<?php
/**
 * Registry of built-in and custom viewer themes.
 *
 * @package BreznFlow
 * @since   1.0.0
 */

namespace BreznFlow\Features;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Manages built-in and custom visual themes for the workflow renderer.
 *
 * @since 1.0.0
 */
class ThemeRegistry {

	/**
	 * Built-in theme IDs and display names.
	 * IDs are used as CSS data-theme attribute values and as stylesheet handles.
	 */
	const BUILTIN = array(
		'dark'    => 'Dark',
		'light'   => 'Light',
		'minimal' => 'Minimal',
		'tech'    => 'Tech',
		'brezn'   => 'Brezn',
	);

	/**
	 * Returns all available themes (built-in + custom) as:
	 * [ 'id' => ['name' => string, 'custom' => bool], ... ]
	 *
	 * @return array<string, array{name: string, custom: bool}>
	 */
	public static function discover(): array {
		$themes = array();

		foreach ( self::BUILTIN as $id => $name ) {
			$themes[ $id ] = array(
				'name'   => $name,
				'custom' => false,
			);
		}

		$customs = get_option( 'breznflow_custom_themes', array() );
		foreach ( $customs as $theme ) {
			$themes[ $theme['id'] ] = array(
				'name'   => $theme['name'],
				'custom' => true,
			);
		}

		return $themes;
	}

	/**
	 * Returns all theme IDs as a flat array.
	 *
	 * @return string[]
	 */
	public static function get_theme_ids(): array {
		return array_keys( self::discover() );
	}

	/**
	 * Returns the URL to a built-in theme CSS file.
	 *
	 * @param string $id Built-in theme ID.
	 * @return string
	 */
	public static function get_builtin_url( string $id ): string {
		return BREZNFLOW_URL . 'assets/themes/' . sanitize_key( $id ) . '.css';
	}

	/**
	 * Generates a CSS block for all custom themes, suitable for wp_add_inline_style().
	 * Tokens are mapped: token_name → --breznflow-token-name
	 *
	 * @return string CSS string (empty if no custom themes stored).
	 */
	public static function get_custom_theme_css(): string {
		$themes = get_option( 'breznflow_custom_themes', array() );
		$css    = '';

		foreach ( $themes as $theme ) {
			$id  = $theme['id'];
			$sel = '.breznflow-wrap[data-theme="' . $id . '"],'
				. '.breznflow-modal-overlay[data-theme="' . $id . '"],'
				. '.breznflow-fs-portal[data-theme="' . $id . '"]';

			$css .= $sel . '{';
			foreach ( $theme['tokens'] as $token => $value ) {
				$var  = '--breznflow-' . str_replace( '_', '-', $token );
				$css .= $var . ':' . $value . ';';
			}
			$css .= '}';
		}

		return $css;
	}
}