/*
 * <one line to give the library's name and an idea of what it does.>
 * Copyright 2013  Luca Beltrame <lbeltrame@kde.org>
 *
 * 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 2 of
 * the License or (at your option) version 3 or any later version
 * accepted by the membership of KDE e.V. (or its successor approved
 * by the membership of KDE e.V.), which shall act as a proxy
 * defined in Section 14 of version 3 of the license.
 *
 * 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/>.
 *
 */

// STL

#include <algorithm>

// Qt

#include <QDebug>
#include <qjson/parser.h>
#include <QDebug>

// KDE

#include <KIO/Job>
#include <KIO/Scheduler>
#include <KImageCache>
#include <KIO/MultiGetJob>

// Own

#include "danbooruservice.h"
#include "danboorupost.h"
#include "danboorupool.h"
#include "danboorutag.h"
#include "utils.h"

namespace Danbooru
{

using KIO::StoredTransferJob;
using KIO::MultiGetJob;

const QString DanbooruService::POST_URL = "post/index.json" ;
const QString DanbooruService::TAG_URL = "tag/index.xml";
const QString DanbooruService::POOL_URL = "pool/index.json";
const QString DanbooruService::ARTIST_URL = "artist/index.json";
const QString DanbooruService::POOL_DATA_URL = "pool/show.xml";
const QString DanbooruService::RELATED_TAG_URL = "tag/related.json";

DanbooruService::DanbooruService(QObject *parent):
        QObject(parent),
        m_url(QUrl()),
        m_username(QString()),
        m_password(QString()),
        m_maxRating(DanbooruPost::Safe),
        m_postsToFetch(0),
        m_cache(0){
}

DanbooruService::DanbooruService(QUrl &boardUrl, QString username,
                                 QString password, KImageCache *cache,
                                 QObject *parent):
    QObject(parent),
    m_url(boardUrl),
    m_username(username),
    m_password(password),
    m_maxRating(Danbooru::DanbooruPost::Safe),
    m_postsToFetch(0),
    m_cache(cache)
{
}

DanbooruService::~DanbooruService()
{
    qDeleteAll(m_posts);
    m_posts.clear();
}

void DanbooruService::getPostList(int page, QStringList tags, int limit)
{

    // We can't fetch more than 100 items, API limitation

    limit = limit > 100 ? 100 : limit;

    QMap<QString, QString> parameters;

    parameters.insert("limit", QString::number(limit));
    parameters.insert("page", QString::number(page));

    QUrl danbooruUrl = requestUrl(m_url, POST_URL, m_username,
                                  m_password, parameters, tags);

//     qDebug() << "Final constructed post URL" << danbooruUrl.url();

    KIO::StoredTransferJob *job = KIO::storedGet(danbooruUrl, KIO::NoReload,
                                  KIO::HideProgressInfo);

    // This job can use JSON data
    job->setProperty("needsXML", false);

    connect(job, &KIO::StoredTransferJob::result, this, &DanbooruService::processPostList);

}

void DanbooruService::getTagList(int limit, QString name)
{
    QMap<QString, QString> parameters;
    parameters.insert("limit", QString::number(limit));

    if (!name.isEmpty()) {
        parameters.insert("name", name);
    }
    parameters.insert("order", "date");

    QUrl danbooruUrl = requestUrl(m_url, TAG_URL, m_username, m_password,
                                  parameters);
    //qDebug() << "Final constructed tag URL" << danbooruUrl.url();

    KIO::StoredTransferJob *job = KIO::storedGet(danbooruUrl, KIO::NoReload,
                                  KIO::HideProgressInfo);

    connect(job, &KIO::StoredTransferJob::result, [this](KJob * job) {

        if (job->error()) {
            Q_EMIT(downloadError(job->errorString()));
            return;
        }

        StoredTransferJob *jobResult = qobject_cast<StoredTransferJob *>(job);
        QByteArray data = jobResult->data();

        bool ok;

        // Most Danbooru implementations return tags in wrong order when
        // using JSON, so we have to fall back to XML
        QList<QVariant> tagList = parseDanbooruResult(data, "tag", &ok);

        if (!ok) {
            Q_EMIT(downloadError(QString("Unable to decode data")));
            return;
        }

        for (auto element : tagList) {
            QVariantMap map = element.toMap();
            DanbooruTag *tag = new DanbooruTag(map);
            Q_EMIT(tagDownloaded(tag));
        }

    }
           );
}

void DanbooruService::getPool(int poolId, int page)
{

    QMap<QString, QString> parameters;

    parameters.insert("id", QString::number(poolId));

    if (page > 1) {
        parameters.insert("page", QString::number(page));
    }

    QUrl danbooruUrl = requestUrl(m_url, POOL_DATA_URL, m_username,
                                  m_password, parameters);

