<?php
/**
 * Generic theme fallback.
 *
 * @package HeadFoot
 */

namespace HeadFoot\Compat;

defined( 'ABSPATH' ) || exit;

/**
 * Replaces header.php and footer.php of a classic theme.
 *
 * WordPress fires the get_header action and then loads header.php with
 * require_once. This class loads the theme file first inside an output buffer
 * and discards the output. The later require_once of WordPress then does
 * nothing. The footer works the same way.
 */
class Generic {

	/**
	 * Adds the hooks.
	 */
	public function __construct() {
		add_action( 'get_header', [ $this, 'override_header' ], 10, 2 );
		add_action( 'get_footer', [ $this, 'override_footer' ], 10, 2 );
	}

	/**
	 * Prints the plugin header and swallows the theme header.
	 *
	 * @param string|null $name Header name from get_header().
	 * @param array       $args Arguments from get_header().
	 * @return void
	 */
	public function override_header( $name = null, $args = [] ) {
		if ( ! headfoot_header_enabled() ) {
			return;
		}

		if ( ! is_array( $args ) ) {
			$args = [];
		}

		require HEADFOOT_DIR . 'templates/theme-header.php';

		// The plugin template already ran these hooks.
		remove_all_actions( 'wp_head' );
		remove_all_actions( 'wp_body_open' );

		$this->swallow( 'header', $name, $args );
	}

	/**
	 * Prints the plugin footer and swallows the theme footer.
	 *
	 * @param string|null $name Footer name from get_footer().
	 * @param array       $args Arguments from get_footer().
	 * @return void
	 */
	public function override_footer( $name = null, $args = [] ) {
		if ( ! headfoot_footer_enabled() ) {
			return;
		}

		if ( ! is_array( $args ) ) {
			$args = [];
		}

		require HEADFOOT_DIR . 'templates/theme-footer.php';

		// The plugin template already ran this hook.
		remove_all_actions( 'wp_footer' );

		$this->swallow( 'footer', $name, $args );
	}

	/**
	 * Loads the theme file once with the same lookup that WordPress uses and discards its output.
	 *
	 * @param string      $part header or footer.
	 * @param string|null $name Template name.
	 * @param array       $args Template arguments.
	 * @return void
	 */
	private function swallow( $part, $name, $args ) {
		$templates = [];
		$name      = (string) $name;

		if ( '' !== $name ) {
			$templates[] = "{$part}-{$name}.php";
		}

		$templates[] = "{$part}.php";

		ob_start();
		locate_template( $templates, true, true, $args );
		ob_end_clean();
	}
}