update models to use weapon_series associations

app/models/collection_weapon.rb

@@ -23,7 +23,7 @@ class CollectionWeapon < ApplicationRecord
   validate :validate_transcendence_requirements
 
   scope :by_weapon, ->(weapon_id) { where(weapon_id: weapon_id) }
-  scope :by_series, ->(series) { joins(:weapon).where(weapons: { series: series }) }
+  scope :by_series, ->(series_id) { joins(:weapon).where(weapons: { weapon_series_id: series_id }) }
   scope :with_keys, -> { where.not(weapon_key1_id: nil) }
   scope :with_ax, -> { where.not(ax_modifier1: nil) }
   scope :by_element, ->(element) { joins(:weapon).where(weapons: { element: element }) }
@@ -45,7 +45,7 @@ class CollectionWeapon < ApplicationRecord
     return unless weapon.present?
 
     # Validate weapon_key4 is only on Opus/Draconic weapons
-    if weapon_key4.present? && ![3, 27].include?(weapon.series)
+    if weapon_key4.present? && !weapon.opus_or_draconic?
       errors.add(:weapon_key4, "can only be set on Opus or Draconic weapons")
     end
 
@@ -78,7 +78,7 @@ class CollectionWeapon < ApplicationRecord
   def validate_element_change
     return unless element.present? && weapon.present?
 
-    unless Weapon.element_changeable?(weapon.series)
+    unless Weapon.element_changeable?(weapon)
       errors.add(:element, "can only be set on element-changeable weapons")
     end
   end

app/models/grid_weapon.rb

@@ -21,9 +21,8 @@
 # @!attribute [r] awakening
 #   @return [Awakening, nil] the associated awakening, if any.
 class GridWeapon < ApplicationRecord
-  # Allowed extra positions and allowed weapon series when in an extra position.
+  # Allowed extra positions (9, 10, 11 are the "extra" grid slots)
   EXTRA_POSITIONS = [9, 10, 11].freeze
-  ALLOWED_EXTRA_SERIES = [11, 16, 17, 28, 29, 32, 34].freeze
 
   belongs_to :weapon, foreign_key: :weapon_id, primary_key: :id
 
@@ -92,7 +91,8 @@ class GridWeapon < ApplicationRecord
       next false unless party_weapon.id.present?
 
       id_match = weapon.id == party_weapon.id
-      series_match = weapon.series == party_weapon.weapon.series
+      series_match = weapon.weapon_series_id.present? &&
+                     weapon.weapon_series_id == party_weapon.weapon.weapon_series_id
       both_opus_or_draconic = weapon.opus_or_draconic? && party_weapon.weapon.opus_or_draconic?
       both_draconic = weapon.draconic_or_providence? && party_weapon.weapon.draconic_or_providence?
 
@@ -105,14 +105,14 @@ class GridWeapon < ApplicationRecord
   ##
   # Validates whether the grid weapon is compatible with the desired position.
   #
-  # For positions 9, 10, or 11 (considered extra positions), the weapon's series must belong to the allowed set.
+  # For positions 9, 10, or 11 (considered extra positions), the weapon's series must have the `extra` flag set.
   # If the weapon is in an extra position but does not match an allowed series, an error is added.
   #
   # @return [void]
   def compatible_with_position
     return unless weapon.present?
 
-    if EXTRA_POSITIONS.include?(position.to_i) && !ALLOWED_EXTRA_SERIES.include?(weapon.series.to_i)
+    if EXTRA_POSITIONS.include?(position.to_i) && !weapon.weapon_series&.extra
       errors.add(:series, 'must be compatible with position')
     end
   end

app/models/weapon.rb

@@ -36,7 +36,10 @@ class Weapon < ApplicationRecord
 
   has_many :weapon_awakenings
   has_many :awakenings, through: :weapon_awakenings
+  belongs_to :weapon_series, optional: true
 
+  # Legacy mapping - kept for backwards compatibility during migration
+  # TODO: Remove after data migration is complete
   SERIES_SLUGS = {
     1 => 'seraphic',
     2 => 'grand',
@@ -94,21 +97,36 @@ class Weapon < ApplicationRecord
   end
 
   def compatible_with_key?(key)
-    key.series.include?(series)
+    return false unless weapon_series.present?
+
+    key.weapon_series.include?(weapon_series)
   end
 
   # Returns whether the weapon is included in the Draconic or Dark Opus series
   def opus_or_draconic?
-    [3, 27].include?(series)
+    return false unless weapon_series.present?
+
+    [WeaponSeries::DARK_OPUS, WeaponSeries::DRACONIC].include?(weapon_series.slug)
   end
 
   # Returns whether the weapon belongs to the Draconic Weapon series or the Draconic Weapon Providence series
   def draconic_or_providence?
-    [27, 40].include?(series)
+    return false unless weapon_series.present?
+
+    [WeaponSeries::DRACONIC, WeaponSeries::DRACONIC_PROVIDENCE].include?(weapon_series.slug)
   end
 
-  def self.element_changeable?(series)
+  def self.element_changeable?(weapon_or_series)
-    [4, 13, 17, 19].include?(series.to_i)
+    if weapon_or_series.is_a?(Weapon)
+      weapon_or_series.weapon_series&.element_changeable || false
+    elsif weapon_or_series.is_a?(WeaponSeries)
+      weapon_or_series.element_changeable
+    elsif weapon_or_series.is_a?(Integer)
+      # Legacy support for integer series IDs during transition
+      [4, 13, 17, 19].include?(weapon_or_series)
+    else
+      false
+    end
   end
 
   # Promotion scopes
@@ -135,11 +153,7 @@ class Weapon < ApplicationRecord
     promotions.filter_map { |p| GranblueEnums::PROMOTIONS.key(p)&.to_s }
   end
 
-  private
-
   def series_slug
-    # Assuming series is an array, take the first value
+    weapon_series&.slug || SERIES_SLUGS[series]
-    series_number = series.first
-    SERIES_SLUGS[series_number]
   end
 end

app/models/weapon_key.rb

@@ -1,7 +1,16 @@
 # frozen_string_literal: true
 
 class WeaponKey < ApplicationRecord
+  has_many :weapon_key_series, dependent: :destroy
+  has_many :weapon_series, through: :weapon_key_series
+
   def blueprint
     WeaponKeyBlueprint
   end
+
+  def compatible_with_weapon?(weapon)
+    return false unless weapon.weapon_series.present?
+
+    weapon_series.include?(weapon.weapon_series)
+  end
 end