<?php
/**
 * Undo of changes write tools made.
 *
 * @package MazeAi
 * @since   0.1.0
 */

declare(strict_types=1);

namespace MazeAi\Http\Controllers;

defined('ABSPATH') || exit;

use Illuminate\MazeAssistant\Http\JsonResponse;
use Illuminate\MazeAssistant\Http\Request;
use Illuminate\MazeAssistant\Routing\Controller;
use MazeAi\I18n\StoredMessage;
use MazeAi\Chat\ConversationStore;
use MazeAi\Chat\Transcript;
use MazeAi\Http\Resources\SessionResource;
use MazeAi\Kernel\Contracts\EventSink;
use MazeAi\Kernel\Support\Event;
use MazeAi\Sessions\SessionRepository;
use MazeAi\Tools\ChangeJournal;

/**
 * `POST /sessions/{id}/changes/{change}/undo` and `POST /changes/{change}/undo` (decision 037): reverts one change a
 * write tool made, once, for the person it was made for. The transcript gets a `change_undone` line so the trace card and the model
 * both see that it was undone.
 *
 * @since 0.1.0
 */
class ChangeController extends Controller
{
    public function __construct(protected SessionRepository $sessions, protected ChangeJournal $journal, protected ConversationStore $store, protected EventSink $events)
    {
        parent::__construct();
    }

    public function undo(Request $request): JsonResponse
    {
        $session = $this->sessions->find($this->userId(), (string) $request->route('id'));
        if ($session === null) {
            return $this->notFound(__('That session does not exist or was deleted.', 'maze-graph'));
        }

        $id     = (int) $request->route('change');
        $change = $this->journal->find($id);
        if ($change === null || (int) $change['session_id'] !== $session->id) {
            return $this->notFound(__('That change does not exist.', 'maze-graph'));
        }

        $result = $this->revert($id, $change);
        if (is_wp_error($result)) {
            return $this->error($result->get_error_message(), 409);
        }

        return $this->ok(['session' => SessionResource::make($session), 'entries' => Transcript::forClient($result === null ? [] : [$result])]);
    }

    /**
     * `POST /changes/{change}/undo`: the same, from the Activity page or the Extensions page, where a change may
     * belong to no session (an import) or to a Studio document.
     */
    public function undoChange(Request $request): JsonResponse
    {
        $id     = (int) $request->route('change');
        $change = $this->journal->find($id);
        if ($change === null || (int) $change['user_id'] !== $this->userId()) {
            return $this->notFound(__('That change does not exist.', 'maze-graph'));
        }

        $result = $this->revert($id, $change);

        return is_wp_error($result) ? $this->error($result->get_error_message(), 409) : $this->ok(['change' => $id, 'status' => 'undone']);
    }

    /**
     * Undo, report it, and add a `change_undone` line to the change's session when it has one.
     *
     * @param array<string, mixed> $change
     * @return array<string, mixed>|\WP_Error|null The transcript line added, if any.
     */
    protected function revert(int $id, array $change): array|\WP_Error|null
    {
        $result = $this->journal->undo($this->userId(), $id);
        if (is_wp_error($result)) {
            return $result;
        }
        $this->events->record(new Event('change.undone', ['change' => $id, 'tool' => (string) $change['tool'], 'user' => $this->userId(), 'session' => (int) $change['session_id']]));
        if ((int) $change['session_id'] <= 0) {
            return null;
        }

        return $this->store->append((int) $change['session_id'], Transcript::event('change_undone', [
            'change'  => $id,
            'tool'    => (string) $change['tool'],
            'message' => StoredMessage::encode('change.undone', [(string) $change['summary']]),
        ]));
    }
}