/**
 * test_samurai_vitest_reporter.mjs
 *
 * Custom Vitest 2.x reporter for test-samurai.
 *
 * Emits one line per completed test case to stdout:
 *   TSAMURAI_RESULT <json>
 *
 * Payload schema:
 *   {
 *     name:     string   -- Describe-hierarchy + test title joined with "/"
 *     status:   "passed" | "failed" | "skipped"
 *     file:     string | null  -- absolute file path
 *     location: { line: number, column: number } | null
 *     output:   string[]  -- error messages / stack traces (failures only)
 *   }
 */

const RESULT_PREFIX = 'TSAMURAI_RESULT ';

export default class TestSamuraiVitestReporter {
  onTestCaseResult(testCase) {
    const name = buildListingName(testCase);
    const status = mapStatus(testCase.task);
    if (!status) return;

    const output = buildOutput(testCase.task);

    const payload = {
      name,
      status,
      file: testCase.file?.filepath ?? null,
      location: testCase.location ?? null,
      output,
    };

    process.stdout.write(`${RESULT_PREFIX}${JSON.stringify(payload)}\n`);
  }
}

/**
 * Builds a slash-separated name from the describe hierarchy.
 * E.g. describe('MyComponent') > describe('renders') > it('the button')
 * → "MyComponent/renders/the button"
 */
function buildListingName(testCase) {
  const parts = [testCase.name];
  let current = testCase.parent;
  while (current && current.type === 'suite') {
    parts.unshift(current.name);
    current = current.parent;
  }
  return parts.filter(Boolean).join('/');
}

/**
 * Maps Vitest task result states to test-samurai status strings.
 * Falls back to task.mode if result.state is missing.
 */
function mapStatus(task) {
  if (!task) return null;
  const state = task.result?.state;
  if (state === 'pass') return 'passed';
  if (state === 'fail') return 'failed';
  if (state === 'skip') return 'skipped';
  const mode = task.mode;
  if (mode === 'skip' || mode === 'todo') return 'skipped';
  return null;
}

/**
 * Collects error messages and stack traces for failed tests.
 */
function buildOutput(task) {
  const lines = [];
  if (!task) return lines;
  const errors = task.result?.errors ?? [];
  for (const err of errors) {
    if (typeof err.message === 'string' && err.message.length > 0) {
      err.message.split('\n').forEach((line) => {
        if (line !== '') lines.push(line);
      });
    }
    if (typeof err.stack === 'string' && err.stack.length > 0) {
      err.stack.split('\n').forEach((line) => {
        if (line !== '') lines.push(line);
      });
    }
  }
  return lines;
}