#!/usr/bin/env node
// Anti-regression gate: asserts a minimum test-file-per-source-file density
// per workspace. Catches "route added without test" without requiring full
// coverage tooling. Floors are deliberate snapshots of the current ratio;
// they must only go down via deliberate commits (= more tests added).

import fs from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";

const repoRoot = path.resolve(fileURLToPath(import.meta.url), "..", "..");

const TARGETS = [
  { name: "apps/api", root: "apps/api/src", minRatio: 0.18 },
  { name: "apps/worker", root: "apps/worker/src", minRatio: 0.18 },
  { name: "apps/web app routes", root: "apps/web/app/routes", minRatio: 0.05 },
  { name: "apps/web app modules", root: "apps/web/app/modules", minRatio: 0.04 },
  { name: "apps/web app utils", root: "apps/web/app/utils", minRatio: 0.10 },
  { name: "packages/foundation", root: "packages/foundation/src", minRatio: 0.10 },
  { name: "packages/db", root: "packages/db/src", minRatio: 0.05 },
  { name: "packages/mail", root: "packages/mail/src", minRatio: 0.30 },
  { name: "packages/queue", root: "packages/queue/src", minRatio: 0.10 },
  { name: "packages/i18n", root: "packages/i18n/src", minRatio: 0.30 },
  { name: "packages/brand", root: "packages/brand/src", minRatio: 0.50 },
  { name: "packages/config", root: "packages/config/src", minRatio: 0.50 },
];

const ignoredDirs = new Set(["node_modules", "dist", "build", "coverage", ".react-router", "generated", "__generated__"]);
const sourcePattern = /\.(?:ts|tsx)$/;
const testPattern = /\.(?:test|spec)\.(?:ts|tsx)$/;
const declarationPattern = /\.d\.ts$/;

export function walk(dir, acc = { source: 0, test: 0 }) {
  if (!fs.existsSync(dir)) return acc;
  for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
    if (ignoredDirs.has(entry.name) || entry.name.startsWith(".")) continue;
    const full = path.join(dir, entry.name);
    if (entry.isDirectory()) {
      walk(full, acc);
      continue;
    }
    if (!entry.isFile()) continue;
    if (declarationPattern.test(entry.name)) continue;
    if (testPattern.test(entry.name)) {
      acc.test += 1;
    } else if (sourcePattern.test(entry.name)) {
      acc.source += 1;
    }
  }
  return acc;
}

export function evaluateTargets(targets, rootDir = repoRoot) {
  const failures = [];
  const passes = [];

  for (const target of targets) {
    const counts = walk(path.join(rootDir, target.root));
    if (counts.source === 0) {
      passes.push(`SKIP ${target.name} no source files`);
      continue;
    }
    const ratio = counts.test / counts.source;
    const line = `${target.name} source=${counts.source} tests=${counts.test} ratio=${ratio.toFixed(3)} min=${target.minRatio.toFixed(3)}`;
    if (ratio >= target.minRatio) {
      passes.push(`PASS ${line}`);
    } else {
      failures.push(`FAIL ${line} (drift=${(ratio - target.minRatio).toFixed(3)})`);
    }
  }

  return { failures, passes };
}

export function formatSummary(result) {
  return `Summary: ${result.passes.length} passed, 0 observed, ${result.failures.length} failed`;
}

function main() {
  const result = evaluateTargets(TARGETS);

  for (const line of result.passes) console.log(line);
  for (const line of result.failures) console.error(line);
  console.log(formatSummary(result));

  if (result.failures.length > 0) process.exit(1);
}

if (import.meta.url === `file://${process.argv[1]}`) {
  main();
}