npm package: @nawab_kibria/bitcoin-lib
Description: A comprehensive Bitcoin HD wallet library with BIP84, BIP44, BIP49 support, mnemonic generation and restoration
Author: Nawab
Latest version: 1.0.0

# @nawab_kibria/bitcoin-lib

A comprehensive, production-ready Bitcoin wallet library with full support for all major Bitcoin address formats. Built with TypeScript and thoroughly tested.

## 🚀 Installation

```bash
npm install @nawab_kibria/bitcoin-lib
```

## 📚 What's Available

This library provides four main classes that work together to provide complete Bitcoin wallet functionality:

### 1. WalletManager - Complete Wallet Solution
### 2. BitcoinWallet - Address Generation & HD Wallet Management  
### 3. TransactionBuilder - Transaction Creation & Signing
### 4. ElectrumClient - Blockchain Connectivity

---

## 🎯 WalletManager - All-in-One Interface

The **WalletManager** is the main class that provides all 9 core Bitcoin wallet features in a single, easy-to-use interface.

### ✅ Core Features

1. **Generate Wallet** - Create new wallets with mnemonic and extended keys
2. **Export Wallet** - Export extended keys and mnemonics  
3. **Import Wallet** - Import from extended keys or mnemonics
4. **Fetch Balance** - Get balance for any address
5. **Fetch UTXOs** - Retrieve unspent transaction outputs
6. **Create Transaction** - Build and sign transactions
7. **Estimate Fees** - Real-time network fee estimation
8. **Broadcast Transaction** - Send transactions to the network
9. **Transaction History** - Get complete transaction history

### 🔧 Quick Start

```typescript
import { WalletManager } from '@nawab_kibria/bitcoin-lib';
import * as bitcoin from 'bitcoinjs-lib';

// Configure wallet manager
const walletManager = new WalletManager({
    electrumServer: {
        host: 'localhost',
        port: 50001,
        ssl: false
    },
    network: bitcoin.networks.regtest,
    defaultAddressType: 'native_segwit'
});

// 1. Generate a new wallet
const wallet = walletManager.generateWallet();
console.log('Mnemonic:', wallet.mnemonic);

// 2. Connect to Electrum server  
await walletManager.connect();

// 3. Derive addresses
const address = walletManager.deriveAddress(0, 'native_segwit');
console.log('Address:', address.address);

// 4. Check balance
const balance = await walletManager.fetchBalance(address.address);
console.log('Balance:', balance.confirmed, 'sats');

// 5. Create and broadcast transaction
const tx = await walletManager.createTransaction(
    fromAddress, toAddress, amount, feeRate, privateKey, 'native_segwit'
);
const result = await walletManager.broadcastTransaction(tx.hex);
console.log('TXID:', result.txid);
```

### 📖 WalletManager API

**Constructor Options:**
```typescript
interface WalletManagerConfig {
    electrumServer: {
        host: string;
        port: number;
        ssl?: boolean;
    };
    network?: bitcoin.Network;
    defaultAddressType?: 'legacy' | 'segwit' | 'native_segwit';
}
```

**Main Methods:**
- `generateWallet()` - Generate new wallet with mnemonic
- `importWallet(mnemonic, derivationPath?)` - Import from mnemonic
- `exportWallet()` - Export wallet data
- `connect()` / `disconnect()` - Manage Electrum connection
- `deriveAddress(index, type?, change?)` - Derive addresses
- `fetchBalance(address)` - Get address balance
- `fetchUTXOs(address)` - Get unspent outputs
- `createTransaction(from, to, amount, feeRate, privateKey, type)` - Build transaction
- `broadcastTransaction(txHex)` - Broadcast to network
- `estimateFee(blocks?)` - Get current fee rates
- `getTransactionHistory(address)` - Get transaction history

---

## 🔑 BitcoinWallet - HD Wallet & Address Generation

The **BitcoinWallet** class handles hierarchical deterministic wallet creation and address generation for all Bitcoin address types.

### ✨ Address Types Supported

- **Legacy (P2PKH)** - `1...` addresses using BIP44 (`m/44'/0'/0'/0/x`)
- **SegWit (P2SH-P2WPKH)** - `3...` addresses using BIP49 (`m/49'/0'/0'/0/x`) 
- **Native SegWit (P2WPKH)** - `bc1q...` addresses using BIP84 (`m/84'/0'/0'/0/x`)

### 🔧 Usage

```typescript
import { BitcoinWallet } from '@nawab_kibria/bitcoin-lib';
import * as bitcoin from 'bitcoinjs-lib';

// Generate a new wallet
const wallet = BitcoinWallet.generate(bitcoin.networks.bitcoin);
console.log('Mnemonic:', wallet.mnemonic);

// Or create from existing mnemonic
const existingWallet = BitcoinWallet.fromMnemonic(
  'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about',
  bitcoin.networks.bitcoin
);

// Generate addresses of all types
const legacyAddresses = wallet.generateLegacyAddresses(3);
const segwitAddresses = wallet.generateSegwitAddresses(3);
const nativeSegwitAddresses = wallet.generateNativeSegwitAddresses(3);

console.log('First Native SegWit Address:', nativeSegwitAddresses[0].address);
// Output: bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq
```

### 📖 BitcoinWallet API

**Static Methods:**
- `BitcoinWallet.generate(network?)` - Generate new wallet with random mnemonic
- `BitcoinWallet.fromMnemonic(mnemonic, network?)` - Create wallet from existing mnemonic

**Instance Methods:**
- `generateLegacyAddresses(count, network?)` - Generate P2PKH addresses
- `generateSegwitAddresses(count, network?)` - Generate P2SH-P2WPKH addresses
- `generateNativeSegwitAddresses(count, network?)` - Generate P2WPKH addresses
- `getAddressByPath(path, type, network?)` - Generate address by custom path
- `getWalletKeys(network?)` - Get all wallet keys (xpub/xprv, zpub/zprv, etc.)
- `setNetwork(network)` - Change wallet's default network

---

## 🔨 TransactionBuilder - Transaction Creation & Signing

The **TransactionBuilder** class handles UTXO selection, transaction building, fee estimation, and signing for all address types.

