#!/usr/bin/env tsx
/* eslint-disable no-console */
import { readdir, readFile, stat } from "node:fs/promises";
import { spawn } from "node:child_process";
import path from "node:path";
import { fileURLToPath } from "node:url";

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

export const removedModuleScanRoots = ["apps", "packages"] as const;

export const sourceFileExtensions = new Set([".ts", ".tsx", ".js", ".jsx", ".mjs", ".cjs", ".json", ".md", ".mdx"]);

export const ignoredDirectoryNames = new Set([
  ".cache",
  ".git",
  ".next",
  ".react-router",
  ".tc",
  ".turbo",
  ".vite",
  "build",
  "cache",
  "coverage",
  "dist",
  "generated",
  "node_modules",
  "out",
  "storybook-static",
  "tmp",
  "temp",
  "vendor",
]);

const ignoredFileNames = new Set(["package-lock.json", "pnpm-lock.yaml", "yarn.lock"]);

export const forbiddenRemovedModulePatterns = [
  { id: "postmark", pattern: /\bpostmark\b/i },
  { id: "rewardful", pattern: /\brewardful\b/i },
  { id: "pageblocks", pattern: /\bPageBlocks?\b/i },
  { id: "site-demo", pattern: /\b(?:Site-Demo|site demo|demo site|SiteDemo|my-site-demo)\b/i },
] as const;

const removedModulePrefilterPatterns = ["postmark", "rewardful", "PageBlock", "Site-Demo", "site demo", "demo site", "SiteDemo", "my-site-demo"] as const;
const maxReadConcurrency = 16;
const maxPrefilterArgBytes = 100_000;

export type RemovedModuleGroupId = (typeof forbiddenRemovedModulePatterns)[number]["id"];

export interface RemovedModuleDiagnostic {
  id: RemovedModuleGroupId;
  file: string;
  line: number;
  excerpt: string;
}

export interface RemovedModuleScanResult {
  roots: string[];
  missingRoots: string[];
  files: string[];
  diagnostics: RemovedModuleDiagnostic[];
}

export function normalizeRelativePath(relativePath: string) {
  return relativePath.split(path.sep).join("/").replace(/^\.\//, "");
}

function toRelativePath(root: string, absolutePath: string) {
  return normalizeRelativePath(path.relative(root, absolutePath));
}

export function isIgnoredDirectory(name: string, relativePath = name) {
  const normalized = normalizeRelativePath(relativePath);
  return ignoredDirectoryNames.has(name) || ignoredDirectoryNames.has(normalized) || name.endsWith(".cache") || normalized.includes("/__generated__/");
}

export function isGeneratedOrIgnoredFile(filePath: string) {
  const name = path.basename(filePath);
  return (
    ignoredFileNames.has(name) ||
    name.endsWith(".d.ts") ||
    name.endsWith(".generated.ts") ||
    name.endsWith(".generated.tsx") ||
    name.endsWith(".gen.ts") ||
    name.endsWith(".gen.tsx") ||
    name.endsWith(".min.js") ||
    name.endsWith(".map")
  );
}

export function isTestStoryFixtureOrMockFile(filePath: string) {
  const normalized = normalizeRelativePath(filePath);
  const name = path.basename(normalized);
  return (
    /(?:^|[._-])(?:test|spec|stories|story|fixture|fixtures|mock|mocks)\.[cm]?[jt]sx?$/.test(name) ||
    /\.(?:test|spec|stories|story|fixture|fixtures|mock|mocks)\.[cm]?[jt]sx?$/.test(name) ||
    normalized.includes("/__tests__/") ||
    normalized.includes("/test/") ||
    normalized.includes("/tests/") ||
    normalized.includes("/fixtures/") ||
    normalized.includes("/fixture/") ||
    normalized.includes("/mocks/") ||
    normalized.includes("/__mocks__/")
  );
}

export function isOptionalPluginOutput(relativePath: string) {
  const normalized = normalizeRelativePath(relativePath);
  return normalized === "packages/plugins" || normalized.startsWith("packages/plugins/");
}

