<?php
/**
 * Icon model and renderer.
 *
 * @package KarmaDocs
 */

namespace KarmaDocs;

defined( 'ABSPATH' ) || exit;

/**
 * Icons of knowledge bases, categories and articles.
 *
 * Stored as JSON in the existing meta keys (`kdocs_icon` term meta, `_kdocs_icon`
 * post meta):
 *
 *     { "type": "icon",  "value": "rocket", "color": "#6d5efc", "bg": "soft" }
 *     { "type": "emoji", "value": "🚀" }
 *     { "type": "image", "id": 512, "url": "…" }   url is only a preview hint
 *     { "type": "svg",   "id": 513, "url": "…" }
 *     { "type": "url",   "value": "https://…" }    legacy
 *
 * Plain strings from earlier versions (an emoji, a dashicon class or an image URL)
 * keep working: parse() reads them as the matching type.
 */
class Icons {

	/**
	 * Background styles of library icons.
	 */
	const BACKGROUNDS = array( 'none', 'soft', 'solid', 'circle' );

	/**
	 * Bundled icon set (name => inner SVG), loaded once per request.
	 *
	 * @var array<string,string>|null
	 */
	private static $set = null;

	/**
	 * Path of the bundled icon set (generated by scripts/build-icons.js).
	 *
	 * @return string
	 */
	public static function file() {
		return KDOCS_PATH . 'assets/icons.json';
	}

	/**
	 * Bundled icons.
	 *
	 * @return array<string,string> Name => inner SVG markup.
	 */
	public static function set() {
		if ( null === self::$set ) {
			self::$set = array();
			$file      = self::file();
			$data      = is_readable( $file ) ? json_decode( (string) file_get_contents( $file ), true ) : null; // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
			foreach ( ( is_array( $data ) && isset( $data['icons'] ) ) ? $data['icons'] : array() as $icon ) {
				self::$set[ $icon[0] ] = $icon[1];
			}
		}
		return self::$set;
	}

	/**
	 * Whether a bundled icon exists.
	 *
	 * @param string $name Name.
	 * @return bool
	 */
	public static function exists( $name ) {
		return isset( self::set()[ (string) $name ] );
	}

	/**
	 * Reads a stored icon (JSON or legacy string) into the icon model.
	 *
	 * @param mixed $value Stored value.
	 * @return array|null Icon, or null when empty.
	 */
	public static function parse( $value ) {
		if ( is_array( $value ) ) {
			$icon = $value;
		} else {
			$value = trim( (string) $value );
			if ( '' === $value ) {
				return null;
			}
			$icon = '{' === $value[0] ? json_decode( $value, true ) : null;
			if ( ! is_array( $icon ) ) {
				if ( preg_match( '#^https?://#i', $value ) ) {
					$icon = array(
						'type'  => 'url',
						'value' => $value,
					);
				} elseif ( 0 === strpos( $value, 'dashicons-' ) ) {
					$icon = array(
						'type'  => 'dashicon',
						'value' => $value,
					);
				} else {
					$icon = array(
						'type'  => 'emoji',
						'value' => $value,
					);
				}
			}
		}
		return empty( $icon['type'] ) ? null : $icon;
	}

	/**
	 * Validates an icon coming from the admin and returns the string to store.
	 *
	 * @param mixed $value JSON string, legacy string or icon array.
	 * @return string Stored value ('' clears the icon).
	 */
	public static function sanitize( $value ) {
		$icon = self::parse( $value );
		if ( ! $icon ) {
			return '';
		}
		$clean = array( 'type' => $icon['type'] );

		switch ( $icon['type'] ) {
			case 'icon':
				$name = sanitize_key( $icon['value'] ?? '' );
				if ( ! self::exists( $name ) ) {
					return '';
				}
				$clean['value'] = $name;
				$color          = sanitize_hex_color( $icon['color'] ?? '' );
				if ( $color ) {
					$clean['color'] = $color;
				}
				if ( isset( $icon['bg'] ) && in_array( $icon['bg'], self::BACKGROUNDS, true ) && 'none' !== $icon['bg'] ) {
					$clean['bg'] = $icon['bg'];
				}
				break;

			case 'emoji':
				// A short glyph: an emoji (possibly with modifiers) or a couple of characters.
				$emoji = wp_strip_all_tags( (string) ( $icon['value'] ?? '' ) );
				$emoji = function_exists( 'mb_substr' ) ? mb_substr( $emoji, 0, 16 ) : substr( $emoji, 0, 32 );
				if ( '' === trim( $emoji ) ) {
					return '';
				}
				$clean['value'] = $emoji;
				break;

