package chapa

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"

	"github.com/SamuelTariku/FortuneBet-Backend/internal/config"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/domain"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/services/user"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/services/wallet"
	"github.com/google/uuid"
)

type Service struct {
	transferStore wallet.TransferStore
	walletStore   wallet.Service
	userStore     user.UserStore
	cfg           *config.Config
	chapaClient   *Client
}

func NewService(
	transferStore wallet.TransferStore,
	walletStore wallet.Service,
	userStore user.UserStore,
	cfg *config.Config,
	chapaClient *Client,

) *Service {
	return &Service{
		transferStore: transferStore,
		walletStore:   walletStore,
		userStore:     userStore,
		cfg:           cfg,
		chapaClient:   chapaClient,
	}
}

// InitiateDeposit starts a new deposit process
func (s *Service) InitiateDeposit(ctx context.Context, userID int64, amount domain.Currency) (string, error) {
	// Validate amount
	if amount <= 0 {
		return "", domain.ErrInvalidPaymentAmount
	}

	// Get user details
	user, err := s.userStore.GetUserByID(ctx, userID)
	if err != nil {
		return "", fmt.Errorf("failed to get user: %w", err)
	}

	var senderWallet domain.Wallet

	// Generate unique reference
	// reference := uuid.New().String()
	reference := fmt.Sprintf("chapa-deposit-%d-%s", userID, uuid.New().String())

	senderWallets, err := s.walletStore.GetWalletsByUser(ctx, userID)
	if err != nil {
		return "", fmt.Errorf("failed to get sender wallets: %w", err)
	}
	for _, wallet := range senderWallets {
		if wallet.IsTransferable {
			senderWallet = wallet
			break
		}
	}

	// Check if payment with this reference already exists
	// if transfer, err := s.transferStore.GetTransferByReference(ctx, reference); err == nil {

	// 	return fmt.Sprintf("%v", transfer), ErrPaymentAlreadyExists
	// }

	// Create payment record
	transfer := domain.CreateTransfer{
		Message:         fmt.Sprintf("Depositing %v into wallet using chapa. Reference Number %v", amount.Float32(), reference),
		Amount:          amount,
		Type:            domain.DEPOSIT,
		PaymentMethod:   domain.TRANSFER_CHAPA,
		ReferenceNumber: reference,
		// ReceiverWalletID: 1,
		SenderWalletID: domain.ValidInt64{
			Value: senderWallet.ID,
			Valid: true,
		},
		Verified: false,
	}

	payload := domain.ChapaDepositRequest{
		Amount:      amount,
		Currency:    "ETB",
		Email:       user.Email,
		FirstName:   user.FirstName,
		LastName:    user.LastName,
		TxRef:       reference,
		CallbackURL: s.cfg.CHAPA_CALLBACK_URL,
		ReturnURL:   s.cfg.CHAPA_RETURN_URL,
	}

	// Initialize payment with Chapa
	response, err := s.chapaClient.InitializePayment(ctx, payload)

	fmt.Printf("\n\nChapa payload is: %+v\n\n", payload)

	if err != nil {
		// Update payment status to failed
		// _ = s.transferStore.(payment.ID, domain.PaymentStatusFailed)
		return "", fmt.Errorf("failed to initialize payment: %w", err)
	}

	tempTransfer, err := s.transferStore.CreateTransfer(ctx, transfer)

	if err != nil {
		return "", fmt.Errorf("failed to save payment: %w", err)
	}

	fmt.Printf("\n\nTemp transfer is: %v\n\n", tempTransfer)

	return response.CheckoutURL, nil
}

func (s *Service) InitiateWithdrawal(ctx context.Context, userID int64, req domain.ChapaWithdrawalRequest) (*domain.Transfer, error) {
	// Parse and validate amount
	amount, err := strconv.ParseInt(req.Amount, 10, 64)
	if err != nil || amount <= 0 {
		return nil, domain.ErrInvalidWithdrawalAmount
	}