export function isScannableSourceFile(filePath: string) {
  return sourceFileExtensions.has(path.extname(filePath)) && !isGeneratedOrIgnoredFile(filePath);
}

async function pathExists(root: string, relativePath: string) {
  try {
    await stat(path.join(root, relativePath));
    return true;
  } catch (error) {
    if ((error as NodeJS.ErrnoException)?.code === "ENOENT") return false;
    throw error;
  }
}

export async function collectRemovedModuleSourceFiles(root = repoRoot, scanRoots: readonly string[] = removedModuleScanRoots) {
  const roots: string[] = [];
  const missingRoots: string[] = [];
  const files: string[] = [];

  async function walk(directory: string) {
    const entries = await readdir(directory, { withFileTypes: true });
    for (const entry of entries) {
      const absolutePath = path.join(directory, entry.name);
      const relativePath = toRelativePath(root, absolutePath);
      if (entry.isDirectory()) {
        if (isIgnoredDirectory(entry.name, relativePath) || isOptionalPluginOutput(relativePath)) continue;
        await walk(absolutePath);
        continue;
      }
      if (!entry.isFile()) continue;
      if (!isScannableSourceFile(entry.name)) continue;
      if (isOptionalPluginOutput(relativePath) || isTestStoryFixtureOrMockFile(relativePath)) continue;
      files.push(absolutePath);
    }
  }

  for (const scanRoot of scanRoots) {
    const normalizedRoot = normalizeRelativePath(scanRoot);
    if (!(await pathExists(root, normalizedRoot))) {
      missingRoots.push(normalizedRoot);
      continue;
    }
    roots.push(normalizedRoot);
    const absoluteRoot = path.join(root, normalizedRoot);
    const rootStat = await stat(absoluteRoot);
    if (rootStat.isFile()) {
      if (isScannableSourceFile(absoluteRoot) && !isTestStoryFixtureOrMockFile(normalizedRoot) && !isOptionalPluginOutput(normalizedRoot)) files.push(absoluteRoot);
      continue;
    }
    await walk(absoluteRoot);
  }

  files.sort((a, b) => toRelativePath(root, a).localeCompare(toRelativePath(root, b)));
  return { roots, missingRoots, files };
}

export function findRemovedModuleMatches(sourceText: string, relativeFilePath: string) {
  const diagnostics: RemovedModuleDiagnostic[] = [];
  const lines = sourceText.split(/\r?\n/);
  lines.forEach((line, index) => {
    for (const { id, pattern } of forbiddenRemovedModulePatterns) {
      pattern.lastIndex = 0;
      if (!pattern.test(line)) continue;
      diagnostics.push({ id, file: normalizeRelativePath(relativeFilePath), line: index + 1, excerpt: line.trim() });
    }
  });
  return diagnostics;
}

function chunkFilesForPrefilter(files: readonly string[]) {
  const chunks: string[][] = [];
  let chunk: string[] = [];
  let chunkBytes = 0;

  for (const file of files) {
    const fileBytes = Buffer.byteLength(file) + 1;
    if (chunk.length > 0 && chunkBytes + fileBytes > maxPrefilterArgBytes) {
      chunks.push(chunk);
      chunk = [];
      chunkBytes = 0;
    }
    chunk.push(file);
    chunkBytes += fileBytes;
  }

  if (chunk.length > 0) chunks.push(chunk);
  return chunks;
}

async function runRipgrepPrefilter(root: string, files: readonly string[]) {
  if (files.length === 0) return [];

  const matchingFiles = new Set<string>();
  const chunks = chunkFilesForPrefilter(files);

  for (const chunk of chunks) {
    const args = [
      "--files-with-matches",
      "--fixed-strings",
      "--ignore-case",
      "--null",
      "--no-ignore",
      "--hidden",
      "--text",
      "--no-messages",
      ...removedModulePrefilterPatterns.flatMap((pattern) => ["--regexp", pattern]),
      "--",
      ...chunk,
    ];

