#!/usr/bin/env node

/**
 * CORRECTED RIN Stratum Proxy - Based on Working Python Implementation
 * Fixes the share validation issue by following the exact Python logic
 */

const net = require('net');
const axios = require('axios');
const crypto = require('crypto');

// Configuration
const CONFIG = {
    stratum: { host: '0.0.0.0', port: 3333 },
    rpc: {
        host: '127.0.0.1', port: 9556,
        user: 'rinrpc', password: '745ce784d5d537fc06105a1b935b7657903cfc71a5fb3b90'
    },
    mining: { targetAddress: 'rin1qahvvv9d5f3443wtckeqavwp9950wacxfmwv20q' }
};

class CorrectedRinProxy {
    constructor() {
        this.server = null;
        this.currentJob = null;
        this.jobCounter = 0;
        this.clients = new Map();
        this.extranonceCounter = 0;
        this.currentDifficulty = 0.001; // Start lower for testing
        
        console.log('🔧 CORRECTED RIN Stratum Proxy - Following Python Logic');
        console.log(`📡 Stratum: ${CONFIG.stratum.host}:${CONFIG.stratum.port}`);
        console.log(`🔗 RPC: ${CONFIG.rpc.host}:${CONFIG.rpc.port}`);
    }

    async rpcCall(method, params = []) {
        try {
            const url = `http://${CONFIG.rpc.host}:${CONFIG.rpc.port}/`;
            const auth = Buffer.from(`${CONFIG.rpc.user}:${CONFIG.rpc.password}`).toString('base64');
            
            const response = await axios.post(url, {
                jsonrpc: '1.0', id: 'proxy', method: method, params: params
            }, {
                headers: { 'Content-Type': 'text/plain', 'Authorization': `Basic ${auth}` },
                timeout: 30000
            });

            return response.data.error ? null : response.data.result;
        } catch (error) {
            console.error(`RPC Error: ${error.message}`);
            return null;
        }
    }

    /**
     * CORRECTED Share Validation - Following Python Implementation Exactly
     */
    async validateShareCorrected(jobId, extranonce1, extranonce2, ntime, nonce) {
        try {
            if (!this.currentJob || this.currentJob.jobId !== jobId) {
                return { isValid: false, difficulty: 0, message: 'Invalid job ID' };
            }

            // Get job data
            const job = this.currentJob;
            const address = CONFIG.mining.targetAddress;
            
            console.log(`🔍 [CORRECTED] Validating share for job ${jobId}`);
            console.log(`🔍 [CORRECTED] ntime=${ntime}, nonce=${nonce}, extranonce=${extranonce1}:${extranonce2}`);
            
            // Simple coinbase construction (following Python simplified approach)
            const heightBytes = Buffer.allocUnsafe(4);
            heightBytes.writeUInt32LE(job.height, 0);
            const scriptsig = Buffer.concat([
                Buffer.from([heightBytes.length]),
                heightBytes,
                Buffer.from('/RinCoin/'),
                Buffer.from(extranonce1, 'hex'),
                Buffer.from(extranonce2, 'hex')
            ]);
            
            // Simple coinbase transaction (minimal for testing)
            const version = Buffer.allocUnsafe(4);
            version.writeUInt32LE(1, 0);
            
            const coinbase = Buffer.concat([
                version,                                    // Version
                Buffer.from([0x01]),                       // Input count
                Buffer.alloc(32),                          // Previous output hash (null)
                Buffer.from([0xff, 0xff, 0xff, 0xff]),    // Previous output index
                Buffer.from([scriptsig.length]),           // Script length
                scriptsig,                                 // Script
                Buffer.from([0xff, 0xff, 0xff, 0xff]),    // Sequence
                Buffer.from([0x01]),                       // Output count
                Buffer.alloc(8),                           // Value (simplified)
                Buffer.from([0x00]),                       // Script length (empty)
                Buffer.alloc(4)                            // Locktime
            ]);
            
