<?php
/**
 * Public Agent Panel Registry
 *
 * Collects the settings panels every public chat integration offers. An
 * integration adds itself through the `aisentic_public_agent_panels` filter and
 * describes its fields as plain data, so the admin UI can draw the panel
 * without any integration-specific React code.
 *
 * @package Aisentic\PublicAgent
 */

declare(strict_types=1);

namespace Aisentic\PublicAgent;

defined( 'ABSPATH' ) || exit;

/**
 * Panel registry class
 */
class Panel_Registry {

	/**
	 * Filter integrations hook into to add a panel.
	 *
	 * @var string
	 */
	const FILTER = 'aisentic_public_agent_panels';

	// Icons the storefront knows how to draw for a topic card.
	const TOPIC_ICONS = [ 'calendar', 'bag', 'ticket', 'chat' ];

	/**
	 * Memoized normalized panels. Null means "not built yet".
	 *
	 * @var array|null
	 */
	private static ?array $panels = null;

	/**
	 * Drop the memoized panel list.
	 *
	 * Only needed by tests and by code that adds a panel after the first read.
	 *
	 * @return void
	 */
	public static function reset(): void {
		self::$panels = null;
	}

	/**
	 * Get every registered panel, keyed by id.
	 *
	 * @return array
	 */
	public static function get_panels(): array {
		if ( null !== self::$panels ) {
			return self::$panels;
		}

		// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.DynamicHooknameFound -- self::FILTER is the literal 'aisentic_public_agent_panels'; phpcs cannot resolve the constant.
		$raw  = apply_filters( self::FILTER, [] );
		$list = [];

		if ( is_array( $raw ) ) {
			foreach ( $raw as $id => $panel ) {
				$normalized = self::normalize( (string) $id, $panel );

				if ( null !== $normalized ) {
					$list[ (string) $id ] = $normalized;
				}
			}
		}

		self::$panels = $list;

		return self::$panels;
	}

	/**
	 * Get only the panels whose plugin is installed and active.
	 *
	 * @return array
	 */
	public static function get_active_panels(): array {
		return array_filter(
			self::get_panels(),
			fn( array $panel ): bool => (bool) call_user_func( $panel['available'] )
		);
	}

	/**
	 * Get one panel by id.
	 *
	 * @param string $id Panel id.
	 * @return array|null
	 */
	public static function get_panel( string $id ): ?array {
		$panels = self::get_panels();

		return $panels[ $id ] ?? null;
	}

	/**
	 * The fixed schema for the global widget settings.
	 *
	 * These belong to the core plugin, not to any integration, because the site
	 * shows a single chat widget.
	 *
	 * @return array
	 */
	public static function get_widget_schema(): array {
		return [
			'botName'             => [
				'type'    => 'text',
				'label'   => __( 'Assistant Name', 'aisentic' ),
				'help'    => __( 'Displayed name in the chat widget header.', 'aisentic' ),
				'default' => 'AI Assistant',
			],
			'headline'            => [
				'type'    => 'text',
				'label'   => __( 'Welcome Headline', 'aisentic' ),
				'help'    => __( 'Shown as the first message when a visitor opens the chat.', 'aisentic' ),
				'default' => 'How can I help you today?',
			],
			// Empty defaults so an untouched field keeps following the site language;
			// the widget fills in the translated text.
			'greeting'            => [
				'type'        => 'text',
				'label'       => __( 'Greeting', 'aisentic' ),
				'help'        => __( 'The big first line in the chat and the pop-up. Leave empty to use the default, translated for your site language.', 'aisentic' ),
				'default'     => '',
				'placeholder' => __( 'Hi there,', 'aisentic' ),
				// Two lines in the header on a phone.
				'maxChars'    => 50,
			],
			'inputPlaceholder'    => [
				'type'        => 'text',
				'label'       => __( 'Message Box Hint', 'aisentic' ),
				'help'        => __( 'Grey text in the empty message box. Leave empty to use the default, translated for your site language.', 'aisentic' ),
				'default'     => '',
				'placeholder' => __( 'Ask me anything…', 'aisentic' ),
				// Two lines in the message box on a phone.
				'maxChars'    => 70,
			],
			// A media library attachment id. Localize turns it into the thumbnail link.
			'avatarId'            => [
				'type'    => 'image',
				'label'   => __( 'Assistant Avatar', 'aisentic' ),
				'help'    => __( 'A square image shown beside the name, like your logo. Empty shows the robot icon.', 'aisentic' ),
				'default' => 0,
			],
			'brandColor'          => [
				'type'    => 'color',
				'label'   => __( 'Brand Color', 'aisentic' ),
				'help'    => __( 'Accent color for the chat widget. Empty uses the default violet.', 'aisentic' ),
				'default' => '',
			],
			'position'            => [
				'type'    => 'select',
				'label'   => __( 'Widget Position', 'aisentic' ),
				'help'    => __( 'Which corner the chat launcher sits in.', 'aisentic' ),
				'options' => [
					'bottom-right' => __( 'Bottom Right', 'aisentic' ),
					'bottom-left'  => __( 'Bottom Left', 'aisentic' ),
				],
				'default' => 'bottom-right',
			],
			'rateLimitPerHour'    => [
				'type'    => 'number',
				'label'   => __( 'Rate Limit (per hour)', 'aisentic' ),
				'help'    => __( 'Max messages per visitor per hour. Prevents abuse of your API quota.', 'aisentic' ),
				'min'     => 1,
				'default' => 20,
			],
			'maxToolCallsPerTurn' => [
				'type'    => 'number',
				'label'   => __( 'Max Tool Calls', 'aisentic' ),
				'help'    => __( 'Max AI tool calls per conversation turn. Higher values use more tokens.', 'aisentic' ),
				'min'     => 1,
				'default' => 3,
			],
		];
	}

