const assert = require("node:assert/strict");
const { readFileSync } = require("node:fs");
const { createRequire } = require("node:module");
const path = require("node:path");
const { setImmediate } = require("node:timers/promises");
const { promisify } = require("node:util");
const vm = require("node:vm");
const { test } = require("node:test");

const root = path.resolve("/workspace/firmware");
const source = readFileSync(path.join(__dirname, "extension.js"), "utf8");
const usb = { Ok: { app: "app.toml", task: "usb", hash: "usb", buildOverrideCommand: ["cargo", "check", "-pusb", "--message-format=json"] } };
const jefe = { Ok: { app: "app.toml", task: "jefe", hash: "jefe", buildOverrideCommand: ["cargo", "check", "-pjefe", "--message-format=json"] } };

function editor(resolve, trusted = true) {
  const settings = {};
  const calls = [];
  const errors = [];
  const files = new Map();
  const timers = new Map();
  const subscriptions = [];
  const status = { show() {}, dispose() {} };
  let change;
  let onUpdate;
  const vscode = {
    ConfigurationTarget: { Workspace: 2 },
    StatusBarAlignment: { Left: 1 },
    workspace: {
      isTrusted: trusted,
      workspaceFolders: [{ uri: { fsPath: root } }],
      getConfiguration(section) {
        if (section === "hubris") return { get: () => "app.toml" };
        const snapshot = structuredClone(settings);
        return {
          get: (key) => snapshot[key],
          async update(key, value) {
            await onUpdate?.(key, value);
            settings[key] = value;
          },
        };
      },
      onDidSaveTextDocument: () => ({ dispose() {} }),
      onDidChangeConfiguration: () => ({ dispose() {} }),
    },
    window: {
      createOutputChannel: () => ({ appendLine() {}, dispose() {} }),
      createStatusBarItem: () => status,
      showErrorMessage: (error) => errors.push(error),
      onDidChangeActiveTextEditor: (callback) => { change = callback; return { dispose() {} }; },
    },
    commands: {
      executeCommand: async (command) => { calls.push(command); },
      registerCommand: () => ({ dispose() {} }),
    },
  };
  const execFile = () => {};
  execFile[promisify.custom] = async (command, args, options) => {
    assert.equal(command, "cargo");
    assert.deepEqual(Array.from(args.slice(0, 2)), ["xtask", "lsp"]);
    assert.equal(options.env.HUBRIS_APP, "app.toml");
    assert.equal(options.env.HUBRIS_TASK, undefined);
    return { stdout: JSON.stringify(await resolve(args)) };
  };
  const module = { exports: {} };
  const require = createRequire(__filename);
  vm.runInNewContext(source, {
    module,
    process: { env: { HUBRIS_TASK: "stale-task" } },
    require(name) {
      if (name === "vscode") return vscode;
      if (name === "node:child_process") return { execFile };
      if (name === "node:fs/promises") return { mkdir: async () => {}, writeFile: async (file, content) => { files.set(file, content); } };
      return require(name);
    },
    setTimeout: (callback) => { const id = Symbol(); timers.set(id, callback); return id; },
    clearTimeout: (id) => timers.delete(id),
  });
  module.exports.activate({ subscriptions, storageUri: { fsPath: "/storage/hubris" }, asAbsolutePath: (file) => path.join(__dirname, file) });
  return {
    settings, calls, errors, files, status,
    open(file) {
      vscode.window.activeTextEditor = { document: { languageId: "rust", uri: { scheme: "file", fsPath: path.resolve(root, file) } } };
      change?.();
    },
    async flush() {
      for (const [id, callback] of timers) { timers.delete(id); callback(); }
      await setImmediate();
    },
    onUpdate(callback) { onUpdate = callback; },
    dispose() { for (const subscription of subscriptions) subscription.dispose(); },
  };
}

