defmodule PhoenixKitWeb.Components.OAuthButtons do
  @moduledoc """
  OAuth authentication buttons component for Google, GitHub, and Facebook Sign-In.

  This component automatically checks if OAuth is available and configured.
  If OAuth is not available (dependencies not installed or not enabled in settings),
  the buttons will not be rendered.
  """

  use Phoenix.Component
  alias PhoenixKit.Users.OAuthAvailability
  alias PhoenixKit.Utils.Routes
  alias PhoenixKitWeb.Components.Core.Icons

  @doc """
  Renders OAuth provider buttons for authentication.

  This component only renders buttons if:
  - OAuth is enabled in settings (oauth_enabled = true)
  - Ueberauth library is loaded
  - At least one provider is configured

  ## Examples

      <.oauth_buttons />
      <.oauth_buttons show_divider={false} />
      <.oauth_buttons class="mt-6" />
  """
  attr :class, :string, default: ""
  attr :show_divider, :boolean, default: true

  attr :return_to, :string,
    default: nil,
    doc:
      "Local post-login destination to carry through the OAuth round-trip. The callback stashes it as :oauth_return_to; without it a user sent to sign in from a protected page lands on the default instead."

  def oauth_buttons(assigns) do
    # Check each provider individually
    assigns =
      assigns
      |> assign(:google_enabled, OAuthAvailability.provider_enabled?(:google))
      |> assign(:github_enabled, OAuthAvailability.provider_enabled?(:github))
      |> assign(:facebook_enabled, OAuthAvailability.provider_enabled?(:facebook))

    # Check if at least one provider is enabled
    any_provider_enabled =
      assigns.google_enabled or assigns.github_enabled or assigns.facebook_enabled

    assigns = assign(assigns, :any_provider_enabled, any_provider_enabled)

    # Only a local path travels; anything else is dropped rather than handed
    # to the callback's session stash.
    assigns =
      assign(assigns, :return_query, oauth_return_query(assigns[:return_to]))

    ~H"""
    <%= if @any_provider_enabled do %>
      <div class={@class}>
        <%= if @show_divider do %>
          <div class="divider text-base-content/60">Or continue with</div>
        <% end %>

        <div class="space-y-2">
          <%!-- Google Sign-In Button --%>
          <%!-- OAuth routes are non-localized, so we use locale: :none --%>
          <%= if @google_enabled do %>
            <.link
              href={Routes.path("/users/auth/google", locale: :none) <> @return_query}
              class="btn btn-outline w-full flex items-center justify-center gap-2 hover:bg-base-200 transition-all hover:scale-[1.02] active:scale-[0.98]"
            >
              <Icons.icon_google class="w-5 h-5" />
              <span>Continue with Google</span>
            </.link>
          <% end %>
          <%!-- GitHub Sign-In Button --%>
          <%= if @github_enabled do %>
            <.link
              href={Routes.path("/users/auth/github", locale: :none) <> @return_query}
              class="btn btn-outline w-full flex items-center justify-center gap-2 hover:bg-base-200 transition-all hover:scale-[1.02] active:scale-[0.98]"
            >
              <Icons.icon_github class="w-5 h-5" />
              <span>Continue with GitHub</span>
            </.link>
          <% end %>
          <%!-- Facebook Sign-In Button --%>
          <%= if @facebook_enabled do %>
            <.link
              href={Routes.path("/users/auth/facebook", locale: :none) <> @return_query}
              class="btn btn-outline w-full flex items-center justify-center gap-2 hover:bg-base-200 transition-all hover:scale-[1.02] active:scale-[0.98]"
            >
              <Icons.icon_facebook class="w-5 h-5" />
              <span>Continue with Facebook</span>
            </.link>
          <% end %>
        </div>
      </div>
    <% end %>
    """
  end

  defp oauth_return_query(return_to) do
    if is_binary(return_to) and Routes.local_path?(return_to) do
      "?" <> URI.encode_query(%{"return_to" => return_to})
    else
      ""
    end
  end
end