            // Calculate coinbase txid
            const hash1 = crypto.createHash('sha256').update(coinbase).digest();
            const hash2 = crypto.createHash('sha256').update(hash1).digest();
            const coinbaseTxid = hash2.reverse(); // Reverse for little-endian
            
            // Simple merkle root (just coinbase for now)
            const merkleRoot = coinbaseTxid;
            
            // Build block header - EXACTLY like Python
            const header = Buffer.concat([
                // Version (little-endian)
                (() => {
                    const buf = Buffer.allocUnsafe(4);
                    buf.writeUInt32LE(job.version, 0);
                    return buf;
                })(),
                
                // Previous block hash (big-endian in block)
                Buffer.from(job.prevhash, 'hex').reverse(),
                
                // Merkle root (already correct endian)
                merkleRoot,
                
                // Timestamp (little-endian) - CRITICAL: Use ntime from miner
                (() => {
                    const buf = Buffer.allocUnsafe(4);
                    buf.writeUInt32LE(parseInt(ntime, 16), 0);
                    return buf;
                })(),
                
                // Bits (big-endian in block)
                Buffer.from(job.bits, 'hex').reverse(),
                
                // Nonce (little-endian)
                (() => {
                    const buf = Buffer.allocUnsafe(4);
                    buf.writeUInt32LE(parseInt(nonce, 16), 0);
                    return buf;
                })()
            ]);
            
            console.log(`🔍 [CORRECTED] Header length: ${header.length} bytes`);
            console.log(`🔍 [CORRECTED] Version: ${job.version}`);
            console.log(`🔍 [CORRECTED] Prevhash: ${job.prevhash}`);
            console.log(`🔍 [CORRECTED] Bits: ${job.bits}`);
            console.log(`🔍 [CORRECTED] ntime (from miner): ${ntime} = ${parseInt(ntime, 16)}`);
            console.log(`🔍 [CORRECTED] nonce (from miner): ${nonce} = ${parseInt(nonce, 16)}`);
            
            // Calculate block hash - EXACTLY like Python
            const blockHash1 = crypto.createHash('sha256').update(header).digest();
            const blockHash2 = crypto.createHash('sha256').update(blockHash1).digest();
            const blockHashHex = blockHash2.reverse().toString('hex'); // Reverse for display
            
            console.log(`🔍 [CORRECTED] Block hash: ${blockHashHex}`);
            
            // Calculate difficulty using target from job
            const hashInt = BigInt('0x' + blockHashHex);
            const targetInt = BigInt('0x' + job.target);
            
            console.log(`🔍 [CORRECTED] Hash as BigInt: ${hashInt.toString(16)}`);
            console.log(`🔍 [CORRECTED] Target: ${job.target}`);
            console.log(`🔍 [CORRECTED] Target as BigInt: ${targetInt.toString(16)}`);
            
            // Calculate share difficulty
            const diff1Target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000n;
            const shareDifficulty = hashInt === 0n ? Number.POSITIVE_INFINITY : Number(diff1Target / hashInt);
            
            console.log(`🔍 [CORRECTED] Share difficulty: ${shareDifficulty}`);
            
            // Validate share
            const isValidShare = hashInt <= targetInt;
            
            console.log(`🔍 [CORRECTED] Hash <= Target? ${isValidShare} (${hashInt <= targetInt})`);
            
            return {
                isValid: isValidShare,
                difficulty: shareDifficulty,
                blockHash: blockHashHex,
                message: 'Corrected validation complete'
            };
            
        } catch (error) {
            console.error(`🔍 [CORRECTED] Validation error: ${error.message}`);
            return { isValid: false, difficulty: 0, message: `Error: ${error.message}` };
        }
    }

    async getBlockTemplate() {
        try {
            const template = await this.rpcCall('getblocktemplate', [{ rules: ['mweb', 'segwit'] }]);
            if (!template) return null;

            this.jobCounter++;
            