    const { code, output } = await new Promise<{ code: number | null; output: string }>((resolve, reject) => {
      const child = spawn("rg", args, { cwd: root });
      const outputChunks: Buffer[] = [];
      const errorChunks: Buffer[] = [];

      child.stdout.on("data", (data: Buffer) => outputChunks.push(data));
      child.stderr.on("data", (data: Buffer) => errorChunks.push(data));
      child.on("error", reject);
      child.on("close", (code) => {
        if (code !== 0 && code !== 1) {
          const details = Buffer.concat(errorChunks).toString("utf8").trim();
          reject(new Error(`removed-module prefilter failed with exit code ${code}${details ? `: ${details}` : ""}`));
          return;
        }
        resolve({ code, output: Buffer.concat(outputChunks).toString("utf8") });
      });
    });

    if (code === 1 || output.length === 0) continue;
    for (const file of output.split("\0")) {
      if (file.length === 0) continue;
      matchingFiles.add(normalizeRelativePath(path.isAbsolute(file) ? path.relative(root, file) : file));
    }
  }

  return files.filter((file) => matchingFiles.has(toRelativePath(root, file)));
}

export async function prefilterRemovedModuleCandidateFiles(root: string, files: readonly string[]) {
  try {
    return await runRipgrepPrefilter(root, files);
  } catch (error) {
    if ((error as NodeJS.ErrnoException)?.code === "ENOENT") return [...files];
    throw error;
  }
}

async function mapWithConcurrency<T, R>(items: readonly T[], limit: number, mapper: (item: T, index: number) => Promise<R>) {
  const results = new Array<R>(items.length);
  let nextIndex = 0;
  const workers = Array.from({ length: Math.min(limit, items.length) }, async () => {
    while (nextIndex < items.length) {
      const index = nextIndex;
      nextIndex += 1;
      results[index] = await mapper(items[index], index);
    }
  });
  await Promise.all(workers);
  return results;
}

export async function scanRemovedModules(root = repoRoot, scanRoots: readonly string[] = removedModuleScanRoots): Promise<RemovedModuleScanResult> {
  const collection = await collectRemovedModuleSourceFiles(root, scanRoots);
  const candidateFiles = await prefilterRemovedModuleCandidateFiles(root, collection.files);
  const diagnosticsByFile = await mapWithConcurrency(candidateFiles, maxReadConcurrency, async (file) => {
    const relativeFilePath = toRelativePath(root, file);
    const sourceText = await readFile(file, "utf8");
    return findRemovedModuleMatches(sourceText, relativeFilePath);
  });
  const diagnostics = diagnosticsByFile.flat();
  return { roots: collection.roots, missingRoots: collection.missingRoots, files: collection.files.map((file) => toRelativePath(root, file)), diagnostics };
}

export function renderRemovedModuleScanResult(result: RemovedModuleScanResult) {
  const lines = [
    `removed-module scan roots: ${result.roots.join(", ") || "(none)"}`,
    `removed-module missing roots skipped: ${result.missingRoots.join(", ") || "(none)"}`,
    `files scanned: ${result.files.length}`,
    `matches found: ${result.diagnostics.length}`,
  ];

  if (result.diagnostics.length === 0) {
    lines.unshift("PASS removed-module scan: no forbidden runtime references found");
    return lines.join("\n");
  }

  lines.unshift("FAIL removed-module scan: forbidden runtime references found");
  for (const diagnostic of result.diagnostics) {
    lines.push(`${diagnostic.file}:${diagnostic.line}: [${diagnostic.id}] ${diagnostic.excerpt}`);
  }
  return lines.join("\n");
}

async function main() {
  const result = await scanRemovedModules(repoRoot);
  const output = renderRemovedModuleScanResult(result);
  if (result.diagnostics.length > 0) {
    console.error(output);
    process.exitCode = 1;
    return;
  }
  console.log(output);
}

if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
  void main().catch((error) => {
    console.error(error);
    process.exitCode = 1;
  });
}