import { app, BrowserWindow } from "electron";
import path from "node:path";

import { getRuntimeConfig } from "./config/runtime-config";
import { showFatalError, log } from "./errors/error-presenter";
import { createNodecgProcessManager, NodecgProcessManager } from "./nodecg/process-manager";
import { prepareUserNodecgRuntime } from "./nodecg/runtime-provisioner";
import { getRemainingDelayMs } from "./utils/timing";
import { createLoadingWindow, createMainWindow } from "./windows/window-factory";

const appConfig = getRuntimeConfig();

// Force a stable userData folder name; overridable via SCOREKO_APP_USER_DATA_DIRECTORY.
app.setName(appConfig.title);
app.setPath("userData", path.join(app.getPath("appData"), appConfig.userDataDirectoryName));

const isDev = !app.isPackaged;
const rootPath = isDev ? path.resolve(__dirname, "../..") : process.resourcesPath;
const sourceNodecgRuntimePath = path.resolve(rootPath, "lib", "nodecg");
const mainDashboardUrl = `http://localhost:${appConfig.nodecgPort}/bundles/${appConfig.bundleName}/${appConfig.mainDashboardRoute}`;
const loadingDashboardUrl = `http://localhost:${appConfig.nodecgPort}/bundles/${appConfig.bundleName}/${appConfig.loadingDashboardRoute}`;
const nodecgBaseUrl = `http://127.0.0.1:${appConfig.nodecgPort}`;

const hasSingleInstanceLock = app.requestSingleInstanceLock();

if (!hasSingleInstanceLock) {
  app.quit();
}

type AppShutdownState = "running" | "stopping" | "stopped";

let mainWindow: BrowserWindow | null = null;
let loadingWindow: BrowserWindow | null = null;
let nodecgManager: NodecgProcessManager | null = null;
let shutdownState: AppShutdownState = "running";

function focusExistingWindow(): void {
  const targetWindow = mainWindow && !mainWindow.isDestroyed() ? mainWindow : loadingWindow;

  if (!targetWindow || targetWindow.isDestroyed()) {
    return;
  }

  if (targetWindow.isMinimized()) {
    targetWindow.restore();
  }

  targetWindow.show();
  targetWindow.focus();
}

async function launchApplication(): Promise<void> {
  const nodecgRootPath = prepareUserNodecgRuntime({
    sourceRuntimePath: sourceNodecgRuntimePath,
    userDataPath: app.getPath("userData"),
    appVersion: app.getVersion(),
    bundleName: appConfig.bundleName,
    log,
  });

  nodecgManager = createNodecgProcessManager({
    isDev,
    nodecgRootPath,
    nodecgBaseUrl,
    appConfig,
    log,
  });

  // We create both windows early so startup feels instant while NodeCG is booting in the background.
  mainWindow = createMainWindow({ appConfig, rootPath, mainDashboardUrl });
  loadingWindow = createLoadingWindow({ appConfig, rootPath });

  await nodecgManager.startNodecgProcess();

  await nodecgManager.waitForNodecgReady(Date.now());

  if (!loadingWindow || loadingWindow.isDestroyed()) {
    return;
  }

  await loadingWindow.loadURL(loadingDashboardUrl);
  loadingWindow.show();

  const loadingShownAt = Date.now();

  if (!mainWindow) {
    return;
  }

  await mainWindow.loadURL(mainDashboardUrl);

  // Keep the loading overlay visible for a minimum amount of time to avoid abrupt flashes.
  const remainingLoadingDelay = getRemainingDelayMs(appConfig.loadDelayMs, loadingShownAt);
  if (remainingLoadingDelay > 0) {
    await sleep(remainingLoadingDelay);
  }

  mainWindow.show();
  closeLoadingWindow();
}

function sleep(ms: number): Promise<void> {
  return new Promise((resolve) => {
    setTimeout(resolve, ms);
  });
}

function closeLoadingWindow(): void {
  if (!loadingWindow || loadingWindow.isDestroyed()) {
    return;
  }

  loadingWindow.close();
  loadingWindow = null;
}

function stopNodecgGracefully(): Promise<void> {
  if (shutdownState === "stopped") {
    return Promise.resolve();
  }

  if (shutdownState === "stopping") {
    return nodecgManager?.stopNodecgProcessGracefully() ?? Promise.resolve();
  }

  shutdownState = "stopping";

  return (nodecgManager?.stopNodecgProcessGracefully() ?? Promise.resolve()).finally(() => {
    shutdownState = "stopped";
  });
}

app.on("ready", () => {
  if (!hasSingleInstanceLock) {
    return;
  }

  if (process.platform === "win32") {
    app.setAppUserModelId(appConfig.userModelId);
  }

  launchApplication().catch((error: unknown) => {
    showFatalError("No se pudo iniciar Scoreko.", error);
    closeLoadingWindow();
    app.exit(1);
  });
});

app.on("second-instance", () => {
  focusExistingWindow();
});

app.on("activate", async () => {
  if (BrowserWindow.getAllWindows().length === 0) {
    mainWindow = createMainWindow({ appConfig, rootPath, mainDashboardUrl });
    await mainWindow.loadURL(mainDashboardUrl);
    mainWindow.show();
  }
});

app.on("window-all-closed", () => {
  if (process.platform !== "darwin") {
    app.quit();
  }
});

app.on("before-quit", (event) => {
  if (shutdownState !== "running") {
    return;
  }

  // Block the default quit flow until we ask NodeCG to stop cleanly.
  event.preventDefault();

  stopNodecgGracefully().finally(() => {
    app.quit();
  });
});

app.on("will-quit", () => {
  if (shutdownState === "running") {
    void stopNodecgGracefully();
  }
});

process.on("exit", () => {
  if (shutdownState === "running") {
    void stopNodecgGracefully();
  }
});

process.on("uncaughtException", (error) => {
  showFatalError("Unexpected error in Electron main process.", error);
});

process.on("unhandledRejection", (reason) => {
  showFatalError("Unhandled promise in Electron main process.", reason);
});