Practice/Amazon/Design Amazon Music

Design Amazon Music

Object Oriented DesignMust

Problem

Design an object-oriented system for a music streaming platform that enables users to stream songs, manage playlists, maintain a personal music library, and download content for offline listening. Your design should support core functionality including song playback control, user library management with favorites, playlist creation and manipulation, search capabilities, and offline download management with storage tracking.

The system should handle multiple concurrent users, each with their own libraries and playlists. Consider how different components interact: the music player for playback control, the download manager for offline access, user profiles for personalization, and the overall service coordination.

Requirements

1. Song Management: Represent songs with metadata including title, artist, album, duration, and file size
2. Playlist Operations: Create playlists, add/remove songs, shuffle order, and associate playlists with users
3. User Library: Allow users to add songs to their personal library and mark favorites
4. Playback Control: Implement a music player that can play, pause, and stop songs with state tracking
5. Search Functionality: Enable searching songs by artist name and title keywords
6. Offline Downloads: Manage downloaded songs with storage limit enforcement and track space usage
7. Data Persistence: Store playlists, user libraries, and song catalog in appropriate data structures

Constraints

• Song file sizes range from 1MB to 20MB
• Playlist can contain 1 to 10,000 songs
• User library can contain up to 50,000 songs
• Offline storage limits can be configured (e.g., 500MB to 10GB)
• Song IDs, Playlist IDs, and User IDs are unique strings
• Search should be case-insensitive and support partial matches
• System should handle concurrent operations gracefully

Examples

Example 1: Basic Music Playback

` service = MusicStreamingService() song = Song("s1", "Imagine", "John Lennon", "Imagine", 183, 5) service.add_song(song)

player = MusicPlayer() result = player.play(song)

Output: "Song 'Imagine' is now playing"

State: PLAYING

`

Example 2: Playlist Management

` playlist = Playlist("p1", "Rock Classics", "user1") song1 = Song("s1", "Stairway to Heaven", "Led Zeppelin", "IV", 482, 12) song2 = Song("s2", "Hotel California", "Eagles", "Hotel California", 391, 10)

playlist.add_song(song1) playlist.add_song(song2)

Playlist contains 2 songs

playlist.shuffle()

Songs are now in random order

playlist.remove_song("s1")

Playlist contains 1 song

`

Example 3: User Library with Favorites

` user = User("u1", "Alice", "alice@example.com") user.add_to_library(song1) user.add_to_library(song2) user.add_to_library(song3)

user.mark_favorite("s1") user.mark_favorite("s3")

favorites = user.get_favorites()

Returns [song1, song3]

`

Example 4: Search Operations

` service.add_song(Song("s1", "Bohemian Rhapsody", "Queen", "A Night at the Opera", 354, 9)) service.add_song(Song("s2", "We Will Rock You", "Queen", "News of the World", 122, 3)) service.add_song(Song("s3", "Love Story", "Taylor Swift", "Fearless", 235, 6))

results = service.search_by_artist("Queen")

Returns 2 songs

results = service.search_by_title("Love")

Returns songs with "Love" in the title (case-insensitive)

`

Example 5: Offline Downloads

` download_mgr = DownloadManager(max_storage_mb=100) song1 = Song("s1", "Title1", "Artist1", "Album1", 180, 5) # 5MB song2 = Song("s2", "Title2", "Artist2", "Album2", 200, 8) # 8MB

success = download_mgr.download_song(song1) # True, 5MB used success = download_mgr.download_song(song2) # True, 13MB used

storage_used = download_mgr.get_storage_used() # Returns 13 downloaded = download_mgr.get_downloaded_songs() # Returns [song1, song2] `