// Squawk messenger. 
// Copyright (C) 2019  Yury Gubich <blue@macaw.me>
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "trusthandler.h"
#include "core/account.h"
#include "core/adapterfunctions.h"

Core::TrustHandler::TrustHandler(Account* account):
    QObject(),
    QXmppTrustStorage(),
    acc(account),
    db(acc->getName() + "/trust"),
    protocols(db.createDirectory() + "/protocols"),
    securityPolicies(db.addCache<QString, uint8_t>("securityPolicies")),
    ownKeys(db.addCache<QString, QByteArray>("ownKeys")),
    keysByProtocol()
{
    if (!protocols.open(QIODevice::ReadWrite | QIODevice::Text)) {               //never supposed to happen since I have just created a directory;
        throw DataBase::Directory(protocols.fileName().toStdString());
    }

    QTextStream in(&protocols);
    while(!in.atEnd()) {
        QString protocol = in.readLine();

        if (protocol.size() > 1) {  //I'm afraid of reading some nonsence like separately standing \n or EF or BOM, so... let it be at least 2 chars long
            KeyCache* cache = db.addCache<QString, Keys>(protocol.toStdString());
            keysByProtocol.insert(std::make_pair(protocol, cache));
        }
    }

    protocols.close();
    db.open();
}

Core::TrustHandler::~TrustHandler() {
    protocols.close();
    db.close();
}

Core::TrustHandler::KeyCache * Core::TrustHandler::getCache(const QString& encryption) {
    std::map<QString, KeyCache*>::iterator itr = keysByProtocol.find(encryption);
    if (itr == keysByProtocol.end()) {
        return createNewCache(encryption);
    } else {
        return itr->second;
    }
}

Core::TrustHandler::KeyCache * Core::TrustHandler::createNewCache(const QString& encryption) {
    db.close();
    KeyCache* cache = db.addCache<QString, Keys>(encryption.toStdString());
    keysByProtocol.insert(std::make_pair(encryption, cache));

    if(!protocols.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text)) {
        throw DataBase::Directory(protocols.fileName().toStdString());
    }
    QTextStream out(&protocols);
    out << encryption + "\n";
    protocols.close();

    db.open();
    return cache;
}

QXmppTask<void> Core::TrustHandler::resetAll(const QString& encryption) {
    securityPolicies->removeRecord(encryption);
    ownKeys->removeRecord(encryption);
    getCache(encryption)->drop();

    return Core::makeReadyTask();
}

QXmppTask<QXmpp::TrustLevel> Core::TrustHandler::trustLevel(
    const QString& encryption,
    const QString& keyOwnerJid,
    const QByteArray& keyId)
{
    KeyCache* cache = getCache(encryption);
    Shared::TrustLevel level = Shared::TrustLevel::undecided;
    try {
        Keys map = cache->getRecord(keyOwnerJid);
        Keys::const_iterator itr = map.find(keyId);
        if (itr != map.end())
            level = itr->second;
    } catch (const DataBase::NotFound& e) {}
    return Core::makeReadyTask(std::move(convert(level)));
}

QXmppTask<QHash<QString, QMultiHash<QString, QByteArray>>> Core::TrustHandler::setTrustLevel(
    const QString& encryption,
    const QList<QString>& keyOwnerJids,
    QXmpp::TrustLevel oldTrustLevel,
    QXmpp::TrustLevel newTrustLevel)
{
    QHash<QString, QMultiHash<QString, QByteArray>> modifiedKeys;
    Shared::TrustLevel oldLevel = convert(oldTrustLevel);
    Shared::TrustLevel newLevel = convert(newTrustLevel);
    KeyCache* cache = getCache(encryption);
    for (const QString& keyOwnerJid : keyOwnerJids) {
        Keys map = cache->getRecord(keyOwnerJid);
        uint count = 0;
        for (std::pair<const QByteArray, Shared::TrustLevel>& pair : map) {
            Shared::TrustLevel& current = pair.second;
            if (current == oldLevel) {
                current = newLevel;
                modifiedKeys[encryption].insert(keyOwnerJid, pair.first);
                ++count;
            }
        }
        if (count > 0) {
            cache->changeRecord(keyOwnerJid, map);
        }
    }
    return Core::makeReadyTask(std::move(modifiedKeys));
}

QXmppTask<QHash<QString, QMultiHash<QString, QByteArray>>> Core::TrustHandler::setTrustLevel(
    const QString& encryption,
    const QMultiHash<QString, QByteArray>& keyIds,
    QXmpp::TrustLevel trustLevel)
{
    QHash<QString, QMultiHash<QString, QByteArray>> modifiedKeys;
    Shared::TrustLevel level = convert(trustLevel);
    KeyCache* cache = getCache(encryption);

    for (MultySB::const_iterator itr = keyIds.begin(), end = keyIds.end(); itr != end; ++itr) {
        const QString& keyOwnerJid = itr.key();
        const QByteArray& keyId = itr.value();
        try {
            Keys map = cache->getRecord(keyOwnerJid);
            std::pair<Keys::iterator, bool> result = map.insert(std::make_pair(keyId, level));
            bool changed = result.second;
            if (!changed && result.first->second != level) {
                result.first->second = level;
                changed = true;
            }
            if (changed) {
                modifiedKeys[encryption].insert(keyOwnerJid, keyId);
                cache->changeRecord(keyOwnerJid, map);
            }
        } catch (const DataBase::NotFound& e) {
            Keys map({{keyId, level}});
            modifiedKeys[encryption].insert(keyOwnerJid, keyId);
            cache->addRecord(keyOwnerJid, map);
        }
    }
    return Core::makeReadyTask(std::move(modifiedKeys));
}

