<?php

declare(strict_types=1);

namespace FlexaLocal\Core;

use FlexaLocal\Support\Capabilities;

defined( 'ABSPATH' ) || exit;

/**
 * Base for every Core content type (CPT). A subclass declares its slug, labels
 * and meta fields; this class handles register_post_type + register_post_meta
 * with the shared conventions (menu grouping, REST exposure, fxlc_ meta prefix).
 *
 * Field config shape (keyed by the unprefixed meta key):
 *   [
 *     'label'    => string,   // admin control label
 *     'tab'      => string,   // General|Content|Media|SEO|Settings
 *     'control'  => string,   // text|textarea|number|url|email|image|select|post
 *     'rest_type'=> string,   // string|number|integer|boolean  (default string)
 *     'default'  => mixed,    // default value (default '')
 *     'sanitize' => callable-string, // sanitize callback (default sanitize_text_field)
 *     'options'  => array<string,string>, // for control=select
 *     'post_type'=> string,   // for control=post: the type listed; see post_field()
 *   ]
 */
abstract class AbstractPostType {

	/**
	 * The post type slug, e.g. `fxlc_service` (max 20 chars, fxlc_ prefixed).
	 */
	abstract public function type(): string;

	/**
	 * @return array{singular:string,plural:string,menu?:string}
	 */
	abstract protected function labels(): array;

	/**
	 * Meta fields for this type, keyed by unprefixed key.
	 *
	 * @return array<string,array<string,mixed>>
	 */
	abstract public function fields(): array;

	/**
	 * Per-type register_post_type overrides merged over the shared defaults.
	 *
	 * @return array<string,mixed>
	 */
	protected function args(): array {
		return [];
	}

	public function register(): void {
		register_post_type( $this->type(), $this->build_args() );
		$this->register_meta();
	}

	/**
	 * Fully-qualified meta key for an unprefixed field key.
	 */
	public function meta_key( string $field ): string {
		return 'fxlc_' . $field;
	}

	/**
	 * A field that points at one post of another type, stored as its ID and
	 * picked by name from a dropdown in the Details box.
	 *
	 * The sanitizer keeps an ID only when it is a post of that type, so a
	 * typo or a page's ID saved through REST is stored as 0 ("none") instead
	 * of quietly pointing somewhere else.
	 *
	 * @return array<string,mixed>
	 */
	protected static function post_field( string $label, string $post_type, string $tab = 'Settings' ): array {
		return [
			'label'     => $label,
			'tab'       => $tab,
			'control'   => 'post',
			'post_type' => $post_type,
			'rest_type' => 'integer',
			'default'   => 0,
			'sanitize'  => static function ( mixed $value ) use ( $post_type ): int {
				$id = is_numeric( $value ) ? absint( $value ) : 0;

				return $id > 0 && get_post_type( $id ) === $post_type ? $id : 0;
			},
		];
	}

	/**
	 * An image from the media library, stored as its attachment ID.
	 *
	 * @return array<string,mixed>
	 */
	protected static function image_field( string $label, string $tab = 'Media' ): array {
		return [
			'label'     => $label,
			'tab'       => $tab,
			'control'   => 'image',
			'rest_type' => 'integer',
			'default'   => 0,
			'sanitize'  => static fn( $v ): int => absint( $v ),
		];
	}

	/**
	 * A number that may have decimals: a price, a cost, a coordinate.
	 *
	 * @return array<string,mixed>
	 */
	protected static function decimal_field( string $label, string $tab = 'General' ): array {
		return [
			'label'     => $label,
			'tab'       => $tab,
			'control'   => 'number',
			'rest_type' => 'number',
			'default'   => 0,
			'sanitize'  => static fn( $v ): float => (float) $v,
		];
	}

	/**
	 * A link, kept only when it is a URL WordPress would print.
	 *
	 * @return array<string,mixed>
	 */
	protected static function url_field( string $label, string $tab = 'General' ): array {
		return [
			'label'    => $label,
			'tab'      => $tab,
			'control'  => 'url',
			'sanitize' => 'esc_url_raw',
		];
	}

	/**
	 * @return array<string,mixed>
	 */
	private function build_args(): array {
		$labels   = $this->labels();
		$singular = $labels['singular'];
		$plural   = $labels['plural'];

		$defaults = [
			'labels'        => [
				'name'               => $plural,
				'singular_name'      => $singular,
				/* translators: %s: singular post type label. */
				'add_new_item'       => sprintf( __( 'Add New %s', 'flexa-local-services' ), $singular ),
				/* translators: %s: singular post type label. */
				'edit_item'          => sprintf( __( 'Edit %s', 'flexa-local-services' ), $singular ),
				/* translators: %s: singular post type label. */
				'new_item'           => sprintf( __( 'New %s', 'flexa-local-services' ), $singular ),
				/* translators: %s: singular post type label. */
				'view_item'          => sprintf( __( 'View %s', 'flexa-local-services' ), $singular ),
				/* translators: %s: plural post type label. */
				'view_items'         => sprintf( __( 'View %s', 'flexa-local-services' ), $plural ),
				/* translators: %s: plural post type label. */
				'search_items'       => sprintf( __( 'Search %s', 'flexa-local-services' ), $plural ),
				// The plural keeps its case: lower-casing it breaks names like "FAQs".
				/* translators: %s: plural post type label. */
				'not_found'          => sprintf( __( 'No %s found.', 'flexa-local-services' ), $plural ),
				/* translators: %s: plural post type label. */
				'not_found_in_trash' => sprintf( __( 'No %s found in Trash.', 'flexa-local-services' ), $plural ),
				'all_items'          => $plural,
				'menu_name'          => $labels['menu'] ?? $plural,
			],
			'public'        => true,
			'show_ui'       => true,
			'show_in_menu'  => 'flexa-local',
			'show_in_rest'  => true,
			'has_archive'   => true,
			'hierarchical'  => false,
			'menu_position' => null,
			'supports'      => [ 'title', 'editor', 'thumbnail', 'excerpt' ],
			'rewrite'       => [ 'slug' => str_replace( 'fxlc_', '', $this->type() ) ],
		];

		$overrides = $this->args();

		/** @var array<string,mixed> $args */
		$args = array_replace_recursive( $defaults, $overrides );

		// A list such as `supports` replaces the default one whole. Merged by
		// index, a shorter list would keep the default's tail entries.
		foreach ( $overrides as $key => $value ) {
			if ( is_array( $value ) && array_values( $value ) === $value ) {
				$args[ $key ] = $value;
			}
		}

		return $args;
	}

	private function register_meta(): void {
		foreach ( $this->fields() as $field => $config ) {
			$rest_type = is_string( $config['rest_type'] ?? null ) ? $config['rest_type'] : 'string';
			$sanitize  = is_callable( $config['sanitize'] ?? null ) ? $config['sanitize'] : 'sanitize_text_field';

			register_post_meta(
				$this->type(),
				$this->meta_key( (string) $field ),
				[
					'type'              => $rest_type,
					'single'            => true,
					'default'           => $config['default'] ?? '',
					'show_in_rest'      => true,
					'sanitize_callback' => $sanitize,

					/*
					 * WordPress passes the post this meta belongs to, so the
					 * answer can be about that post instead of the plugin in
					 * general. Core checks `edit_post` before it gets here on
					 * its own routes; saying so again costs nothing and holds
					 * for anything that writes meta by another path.
					 */
					'auth_callback'     => static fn( bool $allowed, string $meta_key, int $object_id ): bool =>
						Capabilities::can_manage() && current_user_can( 'edit_post', $object_id ),
				]
			);
		}
	}
}