<?php

declare(strict_types=1);

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

namespace KTXM\ProviderImapMail\Stores;

use KTXC\Db\DataStore;

/**
 * MongoDB cache for IMAP messages and mailboxes.
 *
 * Collections:
 *   provider_imap_mail_messages  — one document per (sid, mailbox, uid)
 *   provider_imap_mail_mailboxes — one document per (sid, name)
 *
 * Documents are stored **pre-formatted** in the same internal shape used by
 * EntityResource / MessageProperties and CollectionResource / CollectionProperties
 * so the read path does zero IMAP parsing.
 */
class MessageStore
{
    protected const MESSAGES_COLLECTION  = 'provider_imap_mail_messages';
    protected const MAILBOXES_COLLECTION = 'provider_imap_mail_mailboxes';

    public function __construct(
        protected readonly DataStore $store,
    ) {
        $this->ensureIndexes();
    }

    // ── Index creation ───────────────────────────────────────────────────────

    private function ensureIndexes(): void
    {
        $messages  = $this->store->selectCollection(self::MESSAGES_COLLECTION);
        $mailboxes = $this->store->selectCollection(self::MAILBOXES_COLLECTION);

        $messages->createIndex(['sid' => 1, 'mailbox' => 1, 'uid' => 1], ['unique' => true]);
        $mailboxes->createIndex(['sid' => 1, 'name' => 1], ['unique' => true]);
    }

    // ── Messages ─────────────────────────────────────────────────────────────

    /**
     * Insert or replace a cached message document.
     *
     * @param array $data  Result of EntityResource::toStore() — must include
     *                     sid, mailbox, uid at the top level.
     */
    public function upsertMessage(array $data): void
    {
        $filter = [
            'sid'     => $data['sid'],
            'mailbox' => $data['mailbox'],
            'uid'     => (int)$data['uid'],
        ];
        $data['syncedAt'] = (new \DateTime())->format(\DateTimeInterface::ATOM);

        $this->store->selectCollection(self::MESSAGES_COLLECTION)->updateOne(
            $filter,
            ['$set' => $data],
            ['upsert' => true],
        );
    }

    /**
     * Retrieve a single cached message by service ID, mailbox and UID.
     */
    public function fetchMessage(string $serviceId, string $mailbox, int $uid): ?array
    {
        $doc = $this->store->selectCollection(self::MESSAGES_COLLECTION)->findOne([
            'sid'     => $serviceId,
            'mailbox' => $mailbox,
            'uid'     => $uid,
        ]);

        return $doc ? (array)$doc : null;
    }

    /**
     * Return all cached UIDs for a mailbox/service combination.
     *
     * @return int[]
     */
    public function listUids(string $serviceId, string $mailbox): array
    {
        $cursor = $this->store->selectCollection(self::MESSAGES_COLLECTION)->find(
            ['sid' => $serviceId, 'mailbox' => $mailbox],
            ['projection' => ['uid' => 1]],
        );

        $uids = [];
        foreach ($cursor as $doc) {
            $uids[] = (int)$doc['uid'];
        }

        return $uids;
    }

    /**
     * Fetch multiple cached messages by UID.
     *
     * @param int[] $uids
     * @return array[]
     */
    public function fetchMessages(string $serviceId, string $mailbox, array $uids): array
    {
        $cursor = $this->store->selectCollection(self::MESSAGES_COLLECTION)->find([
            'sid'     => $serviceId,
            'mailbox' => $mailbox,
            'uid'     => ['$in' => $uids],
        ]);

        $result = [];
        foreach ($cursor as $doc) {
            $doc          = (array)$doc;
            $result[$doc['uid']] = $doc;
        }

        return $result;
    }

    /**
     * Delete a cached message entry by UID.
     */
    public function deleteMessage(string $serviceId, string $mailbox, int $uid): void
    {
        $this->store->selectCollection(self::MESSAGES_COLLECTION)->deleteOne([
            'sid'     => $serviceId,
            'mailbox' => $mailbox,
            'uid'     => $uid,
        ]);
    }

    /**
     * Delete multiple cached message entries.
     *
     * @param int[] $uids
     */
    public function deleteMessages(string $serviceId, string $mailbox, array $uids): void
    {
        if (empty($uids)) {
            return;
        }

        $this->store->selectCollection(self::MESSAGES_COLLECTION)->deleteMany([
            'sid'     => $serviceId,
            'mailbox' => $mailbox,
            'uid'     => ['$in' => $uids],
        ]);
    }

    // ── Mailboxes ────────────────────────────────────────────────────────────

    /**
     * Insert or replace a cached mailbox document.
     *
     * @param array $data  Result of CollectionResource::toStore() — must include
     *                     sid and name at the top level.
     */
    public function upsertMailbox(array $data): void
    {
        $filter = [
            'sid'  => $data['sid'],
            'name' => $data['name'],
        ];
        $data['syncedAt'] = (new \DateTime())->format(\DateTimeInterface::ATOM);

        $this->store->selectCollection(self::MAILBOXES_COLLECTION)->updateOne(
            $filter,
            ['$set' => $data],
            ['upsert' => true],
        );
    }

    /**
     * Retrieve a cached mailbox by service ID and name.
     */
    public function fetchMailbox(string $serviceId, string $name): ?array
    {
        $doc = $this->store->selectCollection(self::MAILBOXES_COLLECTION)->findOne([
            'sid'  => $serviceId,
            'name' => $name,
        ]);

        return $doc ? (array)$doc : null;
    }

    /**
     * List all cached mailboxes for a service.
     *
     * @return array[]
     */
    public function listMailboxes(string $serviceId): array
    {
        $cursor = $this->store->selectCollection(self::MAILBOXES_COLLECTION)->find(
            ['sid' => $serviceId],
        );

        $result = [];
        foreach ($cursor as $doc) {
            $doc           = (array)$doc;
            $result[$doc['name']] = $doc;
        }

        return $result;
    }

    /**
     * Delete a cached mailbox entry by service ID and name.
     */
    public function deleteMailbox(string $serviceId, string $name): void
    {
        $this->store->selectCollection(self::MAILBOXES_COLLECTION)->deleteOne([
            'sid'  => $serviceId,
            'name' => $name,
        ]);
    }
}