/**
 * Evidence recording. Every check attaches what it actually observed, so a
 * green run is readable afterwards and a red run is diagnosable without a
 * re-run.
 *
 * This is the harness half of the project's observability rule: a process that
 * discards its own output is a defect, and a test that asserts without
 * recording what it saw is the same defect wearing a different hat.
 */

import { test, type TestInfo } from '@playwright/test';
import { redact } from './env';
import type { CommandResult } from './cluster';

/** Human-readable transcript of one command, for attachment. */
function transcript(result: CommandResult): string {
  const lines = [`$ ${result.command}`, `exit: ${result.code}`];
  if (result.stdout.trim() !== '') lines.push('--- stdout ---', result.stdout.trimEnd());
  if (result.stderr.trim() !== '') lines.push('--- stderr ---', result.stderr.trimEnd());
  return `${lines.join('\n')}\n`;
}

/** Attach one command's full transcript under a stable name. */
export async function recordCommand(
  testInfo: TestInfo,
  name: string,
  result: CommandResult,
): Promise<void> {
  await testInfo.attach(`${name}.txt`, {
    body: Buffer.from(transcript(result)),
    contentType: 'text/plain',
  });
}

/** Attach an arbitrary observation as JSON, redacted. */
export async function recordJson(
  testInfo: TestInfo,
  name: string,
  value: unknown,
): Promise<void> {
  await testInfo.attach(`${name}.json`, {
    body: Buffer.from(redact(JSON.stringify(value, null, 2))),
    contentType: 'application/json',
  });
}

/**
 * Run a command inside a named `test.step` and attach its transcript, whether
 * it succeeded or not. Returns the result so the caller can assert on it.
 *
 * Steps are what make the HTML report read as a walkthrough of the runbook
 * rather than a flat list of assertions.
 */
export async function observed<T extends CommandResult>(
  testInfo: TestInfo,
  label: string,
  invoke: () => Promise<T>,
): Promise<T> {
  return test.step(label, async () => {
    const result = await invoke();
    await recordCommand(testInfo, label.replace(/[^a-z0-9]+/gi, '-').toLowerCase(), result);
    return result;
  });
}