// The ONLY module that touches Tauri. Everything else talks to `backend`.
// Inside the Tauri webview this is a thin typed wrapper over invoke/listen
// (docs/CONTRACT.md); in a plain browser it is the timer-driven mock.
import { invoke } from "@tauri-apps/api/core";
import { listen } from "@tauri-apps/api/event";
import { getCurrentWindow } from "@tauri-apps/api/window";
import { createMockBackend } from "./mock";
import type {
  Backend,
  InstallProgress,
  LogEvent,
  Market,
  Settings,
  SignInResult,
  StackEvent,
  Status,
  SyncConflict,
  Unlisten,
} from "./types";

export const IN_TAURI = typeof window !== "undefined" && "__TAURI_INTERNALS__" in window;

function subscribe<T>(event: string, handler: (payload: T) => void): Promise<Unlisten> {
  return listen<T>(event, (e) => handler(e.payload));
}

function createTauriBackend(): Backend {
  const win = getCurrentWindow();

  return {
    kind: "tauri",
    mock: null,
    window: {
      minimize: () => win.minimize(),
      toggleMaximize: () => win.toggleMaximize(),
      close: () => win.close(),
      isMaximized: () => win.isMaximized(),
      onResized: (handler) => win.onResized(() => handler()),
    },

    getStatus: () => invoke<Status>("get_status"),
    refresh: () => invoke<Status>("refresh"),
    signIn: () => invoke<SignInResult>("sign_in"),
    cancelSignIn: () => invoke<void>("cancel_sign_in"),
    signOut: () => invoke<Status>("sign_out"),
    getNotes: (version) => invoke<string>("get_notes", version === undefined ? {} : { version }),
    openExternal: (url) => invoke<void>("open_external", { url }),
    getStack: () => invoke<StackEvent[]>("get_stack"),
    startInstall: () => invoke<void>("start_install"),
    startInstallFromDrive: (path) => invoke<void>("start_install_from_drive", { path }),
    getMarket: (drive) => invoke<Market>("get_market", drive === undefined ? {} : { drive }),
    applyMarket: (selected) => invoke<void>("apply_market", { selected }),
    setMarket: (selected, drive) => invoke<void>("set_market", drive === undefined ? { selected } : { selected, drive }),
    cancelInstall: () => invoke<void>("cancel_install"),
    launch: () => invoke<void>("launch"),
    stop: () => invoke<void>("stop"),
    getSettings: () => invoke<Settings>("get_settings"),
    setSettings: (settings) => invoke<Status>("set_settings", { settings }),
    pickFolder: () => invoke<string | null>("pick_folder"),
    syncNow: () => invoke<void>("sync_now"),
    getSyncConflicts: () => invoke<SyncConflict[]>("get_sync_conflicts"),
    resolveSyncConflict: (tbl, key, choice, value) =>
      invoke<SyncConflict[]>("resolve_sync_conflict", { tbl, key, choice, value: value === undefined ? null : value }),

    onStatus: (handler) => subscribe<Status>("status", handler),
    onInstallProgress: (handler) => subscribe<InstallProgress>("install-progress", handler),
    onStack: (handler) => subscribe<StackEvent>("stack", handler),
    onLog: (handler) => subscribe<LogEvent>("log", handler),
  };
}

export const backend: Backend = IN_TAURI
  ? createTauriBackend()
  : createMockBackend(new URLSearchParams(window.location.search));