	// Get user's wallet
	wallet, err := s.walletStore.GetCustomerWallet(ctx, userID)
	if err != nil {
		return nil, fmt.Errorf("failed to get user wallets: %w", err)
	}

	// var withdrawWallet domain.Wallet
	// for _, wallet := range wallets {
	// 	if wallet.IsWithdraw {
	// 		withdrawWallet = wallet
	// 		break
	// 	}
	// }

	// if withdrawWallet.ID == 0 {
	// 	return nil, errors.New("withdrawal wallet not found")
	// }
	// Check balance
	if float64(wallet.RegularBalance) < float64(amount) {
		return nil, domain.ErrInsufficientBalance
	}

	// Generate unique reference
	reference := uuid.New().String()

	createTransfer := domain.CreateTransfer{
		Message: fmt.Sprintf("Withdrawing %d into wallet using chapa. Reference Number %s", amount, reference),
		Amount:  domain.Currency(amount),
		Type:    domain.WITHDRAW,
		SenderWalletID: domain.ValidInt64{
			Value: wallet.RegularID,
			Valid: true,
		},
		Status:          string(domain.PaymentStatusPending),
		Verified:        false,
		ReferenceNumber: reference,
		PaymentMethod:   domain.TRANSFER_CHAPA,
	}

	transfer, err := s.transferStore.CreateTransfer(ctx, createTransfer)

	if err != nil {
		return nil, fmt.Errorf("failed to create transfer record: %w", err)
	}
	// Initiate transfer with Chapa
	transferReq := domain.ChapaWithdrawalRequest{
		AccountName:   req.AccountName,
		AccountNumber: req.AccountNumber,
		Amount:        fmt.Sprintf("%d", amount),
		Currency:      req.Currency,
		Reference:     reference,
		// BeneficiaryName: fmt.Sprintf("%s %s", user.FirstName, user.LastName),
		BankCode: req.BankCode,
	}

	success, err := s.chapaClient.InitiateTransfer(ctx, transferReq)
	if err != nil {
		_ = s.transferStore.UpdateTransferStatus(ctx, transfer.ID, string(domain.WithdrawalStatusFailed))
		return nil, fmt.Errorf("failed to initiate transfer: %w", err)
	}

	if !success {
		_ = s.transferStore.UpdateTransferStatus(ctx, transfer.ID, string(domain.WithdrawalStatusFailed))
		return nil, errors.New("chapa rejected the transfer request")
	}

	// Update withdrawal status to processing
	if err := s.transferStore.UpdateTransferStatus(ctx, transfer.ID, string(domain.WithdrawalStatusProcessing)); err != nil {
		return nil, fmt.Errorf("failed to update withdrawal status: %w", err)
	}
	// Deduct from wallet (or wait for webhook confirmation depending on your flow)
	newBalance := float64(wallet.RegularBalance) - float64(amount)
	if err := s.walletStore.UpdateBalance(ctx, wallet.RegularID, domain.Currency(newBalance)); err != nil {
		return nil, fmt.Errorf("failed to update wallet balance: %w", err)
	}

	return &transfer, nil
}

func (s *Service) GetSupportedBanks(ctx context.Context) ([]domain.Bank, error) {
	banks, err := s.chapaClient.FetchSupportedBanks(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to fetch banks: %w", err)
	}
	return banks, nil
}

func (s *Service) ManuallyVerify(ctx context.Context, txRef string) (*domain.ChapaVerificationResponse, error) {
	// Lookup transfer by reference
	transfer, err := s.transferStore.GetTransferByReference(ctx, txRef)
	if err != nil {
		return nil, fmt.Errorf("transfer not found for reference %s: %w", txRef, err)
	}

	if transfer.Verified {
		return &domain.ChapaVerificationResponse{
			Status:   string(domain.PaymentStatusCompleted),
			Amount:   float64(transfer.Amount) / 100,
			Currency: "ETB",
		}, nil
	}

