#!/usr/bin/env node
/**
 * Transaction Mirror Service
 *
 * Off-chain service to mirror Chain-138 transactions to TransactionMirror
 * contract on Ethereum Mainnet for Etherscan visibility.
 *
 * Usage:
 *   node scripts/offchain/transaction-mirror-service.js
 *
 * Environment Variables:
 *   - CHAIN_138_RPC: RPC endpoint for Chain-138
 *   - ETHEREUM_MAINNET_RPC: RPC endpoint for Ethereum Mainnet
 *   - TRANSACTION_MIRROR_ADDRESS: TransactionMirror contract address
 *   - PRIVATE_KEY: Private key for signing transactions
 *   - MIRROR_INTERVAL: Block interval for mirroring (default: 10)
 *   - BATCH_SIZE: Number of transactions per batch (default: 50, max: 100)
 *   - START_BLOCK: Starting block number (default: latest)
 */

const { ethers } = require('ethers');
const fs = require('fs');
const path = require('path');

// Configuration
const CONFIG = {
    CHAIN_138_RPC: process.env.CHAIN_138_RPC || 'http://localhost:8545',
    ETHEREUM_MAINNET_RPC: process.env.ETHEREUM_MAINNET_RPC || '',
    TRANSACTION_MIRROR_ADDRESS: process.env.TRANSACTION_MIRROR_ADDRESS || '',
    PRIVATE_KEY: process.env.PRIVATE_KEY || '',
    MIRROR_INTERVAL: parseInt(process.env.MIRROR_INTERVAL || '10'),
    BATCH_SIZE: Math.min(parseInt(process.env.BATCH_SIZE || '50'), 100),
    START_BLOCK: process.env.START_BLOCK ? parseInt(process.env.START_BLOCK) : null,
    STATE_FILE: path.join(__dirname, '../../data/transaction-mirror-state.json'),
};

// TransactionMirror ABI (simplified)
const TRANSACTION_MIRROR_ABI = [
    "function mirrorTransaction(bytes32 txHash, address from, address to, uint256 value, uint256 blockNumber, uint256 blockTimestamp, uint256 gasUsed, bool success, bytes calldata data) external",
    "function mirrorBatchTransactions(bytes32[] calldata txHashes, address[] calldata froms, address[] calldata tos, uint256[] calldata values, uint256[] calldata blockNumbers, uint256[] calldata blockTimestamps, uint256[] calldata gasUseds, bool[] calldata successes, bytes[] calldata datas) external",
    "function isMirrored(bytes32 txHash) external view returns (bool)",
    "function paused() external view returns (bool)",
    "event TransactionMirrored(bytes32 indexed txHash, address indexed from, address indexed to, uint256 value, uint256 blockNumber, uint256 blockTimestamp, uint256 gasUsed, bool success)"
];

class TransactionMirrorService {
    constructor() {
        this.chain138Provider = new ethers.JsonRpcProvider(CONFIG.CHAIN_138_RPC);
        this.mainnetProvider = new ethers.JsonRpcProvider(CONFIG.ETHEREUM_MAINNET_RPC);
        this.wallet = new ethers.Wallet(CONFIG.PRIVATE_KEY, this.mainnetProvider);
        this.mirrorContract = new ethers.Contract(
            CONFIG.TRANSACTION_MIRROR_ADDRESS,
            TRANSACTION_MIRROR_ABI,
            this.wallet
        );
        this.lastMirroredBlock = this.loadState();
        this.pendingTransactions = [];
    }

    loadState() {
        try {
            if (fs.existsSync(CONFIG.STATE_FILE)) {
                const data = JSON.parse(fs.readFileSync(CONFIG.STATE_FILE, 'utf8'));
                return data.lastMirroredBlock || (CONFIG.START_BLOCK || 0);
            }
        } catch (error) {
            console.error('Error loading state:', error);
        }
        return CONFIG.START_BLOCK || 0;
    }

    saveState(blockNumber) {
        try {
            const dir = path.dirname(CONFIG.STATE_FILE);
            if (!fs.existsSync(dir)) {
                fs.mkdirSync(dir, { recursive: true });
            }
            fs.writeFileSync(CONFIG.STATE_FILE, JSON.stringify({
                lastMirroredBlock: blockNumber,
                lastUpdate: new Date().toISOString()
            }, null, 2));
        } catch (error) {
            console.error('Error saving state:', error);
        }
    }

    async getChain138Transactions(blockNumber) {
        try {
            const block = await this.chain138Provider.getBlock(blockNumber, true);
            if (!block || !block.transactions) {
                return [];
            }

            const transactions = [];
            for (const txHash of block.transactions) {
                try {
                    const tx = await this.chain138Provider.getTransaction(txHash);
                    const receipt = await this.chain138Provider.getTransactionReceipt(txHash);

                    if (tx && receipt) {
                        transactions.push({
                            hash: txHash,
                            from: tx.from,
                            to: tx.to || ethers.ZeroAddress,
                            value: tx.value.toString(),
                            blockNumber: block.number,
                            blockTimestamp: block.timestamp,
                            gasUsed: receipt.gasUsed.toString(),
                            success: receipt.status === 1,
                            data: tx.data || '0x',
                        });
                    }
                } catch (error) {
                    console.warn(`Error fetching transaction ${txHash}:`, error.message);
                }
            }

            return transactions;
        } catch (error) {
            console.error(`Error fetching Chain-138 block ${blockNumber}:`, error);
            return [];
        }
    }

    async mirrorTransaction(tx) {
        try {
            // Check if contract is paused
            const paused = await this.mirrorContract.paused();
            if (paused) {
                console.warn('TransactionMirror is paused, skipping mirror');
                return false;
            }

