// 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 "chrome/browser/drive/drive_api_util.h"

#include <string>

#include "base/command_line.h"
#include "base/logging.h"
#include "base/strings/string16.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/values.h"
#include "chrome/browser/drive/drive_switches.h"
#include "chrome/browser/google_apis/gdata_wapi_parser.h"
#include "content/public/browser/browser_thread.h"
#include "net/base/escape.h"
#include "third_party/re2/re2/re2.h"
#include "url/gurl.h"

namespace drive {
namespace util {

bool IsDriveV2ApiEnabled() {
  const CommandLine* command_line = CommandLine::ForCurrentProcess();

  // Enable Drive API v2 by default.
  if (!command_line->HasSwitch(switches::kEnableDriveV2Api))
    return true;

  std::string value =
      command_line->GetSwitchValueASCII(switches::kEnableDriveV2Api);
  StringToLowerASCII(&value);
  // The value must be "" or "true" for true, or "false" for false.
  DCHECK(value.empty() || value == "true" || value == "false");
  return value != "false";
}

std::string EscapeQueryStringValue(const std::string& str) {
  std::string result;
  result.reserve(str.size());
  for (size_t i = 0; i < str.size(); ++i) {
    if (str[i] == '\\' || str[i] == '\'') {
      result.push_back('\\');
    }
    result.push_back(str[i]);
  }
  return result;
}

std::string TranslateQuery(const std::string& original_query) {
  // In order to handle non-ascii white spaces correctly, convert to UTF16.
  base::string16 query = UTF8ToUTF16(original_query);
  const base::string16 kDelimiter(
      kWhitespaceUTF16 + base::string16(1, static_cast<char16>('"')));

  std::string result;
  for (size_t index = query.find_first_not_of(kWhitespaceUTF16);
       index != base::string16::npos;
       index = query.find_first_not_of(kWhitespaceUTF16, index)) {
    bool is_exclusion = (query[index] == '-');
    if (is_exclusion)
      ++index;
    if (index == query.length()) {
      // Here, the token is '-' and it should be ignored.
      continue;
    }

    size_t begin_token = index;
    base::string16 token;
    if (query[begin_token] == '"') {
      // Quoted query.
      ++begin_token;
      size_t end_token = query.find('"', begin_token);
      if (end_token == base::string16::npos) {
        // This is kind of syntax error, since quoted string isn't finished.
        // However, the query is built by user manually, so here we treat
        // whole remaining string as a token as a fallback, by appending
        // a missing double-quote character.
        end_token = query.length();
        query.push_back('"');
      }

      token = query.substr(begin_token, end_token - begin_token);
      index = end_token + 1;  // Consume last '"', too.
    } else {
      size_t end_token = query.find_first_of(kDelimiter, begin_token);
      if (end_token == base::string16::npos) {
        end_token = query.length();
      }

      token = query.substr(begin_token, end_token - begin_token);
      index = end_token;
    }

    if (token.empty()) {
      // Just ignore an empty token.
      continue;
    }

    if (!result.empty()) {
      // If there are two or more tokens, need to connect with "and".
      result.append(" and ");
    }

    // The meaning of "fullText" should include title, description and content.
    base::StringAppendF(
        &result,
        "%sfullText contains \'%s\'",
        is_exclusion ? "not " : "",
        EscapeQueryStringValue(UTF16ToUTF8(token)).c_str());
  }

  return result;
}

std::string ExtractResourceIdFromUrl(const GURL& url) {
  return net::UnescapeURLComponent(url.ExtractFileName(),
                                   net::UnescapeRule::URL_SPECIAL_CHARS);
}

std::string CanonicalizeResourceId(const std::string& resource_id) {
  // If resource ID is in the old WAPI format starting with a prefix like
  // "document:", strip it and return the remaining part.
  std::string stripped_resource_id;
  if (RE2::FullMatch(resource_id, "^[a-z-]+(?::|%3A)([\\w-]+)$",
                     &stripped_resource_id))
    return stripped_resource_id;
  return resource_id;
}

const char kDocsListScope[] = "https://docs.google.com/feeds/";
const char kDriveAppsScope[] = "https://www.googleapis.com/auth/drive.apps";

void ParseShareUrlAndRun(const google_apis::GetShareUrlCallback& callback,
                         google_apis::GDataErrorCode error,
                         scoped_ptr<base::Value> value) {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));

  if (!value) {
    callback.Run(error, GURL());
    return;
  }

  // Parsing ResourceEntry is cheap enough to do on UI thread.
  scoped_ptr<google_apis::ResourceEntry> entry =
      google_apis::ResourceEntry::ExtractAndParse(*value);
  if (!entry) {
    callback.Run(google_apis::GDATA_PARSE_ERROR, GURL());
    return;
  }

  const google_apis::Link* share_link =
      entry->GetLinkByType(google_apis::Link::LINK_SHARE);
  callback.Run(error, share_link ? share_link->href() : GURL());
}

}  // namespace util
}  // namespace drive