// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/chrome_browser_main_extra_parts_exo.h"

#if defined(USE_GLIB)
#include <glib.h>
#endif

#include "base/command_line.h"
#include "base/macros.h"
#include "base/message_loop/message_loop.h"
#include "chrome/browser/ui/ash/ash_util.h"
#include "chrome/common/chrome_switches.h"
#include "components/exo/display.h"
#include "components/exo/wayland/server.h"
#include "content/public/browser/browser_thread.h"

#if defined(USE_GLIB)
namespace {

struct GLibWaylandSource : public GSource {
  // Note: The GLibWaylandSource is created and destroyed by GLib. So its
  // constructor/destructor may or may not get called.
  exo::wayland::Server* server;
  GPollFD* poll_fd;
};

gboolean WaylandSourcePrepare(GSource* source, gint* timeout_ms) {
  *timeout_ms = -1;
  return FALSE;
}

gboolean WaylandSourceCheck(GSource* source) {
  GLibWaylandSource* wayland_source = static_cast<GLibWaylandSource*>(source);
  return (wayland_source->poll_fd->revents & G_IO_IN) ? TRUE : FALSE;
}

gboolean WaylandSourceDispatch(GSource* source,
                               GSourceFunc unused_func,
                               gpointer data) {
  GLibWaylandSource* wayland_source = static_cast<GLibWaylandSource*>(source);
  wayland_source->server->Dispatch(base::TimeDelta());
  wayland_source->server->Flush();
  return TRUE;
}

GSourceFuncs g_wayland_source_funcs = {WaylandSourcePrepare, WaylandSourceCheck,
                                       WaylandSourceDispatch, nullptr};

}  // namespace

class ChromeBrowserMainExtraPartsExo::WaylandWatcher {
 public:
  explicit WaylandWatcher(exo::wayland::Server* server)
      : wayland_poll_(new GPollFD),
        wayland_source_(static_cast<GLibWaylandSource*>(
            g_source_new(&g_wayland_source_funcs, sizeof(GLibWaylandSource)))) {
    wayland_poll_->fd = server->GetFileDescriptor();
    wayland_poll_->events = G_IO_IN;
    wayland_poll_->revents = 0;
    wayland_source_->server = server;
    wayland_source_->poll_fd = wayland_poll_.get();
    g_source_add_poll(wayland_source_, wayland_poll_.get());
    g_source_set_can_recurse(wayland_source_, TRUE);
    g_source_set_callback(wayland_source_, nullptr, nullptr, nullptr);
    g_source_attach(wayland_source_, g_main_context_default());
  }
  ~WaylandWatcher() {
    g_source_destroy(wayland_source_);
    g_source_unref(wayland_source_);
  }

 private:
  // The poll attached to |wayland_source_|.
  scoped_ptr<GPollFD> wayland_poll_;

  // The GLib event source for wayland events.
  GLibWaylandSource* wayland_source_;

  DISALLOW_COPY_AND_ASSIGN(WaylandWatcher);
};
#else
class ChromeBrowserMainExtraPartsExo::WaylandWatcher
    : public base::MessagePumpLibevent::Watcher {
 public:
  explicit WaylandWatcher(exo::wayland::Server* server) : server_(server) {
    base::MessageLoopForUI::current()->WatchFileDescriptor(
        server_->GetFileDescriptor(),
        true,  // persistent
        base::MessagePumpLibevent::WATCH_READ, &controller_, this);
  }

  // base::MessagePumpLibevent::Watcher:
  void OnFileCanReadWithoutBlocking(int fd) override {
    server_->Dispatch(base::TimeDelta());
    server_->Flush();
  }
  void OnFileCanWriteWithoutBlocking(int fd) override { NOTREACHED(); }

 private:
  base::MessagePumpLibevent::FileDescriptorWatcher controller_;
  exo::wayland::Server* const server_;

  DISALLOW_COPY_AND_ASSIGN(WaylandWatcher);
};
#endif

ChromeBrowserMainExtraPartsExo::ChromeBrowserMainExtraPartsExo()
    : display_(new exo::Display) {}

ChromeBrowserMainExtraPartsExo::~ChromeBrowserMainExtraPartsExo() {}

void ChromeBrowserMainExtraPartsExo::PreProfileInit() {
  if (!chrome::ShouldOpenAshOnStartup())
    return;

  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kEnableWaylandServer)) {
    wayland_server_ = exo::wayland::Server::Create(display_.get());
    wayland_watcher_ =
        make_scoped_ptr(new WaylandWatcher(wayland_server_.get()));
  }
}

void ChromeBrowserMainExtraPartsExo::PostMainMessageLoopRun() {
  wayland_watcher_.reset();
  wayland_server_.reset();
}