<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Assistant;

/**
 * Gravity Forms, through its own API: the forms, their recent entries and
 * the notification emails. Entries are other people's details, so the
 * assistant sees them only for the turn that asked (the plugin never keeps
 * them in a saved conversation). Other form plugins reach the assistant
 * through the abilities they register.
 */
final class FormAbilities
{
    /** @return array<int,Ability> */
    public static function abilities(): array
    {
        $formId = ['minimum' => 1, 'type' => 'integer'];
        return [
            new Ability(
                'sarcio/forms-list',
                __('Look at the forms', 'sarcio'),
                Ability::READ,
                'The site’s Gravity Forms: id, title, how many entries, the fields and where notifications go. Other form plugins show up as their own abilities, if they register any.',
                ['properties' => [], 'required' => [], 'type' => 'object'],
                static fn (array $args): bool => self::canEdit(),
                static fn (array $args): array => self::list(),
            ),
            new Ability(
                'sarcio/form-entries',
                __('Look at form entries', 'sarcio'),
                Ability::READ,
                'Recent entries of a Gravity Form: who wrote what and when. These are people’s details: use them for the question asked and nothing else; they are not kept in the conversation.',
                ['properties' => ['formId' => $formId, 'limit' => ['maximum' => 50, 'minimum' => 1, 'type' => 'integer']], 'required' => ['formId'], 'type' => 'object'],
                static fn (array $args): bool => self::canViewEntries(),
                static fn (array $args): array => self::entries($args),
            ),
            new Ability(
                'sarcio/form-notification-update',
                __('Change where a form’s emails go', 'sarcio'),
                Ability::WRITE,
                'Change a Gravity Forms notification by its id from forms-list: the addresses it goes to (comma-separated), its subject, or its message. Only the fields given change; undo puts the old ones back.',
                [
                    'properties' => [
                        'formId' => $formId,
                        'message' => ['maxLength' => 5000, 'type' => 'string'],
                        'notificationId' => ['maxLength' => 64, 'minLength' => 1, 'type' => 'string'],
                        'subject' => ['maxLength' => 300, 'type' => 'string'],
                        'to' => ['maxLength' => 500, 'type' => 'string'],
                    ],
                    'required' => ['formId', 'notificationId'],
                    'type' => 'object',
                ],
                static fn (array $args): bool => self::canEdit(),
                static fn (array $args): array => self::updateNotification($args),
                null,
                static fn (array $before, array $after): array => self::restoreNotification($before),
            ),
        ];
    }

    public static function available(): bool
    {
        return class_exists('\GFAPI');
    }

    private static function missing(): array
    {
        return ['error' => __('This needs Gravity Forms. Other form plugins show up as their own abilities when they register any.', 'sarcio')];
    }

    private static function canEdit(): bool
    {
        return current_user_can('gravityforms_edit_forms') || current_user_can('manage_options');
    }

    private static function canViewEntries(): bool
    {
        return current_user_can('gravityforms_view_entries') || current_user_can('manage_options');
    }

    private static function list(): array
    {
        if (!self::available()) {
            return self::missing();
        }
        $out = [];
        foreach ((array) \GFAPI::get_forms() as $form) {
            $fields = [];
            foreach ((array) ($form['fields'] ?? []) as $field) {
                $fields[] = ['id' => (string) ($field->id ?? $field['id'] ?? ''), 'label' => (string) ($field->label ?? $field['label'] ?? ''), 'type' => (string) ($field->type ?? $field['type'] ?? '')];
            }
            $notifications = [];
            foreach ((array) ($form['notifications'] ?? []) as $notification) {
                $notifications[] = ['id' => (string) ($notification['id'] ?? ''), 'name' => (string) ($notification['name'] ?? ''), 'subject' => (string) ($notification['subject'] ?? ''), 'to' => (string) ($notification['to'] ?? '')];
            }
            $out[] = [
                'entries' => (int) \GFAPI::count_entries((int) $form['id']),
                'fields' => $fields,
                'id' => (int) $form['id'],
                'notifications' => $notifications,
                'title' => (string) $form['title'],
            ];
        }
        return ['forms' => $out];
    }

