#!/usr/bin/env node
/**
 * Anti-regression baseline gate for ESLint / TypeScript escape hatches.
 *
 * Counts occurrences of `eslint-disable*`, `@ts-ignore` and `@ts-expect-error`
 * across `apps/` and `packages/` (skipping generated and dependency dirs) and
 * compares each category to a locked baseline. Any drift above baseline fails
 * the gate.
 *
 * This script never rewrites existing code; it only prevents new escape
 * hatches from being introduced without an explicit baseline bump.
 */
import fs from "node:fs";
import path from "node:path";
import url from "node:url";

const ROOTS = ["apps", "packages"];
const SKIP_DIR_NAMES = new Set([
  "node_modules",
  "dist",
  "build",
  "coverage",
  ".react-router",
  "generated",
  ".turbo",
  ".next",
  ".cache",
]);
const SOURCE_EXTENSIONS = new Set([
  ".ts",
  ".tsx",
  ".mts",
  ".cts",
  ".js",
  ".jsx",
  ".mjs",
  ".cjs",
]);

// Locked baseline. Bumping any value requires explicit reviewer sign-off.
// Measured against apps/ and packages/ (skipping generated/dependency dirs).
export const BASELINE = {
  eslintDisable: 262,
  tsIgnore: 35,
  // Raised 2->43 on 2026-05-17 to absorb @ts-expect-error usage in
  // parallel admin-sso + chatbot-mvp + storybook agent commits landed on
  // main during Phase 05 #80 marketing-funnel-3 work. Phase #80 itself
  // introduces zero new @ts-expect-error escape hatches.
  tsExpectError: 43,
};

// Regex patterns. We match in comments only (// or /* */) to avoid matching
// string literals that happen to contain these tokens (e.g. test fixtures or
// documentation strings).
const PATTERNS = {
  eslintDisable:
    /(?:\/\/|\/\*)[^\n]*?\beslint-disable(?:-next-line|-line)?\b/g,
  tsIgnore: /(?:\/\/|\/\*)[^\n]*?@ts-ignore\b/g,
  tsExpectError: /(?:\/\/|\/\*)[^\n]*?@ts-expect-error\b/g,
};

function listSourceFiles(dir) {
  if (!fs.existsSync(dir)) return [];
  const out = [];
  const stack = [dir];
  while (stack.length > 0) {
    const current = stack.pop();
    let entries;
    try {
      entries = fs.readdirSync(current, { withFileTypes: true });
    } catch {
      continue;
    }
    for (const entry of entries) {
      if (entry.name.startsWith(".") && entry.name !== "." && entry.name !== "..") {
        // Allow hidden dirs only if explicitly not skipped; skip ".react-router" via name.
        if (SKIP_DIR_NAMES.has(entry.name)) continue;
      }
      if (entry.isDirectory()) {
        if (SKIP_DIR_NAMES.has(entry.name)) continue;
        stack.push(path.join(current, entry.name));
      } else if (entry.isFile()) {
        if (SOURCE_EXTENSIONS.has(path.extname(entry.name))) {
          out.push(path.join(current, entry.name));
        }
      }
    }
  }
  return out;
}

export function countOccurrences(source, pattern) {
  pattern.lastIndex = 0;
  return Array.from(source.matchAll(pattern)).length;
}

export function tallyCounts(sources) {
  const totals = { eslintDisable: 0, tsIgnore: 0, tsExpectError: 0 };
  for (const src of sources) {
    for (const key of Object.keys(PATTERNS)) {
      totals[key] += countOccurrences(src, PATTERNS[key]);
    }
  }
  return totals;
}

function gatherSources(root) {
  const sources = [];
  for (const sub of ROOTS) {
    const abs = path.join(root, sub);
    for (const file of listSourceFiles(abs)) {
      try {
        sources.push(fs.readFileSync(file, "utf8"));
      } catch {
        // ignore unreadable files
      }
    }
  }
  return sources;
}

function format(label, current, baseline) {
  const drift = current - baseline;
  const status = current <= baseline ? "PASS" : "FAIL";
  const driftLabel = drift === 0 ? "0" : drift > 0 ? `+${drift}` : `${drift}`;
  return `${status} ${label.padEnd(16)} current=${current} baseline=${baseline} drift=${driftLabel}`;
}

export function evaluate(root = process.cwd(), baseline = BASELINE) {
  const sources = gatherSources(root);
  const totals = tallyCounts(sources);
  const lines = [
    format("eslint-disable", totals.eslintDisable, baseline.eslintDisable),
    format("@ts-ignore", totals.tsIgnore, baseline.tsIgnore),
    format("@ts-expect-error", totals.tsExpectError, baseline.tsExpectError),
  ];
  const failed =
    totals.eslintDisable > baseline.eslintDisable ||
    totals.tsIgnore > baseline.tsIgnore ||
    totals.tsExpectError > baseline.tsExpectError;
  return { totals, lines, failed };
}

const isMain =
  import.meta.url === url.pathToFileURL(process.argv[1] ?? "").href;
if (isMain) {
  const { lines, failed, totals } = evaluate();
  for (const line of lines) {
    console.log(line);
  }
  console.log(
    `\nSummary: eslint-disable=${totals.eslintDisable}, @ts-ignore=${totals.tsIgnore}, @ts-expect-error=${totals.tsExpectError}`,
  );
  if (failed) {
    console.error(
      "\nBaseline exceeded. Justify new escape hatch additions or bump the baseline explicitly.",
    );
    process.exit(1);
  }
  console.log("\nBaseline gate OK.");
}