<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Assistant;

use Sarcio\WordPress\Admin\ReviewPage;
use WP_REST_Request;
use WP_REST_Response;
use WP_REST_Server;

/**
 * The Assistant page's own endpoints. Every one needs a signed-in WordPress
 * user with the review capability and the REST nonce, which is what makes the
 * assistant act as that person and nobody else. A request from a chat that
 * holds a preview names it in a header, so reads and previews see the site as
 * the preview shows it.
 */
final class Routes
{
    public const NAMESPACE = 'sarcio/v1';

    public function register(): void
    {
        add_action('rest_api_init', [$this, 'registerRoutes']);
    }

    public function registerRoutes(): void
    {
        register_rest_route(self::NAMESPACE, '/assistant/turn', [
            'callback' => [$this, 'turn'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/preview', [
            'callback' => [$this, 'preview'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/run', [
            'callback' => [$this, 'run'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/stage', [
            'callback' => [$this, 'stage'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/stage/apply', [
            'callback' => [$this, 'applyStage'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/stage/clear', [
            'callback' => [$this, 'clearStage'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/stage/schedule', [
            'callback' => [$this, 'scheduleStage'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/stage/request', [
            'callback' => [$this, 'requestStage'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/stage/review', [
            'callback' => [$this, 'reviewStage'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/stage/view', [
            'callback' => [$this, 'viewStage'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/requests', [
            'callback' => [$this, 'requests'],
            'methods' => WP_REST_Server::READABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/requests/(?P<id>[a-f0-9]{16})/(?P<action>apply|decline|withdraw)', [
            'callback' => [$this, 'decideRequest'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/scheduled', [
            'callback' => [$this, 'scheduled'],
            'methods' => WP_REST_Server::READABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/scheduled/(?P<id>[a-f0-9]{12})', [
            'callback' => [$this, 'cancelScheduled'],
            'methods' => WP_REST_Server::DELETABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/undo', [
            'callback' => [$this, 'undo'],
            'methods' => WP_REST_Server::CREATABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/changes', [
            'callback' => [$this, 'changes'],
            'methods' => WP_REST_Server::READABLE,
            'permission_callback' => [self::class, 'canUseAssistant'],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/conversations', [
            [
                'callback' => [$this, 'conversations'],
                'methods' => WP_REST_Server::READABLE,
                'permission_callback' => [self::class, 'canUseAssistant'],
            ],
            [
                'callback' => [$this, 'saveConversation'],
                'methods' => WP_REST_Server::CREATABLE,
                'permission_callback' => [self::class, 'canUseAssistant'],
            ],
        ]);
        register_rest_route(self::NAMESPACE, '/assistant/conversations/(?P<id>\d+)', [
            [
                'callback' => [$this, 'conversation'],
                'methods' => WP_REST_Server::READABLE,
                'permission_callback' => [self::class, 'canUseAssistant'],
            ],
            [
                'callback' => [$this, 'deleteConversation'],
                'methods' => WP_REST_Server::DELETABLE,
                'permission_callback' => [self::class, 'canUseAssistant'],
            ],
        ]);
    }

    public static function canUseAssistant(): bool
    {
        return is_user_logged_in() && current_user_can(ReviewPage::CAPABILITY);
    }

    public function turn(WP_REST_Request $request): WP_REST_Response
    {
        self::activateStage($request);
        $body = $request->get_json_params();
        $messages = is_array($body) && is_array($body['messages'] ?? null) ? $body['messages'] : [];
        $summary = is_array($body) && is_string($body['summary'] ?? null) ? $body['summary'] : '';
        $result = Client::turn(get_current_user_id(), $messages, $summary);
        return new WP_REST_Response($result, isset($result['error']) ? 502 : 200);
    }

    public function preview(WP_REST_Request $request): WP_REST_Response
    {
        self::activateStage($request);
        [$ability, $args] = self::call($request);
        return new WP_REST_Response(Catalog::preview($ability, $args));
    }