	// Validate sender wallet
	if !transfer.SenderWalletID.Valid {
		return nil, fmt.Errorf("invalid sender wallet ID: %v", transfer.SenderWalletID)
	}

	var verification *domain.ChapaVerificationResponse

	// Decide verification method based on type
	switch strings.ToLower(string(transfer.Type)) {
	case "deposit":
		// Use Chapa Payment Verification
		verification, err = s.chapaClient.ManualVerifyPayment(ctx, txRef)
		if err != nil {
			return nil, fmt.Errorf("failed to verify deposit with Chapa: %w", err)
		}

		if verification.Status == string(domain.PaymentStatusSuccessful) {
			// Mark verified
			if err := s.transferStore.UpdateTransferVerification(ctx, transfer.ID, true); err != nil {
				return nil, fmt.Errorf("failed to mark deposit transfer as verified: %w", err)
			}

			// Credit wallet
			_, err := s.walletStore.AddToWallet(ctx, transfer.SenderWalletID.Value,
				transfer.Amount, domain.ValidInt64{}, domain.TRANSFER_CHAPA, domain.PaymentDetails{},
				fmt.Sprintf("Added %v to wallet using Chapa", transfer.Amount.Float32()))
			if err != nil {
				return nil, fmt.Errorf("failed to credit wallet: %w", err)
			}
		}

	case "withdraw":
		// Use Chapa Transfer Verification
		verification, err = s.chapaClient.ManualVerifyTransfer(ctx, txRef)
		if err != nil {
			return nil, fmt.Errorf("failed to verify withdrawal with Chapa: %w", err)
		}

		if verification.Status == string(domain.PaymentStatusSuccessful) {
			// Mark verified (withdraw doesn't affect balance)
			if err := s.transferStore.UpdateTransferVerification(ctx, transfer.ID, true); err != nil {
				return nil, fmt.Errorf("failed to mark withdrawal transfer as verified: %w", err)
			}
		}

	default:
		return nil, fmt.Errorf("unsupported transfer type: %s", transfer.Type)
	}

	return verification, nil
}

func (s *Service) HandleVerifyDepositWebhook(ctx context.Context, transfer domain.ChapaWebHookTransfer) error {
	// Find payment by reference
	payment, err := s.transferStore.GetTransferByReference(ctx, transfer.Reference)
	if err != nil {
		return domain.ErrPaymentNotFound
	}

	if payment.Verified {
		return nil
	}

	// Verify payment with Chapa
	// verification, err := s.chapaClient.VerifyPayment(ctx, transfer.Reference)
	// if err != nil {
	// 	return fmt.Errorf("failed to verify payment: %w", err)
	// }

	// Update payment status
	// verified := false
	// if transfer.Status == string(domain.PaymentStatusCompleted) {
	// 	verified = true
	// }

	// If payment is completed, credit user's wallet
	if transfer.Status == string(domain.PaymentStatusSuccessful) {

		if err := s.transferStore.UpdateTransferVerification(ctx, payment.ID, true); err != nil {
			return fmt.Errorf("failed to update payment status: %w", err)
		}

		if _, err := s.walletStore.AddToWallet(ctx, payment.SenderWalletID.Value, payment.Amount, domain.ValidInt64{}, domain.TRANSFER_CHAPA, domain.PaymentDetails{
			ReferenceNumber: domain.ValidString{
				Value: transfer.Reference,
			},
		}, fmt.Sprintf("Added %v to wallet using Chapa", payment.Amount)); err != nil {
			return fmt.Errorf("failed to credit user wallet: %w", err)
		}
	}

	return nil
}

func (s *Service) HandleVerifyWithdrawWebhook(ctx context.Context, payment domain.ChapaWebHookPayment) error {
	// Find payment by reference
	transfer, err := s.transferStore.GetTransferByReference(ctx, payment.Reference)
	if err != nil {
		return domain.ErrPaymentNotFound
	}

	if transfer.Verified {
		return nil
	}

	// Verify payment with Chapa
	// verification, err := s.chapaClient.VerifyPayment(ctx, payment.Reference)
	// if err != nil {
	// 	return fmt.Errorf("failed to verify payment: %w", err)
	// }

