// Copyright (c) 2012 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 "google_apis/gaia/oauth2_api_call_flow.h"

#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/strings/stringprintf.h"
#include "google_apis/gaia/gaia_urls.h"
#include "net/base/escape.h"
#include "net/base/load_flags.h"
#include "net/http/http_status_code.h"
#include "net/url_request/url_fetcher.h"
#include "net/url_request/url_request_context_getter.h"
#include "net/url_request/url_request_status.h"

using net::ResponseCookies;
using net::URLFetcher;
using net::URLFetcherDelegate;
using net::URLRequestContextGetter;
using net::URLRequestStatus;

namespace {
static const char kAuthorizationHeaderFormat[] =
    "Authorization: Bearer %s";

static std::string MakeAuthorizationHeader(const std::string& auth_token) {
  return base::StringPrintf(kAuthorizationHeaderFormat, auth_token.c_str());
}
}  // namespace

OAuth2ApiCallFlow::OAuth2ApiCallFlow() : state_(INITIAL) {
}

OAuth2ApiCallFlow::~OAuth2ApiCallFlow() {}

void OAuth2ApiCallFlow::Start(net::URLRequestContextGetter* context,
                              const std::string& access_token) {
  CHECK(state_ == INITIAL);
  state_ = API_CALL_STARTED;

  url_fetcher_.reset(CreateURLFetcher(context, access_token));
  url_fetcher_->Start();  // OnURLFetchComplete will be called.
}

void OAuth2ApiCallFlow::EndApiCall(const net::URLFetcher* source) {
  CHECK_EQ(API_CALL_STARTED, state_);

  URLRequestStatus status = source->GetStatus();
  int status_code = source->GetResponseCode();
  if (!status.is_success() ||
      (status_code != net::HTTP_OK && status_code != net::HTTP_NO_CONTENT)) {
    state_ = ERROR_STATE;
    ProcessApiCallFailure(source);
  } else {
    state_ = API_CALL_DONE;
    ProcessApiCallSuccess(source);
  }
}

std::string OAuth2ApiCallFlow::CreateApiCallBodyContentType() {
  return "application/x-www-form-urlencoded";
}

void OAuth2ApiCallFlow::OnURLFetchComplete(const net::URLFetcher* source) {
  CHECK(source);
  CHECK_EQ(API_CALL_STARTED, state_);
  EndApiCall(source);
}

URLFetcher* OAuth2ApiCallFlow::CreateURLFetcher(
    net::URLRequestContextGetter* context,
    const std::string& access_token) {
  std::string body = CreateApiCallBody();
  bool empty_body = body.empty();
  URLFetcher* result = net::URLFetcher::Create(
      0,
      CreateApiCallUrl(),
      empty_body ? URLFetcher::GET : URLFetcher::POST,
      this);

  result->SetRequestContext(context);
  result->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                       net::LOAD_DO_NOT_SAVE_COOKIES);
  result->AddExtraRequestHeader(MakeAuthorizationHeader(access_token));
  // Fetchers are sometimes cancelled because a network change was detected,
  // especially at startup and after sign-in on ChromeOS. Retrying once should
  // be enough in those cases; let the fetcher retry up to 3 times just in case.
  // http://crbug.com/163710
  result->SetAutomaticallyRetryOnNetworkChanges(3);

  if (!empty_body)
    result->SetUploadData(CreateApiCallBodyContentType(), body);

  return result;
}