<?php
namespace Zadex\Frontend;

defined('ABSPATH') || exit;

/**
 * Shared markup helpers for carousel widgets built on the slider runtime (src/frontend/lib/slider.ts):
 * the root `data-zx-*` options, the arrow buttons and the dots container. Mirrors
 * src/frontend/lib/slider-attrs.ts (editor previews), so render.php and Preview.vue print the same DOM.
 *
 * Settings read (same ids in every carousel manifest): slides_to_show (+ @breakpoint), slides_to_scroll, gap,
 * speed, loop, autoplay, autoplay_speed, pause_on_hover, arrows, dots.
 */
final class Slider
{
    /** Max-width breakpoints of the site (desktop is the base), `{key: px}`. */
    public static function breakpoints(): array
    {
        $all = null;
        if (class_exists('\Zadex\Plugin') && defined('ZADEX_WIDGETS_PATH')) {
            try {
                $all = \Zadex\Plugin::instance()->settings->breakpoints();
            } catch (\Throwable $e) {
                $all = null;
            }
        }
        if (!is_array($all)) {
            $all = \Zadex\Settings::default_breakpoints();
        }
        $out = [];
        foreach ($all as $key => $bp) {
            if ($key === 'desktop' || !is_array($bp) || empty($bp['enabled']) || ($bp['direction'] ?? 'max') !== 'max') {
                continue;
            }
            $out[$key] = (int) ($bp['value'] ?? 0);
        }
        return $out;
    }

    /**
     * Slides per view per breakpoint, `{desktop: n, tablet?: n, mobile?: n}`.
     *
     * @param array<string, mixed> $settings
     * @param array<string, int>   $breakpoints
     */
    public static function slides(array $settings, array $breakpoints, int $fallback = 3): array
    {
        $out = ['desktop' => max(1, (int) ($settings['slides_to_show'] ?? $fallback) ?: $fallback)];
        foreach (array_keys($breakpoints) as $key) {
            $v = $settings['slides_to_show@' . $key] ?? null;
            if (is_numeric($v) && (int) $v > 0) {
                $out[$key] = (int) $v;
            }
        }
        return $out;
    }

    /**
     * Adds the slider class, options and layout variables to a widget's root attribute string.
     *
     * @param array<string, mixed> $settings
     * @param array{classes?: string[], slides?: array<string,int>, loop?: bool, extra?: array<string,string>, style?: string} $opts
     */
    public static function attrs(string $attrs, array $settings, array $opts = []): string
    {
        $breakpoints = self::breakpoints();
        $slides = $opts['slides'] ?? self::slides($settings, $breakpoints);
        $gap_value = $settings['gap'] ?? ['size' => 20, 'unit' => 'px'];
        $gap = max(0, is_array($gap_value) ? (int) ($gap_value['size'] ?? 0) : (int) $gap_value);
        $autoplay = !empty($settings['autoplay']) ? max(500, (int) ($settings['autoplay_speed'] ?? 4000)) : 0;
        $loop = array_key_exists('loop', $opts) ? (bool) $opts['loop'] : !empty($settings['loop']);
        $classes = trim('zx-slider ' . implode(' ', array_map('sanitize_html_class', $opts['classes'] ?? [])));

        $attrs = (string) preg_replace('/class="/', 'class="' . $classes . ' ', $attrs, 1);
        $attrs .= ' data-zx-slides="' . esc_attr((string) wp_json_encode($slides)) . '"';
        $attrs .= ' data-zx-breakpoints="' . esc_attr((string) wp_json_encode((object) $breakpoints)) . '"';
        $attrs .= ' data-zx-scroll="' . max(1, (int) ($settings['slides_to_scroll'] ?? 1)) . '" data-zx-gap="' . $gap . '" data-zx-speed="' . max(0, (int) ($settings['speed'] ?? 400)) . '"';
        $attrs .= ' data-zx-loop="' . ($loop ? 'true' : 'false') . '" data-zx-autoplay="' . ($autoplay ?: 'false') . '" data-zx-pause="' . (($settings['pause_on_hover'] ?? true) ? 'true' : 'false') . '"';
        $attrs .= ' data-zx-arrows="' . (!empty($settings['arrows']) ? 'true' : 'false') . '" data-zx-dots="' . (!empty($settings['dots']) ? 'true' : 'false') . '"';
        foreach ($opts['extra'] ?? [] as $name => $value) {
            $attrs .= ' ' . preg_replace('/[^a-z0-9\-]/', '', strtolower((string) $name)) . '="' . esc_attr((string) $value) . '"';
        }
        $attrs .= ' style="--zx-spv:' . (int) $slides['desktop'] . ';--zx-gap:' . $gap . 'px' . (isset($opts['style']) ? ';' . esc_attr($opts['style']) : '') . '"';
        return $attrs;
    }

    /** Previous / next buttons (`<prefix>__arrow`), theme-shielded (has-text-color has-background). */
    public static function arrows(string $prefix): string
    {
        $p = sanitize_html_class($prefix);
        $svg = static fn(string $d): string => '<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"><path d="' . $d . '"/></svg>';
        return '<button type="button" class="' . $p . '__arrow ' . $p . '__arrow--prev zx-slider__prev has-text-color has-background" aria-label="' . esc_attr__('Previous slide', 'zadex') . '">' . $svg('m15 18-6-6 6-6') . '</button>'
            . '<button type="button" class="' . $p . '__arrow ' . $p . '__arrow--next zx-slider__next has-text-color has-background" aria-label="' . esc_attr__('Next slide', 'zadex') . '">' . $svg('m9 18 6-6-6-6') . '</button>';
    }

    public static function dots(string $prefix): string
    {
        return '<div class="' . sanitize_html_class($prefix) . '__dots zx-slider__dots"></div>';
    }
}