/* The node:test differential — fixtures under tests/fixtures/node-test
 * run under Node AND compiled, stdout and exit codes compared with ONE
 * documented normalization applied to BOTH lanes. Node's spec reporter
 * embeds real durations in every line, so raw byte-compare is impossible
 * for ANY node:test program (which is why these are fixtures here, not
 * corpus entries); everything else — result lines, symbols, indentation,
 * # SKIP/# TODO directives, ℹ diagnostics, the summary block, the
 * failing-tests section's "test at file:line:col" and error MESSAGE
 * lines — must match byte-exactly.
 *
 * NORMALIZATIONS (both lanes):
 *   - "(1.234ms)" duration parentheticals → "(Xms)"
 *   - the "ℹ duration_ms N" summary line → "ℹ duration_ms X"
 *   - stack frames ("    at ..."), the "... N lines matching cause stack
 *     trace ..." line that folds an error cause's shared frames, and the
 *     inspect property block a frame opens ("... {" through its closing
 *     "}") are dropped — Node prints its runner-internal frames and an
 *     error-property dump the compiled runtime deliberately omits
 *     (SEMANTICS.md).
 *
 * Fixtures never console.log inside test bodies or hooks: Node's
 * reporter stream lags console output RACILY (its ordering varies run to
 * run under Node alone), while the compiled runtime reports
 * synchronously — mixed programs cannot be byte-compared against any
 * oracle. The `// @exit:` first line documents the expected exit code
 * and is asserted against BOTH lanes. SCRIPTC_SAN=1 rebuilds with ASan +
 * the RC audit over every case. */
import { spawn } from "node:child_process";
import { createHash } from "node:crypto";
import { copyFileSync, globSync, mkdirSync, mkdtempSync, readFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { describe, expect, test } from "vitest";
import { compile } from "@scriptc/compiler";
import { normalizeNodeTestOutput } from "./node-test-normalize.js";

const repoRoot = join(import.meta.dirname, "../..");
const fixturesRoot = join(repoRoot, "tests/fixtures/node-test");
const cacheDir = join(repoRoot, "node_modules/.cache/scriptc-tests");
const sanitize = process.env["SCRIPTC_SAN"] === "1";

interface ProgramRun {
  stdout: string;
  exitCode: number;
}

function runLane(cmd: string, args: string[], cwd = repoRoot): Promise<ProgramRun> {
  return new Promise((resolve, reject) => {
    // cwd pinned to the repo root by default: both reporters render "test
    // at" paths relative to the working directory, so the lanes must share
    // one.
    const child = spawn(cmd, args, { stdio: ["ignore", "pipe", "pipe"], cwd });
    const out: Buffer[] = [];
    let errText = "";
    const timer = setTimeout(() => {
      child.kill("SIGKILL");
      reject(new Error(`node:test program timed out\nstderr so far:\n${errText}`));
    }, 60_000);
    child.stdout.on("data", (c: Buffer) => out.push(c));
    child.stderr.on("data", (c: Buffer) => (errText += c.toString("utf8")));
    child.on("close", (code, signal) => {
      clearTimeout(timer);
      if (signal) {
        reject(new Error(`node:test program died to ${signal}\nstderr:\n${errText}`));
        return;
      }
      resolve({ stdout: Buffer.concat(out).toString("utf8"), exitCode: code ?? 0 });
    });
  });
}

// The documented normalization — durations, frames, the property block —
// lives in node-test-normalize.ts: the Linux lane applies the identical
// scrub to its in-container lanes.
const normalize = normalizeNodeTestOutput;