	// Update payment status
	// verified := false
	// if transfer.Status == string(domain.PaymentStatusCompleted) {
	// 	verified = true
	// }

	if payment.Status == string(domain.PaymentStatusSuccessful) {
		if err := s.transferStore.UpdateTransferVerification(ctx, transfer.ID, true); err != nil {
			return fmt.Errorf("failed to update payment status: %w", err)
		} // If payment is completed, credit user's walle
	} else {
		_, err := s.walletStore.AddToWallet(ctx, transfer.SenderWalletID.Value, transfer.Amount, domain.ValidInt64{},
			domain.TRANSFER_DIRECT, domain.PaymentDetails{},
			fmt.Sprintf("Added %v to wallet by system because chapa withdraw is unsuccessful", transfer.Amount))
		if err != nil {
			return fmt.Errorf("failed to credit user wallet: %w", err)
		}
	}

	return nil
}

func (s *Service) GetPaymentReceiptURL(ctx context.Context, chapaRef string) (string, error) {
	if chapaRef == "" {
		return "", fmt.Errorf("chapa reference ID is required")
	}

	receiptURL := fmt.Sprintf("https://chapa.link/payment-receipt/%s", chapaRef)
	return receiptURL, nil
}

func (s *Service) GetAllTransfers(ctx context.Context) ([]domain.Transfer, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "https://api.chapa.co/v1/transfers", nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", s.cfg.CHAPA_SECRET_KEY))

	resp, err := s.chapaClient.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to fetch transfers: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("unexpected status %d: %s", resp.StatusCode, string(bodyBytes))
	}

	var result struct {
		Status  string            `json:"status"`
		Message string            `json:"message"`
		Data    []domain.Transfer `json:"data"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("failed to decode response: %w", err)
	}

	return result.Data, nil
}

func (s *Service) GetAccountBalance(ctx context.Context, currencyCode string) ([]domain.Balance, error) {
	baseURL := "https://api.chapa.co/v1/balances"
	if currencyCode != "" {
		baseURL = fmt.Sprintf("%s/%s", baseURL, strings.ToLower(currencyCode))
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, baseURL, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create balance request: %w", err)
	}

	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", s.cfg.CHAPA_SECRET_KEY))

	resp, err := s.chapaClient.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to execute balance request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("unexpected status %d: %s", resp.StatusCode, string(bodyBytes))
	}

	var result struct {
		Status  string           `json:"status"`
		Message string           `json:"message"`
		Data    []domain.Balance `json:"data"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("failed to decode balance response: %w", err)
	}

	return result.Data, nil
}

func (s *Service) InitiateSwap(ctx context.Context, amount float64, from, to string) (*domain.SwapResponse, error) {
	if amount < 1 {
		return nil, fmt.Errorf("amount must be at least 1 USD")
	}
	if strings.ToUpper(from) != "USD" || strings.ToUpper(to) != "ETB" {
		return nil, fmt.Errorf("only USD to ETB swap is supported")
	}

	payload := domain.SwapRequest{
		Amount: amount,
		From:   strings.ToUpper(from),
		To:     strings.ToUpper(to),
	}

	// payload := map[string]any{
	// 	"amount": amount,
	// 	"from":   strings.ToUpper(from),
	// 	"to":     strings.ToUpper(to),
	// }

	body, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("failed to encode swap payload: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, "https://api.chapa.co/v1/swap", bytes.NewBuffer(body))
	if err != nil {
		return nil, fmt.Errorf("failed to create swap request: %w", err)
	}

	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", s.cfg.CHAPA_SECRET_KEY))
	req.Header.Set("Content-Type", "application/json")

	resp, err := s.chapaClient.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to execute swap request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("unexpected status %d: %s", resp.StatusCode, string(bodyBytes))
	}

	var result struct {
		Message string              `json:"message"`
		Status  string              `json:"status"`
		Data    domain.SwapResponse `json:"data"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("failed to decode swap response: %w", err)
	}

	return &result.Data, nil
}