/*
    Copyright (C) 2016 Volker Krause <vkrause@kde.org>

    Permission is hereby granted, free of charge, to any person obtaining
    a copy of this software and associated documentation files (the
    "Software"), to deal in the Software without restriction, including
    without limitation the rights to use, copy, modify, merge, publish,
    distribute, sublicense, and/or sell copies of the Software, and to
    permit persons to whom the Software is furnished to do so, subject to
    the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include "categoryaggregationmodel.h"
#include <model/timeaggregationmodel.h>
#include <core/sample.h>

#include <QDebug>
#include <QSet>

#include <algorithm>
#include <string.h>

using namespace KUserFeedback::Console;

CategoryAggregationModel::CategoryAggregationModel(QObject *parent) :
    QAbstractTableModel(parent)
{
}

CategoryAggregationModel::~CategoryAggregationModel()
{
    delete[] m_data;
}

void CategoryAggregationModel::setSourceModel(QAbstractItemModel* model)
{
    Q_ASSERT(model);
    m_sourceModel = model;
    connect(model, &QAbstractItemModel::modelReset, this, &CategoryAggregationModel::recompute);
    recompute();
}

void CategoryAggregationModel::setAggregation(const Aggregation& aggr)
{
    m_aggr = aggr;
    m_depth = m_aggr.elements().size();
    recompute();
}

void CategoryAggregationModel::setDepth(int depth)
{
    if (depth == m_depth)
        return;
    m_depth = std::min(depth, m_aggr.elements().size());
    recompute();
}

int CategoryAggregationModel::columnCount(const QModelIndex& parent) const
{
    Q_UNUSED(parent);
    return m_categories.size() + 1;
}

int CategoryAggregationModel::rowCount(const QModelIndex& parent) const
{
    if (parent.isValid() || !m_sourceModel)
        return 0;
    return m_sourceModel->rowCount();
}

QVariant CategoryAggregationModel::data(const QModelIndex& index, int role) const
{
    if (!index.isValid() || !m_sourceModel)
        return {};

    if (role == TimeAggregationModel::MaximumValueRole)
        return m_maxValue;

    if (index.column() == 0) {
        const auto srcIdx = m_sourceModel->index(index.row(), 0);
        return m_sourceModel->data(srcIdx, role);
    }

    const auto idx = index.row() * m_categories.size() + index.column() - 1;
    switch (role) {
        case TimeAggregationModel::AccumulatedDisplayRole:
            return m_data[idx];
        case Qt::DisplayRole:
        case TimeAggregationModel::DataDisplayRole:
            if (index.column() == 1)
                return m_data[idx];
            return m_data[idx] - m_data[idx - 1];
    }

    return {};
}

QVariant CategoryAggregationModel::headerData(int section, Qt::Orientation orientation, int role) const
{
    if (section < 0 || section >= columnCount())
        return {};

    if (orientation == Qt::Horizontal && m_sourceModel) {
        if (section == 0)
            return m_sourceModel->headerData(section, orientation, role);
        if (role == Qt::DisplayRole) {
            const auto cat = m_categories.at(section - 1);
            if (cat.isEmpty())
                return tr("[empty]");
            return cat;
        }
    }

    return QAbstractTableModel::headerData(section, orientation, role);
}

void CategoryAggregationModel::recompute()
{
    if (!m_sourceModel)
        return;

    const auto rowCount = m_sourceModel->rowCount();
    beginResetModel();
    m_categories.clear();
    delete[] m_data;
    m_data = nullptr;
    m_maxValue = 0;

    if (rowCount <= 0 || !m_aggr.isValid() || m_depth <= 0) {
        endResetModel();
        return;
    }

    // scan all samples to find all categories
    const auto allSamples = m_sourceModel->index(0, 0).data(TimeAggregationModel::AllSamplesRole).value<QVector<Sample>>();
    QVector<QVector<QVector<Sample>>> depthSamples{{allSamples}}; // depth -> parent category index -> samples
    depthSamples.resize(m_depth + 1);
    QVector<QVector<QVector<QString>>> depthCategories{{{{}}}}; // depth -> parent category index -> category values
    depthCategories.resize(m_depth + 1);
    QVector<QVector<int>> depthOffsets{{0}}; // depth -> parent category index -> column offset
    depthOffsets.resize(m_depth + 1);
    for (int i = 0; i < m_depth; ++i) { // for each depth layer...
        depthOffsets[i + 1] = { 0 };
        int prevSize = 0;
        for (int j = 0; j < depthCategories.at(i).size(); ++j) { // ... and for each parent category ...
            for (int k = 0; k < depthCategories.at(i).at(j).size(); ++k) { // ... and for each category value...
                const auto sampleSubSet = depthSamples.at(i).at(depthOffsets.at(i).at(j) + k);
                QHash<QString, QVector<Sample>> catHash;
                for (const auto &s : sampleSubSet) // ... and for each sample
                    catHash[sampleValue(s, i).toString()].push_back(s);
                QVector<QString> cats;
                cats.reserve(catHash.size());
                for (auto it = catHash.cbegin(); it != catHash.cend(); ++it)
                    cats.push_back(it.key());
                std::sort(cats.begin(), cats.end());
                depthCategories[i + 1].push_back(cats);
                for (const auto &cat : cats)
                    depthSamples[i + 1].push_back(catHash.value(cat));
                if (k > 0 || j > 0)
                    depthOffsets[i + 1].push_back(depthOffsets.at(i + 1).constLast() + prevSize);
                prevSize = cats.size();
            }
        }
    }

    for (const auto &cats : depthCategories.at(m_depth))
        m_categories += cats;
    const auto colCount = m_categories.size();

    // compute the counts per cell, we could do that on demand, but we need the maximum for QtCharts...
    m_data = new int[colCount * rowCount];
    memset(m_data, 0, sizeof(int) * colCount * rowCount);
    for (int row = 0; row < rowCount; ++row) {
        const auto samples = m_sourceModel->index(row, 0).data(TimeAggregationModel::SamplesRole).value<QVector<Sample>>();
        for (const auto &sample : samples) {
            int parentIdx = 0;
            for (int i = 1; i <= m_depth; ++i) {
                const auto cats = depthCategories.at(i).at(parentIdx);
                const auto catIt = std::lower_bound(cats.constBegin(), cats.constEnd(), sampleValue(sample, i - 1).toString());
                Q_ASSERT(catIt != cats.constEnd());
                parentIdx = std::distance(cats.constBegin(), catIt) + depthOffsets.at(i).at(parentIdx);
            }
            m_data[colCount * row + parentIdx]++;
        }
        // accumulate per row for stacked plots
        for (int col = 1; col < colCount; ++col) {
            const auto idx = colCount * row + col;
            m_data[idx] += m_data[idx - 1];
        }
        m_maxValue = std::max(m_maxValue, m_data[row * colCount + colCount - 1]);
    }

    endResetModel();
}

QVariant CategoryAggregationModel::sampleValue(const Sample& s, int depth) const
{
    const auto elem = m_aggr.elements().at(depth);
    switch (elem.type()) {
        case AggregationElement::Value:
            return s.value(elem.schemaEntry().name() + QLatin1String(".") + elem.schemaEntryElement().name());
        case AggregationElement::Size:
            const auto l = s.value(elem.schemaEntry().name());
            return l.value<QVariantList>().size();
            break;
    }
    return {};
}
