const { app, BrowserWindow, ipcMain } = require("electron");
const fs = require("node:fs/promises");
const path = require("node:path");

const OUTPUT_FILENAME = "compiled.lua";

/**
 * Resolves the absolute directory where compiled Lua output is stored.
 *
 * @returns {string}
 */
function getOutputDirectory() {
  const applicationData = app.getPath("appData");
  return path.join(applicationData, "pico-8", "carts", "picograph");
}

/**
 * Resolves the absolute path to the generated Lua file.
 *
 * @returns {string}
 */
function getOutputPath() {
  return path.join(getOutputDirectory(), OUTPUT_FILENAME);
}

/** @type {import("electron").BrowserWindow | null} */
let mainWindow = null;

/**
 * Creates the primary application window and loads the web UI.
 *
 * @returns {void}
 */
function createMainWindow() {
  const window = new BrowserWindow({
    width: 1440,
    height: 900,
    minWidth: 960,
    minHeight: 640,
    webPreferences: {
      contextIsolation: true,
      nodeIntegration: false,
        preload: path.join(__dirname, "preload.js"),
    },
    show: false,
  });

  window.once("ready-to-show", () => {
    window.show();
  });

  window.loadFile(path.join(__dirname, "index.html"));

  window.on("closed", () => {
    mainWindow = null;
  });

  mainWindow = window;
}

/**
 * Registers IPC handlers used by renderer processes.
 *
 * @returns {void}
 */
function registerIpcHandlers() {
  ipcMain.handle("lua:compile", async (_event, source) => {
    if (typeof source !== "string") {
      throw new TypeError("Lua source must be a string");
    }

    const outputPath = getOutputPath();
    await fs.mkdir(path.dirname(outputPath), { recursive: true });
    await fs.writeFile(outputPath, source, "utf8");

    return { filePath: outputPath };
  });
}

/**
 * Wires core Electron lifecycle events for the application.
 *
 * @returns {void}
 */
function registerAppLifecycle() {
  app.whenReady().then(() => {
    createMainWindow();
    registerIpcHandlers();

    app.on("activate", () => {
      if (BrowserWindow.getAllWindows().length === 0) {
        createMainWindow();
      }
    });
  });

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

registerAppLifecycle();