    /** A real write, or, with `stage: true`, one laid over the chat's preview. */
    public function run(WP_REST_Request $request): WP_REST_Response
    {
        self::activateStage($request);
        [$ability, $args] = self::call($request);
        $body = $request->get_json_params();
        if (is_array($body) && ($body['stage'] ?? false) === true) {
            $id = is_string($body['id'] ?? null) ? sanitize_text_field($body['id']) : '';
            $staged = Stage::add($id, $ability, $args);
            if (!$staged['ok']) {
                return new WP_REST_Response($staged);
            }
            $output = ['staged' => true, 'summary' => (string) ($staged['summary'] ?? '')];
            if (isset($staged['id'])) {
                $output['id'] = $staged['id'];
            }
            return new WP_REST_Response(['ok' => true, 'output' => $output, 'staged' => true] + $staged);
        }
        $consent = is_array($body) && ($body['consent'] ?? false) === true;
        $result = Catalog::run($ability, $args, $consent);
        if ($result['ok'] && isset($result['output'])) {
            $result['output'] = Transcript::capOutput($result['output']);
        }
        return new WP_REST_Response($result);
    }

    /** The browser's staged list replaces the stored one (a reload, or a chat picked up again). */
    public function stage(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $token = is_array($body) && is_string($body['token'] ?? null) ? sanitize_text_field($body['token']) : '';
        $changes = is_array($body) && is_array($body['changes'] ?? null) ? $body['changes'] : [];
        $result = Stage::sync($token, $changes);
        if ($result['ok']) {
            $result['previewUrl'] = home_url('/');
        }
        return new WP_REST_Response($result, $result['ok'] ? 200 : 400);
    }

    public function applyStage(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $token = is_array($body) && is_string($body['token'] ?? null) ? sanitize_text_field($body['token']) : '';
        if (!Stage::activate($token)) {
            return new WP_REST_Response(['error' => __('That preview has ended. Reload the page and try again.', 'sarcio'), 'ok' => false], 404);
        }
        return new WP_REST_Response(Stage::apply());
    }

    public function scheduleStage(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $token = is_array($body) && is_string($body['token'] ?? null) ? sanitize_text_field($body['token']) : '';
        if (!Stage::activate($token)) {
            return new WP_REST_Response(['error' => __('That preview has ended. Reload the page and try again.', 'sarcio'), 'ok' => false], 404);
        }
        $summaries = [];
        foreach (is_array($body['summaries'] ?? null) ? $body['summaries'] : [] as $id => $summary) {
            if (is_string($id) && is_string($summary)) {
                $summaries[$id] = $summary;
            }
        }
        $result = Scheduled::fromStage(
            is_string($body['applyAt'] ?? null) ? sanitize_text_field($body['applyAt']) : '',
            is_string($body['revertAt'] ?? null) ? sanitize_text_field($body['revertAt']) : null,
            $summaries,
            is_string($body['repeat'] ?? null) ? sanitize_key($body['repeat']) : 'none',
        );
        return new WP_REST_Response($result, $result['ok'] ? 200 : 400);
    }

    public function reviewStage(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $token = is_array($body) && is_string($body['token'] ?? null) ? sanitize_text_field($body['token']) : '';
        if (!Stage::activate($token)) {
            return new WP_REST_Response(['error' => __('That preview has ended. Reload the page and try again.', 'sarcio'), 'ok' => false], 404);
        }
        $result = Review::create();
        return new WP_REST_Response($result, $result['ok'] ? 200 : 400);
    }

    public function requestStage(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $token = is_array($body) && is_string($body['token'] ?? null) ? sanitize_text_field($body['token']) : '';
        if (!Stage::activate($token)) {
            return new WP_REST_Response(['error' => __('That preview has ended. Reload the page and try again.', 'sarcio'), 'ok' => false], 404);
        }
        $previews = [];
        foreach (is_array($body['previews'] ?? null) ? $body['previews'] : [] as $id => $preview) {
            if (is_string($id) && is_array($preview)) {
                $previews[$id] = $preview;
            }
        }
        $result = Requests::fromStage(is_string($body['title'] ?? null) ? $body['title'] : '', $previews);
        return new WP_REST_Response($result, $result['ok'] ? 200 : 400);
    }

    public function requests(WP_REST_Request $request): WP_REST_Response
    {
        return new WP_REST_Response(['canApply' => Requests::canApply(), 'requests' => Requests::list()]);
    }

