main.dart

// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

// Server to basic_writer_client.dart.
// Receives JSON encoded data in a POST request and writes it to
// the file specified in the URI.

import 'dart:io';
import 'dart:convert';
import 'package:sqljocky/sqljocky.dart';
import 'dart:async';

final HOST = InternetAddress.LOOPBACK_IP_V4;
final PORT = 4049;
ConnectionPool myPool = null;

ConnectionPool get pool => myPool==null ? new ConnectionPool(
    host: 'localhost', port: 3306, user: "root", password: null, db: 'project', max: 5)
  : myPool;

void main () {
  HttpServer.bind(HOST, PORT).then(gotMessage, onError: printError);
}

void gotMessage(_server) {
  _server.listen((HttpRequest request) {
    print('got Message');
    switch (request.method) {
      case 'POST':
        handlePost(request);
        break;
      case 'OPTIONS':
        handleOptions(request);
        break;
      default: defaultHandler(request);
    }
  },
      onError: printError); // Listen failed.
  print('Listening for GET and POST on http://$HOST:$PORT');
}

void handleOptions(HttpRequest req) {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  print('${req.method}: ${req.uri.path}');
  res.statusCode = HttpStatus.NO_CONTENT;
  res.close();
}

void addCorsHeaders(HttpResponse res) {
  res.headers.add('Access-Control-Allow-Origin', '*');
  res.headers.add('Access-Control-Allow-Methods', 'POST, OPTIONS');
  res.headers.add('Access-Control-Allow-Headers',
      'Origin, X-Requested-With, Content-Type, Accept');
}

handlePost(HttpRequest req) async {
  try {
    var jsonString = await req.transform(UTF8.decoder).join();
    Map jsonData = JSON.decode(jsonString);

    // switch na jsonData['type']
    switch (jsonData['type']){
      case 'login':
        await login(req, jsonData);
        break;
      case 'register':
        await register(req, jsonData);
        break;
      case 'changePassw':
        await changePassw(req, jsonData);
        break;
      case 'getMyLanguages':
        await getMyLanguages(req, jsonData);
        break;
      case 'changeLanguages':
        await changeLanguages(req, jsonData);
        break;
      case 'createOffer':
        await createOffer(req, jsonData);
        break;
      case 'showMeTable':
        await showMeTable(req, jsonData);
        break;
      case 'getTextOfSentence':
        await getTextOfSentence(req, jsonData);
        break;
      case 'setAsKnown':
        await setAsKnown(req, jsonData);
        break;
      case 'getSentence':
        await getSentence(req, jsonData);
        break;
      default:
        await printTable(req, jsonData);
        break;
    }

  } catch (e) {
    req.response..statusCode = HttpStatus.INTERNAL_SERVER_ERROR
      ..write("Exception during file I/O: $e.")
      ..close();
  }

}


Future printTable(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, String> answer = new Map();

  try{
    var query = await pool.prepare('SELECT * from Usere WHERE name=?');
    var result = await query.execute(['${jsonData['name']}']);

    await result.forEach((row){
      answer['answer'] = "yes";
    });

    answer.putIfAbsent('answer', () => "no");
  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pipojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

Future login(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, String> answer = new Map();

  try {
    var query = await pool.prepare('SELECT * FROM User WHERE (name=? AND pasw=?)');
    var result = await query.execute(['${jsonData['name']}', '${jsonData['passw']}']);

    await result.forEach( (row){
      answer['userId'] = row.id;
      answer['answer'] = "yes";
      answer['info'] = "Vitaj v systeme.";
    });

    answer.putIfAbsent('answer', () => "no");
    answer.putIfAbsent('info', () => "Niekde nastala chyba, nepoznam ta.");
    print(answer);

  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pipojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

Future register(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, String> answer = new Map();

  try{
    var query = await pool.prepare('SELECT * FROM User WHERE (name=? AND pasw=?)');
    var result = await query.execute(['${jsonData['name']}', '${jsonData['passw']}']);

    if (await result.isEmpty){
      // continue
    } else {
      answer['answer'] = "no";
      answer['info'] = "Uzivatel s tvojim menom uz je zaregistrovany. Zvol ine meno a skus znova.";
      res.write(JSON.encode(answer));
      res.close();
    }

    query = await pool.prepare('INSERT INTO User (name, pasw) VALUES (?, ?)');
    result = await query.execute(['${jsonData['name']}', '${jsonData['passw']}']);

    answer['answer'] = "yes";
    answer['info'] = "Registracia prebehla uspesne.";
  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pripojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

