// Copyright (c) 2010 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/chromeos/version_loader.h"

#include <vector>

#include "base/file_path.h"
#include "base/file_util.h"
#include "base/message_loop.h"
#include "base/string_split.h"
#include "base/string_util.h"
#include "base/thread.h"
#include "base/time.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/browser_thread.h"

namespace chromeos {

// File to look for version number in.
static const char kPath[] = "/etc/lsb-release";

VersionLoader::VersionLoader() : backend_(new Backend()) {
}

// Beginning of line we look for that gives full version number.
// Format: x.x.xx.x (Developer|Official build extra info) board info
// static
const char VersionLoader::kFullVersionPrefix[] =
    "CHROMEOS_RELEASE_DESCRIPTION=";

// Same but for short version (x.x.xx.x).
// static
const char VersionLoader::kVersionPrefix[] = "CHROMEOS_RELEASE_VERSION=";

VersionLoader::Handle VersionLoader::GetVersion(
    CancelableRequestConsumerBase* consumer,
    VersionLoader::GetVersionCallback* callback,
    VersionFormat format) {
  if (!g_browser_process->file_thread()) {
    // This should only happen if Chrome is shutting down, so we don't do
    // anything.
    return 0;
  }

  scoped_refptr<GetVersionRequest> request(new GetVersionRequest(callback));
  AddRequest(request, consumer);

  g_browser_process->file_thread()->message_loop()->PostTask(
      FROM_HERE,
      NewRunnableMethod(backend_.get(), &Backend::GetVersion, request, format));
  return request->handle();
}

// static
std::string VersionLoader::ParseVersion(const std::string& contents,
                                        const std::string& prefix) {
  // The file contains lines such as:
  // XXX=YYY
  // AAA=ZZZ
  // Split the lines and look for the one that starts with prefix. The version
  // file is small, which is why we don't try and be tricky.
  std::vector<std::string> lines;
  base::SplitString(contents, '\n', &lines);
  for (size_t i = 0; i < lines.size(); ++i) {
    if (StartsWithASCII(lines[i], prefix, false)) {
      std::string version = lines[i].substr(std::string(prefix).size());
      if (version.size() > 1 && version[0] == '"' &&
          version[version.size() - 1] == '"') {
        // Trim trailing and leading quotes.
        version = version.substr(1, version.size() - 2);
      }
      return version;
    }
  }
  return std::string();
}

void VersionLoader::Backend::GetVersion(
    scoped_refptr<GetVersionRequest> request,
    VersionFormat format) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
  if (request->canceled())
    return;

  std::string version;
  std::string contents;
  const FilePath file_path(kPath);
  if (file_util::ReadFileToString(file_path, &contents)) {
    version = ParseVersion(
        contents,
        (format == VERSION_FULL) ? kFullVersionPrefix : kVersionPrefix);
  }

  if (format == VERSION_SHORT_WITH_DATE) {
    base::PlatformFileInfo fileinfo;
    if (file_util::GetFileInfo(file_path, &fileinfo)) {
      base::Time::Exploded ctime;
      fileinfo.creation_time.UTCExplode(&ctime);
      version += StringPrintf("-%02u.%02u.%02u",
                              ctime.year % 100,
                              ctime.month,
                              ctime.day_of_month);
    }
  }

  request->ForwardResult(GetVersionCallback::TupleType(request->handle(),
                                                       version));
}

}  // namespace chromeos