			case 'image':
			case 'svg':
				$id = absint( $icon['id'] ?? 0 );
				if ( ! $id || 'attachment' !== get_post_type( $id ) ) {
					return '';
				}
				$is_svg = 'image/svg+xml' === get_post_mime_type( $id );
				if ( ! $is_svg && ! wp_attachment_is_image( $id ) ) {
					return '';
				}
				$clean['type'] = $is_svg ? 'svg' : 'image';
				$clean['id']   = $id;
				$clean['url']  = (string) wp_get_attachment_url( $id );
				break;

			case 'url':
				$url = esc_url_raw( (string) ( $icon['value'] ?? '' ), array( 'http', 'https' ) );
				if ( ! $url ) {
					return '';
				}
				$clean['value'] = $url;
				break;

			case 'dashicon':
				$clean['value'] = sanitize_html_class( (string) ( $icon['value'] ?? '' ) );
				break;

			default:
				return '';
		}

		// Legacy plain strings stay plain strings: nothing to gain from re-encoding them.
		if ( in_array( $clean['type'], array( 'emoji', 'url', 'dashicon' ), true ) ) {
			return $clean['value'];
		}
		// No escaped slashes or unicode: update_metadata() unslashes values before storing.
		return (string) wp_json_encode( $clean, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE );
	}

	/**
	 * Inline SVG of a bundled icon.
	 *
	 * @param string $name  Icon name.
	 * @param string $class Extra class.
	 * @return string
	 */
	public static function svg( $name, $class = '' ) {
		$set = self::set();
		if ( ! isset( $set[ $name ] ) ) {
			return '';
		}
		return '<svg class="kdocs-ico-svg' . ( $class ? ' ' . esc_attr( $class ) : '' ) . '" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="24" height="24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true" focusable="false">' . $set[ $name ] . '</svg>';
	}

	/**
	 * Icon markup for the frontend.
	 *
	 * @param mixed  $value    Stored icon.
	 * @param string $fallback Built-in fallback (doc|folder|kb), or '' for none.
	 * @return string HTML.
	 */
	public static function render( $value, $fallback = 'doc' ) {
		$icon = self::parse( $value );
		$html = $icon ? self::markup( $icon ) : '';
		if ( '' === $html ) {
			return $fallback ? Frontend\View::svg( $fallback ) : '';
		}
		return $html;
	}

	/**
	 * Markup for a parsed icon.
	 *
	 * @param array $icon Icon.
	 * @return string
	 */
	private static function markup( array $icon ) {
		switch ( $icon['type'] ) {
			case 'icon':
				$svg = self::svg( (string) ( $icon['value'] ?? '' ) );
				if ( ! $svg ) {
					return '';
				}
				$bg    = isset( $icon['bg'] ) && in_array( $icon['bg'], self::BACKGROUNDS, true ) ? $icon['bg'] : 'none';
				$color = sanitize_hex_color( $icon['color'] ?? '' );
				$style = $color ? ' style="--kdocs-ico:' . esc_attr( $color ) . '"' : '';
				return '<span class="kdocs-ico kdocs-ico-bg-' . esc_attr( $bg ) . '"' . $style . '>' . $svg . '</span>';

			case 'emoji':
				return '<span class="kdocs-emoji" aria-hidden="true">' . esc_html( (string) $icon['value'] ) . '</span>';

			case 'svg':
				$inline = Svg::inline( (int) ( $icon['id'] ?? 0 ) );
				if ( $inline ) {
					return '<span class="kdocs-ico kdocs-ico-custom">' . $inline . '</span>';
				}
				// Falls through to an <img> when the file can't be inlined.

			case 'image':
				$id = (int) ( $icon['id'] ?? 0 );
				if ( ! $id || ! wp_get_attachment_url( $id ) ) {
					return '';
				}
				return wp_get_attachment_image(
					$id,
					'thumbnail',
					false,
					array(
						'class'    => 'kdocs-icon-img',
						'alt'      => '',
						'loading'  => 'lazy',
						'decoding' => 'async',
					)
				);

			case 'url':
				return '<img class="kdocs-icon-img" src="' . esc_url( (string) $icon['value'] ) . '" alt="" width="48" height="48" loading="lazy" decoding="async">';

			case 'dashicon':
				return '<span class="dashicons ' . esc_attr( (string) $icon['value'] ) . '" aria-hidden="true"></span>';
		}
		return '';
	}
}