/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include <cassert>

#include <Poco/Path.h>
#include <Poco/SHA1Engine.h>

#include "LOOLWSD.hpp"
#include "DocumentBroker.hpp"
#include "Storage.hpp"
#include "TileCache.hpp"

namespace
{

/// Returns the cache path for a given document URI.
std::string getCachePath(const std::string& uri)
{
    Poco::SHA1Engine digestEngine;

    digestEngine.update(uri.c_str(), uri.size());

    return (LOOLWSD::Cache + "/" +
            Poco::DigestEngine::digestToHex(digestEngine.digest()).insert(3, "/").insert(2, "/").insert(1, "/"));
}

}

Poco::URI DocumentBroker::sanitizeURI(const std::string& uri)
{
    // The URI of the document should be url-encoded.
    std::string decodedUri;
    Poco::URI::decode(uri, decodedUri);
    auto uriPublic = Poco::URI(decodedUri);

    if (uriPublic.isRelative() || uriPublic.getScheme() == "file")
    {
        // TODO: Validate and limit access to local paths!
        uriPublic.normalize();
    }

    if (uriPublic.getPath().empty())
    {
        throw std::runtime_error("Invalid URI.");
    }

    return uriPublic;
}

std::string DocumentBroker::getDocKey(const Poco::URI& uri)
{
    // Keep the host as part of the key to close a potential security hole.
    std::string docKey;
    Poco::URI::encode(uri.getHost() + uri.getPath(), "", docKey);
    return docKey;
}

DocumentBroker::DocumentBroker(const Poco::URI& uriPublic,
                               const std::string& docKey,
                               const std::string& childRoot,
                               std::shared_ptr<ChildProcess> childProcess) :
    _uriPublic(uriPublic),
    _docKey(docKey),
    _childRoot(childRoot),
    _cacheRoot(getCachePath(uriPublic.toString())),
    _lastSaveTime(std::chrono::steady_clock::now()),
    _childProcess(childProcess)
{
    assert(!_docKey.empty());
    assert(!_childRoot.empty());
    Log::info("DocumentBroker [" + _uriPublic.toString() + "] created. DocKey: [" + _docKey + "]");
}

void DocumentBroker::validate(const Poco::URI& uri)
{
    Log::info("Validating: " + uri.toString());
    auto storage = StorageBase::create("", "", uri);
    if (storage == nullptr || !storage->getFileInfo(uri).isValid())
    {
        throw std::runtime_error("Invalid URI or access denied.");
    }
}

bool DocumentBroker::load(const std::string& jailId)
{
    Log::debug("Loading from URI: " + _uriPublic.toString());

    std::unique_lock<std::mutex> lock(_mutex);

    if (_storage)
    {
        // Already loaded. Nothing to do.
        return true;
    }

    _jailId = jailId;

    // The URL is the publicly visible one, not visible in the chroot jail.
    // We need to map it to a jailed path and copy the file there.

    // user/doc/jailId
    const auto jailPath = Poco::Path(JAILED_DOCUMENT_ROOT, jailId);
    const std::string jailRoot = getJailRoot();

    Log::info("jailPath: " + jailPath.toString() + ", jailRoot: " + jailRoot);

    auto storage = StorageBase::create("", "", _uriPublic);
    if (storage)
    {
        const auto fileInfo = storage->getFileInfo(_uriPublic);
        _tileCache.reset(new TileCache(_uriPublic.toString(), fileInfo.ModifiedTime, _cacheRoot));

        _storage = StorageBase::create(jailRoot, jailPath.toString(), _uriPublic);

        const auto localPath = _storage->loadStorageFileToLocal();
        _uriJailed = Poco::URI(Poco::URI("file://"), localPath);

        return true;
    }

    return false;
}

bool DocumentBroker::save()
{
    std::unique_lock<std::mutex> lock(_saveMutex);

    const auto uri = _uriPublic.toString();
    Log::debug("Saving to URI [" + uri + "].");

    assert(_storage && _tileCache);
    if (_storage->saveLocalFileToStorage())
    {
        _lastSaveTime = std::chrono::steady_clock::now();
        _tileCache->documentSaved();
        Log::debug("Saved to URI [" + uri + "] and updated tile cache.");
        _saveCV.notify_all();
        return true;
    }

