<?php
/**
 * Shortcode handling.
 *
 * @package Plectrum
 */

namespace DA_Plectrum;

defined( 'ABSPATH' ) || exit;

/**
 * Handles shortcode rendering and optional automatic content processing.
 */
class Shortcode {
	/**
	 * Parser instance.
	 *
	 * @var Parser
	 */
	private $parser;

	/**
	 * Renderer instance.
	 *
	 * @var Renderer
	 */
	private $renderer;

	/**
	 * Asset manager.
	 *
	 * @var Assets
	 */
	private $assets;

	/**
	 * Settings manager.
	 *
	 * @var Settings
	 */
	private $settings;

	/**
	 * Instance counter.
	 *
	 * @var int
	 */
	private static $instance_count = 0;

	/**
	 * Constructor.
	 *
	 * @param Parser   $parser Parser.
	 * @param Renderer $renderer Renderer.
	 * @param Assets   $assets Asset manager.
	 * @param Settings $settings Settings manager.
	 */
	public function __construct( Parser $parser, Renderer $renderer, Assets $assets, Settings $settings ) {
		$this->parser   = $parser;
		$this->renderer = $renderer;
		$this->assets   = $assets;
		$this->settings = $settings;
	}

	/**
	 * Register shortcode.
	 *
	 * @return void
	 */
	public function register() {
		add_shortcode( 'ukulele_chords', array( $this, 'render' ) );
		add_filter( 'the_content', array( $this, 'filter_the_content' ), 9 );
	}

	/**
	 * Prime frontend assets before scripts and styles are printed.
	 *
	 * @return void
	 */
	public function prime_frontend_assets() {
		if ( is_admin() ) {
			return;
		}

		global $wp_query;

		if ( ! $wp_query instanceof \WP_Query || empty( $wp_query->posts ) ) {
			return;
		}

		foreach ( $wp_query->posts as $post ) {
			if ( $post instanceof \WP_Post ) {
				$this->prime_post_assets( $post );
			}
		}
	}

	/**
	 * Render shortcode output.
	 *
	 * @param array<string, mixed> $atts Shortcode attributes.
	 * @param string|null          $content Content.
	 * @return string
	 */
	public function render( $atts, $content = null ) {
		$content = is_string( $content ) ? trim( $content ) : '';

		if ( '' === $content ) {
			return '';
		}

		$attributes = shortcode_atts(
			array(
				'controls'              => $this->settings->get( 'show_controls' ) ? 'true' : 'false',
				'diagrams'              => $this->settings->get( 'enable_diagrams' ) ? 'true' : 'false',
				'transpose'             => '0',
				'print_button'          => $this->settings->get( 'enable_print_button' ) ? 'true' : 'false',
				'print_diagrams'        => $this->settings->get( 'print_show_diagrams' ) ? 'true' : 'false',
				'tuning'                => $this->settings->get( 'default_tuning' ),
				'enharmonic_preference' => $this->settings->get( 'enharmonic_preference' ),
			),
			$atts,
			'ukulele_chords'
		);

		$attributes = apply_filters( 'da_plectrum_shortcode_attributes', $attributes, $atts, $content );

		return $this->render_song( $content, $attributes );
	}

	/**
	 * Automatically process supported post content when enabled.
	 *
	 * @param string $content The current post content.
	 * @return string
	 */
	public function filter_the_content( $content ) {
		if ( ! in_the_loop() || ! is_main_query() || is_admin() ) {
			return $content;
		}

		if ( ! $this->settings->get( 'automatic_processing' ) ) {
			return $content;
		}

		$post = get_post();

		if ( ! $post instanceof \WP_Post ) {
			return $content;
		}

		$enabled_post_types = $this->settings->get( 'enabled_post_types' );

		if ( ! is_array( $enabled_post_types ) || ! in_array( $post->post_type, $enabled_post_types, true ) ) {
			return $content;
		}

		if ( has_shortcode( $content, 'ukulele_chords' ) || ! $this->contains_chord_markup( $content ) ) {
			return $content;
		}

		return $this->render_song(
			$content,
			array(
				'controls'              => $this->settings->get( 'show_controls' ) ? 'true' : 'false',
				'diagrams'              => $this->settings->get( 'enable_diagrams' ) ? 'true' : 'false',
				'transpose'             => '0',
				'print_button'          => $this->settings->get( 'enable_print_button' ) ? 'true' : 'false',
				'print_diagrams'        => $this->settings->get( 'print_show_diagrams' ) ? 'true' : 'false',
				'tuning'                => $this->settings->get( 'default_tuning' ),
				'enharmonic_preference' => $this->settings->get( 'enharmonic_preference' ),
			)
		);
	}

