jam-cloud/lib/jam_ruby/models/music_session.rb

module JamRuby
  class MusicSession < ActiveRecord::Base

    self.primary_key = 'id'

    attr_accessible :creator, :musician_access, :approval_required, :fan_chat, :fan_access

    belongs_to :creator, :inverse_of => :music_sessions, :class_name => "JamRuby::User", :foreign_key => "user_id"

    has_many :connections, :class_name => "JamRuby::Connection"
    has_many :users, :through => :connections, :class_name => "JamRuby::User"
    has_and_belongs_to_many :genres, :class_name => "::JamRuby::Genre", :join_table => "genres_music_sessions"
    has_many :invitations, :foreign_key => "music_session_id", :inverse_of => :music_session, :class_name => "JamRuby::Invitation"
    has_many :invited_musicians, :through => :invitations, :class_name => "JamRuby::User", :foreign_key => "receiver_id", :source => :receiver

    has_many :fan_invitations, :foreign_key => "music_session_id", :inverse_of => :music_session, :class_name => "JamRuby::FanInvitation"
    has_many :invited_fans, :through => :fan_invitations, :class_name => "JamRuby::User", :foreign_key => "receiver_id", :source => :receiver

    after_save :require_at_least_one_genre, :limit_to_three_genres

    validates :fan_chat, :inclusion => {:in => [true, false]}
    validates :fan_access, :inclusion => {:in => [true, false]}
    validates :approval_required, :inclusion => {:in => [true, false]}
    validates :musician_access, :inclusion => {:in => [true, false]}
    validates :creator, :presence => true, :if => "creator.musician?"

    def self.index(current_user)
      return MusicSession.includes(:invitations, :connections => [:user => [:friendships]]).order("(invitations.id is NULL) ASC, (friendships.friend_id != '#{current_user.id}' OR friendships.friend_id is NULL) ASC, music_sessions.created_at DESC").where("invitations.receiver_id = '#{current_user.id}' OR (friendships.friend_id = '#{current_user.id}') OR musician_access = true")
     end

    # Verifies that the specified user can join this music session
    def can_join? user
      if self.musician_access
        return true
      else
        # the creator can always join, and the invited users can join
        return self.creator == user || self.invited_musicians.exists?(user)
      end
    end

    # Verifies that the specified user can see this music session
    def can_see? user
      if self.musician_access
        return true
      else
        # the creator can always see, and the invited users can see it too
        return self.creator == user || self.invited_musicians.exists?(user)
      end
    end

    # Verifies that the specified user can delete this music session
    def can_delete? user
      # the creator can delete
      return self.creator == user
    end

    def access? user
      return self.users.exists? user
    end

    def to_s
      return description
    end

    private

    def require_at_least_one_genre
      if genres.count == 0
        errors.add(:genres, "Please select at least one genre")
      end
    end

    def limit_to_three_genres
      if genres.count > 3
        errors.add(:genres, "Three genres at most, please")
      end
    end
  end
end