#!/usr/bin/env bun
/**
 * test-paid-shards — enumerate, shard, and run the paid (gate/periodic) tier.
 *
 * The single-process `test:gate` fan-out has never completed a run: one wedged
 * or spinning file takes the whole tier down, and an in-process `--timeout`
 * cannot save it because a spinning main thread never fires a timer. This
 * runner applies the free tier's proven fix — one Bun process per shard — plus
 * the two things the paid tier additionally needs:
 *
 *   - an EXTERNAL wall-clock timeout that kills the shard's process GROUP, and
 *   - an aggregate that distinguishes failed from timed-out from never-started,
 *     so 26% execution can never again look like a pass.
 *
 * Why not Bun 1.3.13's native `--shard` / isolated runs? Three gaps, each one
 * fatal for this tier:
 *   1. No detached-process-group SIGKILL. Paid tests spawn `claude` / `codex`
 *      PTY grandchildren; when a shard hangs, in-process isolation kills the
 *      Bun worker but the grandchildren survive and burn cores for hours.
 *   2. No never-started taxonomy. A run that aborts partway reports only what
 *      executed — the shards that never ran are invisible, which is exactly
 *      the 26%-execution-looks-like-a-pass bug.
 *   3. No per-shard env / eval dir. Each shard needs its own GSTACK_EVAL_DIR
 *      so eval baselines are per-test-file instead of last-flush-wins.
 *
 * Worst-case wall clock (all shards hit the 30min timeout, 4 parallel jobs):
 * gate tier is 49 shards × 30min / 4 jobs ≈ 6.2h; periodic is 59 shards ≈ 7.4h.
 * The eval:bg:* detach timeouts (25200s / 28800s) are sized against these.
 *
 * Enumeration matches package.json's `test:gate` globs (via the shared
 * test/helpers/paid-test-set.ts) and honors EVALS_TIER against the E2E_TIERS
 * map in test/helpers/touchfiles.ts. Output classification reuses
 * scripts/test-strict-output.ts rather than reimplementing it.
 *
 * Parallelism now lives ACROSS shards (--jobs), not inside one Bun process, so
 * each shard runs its own file sequentially and can be killed independently.
 *
 * Usage:
 *   bun run scripts/test-paid-shards.ts --list                # shard plan only
 *   bun run scripts/test-paid-shards.ts --tier gate           # run gate tier
 *   bun run scripts/test-paid-shards.ts --timeout 600 --jobs 2
 */

import { spawn, type ChildProcess } from 'node:child_process';
import * as fs from 'node:fs';
import * as path from 'node:path';
import { normalizeRelativePath } from './test-free-shards';
import {
  BunTestOutputClassifier,
  exactTestFileSelectors,
  forwardAndClassify,
  installChildSignalForwarding,
  strictTestExitCode,
} from './test-strict-output';
import { PAID_TEST_GLOBS, isPaidTestFile } from '../test/helpers/paid-test-set';
import { getProjectEvalDir } from '../test/helpers/eval-store';

export { PAID_TEST_GLOBS, isPaidTestFile };

const ROOT = path.resolve(import.meta.dir, '..');

export type PaidTier = 'gate' | 'periodic';

export const DEFAULT_TIER: PaidTier = 'gate';
export const DEFAULT_SHARD_TIMEOUT_MS = 30 * 60_000;
export const DEFAULT_MAX_FILES_PER_SHARD = 1;
export const DEFAULT_JOBS = 4;

export function collectPaidTestFiles(rootDir = ROOT): string[] {
  const testDir = path.join(rootDir, 'test');
  if (!fs.existsSync(testDir)) return [];
  return fs.readdirSync(testDir)
    .map((name) => `test/${name}`)
    .filter(isPaidTestFile)
    .sort();
}

