<?php

declare(strict_types=1);

namespace FlexaLocal\Blocks;

use FlexaLocal\Forms\Domain\FormRepository;
use FlexaLocal\Forms\FrontendForm;
use FlexaLocal\Support\Settings;
use FlexaLocal\Support\SingletonTrait;

defined( 'ABSPATH' ) || exit;

/**
 * Registers every block under app/Blocks/* from its block.json (single source of
 * truth). Blocks are server-rendered (render.php) for SEO + theme independence;
 * the shared editor script previews them with ServerSideRender (docs/06).
 */
final class BlockRegistry {

	use SingletonTrait;

	private const HANDLE      = 'fxlc-blocks';
	private const FORM_HANDLE = 'fxlc-form';

	public function register(): void {
		wp_register_script(
			self::HANDLE,
			FXLC_URL . 'assets/js/blocks.js',
			[ 'wp-blocks', 'wp-element', 'wp-block-editor', 'wp-components', 'wp-server-side-render', 'wp-i18n', 'wp-data' ],
			FXLC_VERSION,
			true
		);
		wp_register_style( self::HANDLE, FXLC_URL . 'assets/css/blocks.css', [], FXLC_VERSION );

		$brand = $this->brand_properties();
		if ( '' !== $brand ) {
			wp_add_inline_style( self::HANDLE, $brand );
		}

		// Front-end form submitter. Registered (not enqueued) here; FrontendForm
		// pulls it in only on pages that actually render a form.
		wp_register_script(
			self::FORM_HANDLE,
			FXLC_URL . 'assets/js/form.js',
			[],
			FXLC_VERSION,
			true
		);
		wp_localize_script( self::FORM_HANDLE, 'fxlcForm', FrontendForm::script_data() );

		$config = [];
		foreach ( $this->block_dirs() as $dir ) {
			register_block_type( $dir );
			$meta = $this->read_meta( $dir . '/block.json' );
			if ( null !== $meta ) {
				$config[] = $meta;
			}
		}

		wp_localize_script(
			self::HANDLE,
			'fxlcBlocks',
			[
				'blocks' => $config,
				'lists'  => [
					'forms'         => $this->form_options(),
					'heroVariants'  => [
						[
							'label' => __( 'Full: the opening of the home page', 'flexa-local-services' ),
							'value' => 'full',
						],
						[
							'label' => __( 'Compact: the opening of an inner page', 'flexa-local-services' ),
							'value' => 'compact',
						],
					],
					'serviceScopes' => [
						[
							'label' => __( 'Any service', 'flexa-local-services' ),
							'value' => '',
						],
						[
							'label' => __( 'Only the service being viewed', 'flexa-local-services' ),
							'value' => 'current',
						],
					],
					'areaScopes'    => [
						[
							'label' => __( 'Any area', 'flexa-local-services' ),
							'value' => '',
						],
						[
							'label' => __( 'Only the area being viewed', 'flexa-local-services' ),
							'value' => 'current',
						],
					],
					'areaLayouts'   => [
						[
							'label' => __( 'Cards', 'flexa-local-services' ),
							'value' => 'cards',
						],
						[
							'label' => __( 'List', 'flexa-local-services' ),
							'value' => 'list',
						],
						[
							'label' => __( 'Compact', 'flexa-local-services' ),
							'value' => 'compact',
						],
					],
				],
			]
		);
	}

	/**
	 * Options for the form picker in the editor. Loaded only in the admin: a
	 * visitor's page has no business querying the forms table.
	 *
	 * @return list<array{label:string,value:int}>
	 */
	private function form_options(): array {
		if ( ! is_admin() ) {
			return [];
		}

