#include <flutter/dart_project.h>
#include <flutter/flutter_view_controller.h>
#include <windows.h>

#include "app_links/app_links_plugin_c_api.h"
#include "flutter_window.h"
#include "utils.h"

int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
                      _In_ wchar_t *command_line, _In_ int show_command) {
  // Diagnostic breadcrumb: protocol activations carry the link as the only
  // command-line argument; regular launches have none.
  int argc = 0;
  wchar_t** argv = ::CommandLineToArgvW(::GetCommandLineW(), &argc);
  if (argv != nullptr) {
    std::string cmdline;
    for (int i = 0; i < argc; ++i) {
      cmdline += Utf8FromUtf16(argv[i]);
      cmdline += ' ';
    }
    ::LocalFree(argv);
    LogAppLink("launched with: " + cmdline);
  }

  const bool protocol_launch = HasAppLinkArgument();
  const bool is_primary = AcquireSingleInstanceMutex();

  // (Re)register the per-user custom scheme so OAuth / magic-link redirects
  // launched by the browser can activate this app.
  RegisterAppLinkProtocol();

  // Exactly one instance may own a window: the PKCE code verifier lives in
  // shared secure storage, so a login callback delivered to a window other
  // than the one that initiated the sign-in would silently complete the
  // exchange in the WRONG window while the user keeps staring at a login
  // screen. Duplicate normal launches surface the existing instance and
  // exit instead of starting a competing window.
  if (!protocol_launch && !is_primary) {
    ::SendAppLinkToInstance();  // best-effort: surface the existing window
    LogAppLink("another instance owns the app; exiting");
    return EXIT_SUCCESS;
  }

  // Protocol activation while an instance is already running hands the link
  // to that instance (over WM_COPYDATA, consumed by the app_links plugin)
  // and exits, instead of spawning a second window.
  if (::SendAppLinkToInstance()) {
    LogAppLink("link forwarded to the running instance; exiting");
    return EXIT_SUCCESS;
  }

  if (protocol_launch) {
    LogAppLink(is_primary
                   ? "cold start with link; handling it directly in this "
                     "process"
                   : "forwarding failed; handling the link in this secondary "
                     "process");
  }

  // Attach to console when present (e.g., 'flutter run') or create a
  // new console when running with a debugger.
  if (!::AttachConsole(ATTACH_PARENT_PROCESS) && ::IsDebuggerPresent()) {
    CreateAndAttachConsole();
  }

  // Initialize COM, so that it is available for use in the library and/or
  // plugins.
  ::CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);

  flutter::DartProject project(L"data");

  std::vector<std::string> command_line_arguments =
      GetCommandLineArguments();

  project.set_dart_entrypoint_arguments(std::move(command_line_arguments));

  FlutterWindow window(project);
  Win32Window::Point origin(10, 10);
  Win32Window::Size size(1280, 720);
  if (!window.Create(L"glpcompanion", origin, size)) {
    return EXIT_FAILURE;
  }
  window.SetQuitOnClose(true);

  if (protocol_launch) {
    // Windows protocol activation must not look like a hang: surface the
    // window that will complete the exchange (Windows blocks background
    // processes from stealing focus, so fall back to a taskbar flash).
    HWND hwnd = window.GetHandle();
    if (hwnd != nullptr) {
      ::ShowWindow(hwnd, SW_SHOW);
      if (!::SetForegroundWindow(hwnd)) {
        FLASHWINFO flash = {sizeof(FLASHWINFO), hwnd, FLASHW_ALL, 5, 0};
        ::FlashWindowEx(&flash);
      }
    }
  }

  ::MSG msg;
  while (::GetMessage(&msg, nullptr, 0, 0)) {
    ::TranslateMessage(&msg);
    ::DispatchMessage(&msg);
  }

  ::CoUninitialize();
  return EXIT_SUCCESS;
}