    Log::error("Failed to save to URI [" + uri + "].");
    return false;
}

bool DocumentBroker::autoSave(const bool force)
{
    std::unique_lock<std::mutex> sessionsLock(_wsSessionsMutex);
    if (_wsSessions.empty())
    {
        // Shouldn't happen.
        return false;
    }

    // Find the most recent activity.
    double inactivityTimeMs = std::numeric_limits<double>::max();
    for (auto& sessionIt: _wsSessions)
    {
        inactivityTimeMs = std::min(sessionIt.second->getInactivityMS(), inactivityTimeMs);
    }

    Log::trace("Most recent activity was " + std::to_string((int)inactivityTimeMs) + " ms ago.");
    const auto timeSinceLastSaveMs = getTimeSinceLastSaveMs();
    Log::trace("Time since last save is " + std::to_string((int)timeSinceLastSaveMs) + " ms.");

    // There has been some editing since we saved last?
    if (inactivityTimeMs < timeSinceLastSaveMs)
    {
        // Either we've been idle long enough, or it's auto-save time.
        // Or we are asked to save anyway.
        if (inactivityTimeMs >= IdleSaveDurationMs ||
            timeSinceLastSaveMs >= AutoSaveDurationMs ||
            force)
        {
            Log::info("Auto-save triggered for doc [" + _docKey + "].");

            // Save using session holding the edit-lock
            bool sent = false;
            for (auto& sessionIt: _wsSessions)
            {
                if (!sessionIt.second->isEditLocked())
                    continue;

                auto queue = sessionIt.second->getQueue();
                if (queue)
                {
                    queue->put("uno .uno:Save");
                    sent = true;
                    break;
                }
            }

            if (!sent)
            {
                Log::error("Failed to auto-save doc [" + _docKey + "]: No valid sessions.");
            }

            return sent;
        }
    }

    return false;
}

bool DocumentBroker::waitSave(const size_t timeoutMs)
{
    std::unique_lock<std::mutex> lock(_saveMutex);

    // Remeber the last save time, since this is the predicate.
    const auto lastSaveTime = _lastSaveTime;

    if (_saveCV.wait_for(lock, std::chrono::milliseconds(timeoutMs)) == std::cv_status::no_timeout)
    {
        return true;
    }

    return (lastSaveTime != _lastSaveTime);
}

std::string DocumentBroker::getJailRoot() const
{
    assert(!_jailId.empty());
    return Poco::Path(_childRoot, _jailId).toString();
}

void DocumentBroker::takeEditLock(const std::string& id)
{
    std::lock_guard<std::mutex> sessionsLock(_wsSessionsMutex);
    for (auto& it: _wsSessions)
    {
        if (it.first != id)
        {
            it.second->setEditLock(false);
            it.second->sendTextFrame("editlock: 0");
        }
        else
        {
            it.second->setEditLock(true);
            it.second->sendTextFrame("editlock: 1");
        }
    }
}

void DocumentBroker::addWSSession(const std::string& id, std::shared_ptr<MasterProcessSession>& ws)
{
    std::lock_guard<std::mutex> sessionsLock(_wsSessionsMutex);

    auto ret = _wsSessions.emplace(id, ws);
    if (!ret.second)
    {
        Log::warn("DocumentBroker: Trying to add already existed session.");
    }

    if (_wsSessions.size() == 1)
    {
        ws->setEditLock(true);
        ws->sendTextFrame("editlock: 1");
    }

    // Request a new session from the child kit.
    const std::string aMessage = "session " + id + " " + _docKey + "\n";
    Log::debug("DocBroker to Child: " + aMessage.substr(0, aMessage.length() - 1));
    _childProcess->getWebSocket()->sendFrame(aMessage.data(), aMessage.size());
}

void DocumentBroker::removeWSSession(const std::string& id)
{
    std::lock_guard<std::mutex> sessionsLock(_wsSessionsMutex);

    bool haveEditLock = false;
    auto it = _wsSessions.find(id);
    if (it != _wsSessions.end())
    {
        haveEditLock = it->second->isEditLocked();
        it->second->setEditLock(false);
        _wsSessions.erase(it);
    }

    if (haveEditLock)
    {
        // pass the edit lock to first session in map
        it = _wsSessions.begin();
        if (it != _wsSessions.end())
        {
            it->second->setEditLock(true);
            it->second->sendTextFrame("editlock: 1");
        }
    }
}

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