// Copyright 2019 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <string>

#include "starboard/common/log.h"
#include "starboard/elf_loader/elf_loader.h"
#include "starboard/elf_loader/elf_loader_switches.h"
#include "starboard/event.h"
#include "starboard/mutex.h"
#include "starboard/shared/starboard/command_line.h"
#include "starboard/thread_types.h"

starboard::elf_loader::ElfLoader g_elf_loader;

void (*g_sb_event_func)(const SbEvent*) = NULL;

void LoadLibraryAndInitialize(const std::string& library_path,
                              const std::string& content_path) {
  if (library_path.empty()) {
    SB_LOG(ERROR) << "Library must be specified with --"
                  << starboard::elf_loader::kEvergreenLibrary
                  << "=path/to/library/relative/to/loader/content.";
    return;
  }
  if (content_path.empty()) {
    SB_LOG(ERROR) << "Content must be specified with --"
                  << starboard::elf_loader::kEvergreenContent
                  << "=path/to/content/relative/to/loader/content.";
    return;
  }
  if (!g_elf_loader.Load(library_path, content_path, true)) {
    SB_NOTREACHED() << "Failed to load library at '"
                    << g_elf_loader.GetLibraryPath() << "'.";
    return;
  }

  SB_LOG(INFO) << "Successfully loaded '" << g_elf_loader.GetLibraryPath()
               << "'.";

  g_sb_event_func = reinterpret_cast<void (*)(const SbEvent*)>(
      g_elf_loader.LookupSymbol("SbEventHandle"));

  if (!g_sb_event_func) {
    SB_LOG(ERROR) << "Failed to find SbEventHandle.";
    return;
  }

  SB_LOG(INFO) << "Found SbEventHandle at address: "
               << reinterpret_cast<void*>(g_sb_event_func);
}

void SbEventHandle(const SbEvent* event) {
  static SbMutex mutex = SB_MUTEX_INITIALIZER;

  SB_CHECK(SbMutexAcquire(&mutex) == kSbMutexAcquired);

  if (!g_sb_event_func) {
    const SbEventStartData* data =
        static_cast<SbEventStartData*>(event->data);
    const starboard::shared::starboard::CommandLine command_line(
        data->argument_count,
        const_cast<const char**>(data->argument_values));
    LoadLibraryAndInitialize(
        command_line.GetSwitchValue(starboard::elf_loader::kEvergreenLibrary),
        command_line.GetSwitchValue(starboard::elf_loader::kEvergreenContent));
    SB_CHECK(g_sb_event_func);
  }

  g_sb_event_func(event);

  SB_CHECK(SbMutexRelease(&mutex) == true);
}