/**
 * Shared assertion helpers for holdout scenarios.
 *
 * These wrap Playwright's `expect` with protocol-specific checks so that
 * scenario specs stay at the "what" level rather than encoding RPC details.
 */
import { expect } from '@playwright/test';
import { Interface } from 'ethers';

// ── Internal helpers ─────────────────────────────────────────────────────────

async function rpcCall(rpcUrl: string, method: string, params: unknown[]): Promise<unknown> {
  const resp = await fetch(rpcUrl, {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ jsonrpc: '2.0', id: Date.now(), method, params }),
  });
  const payload = await resp.json();
  if (payload.error) throw new Error(`RPC ${method}: ${payload.error.message}`);
  return payload.result;
}

async function getTokenBalance(rpcUrl: string, token: string, address: string): Promise<bigint> {
  if (token.toLowerCase() === 'eth') {
    const result = (await rpcCall(rpcUrl, 'eth_getBalance', [address, 'latest'])) as string;
    return BigInt(result);
  }
  const selector = '0x70a08231'; // balanceOf(address)
  const data = selector + address.slice(2).padStart(64, '0');
  const result = (await rpcCall(rpcUrl, 'eth_call', [{ to: token, data }, 'latest'])) as string;
  return BigInt(result);
}

const POOL_ABI = [
  'function slot0() external view returns (uint160 sqrtPriceX96, int24 tick, uint16 observationIndex, uint16 observationCardinality, uint16 observationCardinalityNext, uint8 feeProtocol, bool unlocked)',
  'function liquidity() external view returns (uint128)',
];
const poolIface = new Interface(POOL_ABI);

// ── Exported helpers ─────────────────────────────────────────────────────────

/**
 * Snapshot the balance of `token` for `address`, run `action`, then assert the
 * balance increased.
 *
 * @param token - An ERC-20 contract address, or the string `'eth'` for native ETH.
 */
export async function expectBalanceIncrease(
  rpcUrl: string,
  token: string,
  address: string,
  action: () => Promise<void>,
): Promise<void> {
  const before = await getTokenBalance(rpcUrl, token, address);
  await action();
  const after = await getTokenBalance(rpcUrl, token, address);
  expect(after).toBeGreaterThan(before);
}

/**
 * Assert that the Uniswap V3 pool at `poolAddress` is initialised and has
 * non-zero active liquidity at the current tick.
 *
 * Used after a sovereign exit to confirm the pool remains functional and the
 * LiquidityManager's positions are intact.
 */
export async function expectPoolHasLiquidity(rpcUrl: string, poolAddress: string): Promise<void> {
  // slot0() — check pool is initialised (sqrtPriceX96 > 0)
  const slot0Encoded = poolIface.encodeFunctionData('slot0', []);
  const slot0Hex = (await rpcCall(rpcUrl, 'eth_call', [{ to: poolAddress, data: slot0Encoded }, 'latest'])) as string;
  const [sqrtPriceX96] = poolIface.decodeFunctionResult('slot0', slot0Hex);
  expect(sqrtPriceX96).toBeGreaterThan(0n);

  // liquidity() — active liquidity at the current tick must be non-zero
  const liquidityEncoded = poolIface.encodeFunctionData('liquidity', []);
  const liquidityHex = (await rpcCall(rpcUrl, 'eth_call', [
    { to: poolAddress, data: liquidityEncoded },
    'latest',
  ])) as string;
  const [liquidity] = poolIface.decodeFunctionResult('liquidity', liquidityHex);
  expect(liquidity).toBeGreaterThan(0n);
}