<?php
namespace Akram;

defined( 'ABSPATH' ) || exit;

/**
 * Web fonts: bundled default fonts, self-hosted Google Fonts and custom uploaded fonts.
 */
final class Fonts {

	private static $printed = array();

	const SYSTEM = '/^(inherit|initial|system-ui|sans-serif|serif|monospace|var\(|-apple-system|Arial|Helvetica|Georgia|Times|Courier|Verdana|Tahoma|Trebuchet|ui-)/i';

	public static function init() {
		add_action( 'akram_fetch_fonts', array( __CLASS__, 'download' ) );
		add_action( 'wp_enqueue_scripts', array( __CLASS__, 'custom_faces' ) );
	}

	private static function custom_families() {
		return array_column( (array) Options::get( 'custom_fonts', array() ), 'family' );
	}

	/** @param array<string,array> $fonts family => weights */
	private static function normalize( array $fonts ) {
		$custom = array_map( 'strtolower', self::custom_families() );
		$out    = array();
		foreach ( $fonts as $family => $weights ) {
			$family = trim( (string) $family );
			if ( '' === $family || preg_match( self::SYSTEM, $family ) || in_array( strtolower( $family ), $custom, true ) || isset( self::BUNDLED[ $family ] ) ) {
				continue;
			}
			$w = array_values( array_unique( array_filter( array_map( 'intval', (array) $weights ) ) ) );
			sort( $w );
			$out[ $family ] = $w ?: array( 400 );
		}
		ksort( $out );
		return $out;
	}

	public static function google_url( array $fonts ) {
		$parts = array();
		foreach ( $fonts as $family => $weights ) {
			$parts[] = 'family=' . str_replace( ' ', '+', $family ) . ':wght@' . implode( ';', $weights );
		}
		return $parts ? 'https://fonts.googleapis.com/css2?' . implode( '&', $parts ) . '&display=swap' : '';
	}

	/** Fonts shipped with the plugin (OFL, latin, variable): the default design system needs no download. */
	const BUNDLED = array(
		'Bricolage Grotesque' => array( 'bricolage-grotesque.woff2', '200 800' ),
		'Figtree'             => array( 'figtree.woff2', '300 900' ),
	);

	/** @font-face rules for the bundled families in use. */
	private static function bundled_css( array $fonts ) {
		$css = '';
		foreach ( array_intersect_key( self::BUNDLED, $fonts ) as $family => $f ) {
			$css .= '@font-face{font-family:"' . $family . '";font-style:normal;font-weight:' . $f[1]
				. ';font-display:swap;src:url(' . esc_url( AKRAM_URL . 'assets/fonts/' . $f[0] )
				. ') format("woff2")}';
		}
		return $css;
	}

	/**
	 * Google Fonts are self-hosted: the server downloads the files once and visitors load them from this site.
	 * Visitors' browsers only contact Google when the site owner turns on "Load fonts from Google's servers".
	 * Until the download has finished the theme's fallback font is shown.
	 *
	 * @return string|null stylesheet URL to load, if any
	 */
	private static function google_stylesheet( array $fonts, $hash ) {
		$local = self::local_url( $hash );
		if ( $local ) {
			return $local;
		}
		if ( Options::get( 'google_cdn', false ) ) {
			return self::google_url( $fonts );
		}
		self::queue_download( $fonts, $hash );
		return null;
	}

	public static function enqueue( array $fonts ) {
		if ( ! Options::get( 'google_fonts', true ) ) {
			return;
		}
		$bundled = self::bundled_css( $fonts );
		if ( $bundled && ! wp_style_is( 'akram-fonts-bundled', 'enqueued' ) ) {
			wp_register_style( 'akram-fonts-bundled', false, array(), AKRAM_VERSION );
			wp_enqueue_style( 'akram-fonts-bundled' );
			wp_add_inline_style( 'akram-fonts-bundled', $bundled );
		}
		$fonts = self::normalize( $fonts );
		if ( ! $fonts ) {
			return;
		}
		$hash = substr( md5( wp_json_encode( $fonts ) ), 0, 12 );
		if ( isset( self::$printed[ $hash ] ) ) {
			return;
		}
		self::$printed[ $hash ] = true;
		$url = self::google_stylesheet( $fonts, $hash );
		if ( ! $url ) {
			return;
		}
		wp_enqueue_style( 'akram-fonts-' . $hash, $url, array(), null ); // phpcs:ignore WordPress.WP.EnqueuedResourceParameters.MissingVersion -- the URL already carries a content version.
		if ( 0 === strpos( $url, 'https://fonts.googleapis.com/' ) ) {
			add_filter( 'wp_resource_hints', static function ( $urls, $type ) {
				if ( 'preconnect' === $type ) {
					$urls[] = array(
						'href' => 'https://fonts.gstatic.com',
						'crossorigin',
					);
				}
				return $urls;
			}, 10, 2 );
		}
	}

	public static function print_late( array $fonts ) {
		if ( ! Options::get( 'google_fonts', true ) ) {
			return;
		}
		$bundled = self::bundled_css( $fonts );
		if ( $bundled ) {
			Frontend::print_style( 'akram-fonts-bundled', '', $bundled );
		}
		$fonts = self::normalize( $fonts );
		if ( ! $fonts ) {
			return;
		}
		$hash = substr( md5( wp_json_encode( $fonts ) ), 0, 12 );
		if ( isset( self::$printed[ $hash ] ) ) {
			return;
		}
		self::$printed[ $hash ] = true;
		$url = self::google_stylesheet( $fonts, $hash );
		if ( $url ) {
			Frontend::print_style( 'akram-fonts-' . $hash, $url );
		}
	}

