import { expect, test } from 'vitest';
import { isHex } from '@bitauth/libauth';
import { scriptToScriptHash } from '../source/index.ts';

/**
 * Tests that scriptToScriptHash produces the correct reversed SHA256 for a standard P2PKH locking script
 * and returns a 64 character hex string.
 */
const testScriptHashForP2pkhScript = (): void => {
    // Standard P2PKH locking script: OP_DUP OP_HASH160 <20 zero bytes> OP_EQUALVERIFY OP_CHECKSIG
    const p2pkhScript = new Uint8Array([ 0x76, 0xa9, 0x14, ...new Uint8Array(20).fill(0), 0x88, 0xac ]);

    // Precomputed reversed SHA256 of the above script bytes
    const expectedHash = 'acb87996319dca2c2e2afd6c0f7514b18e72e204069718976e1abdc8fcf5de75';

    // Generate the script hash
    const scriptHash = scriptToScriptHash(p2pkhScript);

    // The script hash must match the known-good precomputed value exactly
    expect(scriptHash).toBe(expectedHash);

    // The script hash is 64 characters long
    expect(scriptHash).toHaveLength(64);

    // The script hash is a valid hex string
    expect(isHex(scriptHash)).toBe(true);
};

/**
 * Tests that two different scripts produce different script hashes.
 */
const testScriptHashIsDifferentForDifferentScripts = (): void => {
    // Generate the first script hash
    const hashA = scriptToScriptHash(new Uint8Array([ 0x01 ]));

    // Generate the second script hash
    const hashB = scriptToScriptHash(new Uint8Array([ 0x02 ]));

    // The different scripts produce different script hashes
    expect(hashA).not.toBe(hashB);
};

const runTests = async (): Promise<void> => {
    test('scriptToScriptHash: produces reversed SHA256 for a P2PKH locking script', testScriptHashForP2pkhScript);
    test('scriptToScriptHash: produces different hashes for different scripts', testScriptHashIsDifferentForDifferentScripts);
};

await runTests();