Future changePassw(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, String> answer = new Map();

  try{
  var query = await pool.prepare('UPDATE User SET pasw=? WHERE name=?');
  var result = await query.execute(['${jsonData['passw']}', '${jsonData['name']}']);

  answer['answer'] = "yes";
  answer['info'] = "Heslo bolo uspesne zmenene";
  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pripojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

Future getMyLanguages(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, Map<String, String>> answer = new Map();

  try{
    var query = await pool.prepare('SELECT id, name, short, userId '+
        'FROM Language LEFT OUTER JOIN '+
        '(SELECT * FROM Says WHERE userId=?) AS subquery '+
        'ON Language.id=subquery.languageId '+
        'GROUP BY id, name, short');
    var result = await query.execute([jsonData['userId']]);

    int index = 0;
    await result.forEach((row){
      Map r = new Map(); // TODO col"cislo" asi neni uplne ok
      for (int i = 0; i < row.length - 1; i++){
        r['col${i}'] = row[i];
      }

      if (row.userId == jsonData['userId']){
        r['checked'] = true;
      }

      answer['${index}'] = r;
      index++;
    });
  } catch (e){
    print(e);
    answer['answer']['answer'] = "no";
    answer['answer']['info'] = "Nepodarilo sa pripojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

Future changeLanguages(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, String> answer = new Map();

  try{
    Map<String, bool> myData = jsonData["checkedList"];
    int id = jsonData["userId"];

    List<List<int>> insertValues = new List(), deleteValues = new List();
    int toInsert = 0, toDelete = 0;

    var insertQuery = await pool.prepare("INSERT INTO Says VALUES (?, ?)");
    var deleteQuery = await pool.prepare("DELETE FROM Says WHERE (userId=? AND languageId=?)");

    for (var item in myData.keys){
      if (myData[item] == true){
        toInsert++;
        insertValues.add([id, item]);
      } else {
        toDelete++;
        deleteValues.add([id, item]);
      }
    }

    if (toInsert == 1){
      await insertQuery.execute(insertValues[0]);
    } else if (toInsert > 0) {
      await insertQuery.executeMulti(insertValues);
    }

    if (toDelete == 1){
      await deleteQuery.execute(deleteValues[0]);
    } else if (toDelete > 0) {
      await deleteQuery.executeMulti(deleteValues);
    }

    answer['answer'] = "yes";
    answer['info'] = "Zmena prebehla uspesne";
  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pripojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

//SELECT Film.name AS film, Titles.id AS titlesId, Titles.languageId AS languageId FROM Film,Titles WHERE Film.id=Titles.filmId;
// TODO
Future createOffer(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);

  String query = "SELECT Film.name AS film, Titles.languageId AS languageId, Titles.id AS titlesId FROM Film,Titles WHERE Film.id=Titles.filmId ORDER BY Film.name, Titles.languageId, Titles.id DESC";

  print(query);

  Map object = new Map();
  String filmName = "";
  Map film = new Map();

  /*
  for(int key in answer.keys){
    print (key);
    Map row = answer[key];
    print (row);
    print (row["col0"] != filmName);
    if (row["col0"] != filmName){
      print("kluc ${row["col0"]} este nie je v objekte");
      print (key>0);
      if (key > 0){
        object[filmName] = film;
        film = new Map();
      }
      print ("created new Map 'film'");
    }
    if (film.containsKey(row["col1"])){
      film[row["col1"]][film[row["col1"]].length] = row["col2"];
    } else {
      print("create new key in film ${row["col1"]}");
      film[row["col1"]] = new List();
      film[row["col1"]][0] = row["col2"];
    }
    print(film);
  }
*/
  object[filmName] = film;
  print(object);

  /*
  if (answer.length == 1){
    object['answer'] = "yes";
    object['userId'] = answer["0"]["col0"];
  } else {
    object['answer'] = "no";
  }
  res.write(JSON.encode(object));
  res.close();
*/
}

