fusion/packages/desktop/src/tray.ts

import path from "node:path";
import {
  app,
  BrowserWindow,
  Menu,
  nativeImage,
  Tray,
  type MenuItemConstructorOptions,
  type NativeImage,
} from "electron";

export type EngineStatus = "running" | "paused" | "stopped";

export interface TrayMenuOptions {
  isWindowVisible: boolean;
  engineStatus: EngineStatus;
}

interface TrayState {
  mainWindow: BrowserWindow;
  engineStatus: EngineStatus;
  isQuitting: boolean;
}

const trayState = new WeakMap<Tray, TrayState>();

function toggleMainWindow(mainWindow: BrowserWindow): void {
  if (mainWindow.isVisible()) {
    mainWindow.hide();
    return;
  }

  mainWindow.show();
  mainWindow.focus();
}

function resolveEngineMenuLabel(engineStatus: EngineStatus): string {
  return engineStatus === "running" ? "Pause Engine" : "Resume Engine";
}

function applyTrayMenu(tray: Tray, state: TrayState): void {
  const baseTemplate = buildTrayContextMenu({
    isWindowVisible: state.mainWindow.isVisible(),
    engineStatus: state.engineStatus,
  });

  const contextTemplate = baseTemplate.map((item) => {
    if (item.type === "separator") {
      return item;
    }

    if (item.label === "Show Window" || item.label === "Hide Window") {
      return {
        ...item,
        click: () => toggleMainWindow(state.mainWindow),
      };
    }

    if (item.label === "Pause Engine" || item.label === "Resume Engine") {
      return {
        ...item,
        click: () => {
          if (state.engineStatus === "stopped") {
            return;
          }

          state.engineStatus = state.engineStatus === "running" ? "paused" : "running";
          applyTrayMenu(tray, state);
        },
      };
    }

    return {
      ...item,
      click: () => {
        state.isQuitting = true;
        app.quit();
      },
    };
  });

  tray.setToolTip(getTrayTooltip(state.engineStatus));
  tray.setContextMenu(Menu.buildFromTemplate(contextTemplate));
}

export function createTrayIcon(): NativeImage {
  if (process.platform === "darwin") {
    const iconPath = path.join(import.meta.dirname, "icons", "tray-32.png");
    const retinaIcon = nativeImage.createFromPath(iconPath);
    return retinaIcon.resize({ width: 16, height: 16 });
  }

  const iconPath = path.join(import.meta.dirname, "icons", "tray-48.png");
  return nativeImage.createFromPath(iconPath);
}

export function buildTrayContextMenu(options: TrayMenuOptions): MenuItemConstructorOptions[] {
  return [
    {
      label: options.isWindowVisible ? "Hide Window" : "Show Window",
    },
    {
      type: "separator",
    },
    {
      label: resolveEngineMenuLabel(options.engineStatus),
      enabled: options.engineStatus !== "stopped",
    },
    {
      type: "separator",
    },
    {
      label: "Quit Fusion",
    },
  ];
}

export function getTrayTooltip(status: EngineStatus): string {
  switch (status) {
    case "paused":
      return "Fusion — Paused";
    case "stopped":
      return "Fusion — Stopped";
    case "running":
    default:
      return "Fusion — Running";
  }
}

export function setupTray(mainWindow: BrowserWindow, tray: Tray): Tray {
  const state: TrayState = {
    mainWindow,
    engineStatus: "running",
    isQuitting: false,
  };

  trayState.set(tray, state);

  tray.setImage(createTrayIcon());
  applyTrayMenu(tray, state);

  tray.on("click", () => {
    toggleMainWindow(mainWindow);
  });

  mainWindow.on("show", () => {
    applyTrayMenu(tray, state);
  });

  mainWindow.on("hide", () => {
    applyTrayMenu(tray, state);
  });

  mainWindow.on("close", (event) => {
    if (state.isQuitting) {
      return;
    }

    event.preventDefault();
    mainWindow.hide();
  });

  app.on("before-quit", () => {
    state.isQuitting = true;
  });

  return tray;
}

export function updateTrayStatus(tray: Tray, status: EngineStatus): void {
  const state = trayState.get(tray);

  if (!state) {
    tray.setToolTip(getTrayTooltip(status));
    const menu = Menu.buildFromTemplate(
      buildTrayContextMenu({
        isWindowVisible: false,
        engineStatus: status,
      }),
    );
    tray.setContextMenu(menu);
    return;
  }

  state.engineStatus = status;
  applyTrayMenu(tray, state);
}