    public function decideRequest(WP_REST_Request $request): WP_REST_Response
    {
        $id = sanitize_text_field((string) $request->get_param('id'));
        $body = $request->get_json_params();
        $result = match ((string) $request->get_param('action')) {
            'apply' => Requests::apply($id),
            'decline' => Requests::decline($id, is_array($body) && is_string($body['note'] ?? null) ? $body['note'] : ''),
            default => Requests::withdraw($id),
        };
        return new WP_REST_Response($result, $result['ok'] ? 200 : 400);
    }

    public function scheduled(WP_REST_Request $request): WP_REST_Response
    {
        return new WP_REST_Response(['scheduled' => Scheduled::list()]);
    }

    public function cancelScheduled(WP_REST_Request $request): WP_REST_Response
    {
        $result = Scheduled::cancel(sanitize_text_field((string) $request->get_param('id')));
        return new WP_REST_Response($result, $result['ok'] ? 200 : 400);
    }

    public function viewStage(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $token = is_array($body) && is_string($body['token'] ?? null) ? sanitize_text_field($body['token']) : '';
        $view = is_array($body) && ($body['view'] ?? '') === 'live' ? 'live' : 'staged';
        if (!Stage::activate($token)) {
            return new WP_REST_Response(['error' => __('That preview has ended. Reload the page and try again.', 'sarcio'), 'ok' => false], 404);
        }
        Stage::setView($view === 'live');
        return new WP_REST_Response(['ok' => true, 'view' => $view]);
    }

    /** Also reached by a beacon when the chat's tab closes, so the token may come as a query parameter. */
    public function clearStage(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $token = is_array($body) && is_string($body['token'] ?? null) ? $body['token'] : (string) ($request->get_param('token') ?? '');
        Stage::clear(sanitize_text_field($token));
        return new WP_REST_Response(['ok' => true]);
    }

    public function changes(WP_REST_Request $request): WP_REST_Response
    {
        return new WP_REST_Response(['changes' => JournalAbilities::list()]);
    }

    public function undo(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        $id = is_array($body) ? (int) ($body['id'] ?? 0) : 0;
        return new WP_REST_Response(Catalog::undo($id));
    }

    public function conversations(WP_REST_Request $request): WP_REST_Response
    {
        return new WP_REST_Response(['conversations' => Conversations::listFor(get_current_user_id())]);
    }

    public function conversation(WP_REST_Request $request): WP_REST_Response
    {
        $found = Conversations::get((int) $request->get_param('id'), get_current_user_id());
        if ($found === null) {
            return new WP_REST_Response(['error' => __('That conversation is no longer here.', 'sarcio'), 'ok' => false], 404);
        }
        return new WP_REST_Response(['conversation' => $found, 'ok' => true]);
    }

    public function saveConversation(WP_REST_Request $request): WP_REST_Response
    {
        $body = $request->get_json_params();
        if (!is_array($body) || !is_array($body['messages'] ?? null)) {
            return new WP_REST_Response(['error' => __('Nothing to save.', 'sarcio'), 'ok' => false], 400);
        }
        $saved = Conversations::save(
            (int) ($body['id'] ?? 0),
            get_current_user_id(),
            is_string($body['title'] ?? null) ? $body['title'] : '',
            is_string($body['summary'] ?? null) ? $body['summary'] : '',
            $body['messages'],
            is_array($body['previews'] ?? null) ? $body['previews'] : [],
        );
        if ($saved === null) {
            return new WP_REST_Response(['error' => __('That conversation is no longer here.', 'sarcio'), 'ok' => false], 404);
        }
        return new WP_REST_Response(['ok' => true] + $saved);
    }

    public function deleteConversation(WP_REST_Request $request): WP_REST_Response
    {
        return new WP_REST_Response(['ok' => Conversations::delete((int) $request->get_param('id'), get_current_user_id())]);
    }

    private static function activateStage(WP_REST_Request $request): void
    {
        $token = $request->get_header(Stage::HEADER);
        if (is_string($token) && $token !== '') {
            Stage::activate(sanitize_text_field($token));
        }
    }

    /** @return array{0:string,1:array<string,mixed>} */
    private static function call(WP_REST_Request $request): array
    {
        $body = $request->get_json_params();
        $ability = is_array($body) && is_string($body['ability'] ?? null) ? sanitize_text_field($body['ability']) : '';
        $args = is_array($body) && is_array($body['args'] ?? null) ? $body['args'] : [];
        return [$ability, $args];
    }
}