//SELECT Word.id, Word.text, COUNT(Contains.sentenceId), Contains.sentenceId FROM Contains, Word WHERE Contains.wordId=Word.id AND Word.languageId=3 GROUP BY Word.id, Word.text HAVING COUNT(Contains.sentenceId)>15 ORDER BY COUNT(Contains.sentenceId) DESC;
/*
SELECT Word.id, Word.text FROM Contains, Word WHERE Contains.wordId=Word.id AND Word.languageId=3 AND NOT EXISTS (SELECT * FROM Knows WHERE Knows.userId=1 AND Knows.wordId=Word.id) GROUP BY Word.id, Word.text ORDER BY COUNT(Contains.sentenceId) DESC LIMIT 30;
dva stlpce - id slova a text slova, zoradene podla poctu vyskytov
- mozno treba pridat ku kazdemu slovu v db ze v akom filme je
 */

Future showMeTable(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, Map> answer = new Map();

  try {
    print("checkpoint no.1");

    // co ak sa chcem ucit aj ked nie som prihlasena?
    var query = await pool.prepare("SELECT Word.id, Word.text "+
        "FROM Contains, Word "+
        "WHERE Contains.wordId=Word.id AND Word.languageId=?"+
        " AND NOT EXISTS (SELECT * FROM Knows WHERE Knows.userId=?"+
        " AND Knows.wordId=Word.id)"+
        " GROUP BY Word.id, Word.text"+
        " ORDER BY COUNT(Contains.sentenceId) DESC"+
        " LIMIT ?");
    print(pool);
    // TODO skontroluj nezrovnalosti medzi titles a language
    var result = await query.execute([jsonData['titles1'], jsonData['userId'], jsonData['limit']]);

    await result.forEach( (row){
      int wordId = row.id;
      String wordText = row.text;
      answer['${wordId}'] = new Map();
      answer['${wordId}']['text'] = wordText;

    });

    print("checkpoint no.2");

    for (String key in answer.keys){
      query = await pool.prepare("SELECT sentenceId FROM Contains WHERE wordId=? ORDER BY sentenceId");
      result = await query.execute([key]);

      int i = 0;
      await result.forEach( (row){
        answer[key]['${i++}'] = row.sentenceId;
      });
      answer[key]['sum'] = i;

      //print(answer[key]);

      query = await pool.prepare('SELECT text FROM Sentence WHERE id=?');
      result = await query.execute([answer[key]['0']]);

      StringBuffer sb = new StringBuffer();
      await result.forEach( (row){
        sb.writeln(row.text);
      });

      answer[key]['sentence'] = sb.toString();

    }

    print("checkpoint no.3");
    answer['answer'] = new Map();
    answer['answer']['answer'] = "yes";
    print (answer);
  } catch (e){
    print(e);
    answer['answer'] = new Map();
    answer['answer']['answer'] = "no";
    answer['answer']['info'] = "An exception occured: ${e}";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  print(answer);
  res.write(JSON.encode(answer));
  res.close();
}

Future getTextOfSentence(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  //Map<String, String> answer = new Map();
  Map answer = new Map();

  try{
    var query = await pool.prepare('SELECT text, poradove_cislo FROM Sentence WHERE id=? ORDER BY Sentence.id ASC');
    var result = await query.execute([jsonData['id']]);

    StringBuffer sb = new StringBuffer();
    await result.forEach( (row){
      sb.writeln(row.text);
      answer.putIfAbsent('poradove_cislo', () => row.poradove_cislo);
    });
    answer['answer'] = sb.toString();

    if (jsonData.containsKey('secondLanguage')){
      int languageId = jsonData['secondLanguage'];
      // TODO domysliet ten druhy jazyk - co ak ich tam bude viac moznosti?
      query = await pool.prepare("SELECT Sentence.text, Sentence.poradove_cislo "+
          "FROM Pair, Sentence "+
          "WHERE (((Pair.sentence2=Sentence.id AND Pair.sentence1=?) "+
          "OR (Pair.sentence1=Sentence.id AND Pair.sentence2=?)))");
      result = await query.execute([jsonData['id'], jsonData['id']]);

      sb.clear();
      await result.forEach( (row){
        sb.writeln(row.text);
        answer.putIfAbsent('pc2', () => row.poradove_cislo);
      });
      answer['second'] = sb.toString();
    }

    print(answer);
  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pripojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

Future setAsKnown (HttpRequest req, Map jsonData) async{
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, String> answer = new Map();

  try{
    int userId = jsonData['userId'];
    String word = jsonData['word'];

    var query = await pool.prepare('SELECT id FROM Word WHERE text=?');
    var result = await query.execute(['${word}']);

