<?php

namespace Glovario\Frontend;

use Glovario\Domain\BuiltinVariables;
use Glovario\Domain\Renderer;
use Glovario\Domain\TokenParser;
use Glovario\Domain\VariableResolver;

defined( 'ABSPATH' ) || exit;

final class Tokens {
	private $resolver;
	private $renderer;
	private $parser;

	public function __construct( VariableResolver $resolver, Renderer $renderer, ?TokenParser $parser = null ) {
		$this->resolver = $resolver;
		$this->renderer = $renderer;
		$this->parser   = $parser ? $parser : new TokenParser();
	}

	public function register() {
		add_filter( 'the_content', array( $this, 'filter_content' ), 9 );
		add_filter( 'the_excerpt', array( $this, 'filter_excerpt' ), 9 );
		add_filter( 'widget_text_content', array( $this, 'filter_widget' ), 9 );
		// Block themes render headers, footers, templates, and synced patterns
		// as blocks outside the post content.
		add_filter( 'render_block', array( $this, 'filter_block' ), 9 );
		// Classic menu labels are free text, where a copied token may be pasted.
		add_filter( 'nav_menu_item_title', array( $this, 'filter_menu' ), 9 );
	}

	public function filter_menu( $title ) {
		return $this->filter( $title, 'menu' );
	}

	public function filter_block( $content ) {
		return $this->filter( $content, 'block' );
	}

	public function filter_content( $content ) {
		return $this->filter( $content, 'content' );
	}

	public function filter_excerpt( $content ) {
		return $this->filter( $content, 'excerpt' );
	}

	public function filter_widget( $content ) {
		return $this->filter( $content, 'widget' );
	}

	public function filter( $content, $source = 'token' ) {
		if ( is_admin() || ( defined( 'REST_REQUEST' ) && REST_REQUEST ) || false === strpos( (string) $content, '{{glvr:' ) ) {
			return $content;
		}
		$parts = preg_split( '~(<(?:script|style|pre|code)\b[^>]*>.*?</(?:script|style|pre|code)>|<!--.*?-->)~is', (string) $content, -1, PREG_SPLIT_DELIM_CAPTURE );
		foreach ( $parts as $index => $part ) {
			if ( 1 === $index % 2 ) {
				continue;
			}
			$parts[ $index ] = $this->replace_text_nodes( $part, $source );
		}
		return implode( '', $parts );
	}

	private function replace_text_nodes( $content, $source ) {
		$parts = preg_split( '~(<[^>]+>)~s', $content, -1, PREG_SPLIT_DELIM_CAPTURE );
		foreach ( $parts as $index => $part ) {
			if ( 1 === $index % 2 ) {
				continue;
			}
			$parts[ $index ] = $this->parser->replace(
				$part,
				function ( $key, $original, $date_format ) use ( $source ) {
					$context = array( 'source' => 'token_' . sanitize_key( $source ) );
					if ( BuiltinVariables::CURRENT_DATE_KEY === $key ) {
						$context['date_format'] = $date_format;
					}
					$resolved = $this->resolver->resolve( $key, $context );
					if ( ! $resolved ) {
						return $original;
					}
					return $this->renderer->render( $resolved['value'], $resolved['variable']['type'], $resolved['context'] );
				}
			);
		}
		return implode( '', $parts );
	}
}