    /** @param array<string,mixed> $args */
    private static function entries(array $args): array
    {
        if (!self::available()) {
            return self::missing();
        }
        $form = \GFAPI::get_form((int) $args['formId']);
        if (!is_array($form)) {
            return ['error' => __('There is no form with that id.', 'sarcio')];
        }
        $labels = [];
        foreach ((array) ($form['fields'] ?? []) as $field) {
            $labels[(string) ($field->id ?? $field['id'] ?? '')] = (string) ($field->label ?? $field['label'] ?? '');
        }
        $entries = \GFAPI::get_entries((int) $args['formId'], ['status' => 'active'], ['direction' => 'DESC', 'key' => 'date_created'], ['offset' => 0, 'page_size' => (int) ($args['limit'] ?? 10)]);
        $out = [];
        foreach (is_array($entries) ? $entries : [] as $entry) {
            $values = [];
            foreach ($labels as $fieldId => $label) {
                $value = $entry[$fieldId] ?? '';
                if (!is_scalar($value) || (string) $value === '') {
                    continue;
                }
                $values[$label !== '' ? $label : $fieldId] = mb_substr((string) $value, 0, 500);
            }
            $out[] = ['date' => (string) ($entry['date_created'] ?? ''), 'id' => (int) ($entry['id'] ?? 0), 'values' => $values];
        }
        return ['entries' => $out, 'form' => (string) $form['title'], 'transient' => true];
    }

    /** @param array<string,mixed> $args */
    private static function updateNotification(array $args): array
    {
        if (!self::available()) {
            return self::missing();
        }
        $form = \GFAPI::get_form((int) $args['formId']);
        if (!is_array($form)) {
            return ['error' => __('There is no form with that id.', 'sarcio')];
        }
        $id = (string) $args['notificationId'];
        if (!isset($form['notifications'][$id])) {
            return ['error' => __('That form has no notification with that id.', 'sarcio')];
        }
        $before = array_intersect_key((array) $form['notifications'][$id], array_flip(['message', 'subject', 'to']));
        $changes = [];
        foreach (['to', 'subject', 'message'] as $field) {
            if (array_key_exists($field, $args)) {
                $changes[$field] = $field === 'message' ? wp_kses_post((string) $args[$field]) : sanitize_text_field((string) $args[$field]);
            }
        }
        if ($changes === []) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        if (isset($changes['to'])) {
            foreach (array_map('trim', explode(',', $changes['to'])) as $address) {
                if ($address !== '' && !is_email($address) && !str_starts_with($address, '{')) {
                    return ['error' => sprintf(
                        /* translators: %s: the address. */
                        __('%s is not an email address.', 'sarcio'),
                        $address,
                    )];
                }
            }
        }
        $form['notifications'][$id] = array_merge($form['notifications'][$id], $changes);
        $result = \GFAPI::update_form($form);
        if (is_wp_error($result)) {
            return ['error' => sanitize_text_field($result->get_error_message())];
        }
        return [
            'journal' => [
                'after' => ['formId' => (int) $args['formId'], 'notificationId' => $id, 'values' => $changes],
                'before' => ['formId' => (int) $args['formId'], 'notificationId' => $id, 'values' => $before],
                'summary' => sprintf(
                    /* translators: 1: the notification name, 2: the form title. */
                    __('Changed the “%1$s” email of the form “%2$s”', 'sarcio'),
                    (string) ($form['notifications'][$id]['name'] ?? $id),
                    (string) $form['title'],
                ),
                'target' => 'form:' . $args['formId'],
            ],
            'notification' => $form['notifications'][$id],
        ];
    }

    /** @param array<string,mixed> $before */
    private static function restoreNotification(array $before): array
    {
        if (!self::available()) {
            return self::missing();
        }
        $form = \GFAPI::get_form((int) ($before['formId'] ?? 0));
        $id = (string) ($before['notificationId'] ?? '');
        if (!is_array($form) || !isset($form['notifications'][$id])) {
            return ['error' => __('That notification no longer exists.', 'sarcio')];
        }
        $form['notifications'][$id] = array_merge($form['notifications'][$id], (array) ($before['values'] ?? []));
        $result = \GFAPI::update_form($form);
        return is_wp_error($result) ? ['error' => sanitize_text_field($result->get_error_message())] : ['restored' => true];
    }
}