// Copyright 2014 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/file_system_provider/mount_path_util.h"

#include <vector>

#include "base/stl_util.h"
#include "base/strings/stringprintf.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/chromeos/file_system_provider/provided_file_system.h"
#include "chrome/browser/chromeos/file_system_provider/service.h"
#include "chrome/browser/chromeos/login/users/user.h"
#include "chrome/browser/chromeos/login/users/user_manager.h"
#include "chrome/browser/chromeos/profiles/profile_helper.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/profiles/profile_manager.h"
#include "content/public/browser/browser_thread.h"

using content::BrowserThread;

namespace chromeos {
namespace file_system_provider {
namespace util {

namespace {

// Root mount path for all of the provided file systems.
const base::FilePath::CharType kProvidedMountPointRoot[] =
    FILE_PATH_LITERAL("/provided");

}  // namespace

// Escapes the file system id so it can be used as a file/directory name.
// This is based on net/base/escape.cc: net::(anonymous namespace)::Escape
std::string EscapeFileSystemId(const std::string& file_system_id) {
  std::string escaped;
  for (size_t i = 0; i < file_system_id.size(); ++i) {
    const char c = file_system_id[i];
    if (c == '%' || c == '.' || c == '/') {
      base::StringAppendF(&escaped, "%%%02X", c);
    } else {
      escaped.push_back(c);
    }
  }
  return escaped;
}

base::FilePath GetMountPath(Profile* profile,
                            const std::string& extension_id,
                            const std::string& file_system_id) {
  chromeos::User* const user =
      chromeos::UserManager::IsInitialized()
          ? chromeos::UserManager::Get()->GetUserByProfile(
                profile->GetOriginalProfile())
          : NULL;
  const std::string safe_file_system_id = EscapeFileSystemId(file_system_id);
  const std::string username_suffix = user ? user->username_hash() : "";
  return base::FilePath(kProvidedMountPointRoot).AppendASCII(
      extension_id + ":" + safe_file_system_id + ":" + username_suffix);
}

FileSystemURLParser::FileSystemURLParser(const fileapi::FileSystemURL& url)
    : url_(url), file_system_(NULL) {
}

FileSystemURLParser::~FileSystemURLParser() {
}

bool FileSystemURLParser::Parse() {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);

  if (url_.type() != fileapi::kFileSystemTypeProvided)
    return false;

  // First, find the service handling the mount point of the URL.
  const std::vector<Profile*>& profiles =
      g_browser_process->profile_manager()->GetLoadedProfiles();

  for (size_t i = 0; i < profiles.size(); ++i) {
    Profile* original_profile = profiles[i]->GetOriginalProfile();

    if (original_profile != profiles[i] ||
        chromeos::ProfileHelper::IsSigninProfile(original_profile)) {
      continue;
    }

    Service* service = Service::Get(original_profile);
    if (!service)
      continue;

    ProvidedFileSystemInterface* file_system =
        service->GetProvidedFileSystem(url_.filesystem_id());
    if (!file_system)
      continue;

    // Strip the mount point name from the virtual path, to extract the file
    // path within the provided file system.
    file_system_ = file_system;
    std::vector<base::FilePath::StringType> components;
    url_.virtual_path().GetComponents(&components);
    DCHECK_LT(0u, components.size());
    file_path_ = base::FilePath::FromUTF8Unsafe("/");
    for (size_t i = 1; i < components.size(); ++i) {
      // TODO(mtomasz): This could be optimized, to avoid unnecessary copies.
      file_path_ = file_path_.Append(components[i]);
    }

    return true;
  }

  // Nothing has been found.
  return false;
}

}  // namespace util
}  // namespace file_system_provider
}  // namespace chromeos