### 🔧 Usage

```typescript
import { TransactionBuilder } from '@nawab_kibria/bitcoin-lib';
import * as bitcoin from 'bitcoinjs-lib';

const builder = new TransactionBuilder(bitcoin.networks.regtest);

// Build a transaction
const result = await builder.buildTransaction({
    fromAddress: 'bc1q...',
    toAddress: 'bc1q...',
    amount: 50000, // satoshis
    feeRate: 1, // sat/vB
    utxos: utxoArray,
    privateKey: 'your-private-key-wif',
    addressType: 'native_segwit'
});

console.log('Transaction Hex:', result.hex);
console.log('Transaction ID:', result.txid);
```

### 📖 TransactionBuilder API

**Methods:**
- `buildTransaction(params)` - Build and sign complete transaction
- `estimateTransactionSize(inputs, outputs, addressType)` - Estimate transaction size
- `selectUTXOs(utxos, targetAmount, feeRate)` - Smart UTXO selection
- `createPSBT(params)` - Create Partially Signed Bitcoin Transaction
- `signPSBT(psbt, privateKey, addressType)` - Sign PSBT

**Transaction Parameters:**
```typescript
interface TransactionParams {
    fromAddress: string;
    toAddress: string;
    amount: number; // satoshis
    feeRate: number; // sat/vB
    utxos: UTXO[];
    privateKey: string; // WIF format
    addressType: 'legacy' | 'segwit' | 'native_segwit';
    changeAddress?: string;
}
```

---

## 🌐 ElectrumClient - Blockchain Connectivity

The **ElectrumClient** class provides connectivity to Electrum servers for blockchain data and transaction broadcasting.

### 🔧 Usage

```typescript
import { ElectrumClient, createElectrumClient } from '@nawab_kibria/bitcoin-lib';

// Create and connect to Electrum server
const client = createElectrumClient({
    host: 'localhost',
    port: 50001,
    ssl: false
});

await client.connect();

// Get address balance
const balance = await client.getBalance('bc1q...');
console.log('Confirmed:', balance.confirmed);
console.log('Unconfirmed:', balance.unconfirmed);

// Get UTXOs
const utxos = await client.getUTXOs('bc1q...');

// Broadcast transaction
const result = await client.broadcast('020000000001...');
console.log('TXID:', result.txid);

// Get transaction history
const history = await client.getHistory('bc1q...');

await client.disconnect();
```

### 📖 ElectrumClient API

**Connection Methods:**
- `connect()` - Connect to Electrum server
- `disconnect()` - Disconnect from server
- `isConnected()` - Check connection status

**Blockchain Methods:**
- `getBalance(address)` - Get address balance
- `getUTXOs(address)` - Get unspent transaction outputs
- `getHistory(address)` - Get transaction history
- `getTransaction(txid)` - Get transaction details
- `broadcast(txHex)` - Broadcast transaction
- `estimateFee(blocks?)` - Get fee estimation

**Batch Methods:**
- `getBalanceBatch(addresses)` - Get multiple balances
- `getUTXOsBatch(addresses)` - Get multiple UTXO sets

---

## 🧪 Standards Compliance

This library implements and complies with all major Bitcoin standards:

- ✅ **BIP39** - Mnemonic phrase generation
- ✅ **BIP32** - Hierarchical Deterministic wallets
- ✅ **BIP44** - Multi-Account Hierarchy (Legacy)
- ✅ **BIP49** - Derivation scheme for P2WPKH-nested-in-P2SH
- ✅ **BIP84** - Derivation scheme for P2WPKH (Native SegWit)

## 🌐 Network Support

- **Bitcoin Mainnet** - Production network (`bitcoin.networks.bitcoin`)
- **Bitcoin Testnet** - Testing network (`bitcoin.networks.testnet`)
- **Bitcoin Regtest** - Local development (`bitcoin.networks.regtest`)

## 🧪 Testing

Run the comprehensive test suite:

```bash
# Run all tests
npm test

# Run with coverage
npm run test:coverage

# Run examples
npm run example:wallet-manager
npm run example:complete-wallet
npm run example:electrum
npm run example:transaction
```

## 📁 Examples

The library includes comprehensive examples:

```bash
# Complete wallet demonstration
npm run example:complete-wallet

# Wallet manager features
npm run example:wallet-manager

# Electrum connectivity
npm run example:electrum

# Transaction building
npm run example:transaction

# BIP84 compliance
npm run example:bip84
```

## 🔒 Security Features

- **Deterministic Generation** - Reproducible wallets from seed
- **Proper Key Handling** - Secure cryptographic operations
- **Input Validation** - Safe parameter handling
- **Error Management** - Comprehensive error handling
- **Memory Security** - Proper cleanup of sensitive data

## 📊 Production Ready

This library is **production-ready** with:
- ✅ **90+ comprehensive tests**
- ✅ **Perfect BIP compliance** 
- ✅ **TypeScript type safety**
- ✅ **Professional documentation**
- ✅ **Comprehensive examples**

## 📄 License

MIT License - see [LICENSE](LICENSE) file for details.

---

**Start building modern Bitcoin applications today!** 🚀