            // Check if already mirrored
            const isMirrored = await this.mirrorContract.isMirrored(tx.hash);
            if (isMirrored) {
                return true; // Already mirrored
            }

            // Mirror transaction
            console.log(`Mirroring transaction ${tx.hash}...`);
            const txResponse = await this.mirrorContract.mirrorTransaction(
                tx.hash,
                tx.from,
                tx.to,
                tx.value,
                tx.blockNumber,
                tx.blockTimestamp,
                tx.gasUsed,
                tx.success,
                tx.data,
                { gasLimit: 200000 }
            );

            console.log(`Transaction sent: ${txResponse.hash}`);
            const receipt = await txResponse.wait();
            console.log(`Transaction ${tx.hash} mirrored in transaction ${receipt.hash}`);

            return true;
        } catch (error) {
            console.error(`Error mirroring transaction ${tx.hash}:`, error);
            return false;
        }
    }

    async mirrorBatch(transactions) {
        try {
            // Check if contract is paused
            const paused = await this.mirrorContract.paused();
            if (paused) {
                console.warn('TransactionMirror is paused, skipping batch mirror');
                return false;
            }

            // Filter out already mirrored transactions
            const toMirror = [];
            for (const tx of transactions) {
                const isMirrored = await this.mirrorContract.isMirrored(tx.hash);
                if (!isMirrored) {
                    toMirror.push(tx);
                }
            }

            if (toMirror.length === 0) {
                console.log('All transactions already mirrored');
                return true;
            }

            // Prepare batch data
            const txHashes = toMirror.map(tx => tx.hash);
            const froms = toMirror.map(tx => tx.from);
            const tos = toMirror.map(tx => tx.to);
            const values = toMirror.map(tx => tx.value);
            const blockNumbers = toMirror.map(tx => tx.blockNumber);
            const blockTimestamps = toMirror.map(tx => tx.blockTimestamp);
            const gasUseds = toMirror.map(tx => tx.gasUsed);
            const successes = toMirror.map(tx => tx.success);
            const datas = toMirror.map(tx => tx.data);

            console.log(`Mirroring batch of ${toMirror.length} transactions...`);
            const txResponse = await this.mirrorContract.mirrorBatchTransactions(
                txHashes,
                froms,
                tos,
                values,
                blockNumbers,
                blockTimestamps,
                gasUseds,
                successes,
                datas,
                { gasLimit: 2000000 } // Higher gas limit for batch
            );

            console.log(`Batch transaction sent: ${txResponse.hash}`);
            const receipt = await txResponse.wait();
            console.log(`Batch mirrored in transaction ${receipt.hash}`);

            return true;
        } catch (error) {
            console.error('Error mirroring batch:', error);
            return false;
        }
    }

    async run() {
        console.log('Transaction Mirror Service starting...');
        console.log(`TransactionMirror: ${CONFIG.TRANSACTION_MIRROR_ADDRESS}`);
        console.log(`Last mirrored block: ${this.lastMirroredBlock}`);
        console.log(`Mirror interval: ${CONFIG.MIRROR_INTERVAL} blocks`);
        console.log(`Batch size: ${CONFIG.BATCH_SIZE} transactions`);
        console.log('');

        while (true) {
            try {
                // Get latest Chain-138 block
                const latestBlock = await this.chain138Provider.getBlockNumber();
                const targetBlock = this.lastMirroredBlock + CONFIG.MIRROR_INTERVAL;

                if (targetBlock <= latestBlock) {
                    console.log(`Processing block ${targetBlock} (latest: ${latestBlock})`);
                    const transactions = await this.getChain138Transactions(targetBlock);

                    if (transactions.length > 0) {
                        // Add to pending batch
                        this.pendingTransactions.push(...transactions);

                        // Mirror batch if we have enough transactions
                        if (this.pendingTransactions.length >= CONFIG.BATCH_SIZE) {
                            const batch = this.pendingTransactions.splice(0, CONFIG.BATCH_SIZE);
                            await this.mirrorBatch(batch);
                        }
                    }

                    this.lastMirroredBlock = targetBlock;
                    this.saveState(targetBlock);
                } else {
                    // Mirror any pending transactions if we've been waiting
                    if (this.pendingTransactions.length > 0 &&
                        (latestBlock - targetBlock) > CONFIG.MIRROR_INTERVAL) {
                        const batch = this.pendingTransactions.splice(0, CONFIG.BATCH_SIZE);
                        await this.mirrorBatch(batch);
                    }

                    console.log(`Waiting for block ${targetBlock} (current: ${latestBlock})`);
                    await new Promise(resolve => setTimeout(resolve, 30000)); // Wait 30 seconds
                }
            } catch (error) {
                console.error('Error in main loop:', error);
                await new Promise(resolve => setTimeout(resolve, 10000)); // Wait 10 seconds on error
            }
        }
    }
}

// Run service
if (require.main === module) {
    if (!CONFIG.ETHEREUM_MAINNET_RPC || !CONFIG.TRANSACTION_MIRROR_ADDRESS || !CONFIG.PRIVATE_KEY) {
        console.error('Missing required environment variables:');
        console.error('  - ETHEREUM_MAINNET_RPC');
        console.error('  - TRANSACTION_MIRROR_ADDRESS');
        console.error('  - PRIVATE_KEY');
        process.exit(1);
    }

    const service = new TransactionMirrorService();
    service.run().catch(console.error);
}

module.exports = TransactionMirrorService;