test("task changes update the launcher and build scripts without changing server environment", async (t) => {
  const app = editor((args) => args.at(-1).includes("/usb/") ? usb : jefe);
  t.after(() => app.dispose());
  app.open("tasks/usb/src/main.rs");
  await app.flush();
  const env = JSON.stringify(app.settings["server.extraEnv"]);
  app.open("tasks/jefe/src/main.rs");
  await app.flush();
  assert.equal(app.files.get("/storage/hubris/target"), "app.toml:jefe");
  assert.deepEqual(Array.from(app.settings["cargo.buildScripts.overrideCommand"]), jefe.Ok.buildOverrideCommand);
  assert.equal(JSON.stringify(app.settings["server.extraEnv"]), env);
  assert.equal(app.calls.length, 4);
  assert.deepEqual(app.errors, []);
});

test("shared files pass the current client and do not restart an unchanged context", async (t) => {
  const lookups = [];
  const app = editor((args) => { lookups.push(args); return usb; });
  t.after(() => app.dispose());
  app.open("tasks/usb/src/main.rs");
  await app.flush();
  app.open("lib/shared/src/lib.rs");
  await app.flush();
  assert.deepEqual(JSON.parse(lookups[1][3]), { toml: "app.toml", task: "usb" });
  assert.equal(app.calls.length, 2);
});

test("unresolved files retain the previous context and report the upstream error", async (t) => {
  const app = editor((args) => args.at(-1).includes("/kernel/") ? { Err: "kernel is not used" } : usb);
  t.after(() => app.dispose());
  app.open("tasks/usb/src/main.rs");
  await app.flush();
  app.open("kernel/src/main.rs");
  await app.flush();
  assert.equal(app.files.get("/storage/hubris/target"), "app.toml:usb");
  assert.match(app.status.text, /no task/);
  assert.equal(app.status.tooltip, "kernel is not used");
  assert.equal(app.calls.length, 2);
  app.open("tasks/usb/src/main.rs");
  await app.flush();
  assert.equal(app.status.text, "Hubris: app.toml:usb");
});

test("a slow lookup cannot replace the newer active file's context", async (t) => {
  let release;
  const pending = new Promise((resolve) => { release = resolve; });
  const app = editor((args) => args.at(-1).includes("/usb/") ? pending : jefe);
  t.after(() => app.dispose());
  app.open("tasks/usb/src/main.rs");
  await app.flush();
  app.open("tasks/jefe/src/main.rs");
  release(usb);
  await app.flush();
  assert.equal(app.files.get("/storage/hubris/target"), "app.toml:jefe");
  assert.equal(app.calls.length, 2);
});

test("a file change during configuration application is not lost", async (t) => {
  const app = editor((args) => args.at(-1).includes("/usb/") ? usb : jefe);
  t.after(() => app.dispose());
  app.onUpdate(() => {
    app.onUpdate(undefined);
    app.open("tasks/jefe/src/main.rs");
  });
  app.open("tasks/usb/src/main.rs");
  await app.flush();
  assert.equal(app.files.get("/storage/hubris/target"), "app.toml:jefe");
  assert.equal(app.calls.length, 4);
});

test("a failed settings write does not leave rust-analyzer stopped", async (t) => {
  const app = editor(() => usb);
  t.after(() => app.dispose());
  app.onUpdate(() => { throw new Error("settings are read-only"); });
  app.open("tasks/usb/src/main.rs");
  await app.flush();
  assert.deepEqual(app.calls, ["rust-analyzer.stopServer", "rust-analyzer.startServer"]);
  assert.match(app.errors[0], /read-only/);
});

test("untrusted workspaces and external files never execute Cargo", async (t) => {
  for (const trusted of [false, true]) {
    const app = editor(() => { assert.fail("unexpected cargo invocation"); }, trusted);
    t.after(() => app.dispose());
    app.open(trusted ? "../../../external.rs" : "tasks/usb/src/main.rs");
    await app.flush();
    assert.deepEqual(app.calls, []);
  }
});