export interface TierClassification {
  included: boolean;
  reason: string;
}

/**
 * Decide whether a paid test file has anything to run in `tier`.
 *
 * Per-TEST tier filtering already happens at runtime: test/helpers/e2e-helpers.ts
 * intersects the selected tests with E2E_TIERS whenever EVALS_TIER is set, and
 * this runner passes EVALS_TIER down to every shard. So this file-level pass is
 * only an optimization — skipping a file merely saves one near-instant shard.
 *
 * Exclusion is the dangerous direction (a wrongly-skipped gate test is exactly
 * the invisible-non-execution bug this runner exists to kill), so the only
 * exclusion evidence accepted is an explicit whole-file tier guard: either the
 * raw `EVALS_TIER === '<other>'` predicate or the consolidated helper form
 * `describeE2ETier('<other>')` / `e2eTierEnabled('<other>')` from
 * test/helpers/e2e-gate.ts (same semantics, read from env at module load).
 * Inferring a file's tier from which E2E_TIERS names appear in its source
 * is guesswork that silently drops real work: short keys like 'retro' match
 * unrelated strings, and LLM-judge tests are keyed off LLM_JUDGE_TOUCHFILES and
 * carry no E2E_TIERS name at all. Everything without an explicit other-tier
 * guard runs and self-skips.
 */
export function classifyPaidTestFile(source: string, tier: PaidTier): TierClassification {
  const other: PaidTier = tier === 'gate' ? 'periodic' : 'gate';
  const declares = (candidate: PaidTier) =>
    new RegExp(`EVALS_TIER\\s*===\\s*['"\`]${candidate}['"\`]`).test(source) ||
    new RegExp(`\\b(?:describeE2ETier|e2eTierEnabled)\\(\\s*['"\`]${candidate}['"\`]`).test(source);

  if (declares(tier)) return { included: true, reason: `declares tier '${tier}'` };
  if (declares(other)) return { included: false, reason: `declares tier '${other}' only` };
  return { included: true, reason: 'no whole-file tier guard — runtime E2E_TIERS filter decides' };
}

export interface TierSelection {
  selected: string[];
  excluded: Array<{ file: string; reason: string }>;
}

export function selectPaidTestFiles(files: string[], tier: PaidTier, rootDir = ROOT): TierSelection {
  const selected: string[] = [];
  const excluded: Array<{ file: string; reason: string }> = [];
  for (const file of files) {
    const source = fs.readFileSync(path.join(rootDir, file), 'utf8');
    const classification = classifyPaidTestFile(source, tier);
    if (classification.included) selected.push(file);
    else excluded.push({ file, reason: classification.reason });
  }
  return { selected, excluded };
}

export function planPaidShards(
  files: string[],
  options: { maxFilesPerShard?: number } = {},
): string[][] {
  const size = Math.max(1, options.maxFilesPerShard ?? DEFAULT_MAX_FILES_PER_SHARD);
  const unique = [...new Set(files.map(normalizeRelativePath))].sort();
  const shards: string[][] = [];
  for (let index = 0; index < unique.length; index += size) shards.push(unique.slice(index, index + size));
  return shards;
}

export function buildPaidShardArgs(files: string[], timeoutMs: number): string[] {
  return ['test', ...files, '--retry', '2', `--timeout=${timeoutMs}`];
}

/**
 * Stable per-shard eval-dir slug: test filename sans extension, sanitized.
 * Stable across runs so each shard baselines against its own prior run.
 */
export function shardSlug(files: string[]): string {
  return files
    .map((file) => path.basename(normalizeRelativePath(file)).replace(/\.test\.(?:[cm]?[jt]s|tsx|jsx)$/, ''))
    .join('+')
    .replace(/[^a-zA-Z0-9._+-]/g, '-');
}

export type ShardStatus = 'passed' | 'failed' | 'timed-out' | 'never-started';

export interface ShardOutcome {
  shard: number;
  files: string[];
  status: ShardStatus;
  exitCode: number | null;
  elapsedMs: number;
  groupPid: number | null;
}

export interface ShardCommand {
  command: string;
  args: string[];
}

export interface RunShardsOptions {
  timeoutMs?: number;
  jobs?: number;
  rootDir?: string;
  env?: NodeJS.ProcessEnv;
  /** When set, each shard child gets GSTACK_EVAL_DIR=<evalDirBase>/shards/<slug>/. */
  evalDirBase?: string;
  /** Override the spawned command. Tests inject fake slow/spinning commands. */
  commandFor?: (files: string[]) => ShardCommand;
  log?: (line: string) => void;
}

