add season/series validations, scopes, helpers to Character

app/models/character.rb

@@ -41,6 +41,30 @@ class Character < ApplicationRecord
     { slug: 'character-multi', name_en: 'Multiattack', name_jp: '連続攻撃', order: 3 }
   ].freeze
 
+  # Non-gachable series (characters that must be recruited, not pulled)
+  NON_GACHABLE_SERIES = [
+    GranblueEnums::CHARACTER_SERIES[:Eternal],
+    GranblueEnums::CHARACTER_SERIES[:Evoker],
+    GranblueEnums::CHARACTER_SERIES[:Saint],
+    GranblueEnums::CHARACTER_SERIES[:Event],
+    GranblueEnums::CHARACTER_SERIES[:Collab]
+  ].freeze
+
+  # Validations
+  validates :season,
+            numericality: { only_integer: true },
+            inclusion: { in: GranblueEnums::CHARACTER_SEASONS.values },
+            allow_nil: true
+
+  validate :validate_series_values
+
+  # Scopes
+  scope :by_season, ->(season) { where(season: season) }
+  scope :by_series, ->(series) { where('? = ANY(series)', series) }
+  scope :gachable, -> { where(gacha_available: true) }
+  scope :recruitable, -> { where(gacha_available: false) }
+  scope :seasonal, -> { where.not(season: [nil, GranblueEnums::CHARACTER_SEASONS[:Standard]]) }
+
   def blueprint
     CharacterBlueprint
   end
@@ -48,4 +72,36 @@ class Character < ApplicationRecord
   def display_resource(character)
     character.name_en
   end
+
+  # Helper methods
+  def seasonal?
+    season.present? && season != GranblueEnums::CHARACTER_SEASONS[:Standard]
+  end
+
+  def gachable?
+    gacha_available
+  end
+
+  def season_name
+    return nil if season.nil?
+
+    GranblueEnums::CHARACTER_SEASONS.key(season)&.to_s
+  end
+
+  def series_names
+    return [] if series.blank?
+
+    series.filter_map { |s| GranblueEnums::CHARACTER_SERIES.key(s)&.to_s }
+  end
+
+  private
+
+  def validate_series_values
+    return if series.blank?
+
+    invalid_values = series.reject { |s| GranblueEnums::CHARACTER_SERIES.values.include?(s) }
+    return if invalid_values.empty?
+
+    errors.add(:series, "contains invalid values: #{invalid_values.join(', ')}")
+  end
 end