    //qDebug() << "Final constructed pool URL" << danbooruUrl.url();

    KIO::StoredTransferJob *job = KIO::storedGet(danbooruUrl, KIO::NoReload,
                                  KIO::HideProgressInfo);

    //HACK: Most Danbooru implementations don't provide valid data on
    // pools via JSON, hence we set XML and parse the XML data.

    job->setProperty("needsXML", true);

    connect(job, &KIO::StoredTransferJob::result, this, &DanbooruService::processPostList);

}

void DanbooruService::getPoolList(int page)
{

    QUrl danbooruUrl;

    if (page == 0) {
        danbooruUrl = requestUrl(m_url, POOL_URL, m_username, m_password);
    } else {
        QMap<QString, QString> map;
        map.insert("page", QString::number(page));

        danbooruUrl = requestUrl(m_url, POOL_URL, m_username,
                                 m_password, map);
    }

    //qDebug() << "Final constructed pool list URL" << danbooruUrl.url();

    KIO::StoredTransferJob *job = KIO::storedGet(danbooruUrl, KIO::NoReload,
                                  KIO::HideProgressInfo);
    // This job can use JSON data
    job->setProperty("needsXML", false);

//     connect(job, &KIO::StoredTransferJob::result, this, &DanbooruService::processPoolList);

    connect(job, &KIO::StoredTransferJob::result, [this](KJob * job) {

        if (job->error()) {
            Q_EMIT(downloadError(job->errorString()));
            return;
        }

        StoredTransferJob *jobResult = qobject_cast<StoredTransferJob *>(job);
        QByteArray data = jobResult->data();

        bool ok;
        QList<QVariant> poolList = parseDanbooruResult(data,  &ok).toList();

        if (!ok) {
            Q_EMIT(downloadError(QString("Unable to decode data")));
            return;
        }

        for (auto element : poolList) {
            QVariantMap map = element.toMap();

            DanbooruPool *pool = new DanbooruPool(map);
            Q_EMIT(poolDownloaded(pool));
        }

        //qDebug() << "Pool download finished!";
        Q_EMIT(poolDownloadFinished());
    }

           );

}

void DanbooruService::getRelatedTags(const QStringList &tags,
                                     DanbooruTag::TagType tagType)
{

    QString type;
    switch (tagType) {
    case DanbooruTag::General:
        type = "general";
        break;
    case DanbooruTag::Artist:
        type = "artist";
        break;
    case DanbooruTag::Copyright:
        type = "copyright";
        break;
    case DanbooruTag::Character:
        type = "character";
        break;
    case DanbooruTag::Unknown:
        type = "unknown";
        break;
    }

    QMap<QString, QString> parameters;
    parameters.insert("type", type);

    QUrl danbooruUrl = requestUrl(m_url, RELATED_TAG_URL, m_username,
                                  m_password, parameters, tags);

    //qDebug() << "Final constructed related tag URL" << danbooruUrl.url();

    StoredTransferJob *job = KIO::storedGet(
                                 danbooruUrl, KIO::NoReload,
                                 KIO::HideProgressInfo
                             );

    connect(job, &StoredTransferJob::result, [this](KJob * job) {

        if (job->error()) {
            Q_EMIT(downloadError(job->errorString()));
            return;
        }

        StoredTransferJob *jobResult = qobject_cast<StoredTransferJob *>(job);
        QByteArray data = jobResult->data();
        bool ok;

        QVariantMap tagList = parseDanbooruResult(data, &ok).toMap();

        if (!ok) {
            Q_EMIT(downloadError(QString("Unable to decode data")));
            return;
        }

        QVariantMap::const_iterator iter;

        // The service returns a list of key-related tag list pair,
        // we iterate through them and remove the empty (not found) ones, then
        // we call getTagList. Unfortunately Danbooru doesn't have a method to
        // fetch all tags in batch, so this is done one by one.

        for (iter = tagList.constBegin(); iter != tagList.constEnd(); ++iter) {

            QList<QVariant> tags = iter.value().toList();

            if (tags.isEmpty()) {
                continue;
            }

            for (auto tag : tags) {
                // We get the first element in the list, the second is
                // the ID which is useless (no API methods in Danbooru)
                QString tagName = tag.toList()[0].toString();
                getTagList(1, tagName);
            }

        }

    }

           );

}

// Getters / setters

void DanbooruService::setBlacklist(const QSet< QString > &blacklist)
{

    if (!blacklist.isEmpty()) {
        m_blacklist = blacklist;
    }

}

const QSet< QString > DanbooruService::blacklist() const
{
    return m_blacklist;
}

const QStringList DanbooruService::allowedRatings() const
{
    QStringList ratings;

    if (m_maxRating.testFlag(DanbooruPost::Safe)) {
        ratings.append("Safe");
    }

    if (m_maxRating.testFlag(DanbooruPost::Questionable)) {
        ratings.append("Questionable");
    }

    if (m_maxRating.testFlag(DanbooruPost::Explicit)) {
        ratings.append("Explicit");
    }

    return ratings;