    List<List<int>> insertValues = new List();
    await result.forEach( (row){
      List<int> oneInsert = new List();
      oneInsert.add(userId);
      oneInsert.add(row.id);
      insertValues.add(oneInsert);
    });

    print("word '${word}' has these indeces: ${insertValues.toString()}");

    query = await pool.prepare('INSERT INTO Knows (userId, wordId) VALUES (?, ?)');
    result = await query.executeMulti(insertValues);

    print("executedMulti");

    answer['answer'] = "yes";
    answer['info'] = "user no. ${userId} knows new word ${word}";
    print(answer);
  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pripojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

Future getSentence(HttpRequest req, Map jsonData) async {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  Map<String, String> answer = new Map();

  try{
    var query = await pool.prepare('SELECT text FROM Sentence WHERE titlesId=? AND poradove_cislo=?');
    var result = await query.execute([jsonData['titlesId'], jsonData['poradove_cislo']]);

    StringBuffer sb = new StringBuffer();
    await result.forEach( (row){
      sb.writeln(row.text);
    });
    answer['sentence'] = sb.toString();
    answer['answer'] = "yes";

    print(answer);
  } catch (e){
    print(e);
    answer['answer'] = "no";
    answer['info'] = "Nepodarilo sa pripojiť do databázy.";
    await pool.closeConnectionsNow();
    myPool = null;
  }

  res.write(JSON.encode(answer));
  res.close();
}

void defaultHandler(HttpRequest req) {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  res.statusCode = HttpStatus.NOT_FOUND;
  res.write('Not found: ${req.method}, ${req.uri.path}');
  res.close();
}

void printError(error) => print(error);

/*
 * Encode/Decode functions for Dart
 *
 * Copyright 2011 Google Inc.
 * Neil Fraser (fraser@google.com)
 *
 * 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.
 */

//library('URI Encode Decode');

/**
 * Implementation of JavaScript's encodeURI function.
 * [text] is the string to escape.
 * Returns the escaped string.
 */
String encodeURI(text) {
  StringBuffer encodedText = new StringBuffer();
  final String whiteList = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' +
      'abcdefghijklmnopqrstuvwxyz' +
      '0123456789-_.!~*\'()#;,/?:@&=+\$';
  final String hexDigits = '0123456789ABCDEF';
  for (int i = 0; i < text.length; i++) {
    if (whiteList.indexOf(text[i]) != -1) {
      // This character doesn't need encoding.
      encodedText.write(text[i]);
      continue;
    }
    int charCode = text.charCodeAt(i);
    List<int> byteList = [];
    if (charCode < 0x80) {
      // One-byte code.
      // 0xxxxxxx
      byteList.add(charCode);
    } else if (charCode < 0x800) {
      // Two-byte code.
      // 110xxxxx 10xxxxxx
      byteList.add(charCode >> 6 | 0xC0);
      byteList.add(charCode & 0x3F | 0x80);
    } else if (0xD800 <= charCode && charCode < 0xDC00) {
      // Low surrogate.  Next char must be a high surrogate.
      int nextCharCode = text.length == i + 1 ? 0 : text.charCodeAt(i + 1);
      if (0xDC00 <= nextCharCode && nextCharCode < 0xE000) {
        // Four-byte surrogate pair.
        // 11110xxx 10xxxxxx 10xxyyyy 10yyyyyy
        // Where xxxxxxxxxxx is offset by 1000000 (0x40)
        charCode += 0x40;
        byteList.add(charCode >> 8 & 0x7 | 0xF0);
        byteList.add(charCode >> 2 & 0x3F | 0x80);
        byteList.add(((charCode & 0x3) << 4) |
        (nextCharCode >> 6 & 0xF) | 0x80);
        byteList.add(nextCharCode & 0x3F | 0x80);
      } else {
        throw new
        Exception('URI malformed: Orphaned low surrogate.');
      }
      // Skip next character.
      i++;
    } else if (0xDC00 <= charCode && charCode < 0xE000) {
      throw new
      Exception('URI malformed: Orphaned high surrogate.');
    } else if (charCode < 0x10000) {
      // Three-byte code.
      // 1110xxxx 10xxxxxx 10xxxxxx
      byteList.add(charCode >> 12 | 0xE0);
      byteList.add(charCode >> 6 & 0x3F | 0x80);
      byteList.add(charCode & 0x3F | 0x80);
    }
    for (int i = 0; i < byteList.length; i++) {
      encodedText.write('%');
      encodedText.write(hexDigits[byteList[i] >> 4]);
      encodedText.write(hexDigits[byteList[i] & 0xF]);
    }
  }
  return encodedText.toString();
}

