<?php
namespace Zadex\Forms;

defined('ABSPATH') || exit;

/**
 * Field definitions of a Form widget, normalised from its `fields` repeater. Twin of widgets/form/fields.ts:
 * same ids, option parsing and step grouping, so the markup, the browser checks and the server checks agree.
 */
final class Fields
{
    public const TYPES = ['text', 'email', 'textarea', 'tel', 'number', 'date', 'time', 'select', 'radio', 'checkbox', 'acceptance', 'upload', 'password', 'hidden', 'html', 'step'];
    /** Types that never carry a submitted value. */
    public const NO_VALUE = ['html', 'step'];
    public const WIDTHS = ['100', '50', '33', '25'];

    public static function sanitize_id($raw): string
    {
        $id = strtolower(is_scalar($raw) ? (string) $raw : '');
        return substr(preg_replace('/[^a-z0-9_\-]/', '', $id) ?? '', 0, 40);
    }

    /**
     * `value|label` per line (or just `label`).
     *
     * @return array<int, array{value: string, label: string}>
     */
    public static function parse_options($raw): array
    {
        $out = [];
        foreach (preg_split('/\r?\n/', is_scalar($raw) ? (string) $raw : '') ?: [] as $line) {
            $line = trim($line);
            if ($line === '') {
                continue;
            }
            $bar = strpos($line, '|');
            if ($bar !== false) {
                $value = trim(substr($line, 0, $bar));
                $label = trim(substr($line, $bar + 1));
                $out[] = ['value' => $value, 'label' => $label !== '' ? $label : $value];
            } else {
                $out[] = ['value' => $line, 'label' => $line];
            }
        }
        return $out;
    }

    /**
     * @param mixed $raw repeater value
     * @return array<int, array<string, mixed>>
     */
    public static function normalize($raw): array
    {
        $out = [];
        $used = [];
        $str = static fn($v): string => is_scalar($v) ? (string) $v : '';
        foreach (is_array($raw) ? array_values($raw) : [] as $i => $item) {
            if (!is_array($item)) {
                continue;
            }
            $type = in_array($item['type'] ?? '', self::TYPES, true) ? (string) $item['type'] : 'text';
            $id = self::sanitize_id($item['custom_id'] ?? '');
            if ($id === '') {
                $id = self::sanitize_id($item['_id'] ?? '');
            }
            if ($id === '') {
                $id = 'field_' . ($i + 1);
            }
            if (isset($used[$id])) {
                $n = 2;
                while (isset($used[$id . '_' . $n])) {
                    $n++;
                }
                $id .= '_' . $n;
            }
            $used[$id] = true;
            $max_size = isset($item['max_size']) && is_numeric($item['max_size']) && (float) $item['max_size'] > 0 ? (float) $item['max_size'] : 5.0;
            $rows = isset($item['rows']) && is_numeric($item['rows']) && (int) $item['rows'] > 0 ? min(30, (int) $item['rows']) : 4;
            $out[] = [
                'id'              => $id,
                'type'            => $type,
                'label'           => $str($item['label'] ?? ''),
                'placeholder'     => $str($item['placeholder'] ?? ''),
                'required'        => !empty($item['required']) && !in_array($type, ['html', 'step', 'hidden'], true),
                'width'           => in_array((string) ($item['width'] ?? ''), self::WIDTHS, true) ? (string) $item['width'] : '100',
                'options'         => self::parse_options($item['options'] ?? ''),
                'default'         => $str($item['default'] ?? ''),
                'min'             => $str($item['min'] ?? ''),
                'max'             => $str($item['max'] ?? ''),
                'step'            => $str($item['step'] ?? ''),
                'accept'          => $str($item['accept'] ?? ''),
                'max_size'        => $max_size,
                'multiple'        => !empty($item['multiple']),
                'rows'            => $rows,
                'html'            => $str($item['html'] ?? ''),
                'acceptance_text' => $str($item['acceptance_text'] ?? ''),
            ];
        }
        return $out;
    }

    /**
     * Groups fields into steps: every `step` item starts one (its label is the title); fields placed before
     * the first step item form an untitled first step. Without step items there is a single step.
     *
     * @param array<int, array<string, mixed>> $fields
     * @return array<int, array{index: int, title: string, fields: array<int, array<string, mixed>>}>
     */
    public static function steps(array $fields): array
    {
        $steps = [];
        $open = false;
        foreach ($fields as $field) {
            if ($field['type'] === 'step') {
                $steps[] = ['index' => count($steps), 'title' => (string) $field['label'], 'fields' => []];
                $open = true;
                continue;
            }
            if (!$open) {
                $steps[] = ['index' => count($steps), 'title' => '', 'fields' => []];
                $open = true;
            }
            $steps[count($steps) - 1]['fields'][] = $field;
        }
        if (!$steps) {
            $steps[] = ['index' => 0, 'title' => '', 'fields' => []];
        }
        return $steps;
    }

    /**
     * Fields that carry a value (no html / step), keyed by id.
     *
     * @param array<int, array<string, mixed>> $fields
     * @return array<string, array<string, mixed>>
     */
    public static function inputs(array $fields): array
    {
        $out = [];
        foreach ($fields as $field) {
            if (!in_array($field['type'], self::NO_VALUE, true)) {
                $out[(string) $field['id']] = $field;
            }
        }
        return $out;
    }
}