	/**
	 * Fetch the font files once. WP-Cron is used when it runs; on sites with DISABLE_WP_CRON (common with
	 * real server cron) the download runs after the response has been sent. A lock keeps it to one try per hour.
	 */
	private static function queue_download( array $fonts, $hash ) {
		if ( get_transient( 'akram_font_try_' . $hash ) ) {
			return;
		}
		set_transient( 'akram_font_try_' . $hash, 1, HOUR_IN_SECONDS );
		if ( ! ( defined( 'DISABLE_WP_CRON' ) && DISABLE_WP_CRON ) ) {
			if ( ! wp_next_scheduled( 'akram_fetch_fonts', array( $fonts ) ) ) {
				wp_schedule_single_event( time() + 5, 'akram_fetch_fonts', array( $fonts ) );
			}
			return;
		}
		add_action(
			'shutdown',
			static function () use ( $fonts ) {
				if ( function_exists( 'fastcgi_finish_request' ) ) {
					fastcgi_finish_request();
				}
				self::download( $fonts );
			},
			PHP_INT_MAX
		);
	}

	private static function local_url( $hash ) {
		$d = Document::upload_dir();
		return file_exists( $d['dir'] . 'fonts/' . $hash . '.css' ) ? $d['url'] . 'fonts/' . $hash . '.css' : null;
	}

	/** Download Google CSS + woff2 files into uploads so visitors never contact Google. */
	public static function download( $fonts ) {
		$fonts = self::normalize( (array) $fonts );
		if ( ! $fonts || ! Document::ensure_upload_dir() ) {
			return;
		}
		$hash = substr( md5( wp_json_encode( $fonts ) ), 0, 12 );
		$res  = wp_remote_get( self::google_url( $fonts ), array(
			'timeout'    => 15,
			'user-agent' => 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0 Safari/537.36',
		) );
		if ( is_wp_error( $res ) || 200 !== wp_remote_retrieve_response_code( $res ) ) {
			return;
		}
		$css = wp_remote_retrieve_body( $res );
		$d   = Document::upload_dir();
		wp_mkdir_p( $d['dir'] . 'fonts/' );
		$css = preg_replace_callback(
			'/url\((https:\/\/fonts\.gstatic\.com\/[^)]+\.woff2)\)/',
			static function ( $m ) use ( $d ) {
				$name = substr( md5( $m[1] ), 0, 16 ) . '.woff2';
				$path = $d['dir'] . 'fonts/' . $name;
				// The folder can disappear while files download in the background (e.g. data removed meanwhile): stop quietly.
				if ( ! file_exists( $path ) && is_dir( $d['dir'] . 'fonts' ) ) {
					$f = wp_remote_get( $m[1], array( 'timeout' => 15 ) );
					if ( is_wp_error( $f ) || 200 !== wp_remote_retrieve_response_code( $f ) ) {
						return 'url(' . $m[1] . ')';
					}
					clearstatcache( true, dirname( $path ) ); // is_dir() results are cached per request
					if ( ! is_dir( dirname( $path ) ) || false === file_put_contents( $path, wp_remote_retrieve_body( $f ) ) ) {
						return 'url(' . $m[1] . ')';
					}
				}
				return file_exists( $path ) ? 'url(' . $name . ')' : 'url(' . $m[1] . ')';
			},
			$css
		);
		clearstatcache( true, $d['dir'] . 'fonts' );
		if ( is_dir( $d['dir'] . 'fonts' ) ) {
			file_put_contents( $d['dir'] . 'fonts/' . $hash . '.css', $css );
		}
	}

	public static function custom_faces() {
		$fonts = (array) Options::get( 'custom_fonts', array() );
		if ( ! $fonts ) {
			return;
		}
		$css = '';
		foreach ( $fonts as $font ) {
			foreach ( (array) $font['faces'] as $face ) {
				if ( empty( $face['url'] ) ) {
					continue;
				}
				$ext  = strtolower( pathinfo( wp_parse_url( $face['url'], PHP_URL_PATH ), PATHINFO_EXTENSION ) );
				$fmt  = array(
					'woff2' => 'woff2',
					'woff'  => 'woff',
					'ttf'   => 'truetype',
					'otf'   => 'opentype',
				)[ $ext ] ?? 'woff2';
				$css .= '@font-face{font-family:"' . esc_attr( $font['family'] ) . '";src:url("'
					. esc_url( $face['url'] ) . '") format("' . $fmt . '");font-weight:'
					. (int) $face['weight'] . ';font-style:'
					. ( 'italic' === $face['style'] ? 'italic' : 'normal' ) . ';font-display:swap}';
			}
		}
		if ( $css ) {
			wp_register_style( 'akram-custom-fonts', false, array(), AKRAM_VERSION );
			wp_enqueue_style( 'akram-custom-fonts' );
			wp_add_inline_style( 'akram-custom-fonts', $css );
		}
	}
}