import { chmod, mkdtemp, readFile, readdir, rm, stat, utimes, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { afterEach, expect, test } from "vitest";
import { FrontendInputTracker, trackedFileExists, trackedReadFile } from "../frontend/input-tracker.js";
import { nativeArtifactDependenciesStillMatch } from "../backend/native-toolchain.js";
import {
  publishEarlyExecutableCache,
  readEarlyExecutableCache,
  readRoutedExecutableCache,
  type EarlyExecutableCacheOptions,
  type EarlyExecutableNativeFeatures,
} from "./executable-cache.js";

const scratch: string[] = [];

afterEach(async () => {
  await Promise.all(scratch.splice(0).map((path) => rm(path, { recursive: true, force: true })));
});

const native: EarlyExecutableNativeFeatures = {
  backend: "llvm",
  dynamic: false,
  regex: false,
  copying: false,
  textDecoderLegacy: false,
  fileHandle: false,
  fetch: true,
  netIsland: false,
  zlib: false,
  assert: false,
  inspect: false,
  dynInvoke: false,
  dc: false,
  dynAsync: false,
  events: false,
  emitter: false,
  symbol: false,
  bigint: false,
  searchParams: false,
  qs: false,
  parseArgs: false,
  stream: false,
  net: false,
  http: false,
  http2: false,
  dgram: false,
  watch: false,
  foreignFfi: false,
  nodeTest: false,
  tls: false,
  tlsCa: false,
};

async function fixture(): Promise<{
  root: string;
  options: EarlyExecutableCacheOptions;
  source: string;
  missing: string;
  cPath: string;
  irPath: string;
}> {
  const dir = await mkdtemp(join(tmpdir(), "scriptc-early-executable-"));
  scratch.push(dir);
  const source = join(dir, "entry.ts");
  const cPath = join(dir, "entry.ll");
  const irPath = join(dir, "entry.ir.json");
  await Promise.all([
    writeFile(source, 'console.log("hello");\n'),
    writeFile(cPath, "; generated llvm\n"),
    writeFile(irPath, '{"irVersion":6}\n'),
  ]);
  return {
    root: join(dir, "cache"),
    source,
    missing: join(dir, "missing.ts"),
    cPath,
    irPath,
    options: {
      entryPath: source,
      outDir: dir,
      outPath: join(dir, "entry"),
      emitIr: true,
      sanitize: false,
      dynamic: false,
      backend: "auto",
      npmStatic: null,
      ffiProfile: null,
      target: "test",
      compiler: ["clang"],
      nativeEnvironment: "test-native-environment",
      nodeVersion: "v24-test",
      implementation: "a".repeat(64),
      implementationDependencies: [],
    },
  };
}

test("early executable cache restores the emitted TU, IR, and native feature gates", async () => {
  const f = await fixture();
  const tracker = new FrontendInputTracker();
  tracker.run(() => {
    trackedReadFile(f.source);
    trackedFileExists(f.missing);
  });
  await publishEarlyExecutableCache(f.root, f.options, {
    cPath: f.cPath,
    irPath: f.irPath,
    native,
    executableRestored: false,
    frontend: tracker.snapshot(),
  });
  await Promise.all([rm(f.cPath), rm(f.irPath)]);
  const alternateC = join(f.options.outDir, "entry.c");
  await writeFile(alternateC, "/* saved C backend */\n");

  const hit = await readEarlyExecutableCache(f.root, f.options);
  expect(hit?.native).toEqual(native);
  expect(hit?.executableRestored).toBe(false);
  expect(await readFile(f.cPath, "utf8")).toBe("; generated llvm\n");
  expect(await readFile(f.irPath, "utf8")).toContain("irVersion");
  expect(await readFile(alternateC, "utf8")).toBe("/* saved C backend */\n");
});

test("early executable cache misses on source and resolution changes", async () => {
  const f = await fixture();
  const tracker = new FrontendInputTracker();
  tracker.run(() => {
    trackedReadFile(f.source);
    trackedFileExists(f.missing);
  });
  await publishEarlyExecutableCache(f.root, f.options, {
    cPath: f.cPath,
    irPath: f.irPath,
    native,
    executableRestored: false,
    frontend: tracker.snapshot(),
  });