QXmppTask<bool> Core::TrustHandler::hasKey(const QString& encryption,
                                   const QString& keyOwnerJid,
                                   QXmpp::TrustLevels trustLevels)
{
    KeyCache* cache = getCache(encryption);
    bool found = false;
    try {
        Keys map = cache->getRecord(keyOwnerJid);
        for (const std::pair<const QByteArray, Shared::TrustLevel>& pair : map) {
            if (trustLevels.testFlag(convert(pair.second))) {
                found = true;
                break;
            }
        }
    } catch (const DataBase::NotFound& e) {}
    return Core::makeReadyTask(std::move(found));
}

QXmppTask<QHash<QString, QHash<QByteArray, QXmpp::TrustLevel>>> Core::TrustHandler::keys(
    const QString& encryption,
    const QList<QString>& keyOwnerJids,
    QXmpp::TrustLevels trustLevels)
{
    HSHBTL res;

    KeyCache* cache = getCache(encryption);
    for (const QString& keyOwnerJid : keyOwnerJids) {
        try {
            Keys map = cache->getRecord(keyOwnerJid);
            QHash<QByteArray, QXmpp::TrustLevel>& pRes = res[keyOwnerJid];
            for (const std::pair<const QByteArray, Shared::TrustLevel>& pair : map) {
                QXmpp::TrustLevel level = convert(pair.second);
                if (!trustLevels || trustLevels.testFlag(level)) {
                    pRes.insert(pair.first, level);
                }
            }
        } catch (const DataBase::NotFound& e) {}
    }
    return Core::makeReadyTask(std::move(res));
}

QXmppTask<QHash<QXmpp::TrustLevel, QMultiHash<QString, QByteArray>>> Core::TrustHandler::keys(
    const QString& encryption,
    QXmpp::TrustLevels trustLevels)
{
    QHash<TL, MultySB> res;
    KeyCache* cache = getCache(encryption);
    std::map<QString, Keys> storage = cache->readAll();
    for (const std::pair<const QString, Keys>& value : storage) {
        for (const std::pair<const QByteArray, Shared::TrustLevel>& pair : value.second) {
            QXmpp::TrustLevel level = convert(pair.second);
            if (!trustLevels || trustLevels.testFlag(level))
                res[level].insert(value.first, pair.first);
        }
    }
    return Core::makeReadyTask(std::move(res));
}

QXmppTask<void> Core::TrustHandler::removeKeys(const QString& encryption) {
    getCache(encryption)->drop();
    return Core::makeReadyTask();
}

QXmppTask<void> Core::TrustHandler::removeKeys(const QString& encryption, const QString& keyOwnerJid) {
    getCache(encryption)->removeRecord(keyOwnerJid);
    return Core::makeReadyTask();
}

QXmppTask<void> Core::TrustHandler::removeKeys(const QString& encryption, const QList<QByteArray>& keyIds) {
    std::set<QByteArray> set;
    for (const QByteArray& keyId : keyIds)
        set.insert(keyId);

    KeyCache* cache = getCache(encryption);
    std::map<QString, Keys> data = cache->readAll();
    bool changed = false;
    for (std::map<QString, Keys>::iterator cItr = data.begin(), cEnd = data.end(); cItr != cEnd; /*no increment*/) {
        Keys& byOwner = cItr->second;
        for (Keys::const_iterator itr = byOwner.begin(), end = byOwner.end(); itr != end; /*no increment*/) {
            const QByteArray& keyId = itr->first;
            if (set.erase(keyId)) {
                byOwner.erase(itr++);
                changed = true;
            } else
                ++itr;
        }
        if (byOwner.size() > 0)
            data.erase(cItr++);
        else
            ++cItr;
    }
    if (changed)
        cache->replaceAll(data);

    return Core::makeReadyTask();
}

QXmppTask<void> Core::TrustHandler::addKeys(
    const QString& encryption,
    const QString& keyOwnerJid,
    const QList<QByteArray>& keyIds,
    QXmpp::TrustLevel trustLevel)
{
    KeyCache* cache = getCache(encryption);
    Shared::TrustLevel level = convert(trustLevel);
    Keys data;
    bool had = false;
    try {
        data = cache->getRecord(keyOwnerJid);
        had = true;
    } catch (const DataBase::NotFound& e) {}
    for (const QByteArray& keyId : keyIds) {
        std::pair<Keys::iterator, bool> result = data.insert(std::make_pair(keyId, level));
        if (!result.second)
            result.first->second = level;
    }

    if (had) {
        cache->changeRecord(keyOwnerJid, data);
    } else {
        cache->addRecord(keyOwnerJid, data);
    }

    return Core::makeReadyTask();
}

QXmppTask<QByteArray> Core::TrustHandler::ownKey(const QString& encryption) {
    QByteArray res;
    try {
        res = ownKeys->getRecord(encryption);
    } catch (const DataBase::NotFound& e) {}
    return Core::makeReadyTask(std::move(res));
}

