/**
 * The API Handler handles all API http requests
 */

/*
 * 2011 Peter 'Pita' Martischka (Primary Technology Ltd)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var absolutePaths = require('../utils/AbsolutePaths');
var fs = require("fs");
var api = require("../db/API");
var log4js = require('log4js');
var padManager = require("../db/PadManager");
var randomString = require("../utils/randomstring");
var argv = require('../utils/Cli').argv;
var createHTTPError = require('http-errors');

var apiHandlerLogger = log4js.getLogger('APIHandler');

//ensure we have an apikey
var apikey = null;
var apikeyFilename = absolutePaths.makeAbsolute(argv.apikey || "./APIKEY.txt");

try {
  apikey = fs.readFileSync(apikeyFilename,"utf8");
  apiHandlerLogger.info(`Api key file read from: "${apikeyFilename}"`);
} catch(e) {
  apiHandlerLogger.info(`Api key file "${apikeyFilename}" not found. Creating with random contents.`);
  apikey = randomString(32);
  fs.writeFileSync(apikeyFilename,apikey,"utf8");
}

// a list of all functions
var version = {};

version["1"] = Object.assign({},
  { "createGroup"               : []
  , "createGroupIfNotExistsFor" : ["groupMapper"]
  , "deleteGroup"               : ["groupID"]
  , "listPads"                  : ["groupID"]
  , "createPad"                 : ["padID", "text"]
  , "createGroupPad"            : ["groupID", "padName", "text"]
  , "createAuthor"              : ["name"]
  , "createAuthorIfNotExistsFor": ["authorMapper" , "name"]
  , "listPadsOfAuthor"          : ["authorID"]
  , "createSession"             : ["groupID", "authorID", "validUntil"]
  , "deleteSession"             : ["sessionID"]
  , "getSessionInfo"            : ["sessionID"]
  , "listSessionsOfGroup"       : ["groupID"]
  , "listSessionsOfAuthor"      : ["authorID"]
  , "getText"                   : ["padID", "rev"]
  , "setText"                   : ["padID", "text"]
  , "getHTML"                   : ["padID", "rev"]
  , "setHTML"                   : ["padID", "html"]
  , "getRevisionsCount"         : ["padID"]
  , "getLastEdited"             : ["padID"]
  , "deletePad"                 : ["padID"]
  , "getReadOnlyID"             : ["padID"]
  , "setPublicStatus"           : ["padID", "publicStatus"]
  , "getPublicStatus"           : ["padID"]
  , "setPassword"               : ["padID", "password"]
  , "isPasswordProtected"       : ["padID"]
  , "listAuthorsOfPad"          : ["padID"]
  , "padUsersCount"             : ["padID"]
  }
);

version["1.1"] = Object.assign({}, version["1"],
  { "getAuthorName"             : ["authorID"]
  , "padUsers"                  : ["padID"]
  , "sendClientsMessage"        : ["padID", "msg"]
  , "listAllGroups"             : []
  }
);

version["1.2"] = Object.assign({}, version["1.1"],
  { "checkToken"                : []
  }
);

version["1.2.1"] = Object.assign({}, version["1.2"],
  { "listAllPads"               : []
  }
);

version["1.2.7"] = Object.assign({}, version["1.2.1"],
  { "createDiffHTML"            : ["padID", "startRev", "endRev"]
  , "getChatHistory"            : ["padID", "start", "end"]
  , "getChatHead"               : ["padID"]
  }
);

version["1.2.8"] = Object.assign({}, version["1.2.7"],
  { "getAttributePool"          : ["padID"]
  , "getRevisionChangeset"      : ["padID", "rev"]
  }
);

version["1.2.9"] = Object.assign({}, version["1.2.8"],
  { "copyPad"                   : ["sourceID", "destinationID", "force"]
  , "movePad"                   : ["sourceID", "destinationID", "force"]
  }
);

version["1.2.10"] = Object.assign({}, version["1.2.9"],
  { "getPadID"                  : ["roID"]
  }
);

version["1.2.11"] = Object.assign({}, version["1.2.10"],
  { "getSavedRevisionsCount"    : ["padID"]
  , "listSavedRevisions"        : ["padID"]
  , "saveRevision"              : ["padID", "rev"]
  , "restoreRevision"           : ["padID", "rev"]
  }
);

version["1.2.12"] = Object.assign({}, version["1.2.11"],
  { "appendChatMessage"         : ["padID", "text", "authorID", "time"]
  }
);

version["1.2.13"] = Object.assign({}, version["1.2.12"],
  { "appendText"                : ["padID", "text"]
  }
);

version["1.2.14"] = Object.assign({}, version["1.2.13"],
  { "getStats"                : []
  }
);

version["1.2.15"] = Object.assign({}, version["1.2.14"],
  { "copyPadWithoutHistory"    : ["sourceID", "destinationID", "force"]
  }
);

// set the latest available API version here
exports.latestApiVersion = '1.2.15';

// exports the versions so it can be used by the new Swagger endpoint
exports.version = version;

/**
 * Handles a HTTP API call
 * @param functionName the name of the called function
 * @param fields the params of the called function
 * @req express request object
 * @res express response object
 */
exports.handle = async function(apiVersion, functionName, fields, req, res)
{
  // say goodbye if this is an unknown API version
  if (!(apiVersion in version)) {
    throw new createHTTPError.NotFound('no such api version');
  }

  // say goodbye if this is an unknown function
  if (!(functionName in version[apiVersion])) {
    throw new createHTTPError.NotFound('no such function');
  }

  // check the api key!
  fields["apikey"] = fields["apikey"] || fields["api_key"];

  if (fields["apikey"] !== apikey.trim()) {
    throw new createHTTPError.Unauthorized('no or wrong API Key');
  }

  // sanitize any padIDs before continuing
  if (fields["padID"]) {
    fields["padID"] = await padManager.sanitizePadId(fields["padID"]);
  }
  // there was an 'else' here before - removed it to ensure
  // that this sanitize step can't be circumvented by forcing
  // the first branch to be taken
  if (fields["padName"]) {
    fields["padName"] = await padManager.sanitizePadId(fields["padName"]);
  }

  // put the function parameters in an array
  var functionParams = version[apiVersion][functionName].map(function (field) {
    return fields[field]
  });

  // call the api function
  return api[functionName].apply(this, functionParams);
}