<?php

declare(strict_types=1);

namespace Evomedien\Vitec\Forms;

/**
 * Single source of truth for the VITEC form plugins.
 *
 * The SAME definition drives (a) the JSON the React frontend renders the
 * form from and (b) the server-side validation of submissions in
 * FormSubmissionMiddleware. Field names are camelCase (React contract);
 * mapping to Salesforce field ids happens inside the Salesforce delivery.
 *
 * Field spec: name, type (text|email|tel|select|textarea), label, required,
 * options (select only) OR optionsSource (frontend-supplied list, e.g. the
 * ISO country list).
 */
final class FormDefinitions
{
    public const HONEYPOT_FIELD = '_website';

    /** CType => form key */
    public const CTYPE_MAP = [
        'vitec_contactform' => 'contact',
        'vitec_demoform' => 'demo',
        'vitec_helpdeskform' => 'helpdesk',
    ];

    private const SOLUTION_OPTIONS = [
        'IPTV Distribution',
        'Digital Signage',
        'Video Streaming',
        'Video Contribution',
        'Situational Awareness and ISR',
        'Remote Production',
        'Encoders & Decoders',
        'Custom Design Service',
    ];

    /**
     * @return array<string,mixed>|null
     */
    public static function get(string $formKey): ?array
    {
        $all = self::all();
        return $all[$formKey] ?? null;
    }

    /**
     * @return array<string,array<string,mixed>>
     */
    public static function all(): array
    {
        $contactFields = [
            self::text('firstName', 'First Name', true),
            self::text('lastName', 'Last Name', true),
            self::text('company', 'Company', true),
            self::field('email', 'email', 'Email', true),
            self::field('phone', 'tel', 'Phone', true),
            self::text('street', 'Street', false),
            self::text('city', 'City', false),
            self::text('zip', 'Zip / Postal Code', false),
            self::countrySelect(),
            self::select('state', 'State', false, [], 'usStates'),
            self::select('solution', 'Solution of Interest', false, self::SOLUTION_OPTIONS),
            self::field('message', 'textarea', 'Message', false),
        ];

        return [
            'contact' => [
                'formKey' => 'contact',
                'title' => 'Contact VITEC',
                'fields' => $contactFields,
            ],
            'demo' => [
                'formKey' => 'demo',
                'title' => 'Request a Demo',
                'fields' => $contactFields,
            ],
            'helpdesk' => [
                'formKey' => 'helpdesk',
                'title' => 'Request Access to Online HelpDesk',
                'fields' => [
                    self::text('firstName', 'First Name', true),
                    self::text('lastName', 'Last Name', true),
                    self::text('company', 'Company', true),
                    self::field('phone', 'tel', 'Phone Number', false),
                    self::field('email', 'email', 'Email Address', true),
                    self::countrySelect(true),
                    self::text('product', 'Product', false),
                    self::text('serialNumber', 'Serial Number', false),
                ],
            ],
        ];
    }

    /**
     * Validate a submission payload against the definition.
     *
     * @param array<string,mixed> $payload
     * @return array<string,string> field => error (empty = valid)
     */
    public static function validate(string $formKey, array $payload): array
    {
        $definition = self::get($formKey);
        if ($definition === null) {
            return ['_form' => 'Unknown form'];
        }

        $errors = [];
        foreach ($definition['fields'] as $field) {
            $name = $field['name'];
            $value = trim((string)($payload[$name] ?? ''));

            if (($field['required'] ?? false) && $value === '') {
                $errors[$name] = 'This field is required.';
                continue;
            }
            if ($value === '') {
                continue;
            }
            if ($field['type'] === 'email' && !filter_var($value, FILTER_VALIDATE_EMAIL)) {
                $errors[$name] = 'Please enter a valid email address.';
            }
            if (mb_strlen($value) > 5000) {
                $errors[$name] = 'Value is too long.';
            }
        }

        return $errors;
    }

    /**
     * Reduce a raw payload to the defined fields (drops everything unknown).
     *
     * @param array<string,mixed> $payload
     * @return array<string,string>
     */
    public static function filterPayload(string $formKey, array $payload): array
    {
        $definition = self::get($formKey);
        if ($definition === null) {
            return [];
        }
        $out = [];
        foreach ($definition['fields'] as $field) {
            $out[$field['name']] = trim((string)($payload[$field['name']] ?? ''));
        }
        return $out;
    }

    // ------------------------------------------------------------ field DSL

    /** @return array<string,mixed> */
    private static function field(string $name, string $type, string $label, bool $required): array
    {
        return ['name' => $name, 'type' => $type, 'label' => $label, 'required' => $required];
    }

    /** @return array<string,mixed> */
    private static function text(string $name, string $label, bool $required): array
    {
        return self::field($name, 'text', $label, $required);
    }

    /**
     * @param array<int,string> $options
     * @return array<string,mixed>
     */
    private static function select(string $name, string $label, bool $required, array $options, string $optionsSource = ''): array
    {
        $field = self::field($name, 'select', $label, $required);
        if ($options !== []) {
            $field['options'] = $options;
        }
        if ($optionsSource !== '') {
            // The frontend supplies this list (e.g. ISO countries) — keeps
            // the definition lean and the lists consistent app-wide.
            $field['optionsSource'] = $optionsSource;
        }
        return $field;
    }

    /** @return array<string,mixed> */
    private static function countrySelect(bool $required = false): array
    {
        return self::select('country', 'Country', $required, [], 'countries');
    }
}