  await writeFile(f.source, 'console.log("edited");\n');
  expect(await readEarlyExecutableCache(f.root, f.options)).toBeNull();
  await writeFile(f.source, 'console.log("hello");\n');
  expect(await readEarlyExecutableCache(f.root, f.options)).not.toBeNull();
  await writeFile(f.missing, "export {};\n");
  expect(await readEarlyExecutableCache(f.root, f.options)).toBeNull();
});

test("early executable keys isolate compile modes, paths, implementation, and FFI manifests", async () => {
  const f = await fixture();
  const tracker = new FrontendInputTracker();
  tracker.run(() => trackedReadFile(f.source));
  await publishEarlyExecutableCache(f.root, f.options, {
    cPath: f.cPath,
    irPath: f.irPath,
    native,
    executableRestored: false,
    frontend: tracker.snapshot(),
  });
  const variants: EarlyExecutableCacheOptions[] = [
    { ...f.options, emitIr: false },
    { ...f.options, sanitize: true },
    { ...f.options, dynamic: true },
    { ...f.options, backend: "c" },
    { ...f.options, optimization: "dev" },
    { ...f.options, npmStatic: "auto" },
    { ...f.options, npmStatic: ["commander"] },
    { ...f.options, outPath: join(f.options.outDir, "other") },
    { ...f.options, target: "other" },
    { ...f.options, compiler: ["zig", "cc"] },
    { ...f.options, nativeEnvironment: "other-native-environment" },
    { ...f.options, nodeVersion: "v24-other" },
    { ...f.options, implementation: "other-implementation" },
    { ...f.options, ffiProfile: { path: join(f.options.outDir, "ffi.json"), bytes: Buffer.from("one") } },
  ];
  for (const options of variants) {
    expect(await readEarlyExecutableCache(f.root, options)).toBeNull();
  }
});

test("early executable cache rejects corruption and refreshes payload LRU times", async () => {
  const f = await fixture();
  const tracker = new FrontendInputTracker();
  tracker.run(() => trackedReadFile(f.source));
  await publishEarlyExecutableCache(f.root, f.options, {
    cPath: f.cPath,
    irPath: f.irPath,
    native,
    executableRestored: false,
    frontend: tracker.snapshot(),
  });
  const [key] = await readdir(join(f.root, "early-exe"));
  const directory = join(f.root, "early-exe", key!);
  const paths = [
    join(directory, "stamp.json"),
    join(directory, "program.tu"),
    join(directory, "program.ir.json"),
  ];
  const old = new Date("2000-01-01T00:00:00.000Z");
  await Promise.all(paths.map((path) => utimes(path, old, old)));
  expect(await readEarlyExecutableCache(f.root, f.options)).not.toBeNull();
  for (const path of paths) expect((await stat(path)).mtimeMs).toBeGreaterThan(old.getTime());

  await writeFile(join(directory, "program.tu"), "; poisoned\n");
  expect(await readEarlyExecutableCache(f.root, f.options)).toBeNull();
});

test("early executable cache restores a validated final binary", async () => {
  const f = await fixture();
  const dependency = join(f.options.outDir, "native-tool");
  await writeFile(dependency, "tool-v1\n");
  const info = await stat(dependency);
  const outMode = 0o777 & ~process.umask();
  await writeFile(f.options.outPath, "native-v1\n", { mode: outMode });
  await chmod(f.options.outPath, outMode);
  const tracker = new FrontendInputTracker();
  tracker.run(() => trackedReadFile(f.source));
  await publishEarlyExecutableCache(f.root, f.options, {
    cPath: f.cPath,
    irPath: f.irPath,
    native,
    executableRestored: true,
    nativeDependencies: [{
      path: dependency,
      kind: "file",
      dev: info.dev,
      ino: info.ino,
      size: info.size,
      mtimeMs: info.mtimeMs,
      ctimeMs: info.ctimeMs,
    }],
    frontend: tracker.snapshot(),
  });
  await writeFile(f.options.outPath, "caller-modified\n");