QXmppTask<void> Core::TrustHandler::resetOwnKey(const QString& encryption) {
    try {
        ownKeys->removeRecord(encryption);
    } catch (const DataBase::NotFound& e) {}

    return Core::makeReadyTask();
}

QXmppTask<void> Core::TrustHandler::setOwnKey(const QString& encryption, const QByteArray& keyId) {
    ownKeys->forceRecord(encryption, keyId);
    return Core::makeReadyTask();
}

QXmppTask<QXmpp::TrustSecurityPolicy> Core::TrustHandler::securityPolicy(const QString& encryption) {
    QXmpp::TrustSecurityPolicy res;
    try {
        res = static_cast<QXmpp::TrustSecurityPolicy>(securityPolicies->getRecord(encryption));
    } catch (const DataBase::NotFound& e) {}
    return Core::makeReadyTask(std::move(res));
}

QXmppTask<void> Core::TrustHandler::resetSecurityPolicy(const QString& encryption) {
    try {
        securityPolicies->removeRecord(encryption);
    } catch (const DataBase::NotFound& e) {}
    return Core::makeReadyTask();
}

QXmppTask<void> Core::TrustHandler::setSecurityPolicy(
    const QString& encryption,
    QXmpp::TrustSecurityPolicy securityPolicy)
{
    uint8_t pol = securityPolicy;
    securityPolicies->forceRecord(encryption, pol);

    return Core::makeReadyTask();
}

Core::TrustHandler::Keys Core::TrustHandler::getKeys(Shared::EncryptionProtocol protocol, const QString& jid) const {
    const QString& prt = Shared::TrustSummary::protocolKeys.at(protocol);
    std::map<QString, KeyCache*>::const_iterator itr = keysByProtocol.find(prt);
    if (itr != keysByProtocol.end()) {
        try {
            Keys map = itr->second->getRecord(jid);
            return map;
        } catch (const DataBase::NotFound& e) {
            return Keys();
        }
    } else {
        return Keys();
    }
}

Shared::TrustSummary Core::TrustHandler::getSummary(const QString& jid) const {
    Shared::TrustSummary result;
    for (const std::pair<const QString, KeyCache*>& pair : keysByProtocol) {
        try {
            Keys keys = pair.second->getRecord(jid);
            Shared::EncryptionProtocol protocol = Shared::TrustSummary::protocolValues.at(pair.first);
            for (const std::pair<const QByteArray, Shared::TrustLevel>& trust : keys) {
                result.increment(protocol, trust.second);
            }
        } catch (const DataBase::NotFound& e) {}
    }

    return result;
}

Shared::TrustLevel Core::TrustHandler::convert(Core::TrustHandler::TL level) {
    switch (level) {
        case QXmpp::TrustLevel::Undecided: return Shared::TrustLevel::undecided;
        case QXmpp::TrustLevel::AutomaticallyDistrusted: return Shared::TrustLevel::automaticallyDistrusted;
        case QXmpp::TrustLevel::ManuallyDistrusted: return Shared::TrustLevel::manuallyDistrusted;
        case QXmpp::TrustLevel::AutomaticallyTrusted: return Shared::TrustLevel::automaticallyTrusted;
        case QXmpp::TrustLevel::ManuallyTrusted: return Shared::TrustLevel::manuallyTrusted;
        case QXmpp::TrustLevel::Authenticated: return Shared::TrustLevel::authenticated;
        default: throw 2413;                 //never supposed to get here, switch case if complete, this line is just to suppress a warning
    }
}

Core::TrustHandler::TL Core::TrustHandler::convert(Shared::TrustLevel level) {
    switch (level) {
        case Shared::TrustLevel::undecided: return QXmpp::TrustLevel::Undecided;
        case Shared::TrustLevel::automaticallyDistrusted: return QXmpp::TrustLevel::AutomaticallyDistrusted;
        case Shared::TrustLevel::manuallyDistrusted: return QXmpp::TrustLevel::ManuallyDistrusted;
        case Shared::TrustLevel::automaticallyTrusted: return QXmpp::TrustLevel::AutomaticallyTrusted;
        case Shared::TrustLevel::manuallyTrusted: return QXmpp::TrustLevel::ManuallyTrusted;
        case Shared::TrustLevel::authenticated: return QXmpp::TrustLevel::Authenticated;
        default: throw 2413;                 //never supposed to get here, switch case if complete, this line is just to suppress a warning
    }
}