	/**
	 * Turn one raw panel declaration into the canonical shape.
	 *
	 * @param string $id    Panel id.
	 * @param mixed  $panel Raw declaration from the filter.
	 * @return array|null Null when the declaration is unusable.
	 */
	private static function normalize( string $id, $panel ): ?array {
		if ( '' === $id || ! is_array( $panel ) ) {
			return null;
		}

		if ( empty( $panel['fields'] ) || ! is_array( $panel['fields'] ) ) {
			return null;
		}

		$fields = [
			'enabled' => [
				'type'    => 'toggle',
				'label'   => __( 'Enabled', 'aisentic' ),
				'help'    => '',
				'default' => false,
			],
		];

		foreach ( $panel['fields'] as $key => $field ) {
			$key = (string) $key;

			// The registry owns `enabled`; a panel may not redefine it.
			if ( 'enabled' === $key || ! is_array( $field ) || empty( $field['type'] ) ) {
				continue;
			}

			$field['type']  = (string) $field['type'];
			$field['label'] = isset( $field['label'] ) ? (string) $field['label'] : $key;
			$field['help']  = isset( $field['help'] ) ? (string) $field['help'] : '';

			if ( ! array_key_exists( 'default', $field ) ) {
				$field['default'] = null;
			}

			$fields[ $key ] = $field;
		}

		$available = isset( $panel['available'] ) && is_callable( $panel['available'] )
			? $panel['available']
			: fn(): bool => true;

		return [
			'id'        => $id,
			'label'     => isset( $panel['label'] ) ? (string) $panel['label'] : $id,
			'icon'      => isset( $panel['icon'] ) ? (string) $panel['icon'] : 'plug',
			'slot'      => isset( $panel['slot'] ) ? (string) $panel['slot'] : '',
			// "Read more" on the panel's card. Only a web link, never a script.
			'docs'      => isset( $panel['docs'] ) && preg_match( '#^https?://#i', (string) $panel['docs'] ) ? esc_url_raw( (string) $panel['docs'] ) : '',
			'available' => $available,
			'fields'    => $fields,
			'topic'     => self::normalize_topic( $panel['topic'] ?? null ),
		];
	}

	/**
	 * The storefront topic card a panel declares, in a safe shape.
	 *
	 * @param mixed $topic Raw `topic` declaration.
	 * @return array|null Null when there is no usable label.
	 */
	private static function normalize_topic( $topic ): ?array {
		if ( ! is_array( $topic ) || ! is_string( $topic['label'] ?? null ) || '' === trim( $topic['label'] ) ) {
			return null;
		}

		$icon = (string) ( $topic['icon'] ?? '' );

		return [
			'label'        => trim( $topic['label'] ),
			'description'  => is_string( $topic['description'] ?? null ) ? trim( $topic['description'] ) : '',
			'icon'         => in_array( $icon, self::TOPIC_ICONS, true ) ? $icon : 'chat',
			'matches_page' => isset( $topic['matches_page'] ) && is_callable( $topic['matches_page'] ) ? $topic['matches_page'] : null,
		];
	}
}