/**
 * SIGKILL the shard's whole process group. Orphaned grandchildren (browsers,
 * claude sessions) are how a stalled run once burned a core for 15.7 hours.
 */
function killProcessGroup(child: ChildProcess, signal: NodeJS.Signals): void {
  if (process.platform === 'win32' || typeof child.pid !== 'number') {
    child.kill(signal);
    return;
  }
  try {
    process.kill(-child.pid, signal);
  } catch (err) {
    const code = (err as NodeJS.ErrnoException).code;
    if (code === 'ESRCH') return; // group already gone
    if (code !== 'EPERM') throw err;
    // Observed on macOS after a SIGKILLed group is reaped: signalling the
    // now-empty group id returns EPERM, not ESRCH. Throwing here loses the
    // shard's real outcome (a timeout gets recorded as a failure) and, from
    // the timeout timer, leaves the shard promise unsettled — a hang, which
    // is the exact failure class this runner exists to kill. Fall back to the
    // direct pid so a genuinely-live child is still signalled.
    try {
      child.kill(signal);
    } catch {
      // Best-effort reap: nothing actionable is left if this fails too.
    }
  }
}

export async function runPaidShard(
  files: string[],
  shardNumber: number,
  totalShards: number,
  options: RunShardsOptions = {},
): Promise<ShardOutcome> {
  if (files.length === 0) throw new Error('Cannot run an empty paid-test shard.');
  const rootDir = options.rootDir ?? ROOT;
  const timeoutMs = options.timeoutMs ?? DEFAULT_SHARD_TIMEOUT_MS;
  const streamLive = (options.jobs ?? DEFAULT_JOBS) === 1;
  const log = options.log ?? ((line: string) => console.log(line));
  const label = `[test:paid] shard ${shardNumber}/${totalShards}`;

  const { command, args } = options.commandFor
    ? options.commandFor(files)
    : {
      command: process.execPath,
      args: buildPaidShardArgs(exactTestFileSelectors(files, rootDir), timeoutMs),
    };

  const env = { ...(options.env ?? process.env) };
  if (options.evalDirBase) {
    env.GSTACK_EVAL_DIR = path.join(options.evalDirBase, 'shards', shardSlug(files));
  }

  const startedAt = Date.now();
  log(`${label} START ${files.join(' ')} (timeout ${Math.round(timeoutMs / 1000)}s)`);

  const child = spawn(command, args, {
    cwd: rootDir,
    env,
    stdio: ['ignore', 'pipe', 'pipe'],
    detached: process.platform !== 'win32',
    windowsHide: true,
  });
  const groupPid = child.pid ?? null;
  // Group-kill on parent SIGINT/SIGTERM too, not just on timeout.
  const forwarding = installChildSignalForwarding({
    kill: (signal?: NodeJS.Signals | number) => {
      killProcessGroup(child, (signal as NodeJS.Signals) ?? 'SIGTERM');
      return true;
    },
  });

  const classifier = new BunTestOutputClassifier();
  const buffered: Buffer[] = [];
  const sink = (destination: NodeJS.WriteStream): NodeJS.WriteStream => (streamLive
    ? destination
    : ({ write: (chunk: Buffer | string) => buffered.push(Buffer.from(chunk)) } as unknown as NodeJS.WriteStream));

  let timedOut = false;
  const killTimer = setTimeout(() => {
    timedOut = true;
    killProcessGroup(child, 'SIGKILL');
  }, timeoutMs);

  let exitCode: number | null = null;
  try {
    const streams: Array<Promise<void>> = [];
    if (child.stdout) streams.push(forwardAndClassify(child.stdout, sink(process.stdout), classifier));
    if (child.stderr) streams.push(forwardAndClassify(child.stderr, sink(process.stderr), classifier));
    exitCode = await new Promise<number | null>((resolve, reject) => {
      child.once('error', reject);
      child.once('close', (code) => resolve(code));
    });
    await Promise.all(streams);
  } finally {
    clearTimeout(killTimer);
    forwarding.dispose();
    // Reap survivors of this shard even on the clean path.
    killProcessGroup(child, 'SIGKILL');
  }

  const summary = classifier.end();
  if (!streamLive && buffered.length > 0) process.stdout.write(Buffer.concat(buffered));