/**
 * Implementation of JavaScript's encodeURIComponent function.
 * [text] is the string to escape.
 * Return the escaped string.
 */
String encodeURIComponent(text) {
  // This is the same as encodeURI except the following are also escaped:
  // #;,/?:@&=+$  -> %23%3B%2C%2F%3F%3A%40%26%3D%2B%24
  text = encodeURI(text);
  return text.replaceAll('#', '%23')
      .replaceAll(';', '%3B')
      .replaceAll(',', '%2C')
      .replaceAll('/', '%2F')
      .replaceAll('?', '%3F')
      .replaceAll(':', '%3A')
      .replaceAll('@', '%40')
      .replaceAll('&', '%26')
      .replaceAll('=', '%3D')
      .replaceAll('+', '%2B')
      .replaceAll('\$', '%24');
}

/**
 * Implementation of JavaScript's decodeURI function.
 * [text] is the string to unescape.
 * Returns the unescaped string.
 */
String decodeURI(text) {
  final String hexDigits = '0123456789ABCDEF';
  // First, break up the text into parts.
  List<String> parts = text.split('%');
  int state = 0;
  int multiByte;  // Temp register for assembling a multi-byte value.
  bool surrogate = false;
  // Skip the first element, it's guaranteed to be a (possibly empty) string.
  for (int i = 1; i < parts.length; i++) {
    String part = parts[i];
    if (part.length < 2) {
      throw new Exception('URI malformed: Missing digits.');
    }
    int hex1 = hexDigits.indexOf(part[0].toUpperCase());
    int hex2 = hexDigits.indexOf(part[1].toUpperCase());
    parts[i] = part.substring(2);
    if (hex1 == -1 || hex2 == -1) {
      throw new Exception('URI malformed: Invalid digits.');
    }
    int charCode = hex1 * 16 + hex2;
    if (state == 0) {
      if (charCode < 0x80) {
        // One-byte code.
        // 0xxxxxxx
        multiByte = charCode;
        state = 0;
      } else if ((charCode & 0xE0) == 0xC0) {
        // Two-byte code.
        // 110xxxxx 10xxxxxx
        multiByte = charCode & 0x1F;
        state = 1;
      } else if ((charCode & 0xF0) == 0xE0) {
        // Three-byte code.
        // 1110xxxx 10xxxxxx 10xxxxxx
        multiByte = charCode & 0xF;
        state = 2;
      } else if ((charCode & 0xF8) == 0xF0) {
        // Four-byte surrogate pair.
        // 11110xxx 10xxxxxx 10xxyyyy 10yyyyyy
        multiByte = charCode & 0x7;
        state = 3;
        surrogate = true;
      } else {
        throw new Exception('URI malformed: Unknown Unicode.');
      }
    } else {
      // All continuation bytes are in the form 10xxxxxx.
      if ((charCode & 0xC0) != 0x80) {
        throw new Exception('URI malformed: Expect 10xxxxxx.');
      }
      multiByte = (multiByte << 6) | (charCode & 0x3F);
      state--;
    }
    if (state == 0) {
      // Character is fully assembled.  Add to string.
      if (surrogate) {
        surrogate = false;
        // Insert surrogate pair.
        // xxxxxxxxxxxyyyyyyyyyy (21 bits)
        // Where xxxxxxxxxxx is offset by 1000000 (0x40)
        int x = (multiByte >> 10) - 0x40 + 0xD800;
        int y = (multiByte & 0x3FF) + 0xDC00;
        if (x >= 0xDC00 || y >= 0xE000) {
          throw new
          Exception('URI malformed: Invalid surrogate.');
        }
        parts.insert(i, new String.fromCharCodes([x, y]));
      } else {
        // Insert a single character.
        parts.insert(i, new String.fromCharCodes([multiByte]));
      }
      // Skip the element we just inserted.
      i++;
    } else {
      // This code must be directly followed by another code.
      if (!parts[i].isEmpty) {
        throw new Exception('URI malformed: Incomplete code.');
      }
    }
  }
  if (state != 0) {
    throw new Exception('URI malformed: Truncated code.');
  }
  StringBuffer answ = new StringBuffer();
  answ.writeAll(parts);
  return answ.toString();
}

/**
 * Implementation of JavaScript's decodeURIComponent function.
 * [text] is the string to unescape.
 * Returns the unescaped string.
 */
String decodeURIComponent(text) {
  return decodeURI(text);
}