add party_shares table and model with associations

app/models/crew.rb

@@ -10,6 +10,8 @@ class Crew < ApplicationRecord
   has_many :crew_gw_participations, dependent: :destroy
   has_many :gw_events, through: :crew_gw_participations
   has_many :phantom_players, dependent: :destroy
+  has_many :party_shares, as: :shareable, dependent: :destroy
+  has_many :shared_parties, through: :party_shares, source: :party
 
   validates :name, presence: true, length: { maximum: 100 }
   validates :gamertag, length: { maximum: 50 }, allow_nil: true

app/models/party.rb

@@ -156,6 +156,8 @@ class Party < ApplicationRecord
            inverse_of: :party
 
   has_many :favorites, dependent: :destroy
+  has_many :party_shares, dependent: :destroy
+  has_many :shared_crews, through: :party_shares, source: :shareable, source_type: 'Crew'
 
   accepts_nested_attributes_for :characters
   accepts_nested_attributes_for :summons
@@ -261,6 +263,38 @@ class Party < ApplicationRecord
     visibility == 3
   end
 
+  ##
+  # Checks if the party is shared with a specific crew.
+  #
+  # @param crew [Crew] the crew to check.
+  # @return [Boolean] true if shared with the crew; false otherwise.
+  def shared_with_crew?(crew)
+    return false unless crew
+
+    party_shares.exists?(shareable_type: 'Crew', shareable_id: crew.id)
+  end
+
+  ##
+  # Checks if a user can view this party based on visibility and sharing rules.
+  # A user can view if:
+  # - The party is public
+  # - The party is unlisted (accessible via direct link)
+  # - They own the party
+  # - They are an admin
+  # - The party is shared with a crew they belong to
+  #
+  # @param user [User, nil] the user to check.
+  # @return [Boolean] true if the user can view the party; false otherwise.
+  def viewable_by?(user)
+    return true if public?
+    return true if unlisted?
+    return true if user && user_id == user.id
+    return true if user&.admin?
+    return true if user&.crew && shared_with_crew?(user.crew)
+
+    false
+  end
+
   ##
   # Checks if the party is favorited by a given user.
   #

app/models/party_share.rb

@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+##
+# PartyShare represents a sharing relationship between a party and a group (e.g., a crew).
+# It allows party owners to share their parties with specific groups, granting view access
+# to members of those groups without changing the party's base visibility.
+#
+# @!attribute [rw] party
+#   @return [Party] the party being shared.
+# @!attribute [rw] shareable
+#   @return [Crew] the polymorphic group the party is shared with.
+# @!attribute [rw] shared_by
+#   @return [User] the user who created this share.
+class PartyShare < ApplicationRecord
+  # Associations
+  belongs_to :party
+  belongs_to :shareable, polymorphic: true
+  belongs_to :shared_by, class_name: 'User'
+
+  # Validations
+  validates :party_id, uniqueness: {
+    scope: [:shareable_type, :shareable_id],
+    message: 'has already been shared with this group'
+  }
+  validate :owner_can_share
+  validate :sharer_is_member_of_shareable
+
+  # Scopes
+  scope :for_crew, ->(crew) { where(shareable_type: 'Crew', shareable_id: crew.id) }
+  scope :for_crews, ->(crew_ids) { where(shareable_type: 'Crew', shareable_id: crew_ids) }
+  scope :for_party, ->(party) { where(party_id: party.id) }
+
+  ##
+  # Returns the blueprint class for serialization.
+  #
+  # @return [Class] the PartyShareBlueprint class.
+  def blueprint
+    PartyShareBlueprint
+  end
+
+  private
+
+  ##
+  # Validates that only the party owner can share the party.
+  #
+  # @return [void]
+  def owner_can_share
+    return if party&.user_id == shared_by_id
+
+    errors.add(:shared_by, 'must be the party owner')
+  end
+
+  ##
+  # Validates that the sharer is a member of the group they're sharing to.
+  #
+  # @return [void]
+  def sharer_is_member_of_shareable
+    return unless shareable_type == 'Crew'
+    return if shareable&.active_memberships&.exists?(user_id: shared_by_id)
+
+    errors.add(:shareable, 'you must be a member of this crew')
+  end
+end