  // Pass expectedFiles so a shard whose bun child ran fewer files than planned
  // (or zero, all self-skipped) with exit 0 is NOT recorded 'passed' — the
  // invisible-non-execution class this runner exists to kill. bun prints
  // "Ran N tests across M files" with M = selected files even when every test
  // self-skips, so terminalFileCounts must include files.length. Only enforced
  // on the real bun path: an injected commandFor (tests) isn't bun and emits no
  // terminal summary, so there's no file count to check against.
  const expectedFiles = options.commandFor ? undefined : files.length;
  const status: ShardStatus = timedOut
    ? 'timed-out'
    : strictTestExitCode(exitCode ?? 1, summary, expectedFiles) === 0 ? 'passed' : 'failed';
  const elapsedMs = Date.now() - startedAt;
  log(`${label} ${status.toUpperCase()} in ${Math.round(elapsedMs / 1000)}s (exit ${exitCode ?? 'signal'})`);

  return { shard: shardNumber, files, status, exitCode, elapsedMs, groupPid };
}

export interface RunSummary {
  total: number;
  executed: number;
  passed: number;
  failed: number;
  timedOut: number;
  neverStarted: number;
  outcomes: ShardOutcome[];
}

export function summarize(outcomes: ShardOutcome[]): RunSummary {
  const count = (status: ShardStatus) => outcomes.filter((o) => o.status === status).length;
  return {
    total: outcomes.length,
    executed: outcomes.length - count('never-started'),
    passed: count('passed'),
    failed: count('failed'),
    timedOut: count('timed-out'),
    neverStarted: count('never-started'),
    outcomes,
  };
}

/** Run every shard in its own process. A timeout or failure never aborts the run. */
export async function runPaidShards(
  shards: string[][],
  options: RunShardsOptions = {},
): Promise<RunSummary> {
  const jobs = Math.max(1, options.jobs ?? DEFAULT_JOBS);
  const outcomes: ShardOutcome[] = shards.map((files, index) => ({
    shard: index + 1,
    files,
    status: 'never-started',
    exitCode: null,
    elapsedMs: 0,
    groupPid: null,
  }));

  let next = 0;
  const worker = async (): Promise<void> => {
    while (true) {
      const index = next;
      next += 1;
      if (index >= shards.length) return;
      try {
        outcomes[index] = await runPaidShard(shards[index], index + 1, shards.length, { ...options, jobs });
      } catch (error) {
        outcomes[index] = {
          shard: index + 1,
          files: shards[index],
          status: 'failed',
          exitCode: null,
          elapsedMs: 0,
          groupPid: null,
        };
        console.error(`[test:paid] shard ${index + 1} could not run: ${error instanceof Error ? error.message : String(error)}`);
      }
    }
  };

  await Promise.all(Array.from({ length: Math.min(jobs, shards.length) }, worker));
  return summarize(outcomes);
}

export function formatSummary(summary: RunSummary): string[] {
  const lines = [
    '',
    `[test:paid] ${summary.executed}/${summary.total} shards executed — `
    + `${summary.passed} passed, ${summary.failed} failed, `
    + `${summary.timedOut} timed out, ${summary.neverStarted} never started`,
  ];
  for (const outcome of summary.outcomes) {
    lines.push(
      `  ${outcome.status.padEnd(13)} ${String(Math.round(outcome.elapsedMs / 1000)).padStart(5)}s  `
      + outcome.files.join(' '),
    );
  }
  return lines;
}

type CliOptions = {
  tier: PaidTier;
  listOnly: boolean;
  timeoutMs: number;
  jobs: number;
  maxFilesPerShard: number;
};

function parsePositiveInt(value: string | undefined, flag: string): number {
  const parsed = Number.parseInt(value ?? '', 10);
  if (!Number.isInteger(parsed) || parsed <= 0) throw new Error(`${flag} needs a positive integer. Received: ${value}`);
  return parsed;
}

