CustomerOrderSummary]{
		Data: data,
		Pagination: models.Pagination{
			Page:       page,
			Limit:      limit,
			Total:      total,
			TotalPages: int((total + int64(limit) - 1) / int64(limit)),
		},
	}, nil
}

// Detail is GET /customer/orders/:id. Another customer's order is
// repository.ErrCustomerOrderNotFound, like one that does not exist.
func (p *CustomerOrderProcessor) Detail(ctx context.Context, customerID, orderID uuid.UUID) (*models.CustomerOrderDetail, error) {
	row, err := p.repo.GetOrder(ctx, customerID, orderID)
	if err != nil {
		return nil, err
	}
	items, err := p.repo.ListItems(ctx, orderID)
	if err != nil {
		return nil, err
	}
	payments, err := p.repo.ListPayments(ctx, orderID)
	if err != nil {
		return nil, err
	}
	earned, err := p.earned.EarnedByOrders(ctx, []uuid.UUID{orderID})
	if err != nil {
		return nil, err
	}

	detail := &models.CustomerOrderDetail{
		CustomerOrderSummary: customerOrderSummary(*row, earned[orderID]),
		TableNumber:          row.TableNumber,
		Subtotal:             row.Subtotal,
		DiscountAmount:       row.DiscountAmount,
		TaxAmount:            row.TaxAmount,
		RefundAmount:         row.RefundAmount,
		Items:                make([]models.CustomerOrderItem, 0, len(items)),
		Payments:             make([]models.CustomerOrderPayment, 0, len(payments)),
	}
	for _, it := range items {
		modifiers := []map[string]interface{}(it.Modifiers)
		if modifiers == nil {
			modifiers = []map[string]interface{}{}
		}
		detail.Items = append(detail.Items, models.CustomerOrderItem{
			ID:             it.ID,
			ProductID:      it.ProductID,
			ProductName:    it.ProductName,
			VariantName:    it.VariantName,
			Quantity:       it.Quantity,
			Weight:         it.Weight,
			UnitName:       it.UnitName,
			UnitPrice:      it.UnitPrice,
			TotalPrice:     it.TotalPrice,
			RefundQuantity: it.RefundQuantity,
			Modifiers:      modifiers,
			Notes:          it.Notes,
			Status:         it.Status,
		})
	}
	for _, pay := range payments {
		detail.Payments = append(detail.Payments, models.CustomerOrderPayment{
			ID:           pay.ID,
			MethodName:   pay.MethodName,
			MethodType:   pay.MethodType,
			Amount:       pay.Amount,
			Status:       pay.Status,
			RefundAmount: pay.RefundAmount,
			CreatedAt:    pay.CreatedAt,
		})
	}
	return detail, nil
}

func customerOrderSummary(r repository.CustomerOrderRow, earned OrderEarned) models.CustomerOrderSummary {
	return models.CustomerOrderSummary{
		ID:            r.ID,
		OrderNumber:   r.OrderNumber,
		OutletID:      r.OutletID,
		OutletName:    r.OutletName,
		OrderType:     r.OrderType,
		Status:        r.Status,
		PaymentStatus: r.PaymentStatus,
		TotalAmount:   r.TotalAmount,
		ItemCount:     r.ItemCount,
		IsVoid:        r.IsVoid,
		IsRefund:      r.IsRefund,
		PointsEarned:  earned.Points,
		CoinsEarned:   earned.Coins,
		CreatedAt:     r.CreatedAt,
	}
}