General Planning Implementation task of Managing Playlists in Chinook

[jthompsonnait]

This task list area will be completed once the implementation plan has been outlined. This area is where one creates the task list associated with the milestone.

• [ ] Create Data Models
  • Create Query Models
  • [ ] ViewModel -> TrackSelectionView
  • [ ] ViewModel -> PlaylistTrackView
  • Create Command Models
  • [ ] ViewModel -> MoveTrackModel
• [ ] Create Transactional Services (methods)
  • [ ] Add a track (AddTracks)
  • [ ] Remove tracks from playlist (RemoveTracks)
  • [ ] Reorganize playlist tracks (MoveTracks)
  • [ ] #5

[jthompsonnait]

UI Experience

This comment outlines the actions that can happen on the forms. Actions are in response to the user interacting with the form, pressing buttons or controls.

PRG Post Redirect Get (Query)

• Using routing parameters {searchType?}/{searchValue?}/{playlistName?}
• PRG clicking the Clear empties bound properties and routing parameters (page only)
• PRG clicking the Fetch will retrieve the existing playlist for the specified playlist name {playlistName?}
  • rule: playlist name cannot be empty
  • rule: playlist must exist in the database
• PRG clicking the Fetch Artist tracks or Fetch Album tracks will retrieve the tracks for the indicated search and display in a table {searchType?}/{searchValue?}
  • rule: search value cannot be empty
• Post/PRG clicking the Add [+] on the track will attempt to add the track to the playlist: <<< AddTrack >>>
  • rule: unique track on the playlist
  • rule: playlist name needs to be unique for the user
  • rule: appended track to the playlist
• Post/PRG clicking the Remove Tracks will attempt to remove one or more tracks from the playlist: <<< RemoveTracks >>>
• Post/PRG clicking the Re-Org Tracks will reorder the tracks based on the values that are in the edit box: <<< MoveTrack s>>>
  • rule: Only one track can be changed at a time.
  • rule: Track numbers must be in the current ranges of known tracks.

  • rule: Numbers must be unique (no repeating track numbers).

[jthompsonnait]

Data Model

The data models are the C# classes that we be coded in the folder (ViewModels) that holds the data classes in our solution. These classes represent the query class models and the command class models (CQRS - Command and Query Responsibility Segregation Pattern)

---

Query Models

Artist and Album Tracks Fetch

public class TrackSelectionView
{
        public int TrackId { get; set; }
        public string SongName { get; set; }
        public string AlbumTitle { get; set; }
        public string ArtistName { get; set; }
        public int Milliseconds { get; set; }
        public decimal Price { get; set; }
        public string Length
        {
            get { return $"{(int)Milliseconds / 60 / 1000}:{Milliseconds / 1000 % 60}"; }
        }
}

Current Playlist Tracks

public class PlaylistTrackView
{
        public int TrackId { get; set; }
        public bool Remove { get; set; }
        public int TrackNumber { get; set; }
        public string SongName { get; set; }
        public int Milliseconds { get; set; }
        public string Length
        {
            get { return $"{(int)Milliseconds / 60 / 1000}:{Milliseconds / 1000 % 60}"; }
        }
        public int NewTrackNumber { get; set; }
}

---

Command Model

Add Track

No model class, individual parameters public string AddTracks(string userName, string playlistName, int trackId)

Remove Tracks

No model class, individual parameters public string RemoveTracks(int playlistId, list<int> trackIDs)

Move Tracks

public class MoveTrackCommand
{
  public int TrackId {get; set;}
  public int TrackNumber {get; set;}
}

[jthompsonnait]

Business Processing Requirements

This comment will describe the various methods that will be used for Commands (CRQS) that alter the database. Queries are read-only and require, on average, no complex processing. You may in another comment, outline your query methods. However, commands require business rules, data validation and manipulations of one or more tables and/or records. Therefore, the processing of commands could require extensive logic to be outlined.

Include the method signature and a bullet list of processing (pseido-code)

Fetch Playlist

list<PlaylistTrackView> PlaylistTrackServices_FetchPlaylist(string userName, string playlistName)

• check if the playlist name exists

  • no (empty playlist name)
  • empty playlist name, throw NullArgumentException
  • yes (playlist name exists)
  • check if the playlist exists in the database
    • no (no playlist found)
    • empty playlist, throw NullArgumentException
    • yes

    • return the playlist

      Fetch Artist or Album Tracks

      list<TrackSelectionView> PlaylistTrackServices_FetchArtistOrAlbumTracks(string searchType, string searchValue)

• check if the searchValue exists

  • no (empty searchValue)
  • does not exist, throw NullArgumentException for search value
  • yes (searchValueexists)

  • return the selected tracks for either artist or albums

    Add Track

    void PlayListTrackService_AddTrack(string userName, string playlistName, int trackId)

• check if the incoming data is complete (all parameter exists)

  • if a problem exists, throw an ArgumentNullException for missing incoming values.

• check that track exists

  • does not exist, throw ArgumentException on trackId

• check to see if playlist exists

  • no (new playlist)
  • create a new playlist record
  • set track number to 1
  • yes (appending to existing playlist)
  • check if the track already exists on the playlist
    • yes
    • throw an Exception that tracks already exist
    • no
    • determine the next track number
  • add track to playlist tracks
  • check for any errors
  • yes: throw the list of all collected exceptions
  • no: save all work to the database

---

Remove Track(s)

void PlayListTrackService_RemoveTracks(int playlistId, list<int> trackIDs)

• Check that the incoming data exists
  • if a problem exists, throw an ArgumentNullException for missing incoming value
• check if the playlist exists
  • does not exist, throw ArgumentException on playlist id
  • yes
  • for each track to be removed
    • check that the track exists
    • yes: remove the track
    • no: add track id to exceptions
    • for each track in the remaining list
    • re-sequence the tracking number (starting at 1, increment of 1)
    • stage each track for update
• check for any errors
  • yes: throw the list of all collected exceptions

  • no: save all the tracks to the database

    Move Tracks

    PlaylistTrackService_MoveTracks(int playlistId, list<MoveTrack> moveTracks)

• Check that the incoming data exists
  • if a problem exists, throw an ArgumentNullException for missing incoming value
• check if the playlist exists
  • does not exist, throw ArgumentException on playlist id
  • yes
  • check tracks to move the sequence
    • for each track:
    • track number is positive numeric (add any exception)
    • track number is unique (add any exception)
    • for each track:
    • re-sequence track number (start 1, increment by 1)
    • stage update
• check for any exception
  • yes: throw new exception list
  • no: save all staged work