package chapa

import (
	"context"
	"fmt"
	"strconv"

	"github.com/SamuelTariku/FortuneBet-Backend/internal/domain"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/repository"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/services/transaction"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/services/wallet"
	"github.com/shopspring/decimal"
)

type Service struct {
	transactionStore transaction.TransactionStore
	walletStore      wallet.WalletStore
	store            *repository.Store
}

func (s *Service) HandleChapaTransferWebhook(ctx context.Context, req domain.ChapaWebHookTransfer) error {
	tx, err := s.store.Begin(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback(ctx)

	// 1. Fetch transaction
	referenceID, err := strconv.ParseInt(req.Reference, 10, 64)
	txn, err := s.transactionStore.GetTransactionByID(ctx, referenceID)
	if err != nil {
		return err
	}
	if txn.Verified {
		return nil // already processed
	}

	// 2. Compare amount
	webhookAmount, _ := decimal.NewFromString(req.Amount)
	storedAmount, _ := decimal.NewFromString(txn.Amount.String())
	if !webhookAmount.Equal(storedAmount) {
		return fmt.Errorf("amount mismatch")
	}

	// 3. Update transaction
	txn.Verified = true

	if err := s.transactionStore.UpdateTransactionVerified(ctx, txn.ID, txn.Verified, txn.ApprovedBy.Value, txn.ApproverName.Value); err != nil {
		return err
	}

	return tx.Commit(ctx)
}

func (s *Service) HandleChapaPaymentWebhook(ctx context.Context, req domain.ChapaWebHookPayment) error {
	tx, err := s.store.Begin(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback(ctx)

	if req.Status != "success" {
		return fmt.Errorf("payment status not successful")
	}

	// 1. Parse reference ID
	referenceID, err := strconv.ParseInt(req.TxRef, 10, 64)
	if err != nil {
		return fmt.Errorf("invalid tx_ref: %w", err)
	}

	// 2. Fetch transaction
	txn, err := s.transactionStore.GetTransactionByID(ctx, referenceID)
	if err != nil {
		return err
	}
	if txn.Verified {
		return nil // already processed
	}

	// 3. Amount validation
	webhookAmount, _ := decimal.NewFromString(req.Amount)
	storedAmount := txn.Amount // assuming it's domain.Currency (decimal.Decimal alias)

	if webhookAmount.LessThan(storedAmount) {
		return fmt.Errorf("webhook amount is less than expected")
	}

	// 4. Fetch wallet
	wallet, err := s.walletStore.GetWalletByID(ctx, txn.ID)
	if err != nil {
		return err
	}

	// 5. Update wallet balance
	newBalance := wallet.Balance.Add(storedAmount)
	if err := s.walletStore.UpdateBalance(ctx, wallet.ID, newBalance); err != nil {
		return err
	}

	// 6. Mark transaction as verified
	if err := s.transactionStore.UpdateTransactionVerified(ctx, txn.ID, true, txn.ApprovedBy.Value, txn.ApproverName.Value); err != nil {
		return err
	}

	// 7. Check & generate referral code
	hasCode, err := s.userStore.HasReferralCode(ctx, wallet.UserID)
	if err != nil {
		return err
	}

	if !hasCode {
		code := misc.GenerateReferralCode(req.FirstName)

		if err := s.userStore.SetReferralCode(ctx, wallet.UserID, code); err != nil {
			return err
		}

		if err := s.referralStore.CreateReferralCode(ctx, domain.ReferralCode{
			Code:   code,
			Amount: config.ReferralRewardBase,
		}); err != nil {
			return err
		}
	}

	return tx.Commit(ctx)
}