<?php
/**
 * Theme integration mode selection.
 *
 * @package HeadFoot
 */

namespace HeadFoot\Compat;

use HeadFoot\Elementor\Canvas;
use HeadFoot\Plugin;
use HeadFoot\Settings;

defined( 'ABSPATH' ) || exit;

/**
 * Picks how the plugin puts its markup into the active theme.
 */
class Theme_Loader {

	/**
	 * Known themes: template slug => integration class.
	 *
	 * @var array
	 */
	const KNOWN_THEMES = [
		'astra'           => Themes\Astra::class,
		'generatepress'   => Themes\GeneratePress::class,
		'oceanwp'         => Themes\OceanWP::class,
		'hello-elementor' => Themes\Hello_Elementor::class,
	];

	/**
	 * The method that the loader picked for this request.
	 *
	 * @var string
	 */
	private static $method = '';

	/**
	 * Adds the hooks.
	 */
	public function __construct() {
		add_action( 'after_setup_theme', [ $this, 'setup' ], 20 );
	}

	/**
	 * Resolves the integration method and starts it.
	 *
	 * @return void
	 */
	public function setup() {
		$mode = Settings::get( 'theme_mode' );

		if ( Plugin::instance()->is_uae_active() ) {
			$mode = 'off';
		}

		/**
		 * Filters the theme integration mode.
		 *
		 * @param string $mode auto, theme_support, generic, or off.
		 */
		$mode = apply_filters( 'headfoot_theme_mode', $mode );

		switch ( $mode ) {
			case 'off':
				self::$method = 'off';
				return;

			case 'theme_support':
				self::$method = 'theme_support';
				break;

			case 'generic':
				self::$method = 'generic';
				break;

			default:
				self::$method = self::detect_auto_method();
		}

		$this->start( self::$method );

		// Canvas pages print no theme header, so every method except off needs this.
		new Canvas();
	}

	/**
	 * Starts the integration for a method.
	 *
	 * @param string $method Method name.
	 * @return void
	 */
	private function start( $method ) {
		if ( 'generic' === $method ) {
			new Generic();
			return;
		}

		if ( 'block_theme' === $method ) {
			new Block_Theme();
			return;
		}

		if ( isset( self::KNOWN_THEMES[ $method ] ) ) {
			$class = self::KNOWN_THEMES[ $method ];
			new $class();
		}
	}

	/**
	 * Returns the method that the automatic mode picks for the active theme.
	 *
	 * The order is theme support, known theme, block theme, generic fallback.
	 *
	 * @return string
	 */
	public static function detect_auto_method() {
		if ( current_theme_supports( 'headfoot' ) || current_theme_supports( 'header-footer-elementor' ) ) {
			return 'theme_support';
		}

		$known = self::get_known_theme();

		if ( $known ) {
			return $known;
		}

		if ( function_exists( 'wp_is_block_theme' ) && wp_is_block_theme() ) {
			return 'block_theme';
		}

		return 'generic';
	}

	/**
	 * Returns the slug of the known theme that is active, or an empty string.
	 *
	 * The parent theme counts, so child themes work.
	 *
	 * @return string
	 */
	public static function get_known_theme() {
		foreach ( [ get_template(), get_stylesheet() ] as $slug ) {
			if ( isset( self::KNOWN_THEMES[ $slug ] ) ) {
				return $slug;
			}
		}

		return '';
	}

	/**
	 * Returns the method that the loader picked.
	 *
	 * @return string off, theme_support, generic, block_theme, or a known theme slug.
	 */
	public static function get_method() {
		return self::$method;
	}

	/**
	 * Returns a method name in plain words.
	 *
	 * @param string $method Method name.
	 * @return string
	 */
	public static function describe_method( $method ) {
		switch ( $method ) {
			case 'off':
				return esc_html__( 'Off. The plugin renders nothing.', 'headfoot' );
			case 'theme_support':
				return esc_html__( 'Theme support. The theme calls the plugin functions.', 'headfoot' );
			case 'generic':
				return esc_html__( 'Generic fallback. The plugin replaces header.php and footer.php.', 'headfoot' );
			case 'block_theme':
				return esc_html__( 'Block theme. The plugin replaces the header and footer template parts.', 'headfoot' );
		}

		if ( isset( self::KNOWN_THEMES[ $method ] ) ) {
			$theme = wp_get_theme( $method );
			$name  = $theme->exists() ? $theme->get( 'Name' ) : $method;

			/* translators: %s: Theme name. */
			return sprintf( esc_html__( 'Dedicated integration for %s.', 'headfoot' ), $name );
		}

		return esc_html__( 'Not resolved yet.', 'headfoot' );
	}
}