// 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/drive/gdata_wapi_url_generator.h"

#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "net/base/escape.h"
#include "net/base/url_util.h"
#include "url/gurl.h"

namespace google_apis {
namespace {

// Content URL for modification or resource list retrieval in a particular
// directory specified by "%s" which will be replaced with its resource id.
const char kContentURLFormat[] = "/feeds/default/private/full/%s/contents";

// Content URL for removing a resource specified by the latter "%s" from the
// directory specified by the former "%s".
const char kResourceURLForRemovalFormat[] =
    "/feeds/default/private/full/%s/contents/%s";

// URL requesting single resource entry whose resource id is followed by this
// prefix.
const char kGetEditURLPrefix[] = "/feeds/default/private/full/";

// Root resource list url.
const char kResourceListRootURL[] = "/feeds/default/private/full";

// Metadata feed with things like user quota.
const char kAccountMetadataURL[] = "/feeds/metadata/default";

// URL to upload a new file under a particular directory specified by "%s".
const char kInitiateUploadNewFileURLFormat[] =
    "/feeds/upload/create-session/default/private/full/%s/contents";

// URL to upload a file content to overwrite a file whose resource id is
// followed by this prefix.
const char kInitiateUploadExistingFileURLPrefix[] =
    "/feeds/upload/create-session/default/private/full/";

// Maximum number of resource entries to include in a feed.
// Be careful not to use something too small because it might overload the
// server. Be careful not to use something too large because it makes the
// "fetched N items" UI less responsive.
const int kMaxDocumentsPerFeed = 500;
const int kMaxDocumentsPerSearchFeed = 50;

// URL requesting documents list of changes to documents collections.
const char kGetChangesListURL[] = "/feeds/default/private/changes";

}  // namespace

const char GDataWapiUrlGenerator::kBaseUrlForProduction[] =
    "https://docs.google.com/";

const char GDataWapiUrlGenerator::kBaseDownloadUrlForProduction[] =
    "https://www.googledrive.com/host/";

// static
GURL GDataWapiUrlGenerator::AddStandardUrlParams(const GURL& url) {
  GURL result = net::AppendOrReplaceQueryParameter(url, "v", "3");
  result = net::AppendOrReplaceQueryParameter(result, "alt", "json");
  result = net::AppendOrReplaceQueryParameter(result, "showroot", "true");
  return result;
}

// static
GURL GDataWapiUrlGenerator::AddInitiateUploadUrlParams(const GURL& url) {
  GURL result = net::AppendOrReplaceQueryParameter(url, "convert", "false");
  return AddStandardUrlParams(result);
}

// static
GURL GDataWapiUrlGenerator::AddFeedUrlParams(
    const GURL& url,
    int num_items_to_fetch) {
  GURL result = AddStandardUrlParams(url);
  result = net::AppendOrReplaceQueryParameter(result, "showfolders", "true");
  result = net::AppendOrReplaceQueryParameter(result, "include-shared", "true");
  result = net::AppendOrReplaceQueryParameter(
      result, "max-results", base::IntToString(num_items_to_fetch));
  return result;
}

GDataWapiUrlGenerator::GDataWapiUrlGenerator(const GURL& base_url,
                                             const GURL& base_download_url)
    : base_url_(base_url),
      base_download_url_(base_download_url) {
}

GDataWapiUrlGenerator::~GDataWapiUrlGenerator() {
}

GURL GDataWapiUrlGenerator::GenerateResourceListUrl(
    const GURL& override_url,
    int64 start_changestamp,
    const std::string& search_string,
    const std::string& directory_resource_id) const {
  DCHECK_LE(0, start_changestamp);

  int max_docs = search_string.empty() ? kMaxDocumentsPerFeed :
                                         kMaxDocumentsPerSearchFeed;
  GURL url;
  if (!override_url.is_empty()) {
    // |override_url| specifies the URL of the continuation feed when the feed
    // is broken up to multiple chunks. In this case we must not add the
    // |start_changestamp| that provides the original start point.
    start_changestamp = 0;
    url = override_url;
  } else if (start_changestamp > 0) {
    // The start changestamp shouldn't be used for a search.
    DCHECK(search_string.empty());
    url = base_url_.Resolve(kGetChangesListURL);
  } else if (!directory_resource_id.empty()) {
    url = base_url_.Resolve(
        base::StringPrintf(kContentURLFormat,
                           net::EscapePath(
                               directory_resource_id).c_str()));
  } else {
    url = base_url_.Resolve(kResourceListRootURL);
  }

  url = AddFeedUrlParams(url, max_docs);

  if (start_changestamp) {
    url = net::AppendOrReplaceQueryParameter(
        url, "start-index", base::Int64ToString(start_changestamp));
  }
  if (!search_string.empty()) {
    url = net::AppendOrReplaceQueryParameter(url, "q", search_string);
  }

  return url;
}

GURL GDataWapiUrlGenerator::GenerateSearchByTitleUrl(
    const std::string& title,
    const std::string& directory_resource_id) const {
  DCHECK(!title.empty());

