diff --git a/index.js b/index.js
index 10f4784..b2e4afc 100644
--- a/index.js
+++ b/index.js
@@ -1,4 +1,6 @@
 const player = {
+  MAX_SONGS: 100000,
+  MAX_PLAYLIST: 1000,
   songs: [
     {
       id: 1,
@@ -47,51 +49,293 @@ const player = {
     { id: 1, name: 'Metal', songs: [1, 7, 4] },
     { id: 5, name: 'Israeli', songs: [4, 5] },
   ],
-  playSong(song) {
-    console.log(/* your code here */)
+
+  playSong(id) {
+    const songObj = this.findSongByID(id);
+    console.log("Playing " + songObj.title + " from " + songObj.album + " by " + songObj.artist + " | " + calcPlayTime(songObj.duration) + ".");    
+  },
+
+  // ===> Returns the song by the ID given <===
+  findSongByID(id){    
+    return player.songs.find(songObj => songObj.id === id);        
   },
+
+  // ===> Returns the playlist by the ID given <===
+  findPlaylistByID(id){    
+    return player.playlists.find(playlistObj => playlistObj.id === id);       
+  }
 }
 
+//===============================================
+// ============ Player Functions ================
+//===============================================
+//
+//
+
 function playSong(id) {
-  // your code here
+  player.playSong(id);
 }
 
 function removeSong(id) {
-  // your code here
+  let existFlag = false;
+
+  validateID(id);
+  player.songs.forEach((Obj, index) => {
+    if(Obj.id === id){
+      player.songs.splice(index, 1);
+      // Song Existed - remove from all playlists
+      player.playlists.forEach(playlistObj => {
+        const index = playlistObj.songs.indexOf(id);
+        if(index > -1){
+          playlistObj.songs.splice(index, 1);
+        }
+      });
+      existFlag = true;      
+    }  
+  });      
+  
+  if (!existFlag)
+    throw  "remove song: non existent Song ID: " + id; 
 }
 
-function addSong(title, album, artist, duration, id) {
-  // your code here
+function addSong(title, album, artist, duration, id) {  
+  
+  validateTimeString(duration);  
+  validateString(title,"title");
+  validateString(album,"album");
+  validateString(artist,"artist");
+  
+  const durationSec = convertTimeToSec(duration);  
+  
+  // If ID omitted - generate ID
+  if(id === undefined){
+    id = generateSongID();
+  }
+  else{
+    validateID(id);
+    if (player.findSongByID(id) !== undefined){
+      throw "song already exist: " + id;  
+    }
+  }
+  
+  player.songs.push({title, album, duration: durationSec, artist, id});
+  
+  return id;
 }
 
-function removePlaylist(id) {
-  // your code here
+function removePlaylist(id) {    
+  validatePlaylist(id);
+  player.playlists.forEach((Obj, index) => {
+    if(Obj.id === id){
+      player.playlists.splice(index, 1);      
+    }  
+  });      
 }
 
-function createPlaylist(name, id) {
-  // your code here
+function createPlaylist(name, id) { 
+  validateString(name, "playlist name");
+
+  // If ID omitted - generate ID
+  if(id === undefined){
+    id = generatePlaylistID();
+  }
+  else{
+    validateID(id);
+    if (player.findPlaylistByID(id) !== undefined)
+      throw "song already exist: " + id;  
+  }
+  
+  player.playlists.push({id, name, songs: []});
+  
+  return id;
 }
 
 function playPlaylist(id) {
-  // your code here
+  validatePlaylist(id);
+  const playlistObj = player.findPlaylistByID(id);
+  playlistObj.songs.forEach(song => playSong(song));
 }
 
 function editPlaylist(playlistId, songId) {
-  // your code here
+  validatePlaylist(playlistId);
+  validateSong(songId);
+  const myPlaylist = player.findPlaylistByID(playlistId);    
+  let songIndex = myPlaylist.songs.indexOf(songId);
+
+  if(songIndex > -1){
+    myPlaylist.songs.splice(songIndex, 1);      
+    if(myPlaylist.songs.length === 0)
+      removePlaylist(playlistId);
+  }  
+  else
+    myPlaylist.songs.push(songId);       
 }
 
-function playlistDuration(id) {
-  // your code here
+function playlistDuration(id) {  
+  validatePlaylist(id);
+  const myPlaylist = player.findPlaylistByID(id);
+  let durationInSeconds = 0;
+  myPlaylist.songs.forEach(song => {   
+    durationInSeconds += player.findSongByID(song).duration;
+  });
+  return durationInSeconds;  
 }
 
