Add schedule interval as attribute of a program

Also, the part of the schedule event is deleted and the length of the event types
changes to the nearest suitable after changing the length of the interval.

This closes #1220

app/models/event_type.rb

@@ -15,17 +15,13 @@ class EventType < ActiveRecord::Base
 
   alias_attribute :name, :title
 
-  # If LENGTH_STEP must be divisor of 60, otherwise the schedule wont be displayed properly
-
-  LENGTH_STEP = defined?(SCHEDULE_CELL_SIZE) ? SCHEDULE_CELL_SIZE : 15
-
   private
 
   ##
-  # Check if length is multiple of LENGTH_STEP. Used as validation.
+  # Check if length is a divisor of program schedule cell size. Used as validation.
   #
   def length_step
-    errors.add(:length, "must be multiple of #{LENGTH_STEP}") if length % LENGTH_STEP != 0
+    errors.add(:length, "must be a divisor of #{program.schedule_interval}") if program && length % program.schedule_interval != 0
   end
 
   def capitalize_color

app/models/program.rb

@@ -38,6 +38,7 @@ class Program < ActiveRecord::Base
       where(state: :confirmed, is_highlight: true)
     end
   end
+  has_many :event_schedules, through: :events
 
   has_many :event_users, through: :events
   has_many :speakers, -> { distinct }, through: :event_users, source: :user do
@@ -52,11 +53,15 @@ class Program < ActiveRecord::Base
 
 #   validates :conference_id, presence: true, uniqueness: true
   validates :rating, numericality: { greater_than_or_equal_to: 0, less_than_or_equal_to: 10, only_integer: true }
+  validates :schedule_interval, numericality: { greater_than_or_equal_to: 5, less_than_or_equal_to: 60 }, presence: true
+  validate :schedule_interval_divisor_60
   validate :voting_start_date_before_end_date
   validate :voting_dates_exist
 
   after_create :create_event_types
   after_create :create_difficulty_levels
+  after_save :unschedule_unfit_events, if: :schedule_interval_changed?
+  after_save :normalize_event_types_length, if: :schedule_interval_changed?
   validate :check_languages_format
 
   # Returns all event_schedules for the selected schedule ordered by start_time
@@ -199,4 +204,31 @@ class Program < ActiveRecord::Base
     # We check if every language is a valid ISO 639-1 language
     errors.add(:languages, 'must be ISO 639-1 valid codes') unless languages_array.select{ |x| ISO_639.find(x).nil? }.empty?
   end
+
+  ##
+  # Check if schedule_interval is a divisor of 60 minutes
+  #
+  def schedule_interval_divisor_60
+    errors.add(:schedule_interval, 'must be a divisor of 60') if schedule_interval > 0 && 60 % schedule_interval > 0
+  end
+
+  ##
+  # Unschedule all the events which don't fit
+  #
+  def unschedule_unfit_events
+    unfit_schedules = event_schedules.select do |event_schedule|
+      event_schedule.start_time.min % schedule_interval > 0
+    end
+    EventSchedule.where(id: unfit_schedules.map(&:id)).destroy_all
+  end
+
+  ##
+  # Change event type length according schedule interval
+  #
+  def normalize_event_types_length
+    event_types.each do |event_type|
+      new_length = event_type.length > schedule_interval ? event_type.length - (event_type.length % schedule_interval) : schedule_interval
+      event_type.update_attributes length: new_length
+    end
+  end
 end