app/models/user.rb

@@ -19,6 +19,7 @@ class User < ApplicationRecord
   has_many :crew_invitations, dependent: :destroy
   has_many :pending_crew_invitations, -> { where(status: :pending) }, class_name: 'CrewInvitation'
   has_many :sent_crew_invitations, class_name: 'CrewInvitation', foreign_key: :invited_by_id, dependent: :nullify
+  has_many :party_shares, foreign_key: :shared_by_id, dependent: :destroy
 
   ##### ActiveRecord Validations
   validates :username,

db/data_schema.rb

@@ -1 +1 @@
-DataMigrate::Data.define(version: 20251230000002)
+DataMigrate::Data.define(version: 20260104000002)

db/migrate/20260105053753_create_party_shares.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class CreatePartyShares < ActiveRecord::Migration[8.0]
+  def change
+    create_table :party_shares, id: :uuid do |t|
+      t.references :party, type: :uuid, null: false, foreign_key: true
+      t.references :shareable, type: :uuid, null: false, polymorphic: true
+      t.references :shared_by, type: :uuid, null: false, foreign_key: { to_table: :users }
+
+      t.timestamps
+    end
+
+    # Prevent duplicate shares of the same party to the same group
+    add_index :party_shares, [:party_id, :shareable_type, :shareable_id],
+              unique: true,
+              name: 'index_party_shares_unique_per_shareable'
+
+    # Quick lookup of all parties shared with a specific group
+    add_index :party_shares, [:shareable_type, :shareable_id]
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_12_30_000004) do
+ActiveRecord::Schema[8.0].define(version: 2026_01_05_053753) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "btree_gin"
   enable_extension "pg_catalog.plpgsql"
@@ -677,6 +677,20 @@ ActiveRecord::Schema[8.0].define(version: 2025_12_30_000004) do
     t.index ["weapons_count", "characters_count", "summons_count"], name: "index_parties_on_counters"
   end
 
+  create_table "party_shares", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
+    t.uuid "party_id", null: false
+    t.string "shareable_type", null: false
+    t.uuid "shareable_id", null: false
+    t.uuid "shared_by_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["party_id", "shareable_type", "shareable_id"], name: "index_party_shares_unique_per_shareable", unique: true
+    t.index ["party_id"], name: "index_party_shares_on_party_id"
+    t.index ["shareable_type", "shareable_id"], name: "index_party_shares_on_shareable"
+    t.index ["shareable_type", "shareable_id"], name: "index_party_shares_on_shareable_type_and_shareable_id"
+    t.index ["shared_by_id"], name: "index_party_shares_on_shared_by_id"
+  end
+
   create_table "pg_search_documents", force: :cascade do |t|
     t.text "content"
     t.string "granblue_id"
@@ -1029,6 +1043,7 @@ ActiveRecord::Schema[8.0].define(version: 2025_12_30_000004) do
     t.string "forged_from"
     t.uuid "forge_chain_id"
     t.integer "forge_order"
+    t.integer "max_exorcism_level"
     t.index ["forge_chain_id"], name: "index_weapons_on_forge_chain_id"
     t.index ["forged_from"], name: "index_weapons_on_forged_from"
     t.index ["gacha"], name: "index_weapons_on_gacha"
@@ -1111,6 +1126,8 @@ ActiveRecord::Schema[8.0].define(version: 2025_12_30_000004) do
   add_foreign_key "parties", "parties", column: "source_party_id"
   add_foreign_key "parties", "raids"
   add_foreign_key "parties", "users"
+  add_foreign_key "party_shares", "parties"
+  add_foreign_key "party_shares", "users", column: "shared_by_id"
   add_foreign_key "phantom_players", "crew_memberships", column: "claimed_from_membership_id"
   add_foreign_key "phantom_players", "crews"
   add_foreign_key "phantom_players", "users", column: "claimed_by_id"