/** Expected exit code: 0 unless the fixture's first line says otherwise. */
function expectedExitCode(file: string): number {
  const firstLine = readFileSync(file, "utf8").split("\n", 1)[0] ?? "";
  const m = /^\/\/ @exit:\s*(\d+)\s*$/.exec(firstLine);
  return m ? Number(m[1]) : 0;
}

async function build(entry: string): Promise<string> {
  const hash = createHash("sha256");
  hash.update(entry).update(readFileSync(entry));
  const key = hash
    .update(sanitize ? "san" : "plain")
    .digest("hex")
    .slice(0, 16);
  const outDir = join(cacheDir, `node-test-${key}`);
  mkdirSync(outDir, { recursive: true });
  const result = await compile(entry, {
    outPath: join(outDir, "program"),
    outDir,
    sanitize,
    // Pinned: the spec-reporter normalizations here were written against
    // the C lane; lane identity stays fixed so a diff means the reporter
    // (or Node) changed, never that the default backend moved.
    backend: "llvm",
  });
  if (!result.ok) {
    throw new Error(
      "node:test fixture failed to compile:\n" +
        result.diagnostics.map((d) => `${d.code}: ${d.message}`).join("\n"),
    );
  }
  return result.binaryPath;
}

const cases = globSync(join(fixturesRoot, "cases/*.ts"))
  .sort()
  .map((entry) => ({ name: entry.split("/").at(-1)!.replace(/\.ts$/, ""), entry }));

describe(`node:test differential (${cases.length} programs${sanitize ? ", sanitized" : ""})`, () => {
  test.for(cases.map((c) => [c.name, c] as const))(
    "%s",
    async ([, c]) => {
      const binary = await build(c.entry);
      const [nodeRes, nativeRes] = await Promise.all([
        runLane("node", [c.entry]),
        runLane(binary, []),
      ]);
      expect(normalize(nativeRes.stdout)).toBe(normalize(nodeRes.stdout));
      const wanted = expectedExitCode(c.entry);
      expect(nodeRes.exitCode).toBe(wanted); // keeps `// @exit:` honest
      expect(nativeRes.exitCode).toBe(wanted);
    },
    120_000,
  );
});

/* Snapshot update mode: Node's --test-update-snapshots flag, which the
 * compiled binary takes as its leading argument. Each lane runs the
 * fixture from its own temporary copy (the snapshot file sits beside the
 * entry file and fileSnapshot paths resolve against the working
 * directory), writes the snapshot files, and then passes in compare mode
 * against them. The written files and the printed argv/execArgv match. */
describe(`node:test snapshot update mode${sanitize ? " (sanitized)" : ""}`, () => {
  test("--test-update-snapshots writes the files Node writes", async () => {
    const fixture = join(fixturesRoot, "update/snapshot-update.ts");
    const lanes = await Promise.all(
      (["node", "native"] as const).map(async (lane) => {
        const dir = mkdtempSync(join(tmpdir(), `scriptc-snapshot-${lane}-`));
        const entry = join(dir, "snapshot-update.ts");
        copyFileSync(fixture, entry);
        const binary = lane === "native" ? await build(entry) : null;
        const run = (update: boolean) =>
          binary
            ? runLane(binary, [...(update ? ["--test-update-snapshots"] : []), "one", "two"], dir)
            : runLane(
                "node",
                [...(update ? ["--test-update-snapshots"] : []), entry, "one", "two"],
                dir,
              );
        const update = await run(true);
        const compare = await run(false);
        return {
          update,
          compare,
          snapshot: readFileSync(`${entry}.snapshot`, "utf8"),
          file: readFileSync(join(dir, "out/value.json"), "utf8"),
        };
      }),
    );
    const [node, native] = lanes as [(typeof lanes)[number], (typeof lanes)[number]];
    expect(native.snapshot).toBe(node.snapshot);
    expect(native.file).toBe(node.file);
    expect(normalize(native.update.stdout)).toBe(normalize(node.update.stdout));
    expect(normalize(native.compare.stdout)).toBe(normalize(node.compare.stdout));
    for (const lane of lanes) {
      expect(lane.update.exitCode).toBe(0);
      expect(lane.compare.exitCode).toBe(0);
    }
  }, 120_000);
});