	/**
	 * Prime front-end assets for a specific queried post.
	 *
	 * @param \WP_Post $post Post to inspect.
	 * @return void
	 */
	private function prime_post_assets( \WP_Post $post ) {
		$content = (string) $post->post_content;

		if ( has_shortcode( $content, 'ukulele_chords' ) ) {
			$this->assets->mark_frontend_required();

			foreach ( $this->get_shortcode_tunings( $content ) as $tuning ) {
				$this->assets->mark_tuning_required( $tuning );
			}

			return;
		}

		if ( ! $this->settings->get( 'automatic_processing' ) ) {
			return;
		}

		$enabled_post_types = $this->settings->get( 'enabled_post_types' );

		if ( ! is_array( $enabled_post_types ) || ! in_array( $post->post_type, $enabled_post_types, true ) ) {
			return;
		}

		if ( ! $this->contains_chord_markup( $content ) ) {
			return;
		}

		$this->assets->mark_frontend_required();
		$this->assets->mark_tuning_required( (string) $this->settings->get( 'default_tuning' ) );
	}

	/**
	 * Render parsed song content using shared context.
	 *
	 * @param string               $content Chord-marked content.
	 * @param array<string, mixed> $attributes Render attributes.
	 * @return string
	 */
	private function render_song( $content, $attributes ) {
		++self::$instance_count;
		$instance_id = 'da-plectrum-' . self::$instance_count;
		$parsed      = $this->parser->parse( $content );
		$library     = da_plectrum_get_chord_library( $attributes['tuning'] );
		$post_id     = get_the_ID();
		$post_title  = $post_id ? get_the_title( $post_id ) : '';
		$author_id   = $post_id ? (int) get_post_field( 'post_author', $post_id ) : 0;

		$this->assets->mark_frontend_required();
		$this->assets->mark_tuning_required( $attributes['tuning'] );

		return $this->renderer->render(
			$parsed,
			array(
				'instance_id' => $instance_id,
				'attributes'  => $attributes,
				'library'     => $library,
				'settings'    => array(
					'footer_notice'          => $this->settings->get( 'print_footer_notice' ),
					'default_diagram_width'  => (int) $this->settings->get( 'default_diagram_width' ),
					'default_song_scale'     => (float) $this->settings->get( 'default_song_scale' ),
					'chord_prompt_font_size' => (int) $this->settings->get( 'chord_prompt_font_size' ),
					'block_spacing'          => (int) $this->settings->get( 'block_spacing' ),
					'section_break_spacing'  => (int) $this->settings->get( 'section_break_spacing' ),
				),
				'post'        => array(
					'id'        => $post_id,
					'title'     => $post_title,
					'author_id' => $author_id,
					'author'    => $author_id ? get_the_author_meta( 'display_name', $author_id ) : '',
					'site_name' => get_bloginfo( 'name' ),
					'year'      => gmdate( 'Y' ),
				),
			)
		);
	}

	/**
	 * Detect likely chord markup before automatic processing.
	 *
	 * @param string $content Content to inspect.
	 * @return bool
	 */
	private function contains_chord_markup( $content ) {
		return 1 === preg_match( '/\[[A-G](?:#|b)?(?:m|min|maj|sus|add|dim|aug|\+)?[^\]]*\]/', $content );
	}

	/**
	 * Extract tuning values from shortcode markup.
	 *
	 * @param string $content Raw post content.
	 * @return array<int, string>
	 */
	private function get_shortcode_tunings( $content ) {
		$tunings = array();
		$pattern = get_shortcode_regex( array( 'ukulele_chords' ) );

		if ( ! preg_match_all( "/$pattern/", $content, $matches, PREG_SET_ORDER ) ) {
			return array( 'gCEA' );
		}

		foreach ( $matches as $match ) {
			$attributes = shortcode_parse_atts( $match[3] ?? '' );
			$tuning     = isset( $attributes['tuning'] ) && is_string( $attributes['tuning'] ) && '' !== $attributes['tuning'] ? $attributes['tuning'] : 'gCEA';
			$tunings[]  = $tuning;
		}

		return array_values( array_unique( $tunings ) );
	}
}