		$options = [
			[
				'label' => __( 'Select a form', 'flexa-local-services' ),
				'value' => 0,
			],
		];

		foreach ( ( new FormRepository() )->all( 1, 100 ) as $form ) {
			$options[] = [
				'label' => '' !== $form->name ? $form->name : sprintf( /* translators: %d: form id. */ __( 'Form #%d', 'flexa-local-services' ), $form->id ),
				'value' => $form->id,
			];
		}

		return $options;
	}

	/**
	 * Add the "Flexa Local" block category.
	 *
	 * @param array<int,array<string,mixed>> $categories
	 * @return array<int,array<string,mixed>>
	 */
	public function category( array $categories ): array {
		array_unshift(
			$categories,
			[
				'slug'  => 'flexa-local',
				'title' => __( 'Flexa Local', 'flexa-local-services' ),
				'icon'  => null,
			]
		);

		return $categories;
	}

	/**
	 * The two brand colors from Settings, pushed into the custom properties the
	 * block stylesheet already reads. Without this the color pickers would be a
	 * setting that changes nothing on the front end.
	 *
	 * The text colour on a primary button comes with it: dark on a light brand
	 * colour, white on a dark one. CSS cannot pick between the two yet, and a
	 * fixed choice fails one half of the colours an owner might choose.
	 */
	private function brand_properties(): string {
		/** @var array<string,mixed> $colors */
		$colors    = (array) Settings::get( 'colors', [] );
		$primary   = (string) sanitize_hex_color( (string) ( $colors['primary'] ?? '' ) );
		$secondary = (string) sanitize_hex_color( (string) ( $colors['secondary'] ?? '' ) );

		$rules = [];
		if ( '' !== $primary ) {
			$rules[] = '--fxlc-primary:' . $primary . ';';
			$rules[] = '--fxlc-on-primary:' . self::text_on( $primary ) . ';';
		}
		if ( '' !== $secondary ) {
			$rules[] = '--fxlc-accent:' . $secondary . ';';
		}

		return [] === $rules ? '' : ':root{' . implode( '', $rules ) . '}';
	}

	/**
	 * White or near-black, whichever reads better on $hex (WCAG contrast).
	 */
	private static function text_on( string $hex ): string {
		$dark = '#1c1917';

		$hex = ltrim( $hex, '#' );
		if ( 3 === strlen( $hex ) ) {
			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
		}

		$luminance = static function ( string $rgb ): float {
			$channels = [];
			foreach ( str_split( $rgb, 2 ) as $pair ) {
				$c          = hexdec( $pair ) / 255;
				$channels[] = $c <= 0.03928 ? $c / 12.92 : ( ( $c + 0.055 ) / 1.055 ) ** 2.4;
			}

			return 0.2126 * $channels[0] + 0.7152 * $channels[1] + 0.0722 * $channels[2];
		};

		$bg       = $luminance( $hex );
		$on_white = 1.05 / ( $bg + 0.05 );
		$on_dark  = ( $bg + 0.05 ) / ( $luminance( ltrim( $dark, '#' ) ) + 0.05 );

		return $on_white >= $on_dark ? '#ffffff' : $dark;
	}

	/**
	 * @return list<string>
	 */
	private function block_dirs(): array {
		$dirs = glob( FXLC_PATH . 'app/Blocks/*', GLOB_ONLYDIR );
		if ( false === $dirs ) {
			return [];
		}

		$out = [];
		foreach ( $dirs as $dir ) {
			if ( is_readable( $dir . '/block.json' ) ) {
				$out[] = $dir;
			}
		}

		return $out;
	}

	/**
	 * Pull the editor config (name/title/icon/attributes/controls) from block.json.
	 *
	 * @return array<string,mixed>|null
	 */
	private function read_meta( string $file ): ?array {
		$json = wp_json_file_decode( $file, [ 'associative' => true ] );
		if ( ! is_array( $json ) || ! isset( $json['name'] ) ) {
			return null;
		}

		$fxlc = is_array( $json['fxlc'] ?? null ) ? $json['fxlc'] : [];

		return [
			'name'       => (string) $json['name'],
			'title'      => (string) ( $json['title'] ?? $json['name'] ),
			'category'   => (string) ( $json['category'] ?? 'flexa-local' ),
			'icon'       => (string) ( $json['icon'] ?? 'location-alt' ),
			'attributes' => is_array( $json['attributes'] ?? null ) ? $json['attributes'] : [],
			'controls'   => is_array( $fxlc['controls'] ?? null ) ? $fxlc['controls'] : [],
			// A line at the top of the panel, for a block whose content comes
			// from somewhere other than its own settings.
			'help'       => is_string( $fxlc['help'] ?? null ) ? $fxlc['help'] : '',
		];
	}
}