<?php

namespace App\Support;

use App\Models\Customer;

final class MailPlaceholders
{
    public const PATTERN = '/\{\{\s*\$?([a-zA-Z_][a-zA-Z0-9_]*)\s*\}\}/';

    private const CONDITIONAL = '/\{\{\s*#if\s+([a-zA-Z_][a-zA-Z0-9_]*)\s*\}\}(.*?)(?:\{\{\s*else\s*\}\}(.*?))?\{\{\s*\/if\s*\}\}/s';

    private const LAYOUT_SLOT = 'content';

    public const RECIPIENT_FIELDS = [
        'client_name'    => 'name',
        'customer_name'  => 'name',
        'full_name'      => 'name',
        'fullname'       => 'name',
        'name'           => 'name',
        'customer_email' => 'email',
        'email'          => 'email',
        'account_email'  => 'email',
        'customer_phone' => 'phone',
        'phone'          => 'phone',
    ];

    /**
     * @return array<int, string>
     */
    public static function extract(?string ...$contents): array
    {
        preg_match_all(self::PATTERN, implode("\n", array_map('strval', $contents)), $matches);

        return array_values(array_diff(array_unique($matches[1]), [self::LAYOUT_SLOT, 'else']));
    }

    /**
     * @param array<string, string|null> $values
     */
    public static function resolveConditionals(string $content, array $values): string
    {
        return preg_replace_callback(
            self::CONDITIONAL,
            fn (array $match) => trim((string) ($values[$match[1]] ?? '')) !== '' ? $match[2] : ($match[3] ?? ''),
            $content,
        ) ?? $content;
    }

    /**
     * @param array<string, string|null> $values
     */
    public static function fill(string $content, array $values, bool $escapeHtml = true): string
    {
        $content = self::resolveConditionals($content, $values);

        return preg_replace_callback(self::PATTERN, function (array $match) use ($values, $escapeHtml) {
            if ($match[1] === self::LAYOUT_SLOT) {
                return $match[0];
            }

            $value = (string) ($values[$match[1]] ?? '');

            return $escapeHtml ? nl2br(htmlspecialchars($value, ENT_QUOTES, 'UTF-8')) : $value;
        }, $content) ?? $content;
    }

    /**
     * @return array<string, string>
     */
    public static function recipientValues(?Customer $customer, string $email): array
    {
        $fields = [
            'name'  => $customer?->fullname ?: $email,
            'email' => $email,
            'phone' => (string) ($customer?->phone ?? ''),
        ];

        return array_map(fn (string $field) => $fields[$field], self::RECIPIENT_FIELDS);
    }
}