function validatedTier(value: string | undefined, source: string): PaidTier {
  if (value === undefined || value === '') return DEFAULT_TIER;
  // A typo'd EVALS_TIER (e.g. 'e2e', the tier string eval-store uses) would
  // otherwise cast through unchecked, match nothing in the runtime E2E_TIERS
  // filter, self-skip every test, and exit 0 with all shards 'passed' — the
  // exact 0%-execution-looks-like-a-pass class this runner exists to kill.
  if (value !== 'gate' && value !== 'periodic') {
    throw new Error(`${source} must be gate or periodic. Received: ${value}`);
  }
  return value;
}

export function parseCliOptions(argv: string[], env: NodeJS.ProcessEnv = process.env): CliOptions {
  const options: CliOptions = {
    tier: validatedTier(env.EVALS_TIER, 'EVALS_TIER'),
    listOnly: false,
    timeoutMs: env.EVALS_SHARD_TIMEOUT_MS
      ? parsePositiveInt(env.EVALS_SHARD_TIMEOUT_MS, 'EVALS_SHARD_TIMEOUT_MS')
      : DEFAULT_SHARD_TIMEOUT_MS,
    jobs: env.EVALS_CONCURRENCY ? parsePositiveInt(env.EVALS_CONCURRENCY, 'EVALS_CONCURRENCY') : DEFAULT_JOBS,
    maxFilesPerShard: DEFAULT_MAX_FILES_PER_SHARD,
  };

  for (let index = 0; index < argv.length; index += 1) {
    const arg = argv[index];
    if (arg === '--list') { options.listOnly = true; continue; }
    if (arg === '--tier') {
      const value = argv[index += 1];
      if (value !== 'gate' && value !== 'periodic') throw new Error(`--tier must be gate or periodic. Received: ${value}`);
      options.tier = value;
      continue;
    }
    if (arg === '--timeout') { options.timeoutMs = parsePositiveInt(argv[index += 1], '--timeout') * 1000; continue; }
    if (arg === '--jobs') { options.jobs = parsePositiveInt(argv[index += 1], '--jobs'); continue; }
    if (arg === '--files-per-shard') { options.maxFilesPerShard = parsePositiveInt(argv[index += 1], '--files-per-shard'); continue; }
    throw new Error(`Unknown argument: ${arg}`);
  }
  return options;
}

async function main(): Promise<number> {
  const options = parseCliOptions(process.argv.slice(2));
  const discovered = collectPaidTestFiles();
  if (discovered.length === 0) throw new Error('No paid test files were discovered.');

  const { selected, excluded } = selectPaidTestFiles(discovered, options.tier);
  const shards = planPaidShards(selected, { maxFilesPerShard: options.maxFilesPerShard });
  console.log(
    `[test:paid] tier=${options.tier}: ${selected.length}/${discovered.length} files, `
    + `${shards.length} shards, jobs=${options.jobs}, timeout=${Math.round(options.timeoutMs / 1000)}s`,
  );

  if (options.listOnly) {
    for (let index = 0; index < shards.length; index += 1) {
      console.log(`  shard ${index + 1}/${shards.length}: ${shards[index].join(' ')}`);
    }
    if (excluded.length > 0) {
      console.log(`\nExcluded (${excluded.length}):`);
      for (const { file, reason } of excluded) console.log(`  - ${file}  [${reason}]`);
    }
    return 0;
  }

  const summary = await runPaidShards(shards, {
    // Tier reaches the children only via EVALS_TIER below; the runtime
    // E2E_TIERS filter inside each child is the real selection mechanism.
    timeoutMs: options.timeoutMs,
    jobs: options.jobs,
    env: { ...process.env, EVALS: '1', EVALS_TIER: options.tier },
    evalDirBase: process.env.GSTACK_EVAL_DIR || getProjectEvalDir(),
  });
  for (const line of formatSummary(summary)) console.log(line);
  return summary.passed === summary.total ? 0 : 1;
}

if (import.meta.main) {
  try {
    process.exitCode = await main();
  } catch (error) {
    console.error(`[test:paid] ${error instanceof Error ? error.message : String(error)}`);
    process.exitCode = 1;
  }
}