}

void DanbooruService::setMaximumAllowedRating(DanbooruPost::Rating rating)
{
    DanbooruPost::Ratings flags;

    switch (rating) {
    case DanbooruPost::Safe:
        flags = DanbooruPost::Safe;
        break;
    case DanbooruPost::Questionable:
        flags = DanbooruPost::Safe | DanbooruPost::Questionable;
        break;
    case DanbooruPost::Explicit:
        flags = DanbooruPost::Safe | DanbooruPost::Questionable | DanbooruPost::Explicit;
        break;
    }

    m_maxRating = flags;

}

const DanbooruPost::Ratings DanbooruService::maximumAllowedRating() const
{

    return m_maxRating;

}

// Slots

void DanbooruService::processPostList(KJob *job)
{

//     qDebug() << "Got post data OK";

    if (!m_posts.isEmpty()) {
        m_posts.clear();
    }

    if (job->error()) {
        Q_EMIT(downloadError(job->errorString()));
    }

    StoredTransferJob *jobResult = qobject_cast<StoredTransferJob *>(job);

    if (jobResult == 0) {
        Q_EMIT(downloadError(QString("Internal error")));
        return;

    }

    QByteArray data = jobResult->data();

    bool ok;
    bool needsXML = job->property("needsXML").toBool();

    QList<QVariant> postList;

    if (needsXML) {
        // Special cases for pools
        postList = parseDanbooruResult(data, QString("post"), &ok);
    } else {
        postList = parseDanbooruResult(data, &ok).toList();
    }

    if (!ok) {
        Q_EMIT(downloadError(QString("Unable to decode data")));
        return;
    }

    // How many posts do we have to fetch?

    m_postsToFetch = postList.length();

    int postId = 0;

    for (auto element: postList) {
        QVariantMap map = element.toMap();
        DanbooruPost *post = new DanbooruPost(map);
        if (isPostBlacklisted(post, m_blacklist, m_maxRating)) {
            m_postsToFetch--;
            delete post;
            continue;
        }
        m_posts.insert(postId, post);
        postId++;

    }

    for (auto element : postList) {

        QVariantMap map = element.toMap();
        DanbooruPost *post = new DanbooruPost(map);

        // Remove unwanted posts

        if (isPostBlacklisted(post, m_blacklist, m_maxRating)) {
            m_postsToFetch--;
            delete post;
            continue;
        }

        QPixmap pix;

        // Usare QHash<id, url> per KIO::multi_get!

        if (m_cache->findPixmap(post->thumbnailUrl().url(), &pix)) {

            post->setPixmap(pix);
            Q_EMIT(postDownloaded(post));
            m_postsToFetch--;

            if (m_postsToFetch == 0) {
                qDebug() << "Post download finished";
                Q_EMIT(postDownloadFinished());
            }

        } else {

            StoredTransferJob *pixmapJob = KIO::storedGet(post->thumbnailUrl(),
                                           KIO::NoReload, KIO::HideProgressInfo
                                                         );

            KIO::Scheduler::setJobPriority(static_cast<KIO::SimpleJob *>(job), 1);

            QVariant variant;
            variant.setValue(post);

            // We don't want to overload the servers, so set some rational
            // priority

            pixmapJob->setProperty("danbooruPost", variant);

            connect(pixmapJob, &StoredTransferJob::result, [post, this, pix](KJob * job) mutable {

                if (job->error())
                {
                    Q_EMIT(downloadError(job->errorString()));
                    return;
                }

                StoredTransferJob *jobResult = qobject_cast<StoredTransferJob *>(job);

                if (!pix.loadFromData(jobResult->data()))
                {
                    Q_EMIT(downloadError(QString("Pixmap data could not be loaded")));
                    return;
                }

                post->setPixmap(pix);

                if (m_cache)
                {
                    //qDebug() << "Inserting item in cache";
                    m_cache->insertPixmap(post->thumbnailUrl().url(), pix);
                }

                m_postsToFetch--; // One less post to do

                //qDebug() << "Current posts remaining" << m_currentPosts;
                Q_EMIT(postDownloaded(post));

                if (m_postsToFetch == 0)
                {
                    qDebug() << "Post download finished";
                    Q_EMIT(postDownloadFinished());
                }

            });

        }

    }

}


void DanbooruService::downloadAllTags(KJob *job)
{
    Q_UNUSED(job)
}


} // namespace Danbooru