  const hit = await readEarlyExecutableCache(f.root, f.options);
  expect(hit?.executableRestored).toBe(true);
  expect(await readFile(f.options.outPath, "utf8")).toBe("native-v1\n");

  await writeFile(dependency, "tool-v2\n");
  await writeFile(f.options.outPath, "keep-current\n");
  const staleNative = await readEarlyExecutableCache(f.root, f.options);
  expect(staleNative?.executableRestored).toBe(false);
  expect(await readFile(f.options.outPath, "utf8")).toBe("keep-current\n");
});

test("routed executable hits require an unchanged compiler implementation proof", async () => {
  const f = await fixture();
  const dependency = join(f.options.outDir, "compiler-file.js");
  const nativeDependency = join(f.options.outDir, "native-tool");
  await Promise.all([
    writeFile(dependency, "compiler-v1\n"),
    writeFile(nativeDependency, "tool-v1\n"),
    writeFile(f.options.outPath, "native-v1\n"),
  ]);
  const [implementationInfo, nativeInfo] = await Promise.all([
    stat(dependency),
    stat(nativeDependency),
  ]);
  f.options.implementationDependencies = [{
    path: dependency,
    kind: "file",
    dev: implementationInfo.dev,
    ino: implementationInfo.ino,
    size: implementationInfo.size,
    mtimeMs: implementationInfo.mtimeMs,
    ctimeMs: implementationInfo.ctimeMs,
  }];
  const tracker = new FrontendInputTracker();
  tracker.run(() => trackedReadFile(f.source));
  await publishEarlyExecutableCache(f.root, f.options, {
    cPath: f.cPath,
    irPath: f.irPath,
    native,
    executableRestored: true,
    nativeDependencies: [{
      path: nativeDependency,
      kind: "file",
      dev: nativeInfo.dev,
      ino: nativeInfo.ino,
      size: nativeInfo.size,
      mtimeMs: nativeInfo.mtimeMs,
      ctimeMs: nativeInfo.ctimeMs,
    }],
    frontend: tracker.snapshot(),
  });
  const route = { ...f.options };
  delete (route as Partial<EarlyExecutableCacheOptions>).implementation;
  delete (route as Partial<EarlyExecutableCacheOptions>).implementationDependencies;
  const routeDirectory = join(f.root, "early-exe-route");
  const [routeName] = await readdir(routeDirectory);
  const routePath = join(routeDirectory, routeName!);
  const proofInstallDirectory = join(f.root, "early-exe-implementation");
  const [proofInstall] = await readdir(proofInstallDirectory);
  const proofPath = join(proofInstallDirectory, proofInstall!, f.options.implementation);
  const old = new Date("2000-01-01T00:00:00.000Z");
  await Promise.all([routePath, proofPath].map((path) => utimes(path, old, old)));
  expect(await readRoutedExecutableCache(f.root, route)).not.toBeNull();
  for (const path of [routePath, proofPath]) {
    expect((await stat(path)).mtimeMs).toBeGreaterThan(old.getTime());
  }

  // Publishing the same route again must replace its metadata on every
  // platform (notably Windows, whose rename does not overwrite files).
  await publishEarlyExecutableCache(f.root, f.options, {
    cPath: f.cPath,
    irPath: f.irPath,
    native,
    executableRestored: true,
    nativeDependencies: [{
      path: nativeDependency,
      kind: "file",
      dev: nativeInfo.dev,
      ino: nativeInfo.ino,
      size: nativeInfo.size,
      mtimeMs: nativeInfo.mtimeMs,
      ctimeMs: nativeInfo.ctimeMs,
    }],
    frontend: tracker.snapshot(),
  });
  expect(await readRoutedExecutableCache(f.root, route)).not.toBeNull();
  await writeFile(dependency, "compiler-v2\n");
  expect(await readRoutedExecutableCache(f.root, route)).toBeNull();
});

test("native dependency validation rejects malformed cache data", async () => {
  expect(await nativeArtifactDependenciesStillMatch([
    { path: "/tmp/not-enough-fields", kind: "file" },
  ] as never)).toBe(false);
});