<?php

declare(strict_types=1);

/**
 * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

namespace KTXM\ProviderImap\Service\Cache;

use KTXM\ProviderImap\Providers\CollectionResource;
use KTXM\ProviderImap\Providers\EntityResource;
use KTXM\ProviderImap\Stores\MessageStore;

/**
 * Cache Mail Service
 *
 * Provides read-only access to locally cached IMAP data stored in MongoDB by
 * CacheService.  Call CacheService::syncMailboxes() / syncMessages() to keep
 * the cache up to date before reading from here.
 */
class CacheMailService
{
    public function __construct(
        private readonly MessageStore $messageStore,
        private readonly string       $provider,
        private readonly string|int   $service,
    ) {}

    // ── Collection (mailbox) reads ────────────────────────────────────────────

    /**
     * Return all cached mailboxes for this service.
     *
     * @return CollectionResource[]  keyed by mailbox name
     */
    public function collectionList(): array
    {
        $docs   = $this->messageStore->listMailboxes((string) $this->service);
        $result = [];
        foreach ($docs as $doc) {
            $resource = new CollectionResource($this->provider, $this->service);
            $resource->fromStore($doc);
            $result[$resource->identifier()] = $resource;
        }
        return $result;
    }

    /**
     * Fetch a single cached mailbox by name.
     */
    public function collectionFetch(string $name): ?CollectionResource
    {
        $doc = $this->messageStore->fetchMailbox((string) $this->service, $name);
        if ($doc === null) {
            return null;
        }
        $resource = new CollectionResource($this->provider, $this->service);
        $resource->fromStore($doc);
        return $resource;
    }

    // ── Entity (message) reads ────────────────────────────────────────────────

    /**
     * Return all cached UIDs for a mailbox.
     *
     * @return int[]
     */
    public function entityList(string $collection): array
    {
        return $this->messageStore->listUids((string) $this->service, $collection);
    }

    /**
     * Fetch one or more cached messages by UID.
     *
     * @param int ...$uids
     * @return EntityResource[]  keyed by UID
     */
    public function entityFetch(string $collection, int ...$uids): array
    {
        if (empty($uids)) {
            return [];
        }

        $docs   = $this->messageStore->fetchMessages(
            (string) $this->service,
            $collection,
            array_values($uids),
        );
        $result = [];
        foreach ($docs as $uid => $doc) {
            $resource = new EntityResource($this->provider, $this->service);
            $resource->fromStore($doc);
            $result[$uid] = $resource;
        }
        return $result;
    }

    /**
     * Fetch a single cached message.
     */
    public function entityFetchOne(string $collection, int $uid): ?EntityResource
    {
        $doc = $this->messageStore->fetchMessage((string) $this->service, $collection, $uid);
        if ($doc === null) {
            return null;
        }
        $resource = new EntityResource($this->provider, $this->service);
        $resource->fromStore($doc);
        return $resource;
    }
}