package main

import (
	"context"
	"fmt"
	"math/big"
	"strings"

	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/ethclient"
)

const membershipABI = `[{"inputs":[{"internalType":"address","name":"recipient","type":"address"}],"name":"mintMembership","outputs":[{"internalType":"uint256","name":"tokenId","type":"uint256"}],"stateMutability":"payable","type":"function"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"wallet","type":"address"},{"indexed":true,"internalType":"uint256","name":"tokenId","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"amountPaid","type":"uint256"},{"indexed":false,"internalType":"address","name":"currency","type":"address"}],"name":"MembershipMinted","type":"event"}]`

func encodeMintMembershipCalldata(recipient string) (string, error) {
	parsed, err := abi.JSON(strings.NewReader(membershipABI))
	if err != nil {
		return "", fmt.Errorf("parse membership abi: %w", err)
	}
	address := common.HexToAddress(recipient)
	data, err := parsed.Pack("mintMembership", address)
	if err != nil {
		return "", fmt.Errorf("pack mint calldata: %w", err)
	}
	return "0x" + common.Bytes2Hex(data), nil
}

func verifyMintedOnChain(ctx context.Context, cfg Config, txHash string, expectedWallet string) error {
	if strings.TrimSpace(cfg.ChainRPCURL) == "" {
		return nil
	}

	client, err := ethclient.DialContext(ctx, cfg.ChainRPCURL)
	if err != nil {
		return fmt.Errorf("dial chain rpc: %w", err)
	}
	defer client.Close()

	hash := common.HexToHash(txHash)
	receipt, err := client.TransactionReceipt(ctx, hash)
	if err != nil {
		return fmt.Errorf("read tx receipt: %w", err)
	}
	if receipt == nil {
		return fmt.Errorf("tx receipt not found")
	}
	if receipt.Status != types.ReceiptStatusSuccessful {
		return fmt.Errorf("tx failed status=%d", receipt.Status)
	}

	parsed, err := abi.JSON(strings.NewReader(membershipABI))
	if err != nil {
		return fmt.Errorf("parse membership abi: %w", err)
	}
	mintedEvent := parsed.Events["MembershipMinted"]
	expectedWallet = strings.ToLower(common.HexToAddress(expectedWallet).Hex())

	for _, lg := range receipt.Logs {
		if strings.ToLower(lg.Address.Hex()) != strings.ToLower(common.HexToAddress(cfg.MembershipContract).Hex()) {
			continue
		}
		if len(lg.Topics) == 0 || lg.Topics[0] != mintedEvent.ID {
			continue
		}
		if len(lg.Topics) < 2 {
			continue
		}
		wallet := common.HexToAddress(lg.Topics[1].Hex()).Hex()
		if strings.ToLower(wallet) == expectedWallet {
			return nil
		}
	}
	return fmt.Errorf("membership mint event not found for wallet")
}

func verifyTransactionSenderOnChain(ctx context.Context, cfg Config, txHash string, expectedSender string) error {
	if strings.TrimSpace(cfg.ChainRPCURL) == "" {
		return nil
	}
	expectedSender = strings.TrimSpace(expectedSender)
	if expectedSender == "" {
		return fmt.Errorf("expected sender missing")
	}

	client, err := ethclient.DialContext(ctx, cfg.ChainRPCURL)
	if err != nil {
		return fmt.Errorf("dial chain rpc: %w", err)
	}
	defer client.Close()

	hash := common.HexToHash(txHash)
	receipt, err := client.TransactionReceipt(ctx, hash)
	if err != nil {
		return fmt.Errorf("read tx receipt: %w", err)
	}
	if receipt == nil {
		return fmt.Errorf("tx receipt not found")
	}
	if receipt.Status != types.ReceiptStatusSuccessful {
		return fmt.Errorf("tx failed status=%d", receipt.Status)
	}

	tx, pending, err := client.TransactionByHash(ctx, hash)
	if err != nil {
		return fmt.Errorf("read tx body: %w", err)
	}
	if pending {
		return fmt.Errorf("tx pending")
	}

	chainID := tx.ChainId()
	if chainID == nil || chainID.Sign() <= 0 {
		chainID = big.NewInt(cfg.ChainID)
	}
	signer := types.LatestSignerForChainID(chainID)
	from, err := types.Sender(signer, tx)
	if err != nil {
		return fmt.Errorf("resolve tx sender: %w", err)
	}

	gotSender := strings.ToLower(from.Hex())
	wantSender := strings.ToLower(common.HexToAddress(expectedSender).Hex())
	if gotSender != wantSender {
		return fmt.Errorf("tx sender mismatch got=%s want=%s", gotSender, wantSender)
	}
	return nil
}