  GURL url = directory_resource_id.empty() ?
      base_url_.Resolve(kResourceListRootURL) :
      base_url_.Resolve(base::StringPrintf(
          kContentURLFormat, net::EscapePath(directory_resource_id).c_str()));
  url = AddFeedUrlParams(url, kMaxDocumentsPerFeed);
  url = net::AppendOrReplaceQueryParameter(url, "title", title);
  url = net::AppendOrReplaceQueryParameter(url, "title-exact", "true");
  return url;
}

GURL GDataWapiUrlGenerator::GenerateEditUrl(
    const std::string& resource_id) const {
  return AddStandardUrlParams(GenerateEditUrlWithoutParams(resource_id));
}

GURL GDataWapiUrlGenerator::GenerateEditUrlWithoutParams(
    const std::string& resource_id) const {
  return base_url_.Resolve(kGetEditURLPrefix + net::EscapePath(resource_id));
}

GURL GDataWapiUrlGenerator::GenerateEditUrlWithEmbedOrigin(
    const std::string& resource_id, const GURL& embed_origin) const {
  GURL url = GenerateEditUrl(resource_id);
  if (!embed_origin.is_empty()) {
    // Construct a valid serialized embed origin from an url, according to
    // WD-html5-20110525. Such string has to be built manually, since
    // GURL::spec() always adds the trailing slash. Moreover, ports are
    // currently not supported.
    DCHECK(!embed_origin.has_port());
    DCHECK(!embed_origin.has_path() || embed_origin.path() == "/");
    const std::string serialized_embed_origin =
        embed_origin.scheme() + "://" + embed_origin.host();
    url = net::AppendOrReplaceQueryParameter(
        url, "embedOrigin", serialized_embed_origin);
  }
  return url;
}

GURL GDataWapiUrlGenerator::GenerateContentUrl(
    const std::string& resource_id) const {
  if (resource_id.empty()) {
    // |resource_id| must not be empty. Return an empty GURL as an error.
    return GURL();
  }

  GURL result = base_url_.Resolve(
      base::StringPrintf(kContentURLFormat,
                         net::EscapePath(resource_id).c_str()));
  return AddStandardUrlParams(result);
}

GURL GDataWapiUrlGenerator::GenerateResourceUrlForRemoval(
    const std::string& parent_resource_id,
    const std::string& resource_id) const {
  if (resource_id.empty() || parent_resource_id.empty()) {
    // Both |resource_id| and |parent_resource_id| must be non-empty.
    // Return an empty GURL as an error.
    return GURL();
  }

  GURL result = base_url_.Resolve(
      base::StringPrintf(kResourceURLForRemovalFormat,
                         net::EscapePath(parent_resource_id).c_str(),
                         net::EscapePath(resource_id).c_str()));
  return AddStandardUrlParams(result);
}

GURL GDataWapiUrlGenerator::GenerateInitiateUploadNewFileUrl(
    const std::string& parent_resource_id) const {
  GURL result = base_url_.Resolve(
      base::StringPrintf(kInitiateUploadNewFileURLFormat,
                         net::EscapePath(parent_resource_id).c_str()));
  return AddInitiateUploadUrlParams(result);
}

GURL GDataWapiUrlGenerator::GenerateInitiateUploadExistingFileUrl(
    const std::string& resource_id) const {
  GURL result = base_url_.Resolve(
      kInitiateUploadExistingFileURLPrefix + net::EscapePath(resource_id));
  return AddInitiateUploadUrlParams(result);
}

GURL GDataWapiUrlGenerator::GenerateResourceListRootUrl() const {
  return AddStandardUrlParams(base_url_.Resolve(kResourceListRootURL));
}

GURL GDataWapiUrlGenerator::GenerateAccountMetadataUrl(
    bool include_installed_apps) const {
  GURL result = AddStandardUrlParams(base_url_.Resolve(kAccountMetadataURL));
  if (include_installed_apps) {
    result = net::AppendOrReplaceQueryParameter(
        result, "include-installed-apps", "true");
  }
  return result;
}

GURL GDataWapiUrlGenerator::GenerateDownloadFileUrl(
    const std::string& resource_id) const {
  // Strip the file type prefix before the colon character.
  size_t colon = resource_id.find(':');
  return base_download_url_.Resolve(net::EscapePath(
      colon == std::string::npos ? resource_id
                                 : resource_id.substr(colon + 1)));
}

}  // namespace google_apis