 function searchByQuery(query) {
-  // your code here
+  const lowerCaseQuery  = query.toLowerCase();
+  const objectReturned = {
+    "songs": [],
+    "playlists": []
+  }
+
+  player.songs.forEach(song => {
+    if(song.title.toLowerCase().includes(lowerCaseQuery) || 
+       song.album.toLowerCase().includes(lowerCaseQuery) || 
+       song.artist.toLowerCase().includes(lowerCaseQuery)){
+      objectReturned.songs.push(song);
+    }
+  });
+
+  // Sorting Songs by title
+  objectReturned.songs.sort(function(name1, name2) {    
+    var nameA = name1.title.toUpperCase(); 
+    var nameB = name2.title.toUpperCase(); 
+    return (nameA < nameB) ? -1 : (nameA > nameB) ? 1 : 0;   
+  })
+
+  player.playlists.forEach(playlist => {
+    if(playlist.name.toLowerCase().includes(lowerCaseQuery)){
+      objectReturned.playlists.push(playlist);
+    }
+  });
+
+  // Sorting Playlists by names
+  objectReturned.playlists.sort(function(name1, name2) {    
+    var nameA = name1.name.toUpperCase(); 
+    var nameB = name2.name.toUpperCase(); 
+    return (nameA < nameB) ? -1 : (nameA > nameB) ? 1 : 0;      
+  });
+
+  return objectReturned;
 }
 
 function searchByDuration(duration) {
-  // your code here
+  if(player.songs.length === 0){
+    throw "No songs exists";
+  }  
+  validateTimeString(duration);    
+  const secondsDuration = convertTimeToSec(duration);
+
+  let lowestDiffrenceSec = Math.abs(player.songs[0].duration - secondsDuration);
+  let lowestDiffrenceID = player.songs[0].id;  
+  let lowestDiffrenceType = "song";
+    
+  player.songs.forEach(song => {
+    let diffrence = Math.abs(song.duration - secondsDuration);
+    if(lowestDiffrenceSec > diffrence){
+      lowestDiffrenceSec = diffrence;
+      lowestDiffrenceID = song.id;      
+    }
+  });
+
+  player.playlists.forEach(playlist => {
+    let diffrence = Math.abs(playlistDuration(playlist.id) - secondsDuration);
+    if(lowestDiffrenceSec > diffrence){
+      lowestDiffrenceSec = diffrence;
+      lowestDiffrenceID = playlist.id;
+      lowestDiffrenceType = "playlist";
+    }
+  });
+
+  if(lowestDiffrenceType === "song"){
+    return player.findSongByID(lowestDiffrenceID);
+  }
+  else if (lowestDiffrenceType === "playlist"){
+    return player.findPlaylistByID(lowestDiffrenceID);
+  }
 }
 
+//==============================================
+// ============ Internal Functions ================
+//==============================================
+
+// ===> Check if String is in MM:SS format <===
+function validateTimeString(str){
+  const regex = new RegExp('^[0-9]{2}:[0-9]{2}$');
+  if(!regex.test(str))
+    throw "Duration is not valid format (MM:SS) :" + str;  
+}
+
+function validateString(str, stringLabel){
+  
+  if(str === "" || str === undefined)
+    throw stringLabel + " is not valid :" + str;  
+}
+
+function validateSong(id){
+  let Obj;
+  
+  validateID(id);
+  Obj = player.findSongByID(id);
+  if(Obj === undefined)
+    throw "non existent Song ID: " + id;
+}
+
+function validatePlaylist(id){
+  let Obj;
+   
+  validateID(id);
+  Obj = player.findPlaylistByID(id);
+  if(Obj === undefined)
+    throw "non existent Song ID: " + id;  
+}
+
+// ===> Validation wheter id is a number <===
+function validateID(id){
+  if(isNaN(id))
+    throw "ID must be a number: " + id;
+  if (id === undefined)
+    throw "ID is undefined";
+} 
+
+// ===> Convert MM:SS to Seconds <===
+function convertTimeToSec(duration){
+  const newDuration = duration.split(":")
+  return parseInt(newDuration[0]) * 60 + parseInt(newDuration[1]);
+}
+
+// ===> Reformat from seconds to MM:SS <===
+function calcPlayTime(durationTime) {
+  const min = Math.floor(durationTime / 60);
+  const sec = durationTime - min * 60;
+  // Should add 0 before the number?   
+  const numberAsString1 = (min < 10) ? "0" : "";
+  const numberAsString2 = (sec < 10) ? "0" : "";
+  return numberAsString1 + min + ":" + numberAsString2 + sec;
+}
+
+function generateSongID(){
+  for (i=1; i < player.MAX_SONGS; i++) {
+    const songObj = player.findSongByID(i);    
+    if(songObj === undefined)      
+      return i;
+  }
+  throw "Sorry, Songs reached max capacity";
+}
+
+function generatePlaylistID(){
+  for (i=1; i < player.MAX_PLAYLIST; i++) {
+    const playlistObj = player.findPlaylistByID(i);    
+    if(playlistObj === undefined)
+      return i;
+  }
+  throw "Sorry, Playlists reached max capacity";
+}
+
+//==============================================
+// ============ Test Export     ================
+//==============================================
+
 module.exports = {
   player,
   playSong,