defmodule Mv.Membership.Setting do
  @moduledoc """
  Ash resource representing global application settings.

  ## Overview
  Settings is a singleton resource that stores global configuration for the association,
  such as the club name and branding information. There should only ever be one settings
  record in the database.

  ## Attributes
  - `club_name` - The name of the association/club (required, cannot be empty)
  - `member_field_visibility` - JSONB map storing visibility configuration for member fields
    (e.g., `%{"street" => false, "house_number" => false}`). Fields not in the map default to `true`.

  ## Singleton Pattern
  This resource uses a singleton pattern - there should only be one settings record.
  The resource is designed to be read and updated, but not created or destroyed
  through normal CRUD operations. Initial settings should be seeded.

  ## Environment Variable Support
  The `club_name` can be set via the `ASSOCIATION_NAME` environment variable.
  If set, the environment variable value is used as a fallback when no database
  value exists. Database values always take precedence over environment variables.

  ## Examples

      # Get current settings
      {:ok, settings} = Mv.Membership.get_settings()
      settings.club_name  # => "My Club"

      # Update club name
      {:ok, updated} = Mv.Membership.update_settings(settings, %{club_name: "New Name"})

      # Update member field visibility
      {:ok, updated} = Mv.Membership.update_member_field_visibility(settings, %{"street" => false, "house_number" => false})
  """
  use Ash.Resource,
    domain: Mv.Membership,
    data_layer: AshPostgres.DataLayer

  postgres do
    table "settings"
    repo Mv.Repo
  end

  resource do
    description "Global application settings (singleton resource)"
  end

  actions do
    defaults [:read]

    # Internal create action - not exposed via code interface
    # Used only as fallback in get_settings/0 if settings don't exist
    # Settings should normally be created via seed script
    create :create do
      accept [:club_name, :member_field_visibility]
    end

    update :update do
      primary? true
      require_atomic? false
      accept [:club_name, :member_field_visibility]
    end

    update :update_member_field_visibility do
      description "Updates the visibility configuration for member fields in the overview"
      require_atomic? false
      accept [:member_field_visibility]
    end
  end

  validations do
    validate present(:club_name), on: [:create, :update]
    validate string_length(:club_name, min: 1), on: [:create, :update]

    # Validate member_field_visibility map structure and content
    validate fn changeset, _context ->
               visibility = Ash.Changeset.get_attribute(changeset, :member_field_visibility)

               if visibility && is_map(visibility) do
                 # Validate all values are booleans
                 invalid_values =
                   Enum.filter(visibility, fn {_key, value} ->
                     not is_boolean(value)
                   end)

                 # Validate all keys are valid member fields
                 valid_field_strings = Mv.Constants.member_fields() |> Enum.map(&Atom.to_string/1)

                 invalid_keys =
                   Enum.filter(visibility, fn {key, _value} ->
                     key not in valid_field_strings
                   end)
                   |> Enum.map(fn {key, _value} -> key end)

                 cond do
                   not Enum.empty?(invalid_values) ->
                     {:error,
                      field: :member_field_visibility,
                      message: "All values in member_field_visibility must be booleans"}

                   not Enum.empty?(invalid_keys) ->
                     {:error,
                      field: :member_field_visibility,
                      message: "Invalid member field keys: #{inspect(invalid_keys)}"}

                   true ->
                     :ok
                 end
               else
                 :ok
               end
             end,
             on: [:create, :update]
  end

  attributes do
    uuid_primary_key :id

    attribute :club_name, :string,
      allow_nil?: false,
      public?: true,
      description: "The name of the association/club",
      constraints: [
        trim?: true,
        min_length: 1
      ]

    attribute :member_field_visibility, :map,
      allow_nil?: true,
      public?: true,
      description:
        "Configuration for member field visibility in overview (JSONB map). Keys are member field names (atoms), values are booleans."

    timestamps()
  end
end