            // Convert bits to target (Bitcoin-style)
            const bits = parseInt(template.bits, 16);
            const exponent = bits >> 24;
            const mantissa = bits & 0xffffff;
            
            let target;
            if (exponent <= 3) {
                target = BigInt(mantissa) >> BigInt(8 * (3 - exponent));
            } else {
                target = BigInt(mantissa) << BigInt(8 * (exponent - 3));
            }
            
            const targetHex = target.toString(16).padStart(64, '0');
            
            this.currentJob = {
                jobId: `job_${this.jobCounter.toString(16).padStart(8, '0')}`,
                template: template,
                prevhash: template.previousblockhash || '0'.repeat(64),
                version: template.version || 1,
                bits: template.bits || '1d00ffff',
                target: targetHex,
                ntime: Math.floor(Date.now() / 1000).toString(16).padStart(8, '0'),
                height: template.height || 0,
                transactions: template.transactions || []
            };

            console.log(`🆕 NEW JOB: ${this.currentJob.jobId} | Height: ${this.currentJob.height}`);
            console.log(`   🎯 Target: ${targetHex.substring(0, 16)}...`);
            return this.currentJob;
        } catch (error) {
            console.error(`Get block template error: ${error.message}`);
            return null;
        }
    }

    sendResponse(client, id, result, error = null) {
        try {
            const response = { id: id, result: result, error: error };
            client.write(JSON.stringify(response) + '\n');
        } catch (error) {
            console.error(`Send response error: ${error.message}`);
        }
    }

    sendNotification(client, method, params) {
        try {
            const notification = { id: null, method: method, params: params };
            client.write(JSON.stringify(notification) + '\n');
        } catch (error) {
            console.error(`Send notification error: ${error.message}`);
        }
    }

    async handleMessage(client, addr, message) {
        try {
            const data = JSON.parse(message.trim());
            const method = data.method;
            const id = data.id;
            const params = data.params || [];
            
            console.log(`📨 [${addr}] ${method}: ${JSON.stringify(params)}`);
            
            if (method === 'mining.subscribe') {
                this.extranonceCounter++;
                const extranonce1 = this.extranonceCounter.toString(16).padStart(8, '0');
                
                this.clients.set(client, { addr: addr, extranonce1: extranonce1, username: null });
                
                this.sendResponse(client, id, [
                    [['mining.set_difficulty', 'subscription_id'], ['mining.notify', 'subscription_id']],
                    extranonce1,
                    4
                ]);
                
                console.log(`📝 [${addr}] Subscription: extranonce1=${extranonce1}`);
                this.sendNotification(client, 'mining.set_difficulty', [this.currentDifficulty]);
                
                if (this.currentJob) {
                    this.sendJobToClient(client);
                }
                
            } else if (method === 'mining.authorize') {
                const username = params[0] || 'anonymous';
                this.sendResponse(client, id, true);
                console.log(`🔐 [${addr}] Authorized as ${username}`);
                
                if (this.currentJob) {
                    this.sendJobToClient(client);
                }
                
            } else if (method === 'mining.submit') {
                if (params.length >= 5) {
                    const [username, jobId, extranonce2, ntime, nonce] = params;
                    
                    const clientInfo = this.clients.get(client);
                    const extranonce1 = clientInfo ? clientInfo.extranonce1 : '00000000';
                    
                    console.log(`📊 [${addr}] Submit: ${username} | job=${jobId} | nonce=${nonce}`);
                    
                    // CORRECTED VALIDATION
                    const validation = await this.validateShareCorrected(jobId, extranonce1, extranonce2, ntime, nonce);
                    
                    const timestamp = new Date().toLocaleTimeString();
                    console.log(`[${timestamp}] 🎯 SHARE: job=${jobId} | nonce=${nonce}`);
                    console.log(`   📈 Share Diff: ${validation.difficulty.toExponential(2)}`);
                    console.log(`   📈 Result: ${validation.isValid ? 'ACCEPTED' : 'REJECTED'} | ${validation.message}`);
                    
                    if (validation.isValid) {
                        console.log(`✅ [${addr}] Share ACCEPTED!`);
                    } else {
                        console.log(`❌ [${addr}] Share REJECTED: ${validation.message}`);
                    }
                    
                    this.sendResponse(client, id, validation.isValid);
                } else {
                    this.sendResponse(client, id, false, 'Invalid parameters');
                }
                
            } else {
                console.log(`❓ [${addr}] Unknown method: ${method}`);
                this.sendResponse(client, id, null, 'Unknown method');
            }
            
        } catch (error) {
            console.error(`[${addr}] Message error: ${error.message}`);
            this.sendResponse(client, null, null, 'Invalid JSON');
        }
    }

    sendJobToClient(client) {
        if (!this.currentJob) return;
        
        try {
            this.sendNotification(client, 'mining.notify', [
                this.currentJob.jobId,
                this.currentJob.prevhash,
                '', '', [],
                this.currentJob.version.toString(16).padStart(8, '0'),
                this.currentJob.bits,
                this.currentJob.ntime,
                true
            ]);
        } catch (error) {
            console.error(`Failed to send job: ${error.message}`);
        }
    }

    handleClient(client, addr) {
        console.log(`🔌 [${addr}] Connected`);
        
        client.on('data', (data) => {
            const messages = data.toString().trim().split('\n');
            for (const message of messages) {
                if (message) {
                    this.handleMessage(client, addr, message);
                }
            }
        });
        
        client.on('close', () => {
            console.log(`🔌 [${addr}] Disconnected`);
            this.clients.delete(client);
        });
        
        client.on('error', (error) => {
            console.error(`❌ [${addr}] Error: ${error.message}`);
            this.clients.delete(client);
        });
    }

    async start() {
        try {
            const blockchainInfo = await this.rpcCall('getblockchaininfo');
            if (!blockchainInfo) {
                console.error('❌ Failed to connect to RIN node!');
                return;
            }

            console.log('✅ Connected to RIN node');
            console.log(`📊 Current height: ${blockchainInfo.blocks || 'unknown'}`);

            if (!(await this.getBlockTemplate())) {
                console.error('❌ Failed to get initial block template!');
                return;
            }

            // Job updater
            setInterval(async () => {
                try {
                    const oldHeight = this.currentJob ? this.currentJob.height : 0;
                    if (await this.getBlockTemplate()) {
                        const newHeight = this.currentJob.height;
                        if (newHeight > oldHeight) {
                            console.log('🔄 Broadcasting new job...');
                            for (const [client, clientInfo] of this.clients) {
                                this.sendJobToClient(client);
                            }
                        }
                    }
                } catch (error) {
                    console.error(`Job updater error: ${error.message}`);
                }
            }, 30000);

            this.server = net.createServer((client) => {
                const addr = `${client.remoteAddress}:${client.remotePort}`;
                this.handleClient(client, addr);
            });

            this.server.listen(CONFIG.stratum.port, CONFIG.stratum.host, () => {
                console.log(`🚀 CORRECTED RIN Proxy ready!`);
                console.log(`   📡 Listening on ${CONFIG.stratum.host}:${CONFIG.stratum.port}`);
                console.log(`   📊 Current job: ${this.currentJob ? this.currentJob.jobId : 'None'}`);
                console.log('');
                console.log('   🔧 Test with:');
                console.log(`   ./cpuminer -a rinhash -o stratum+tcp://127.0.0.1:3333 -u user -p x -t 8`);
                console.log('');
                console.log('   🔧 CORRECTED: Following Python implementation exactly!');
                console.log('');
            });

        } catch (error) {
            console.error(`❌ Failed to start: ${error.message}`);
        }
    }
}

// Handle shutdown
process.on('SIGINT', () => {
    console.log('\n🛑 Shutting down...');
    process.exit(0);
});

// Start corrected proxy
const proxy = new CorrectedRinProxy();
proxy.start().catch(error => {
    console.error(`❌ Failed to start proxy: ${error.message}`);
    process.exit(1);
});