/*
  TimeTrackingView.cpp

  This file is part of Charm, a task-based time tracking application.

  Copyright (C) 2014-2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com

  Author: Frank Osterfeld <frank.osterfeld@kdab.com>

  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) 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 "TimeTrackingView.h"
#include "Data.h"
#include "ViewHelpers.h"

#include "Core/CharmConstants.h"
#include "Core/Configuration.h"

#include <QFont>
#include <QFontMetrics>
#include <QMessageBox>
#include <QPaintEvent>
#include <QPainter>

#include <algorithm>
#include <functional>
#include <numeric>

const int Margin = 2;

TimeTrackingView::TimeTrackingView(QWidget *parent)
    : QWidget(parent)
    , m_taskSelector(new TimeTrackingTaskSelector(this))
{
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    // plumbing
    m_paintAttributes.initialize(palette());
    for (int i = 0; i < 7; ++i)
        m_shortDayNames[i] = QDate::shortDayName(i + 1);
    connect(m_taskSelector, &TimeTrackingTaskSelector::startEvent,
            this, &TimeTrackingView::startEvent);
    connect(m_taskSelector, &TimeTrackingTaskSelector::stopEvents,
            this, &TimeTrackingView::stopEvents);
    connect(m_taskSelector, &TimeTrackingTaskSelector::updateSummariesPlease,
            this, &TimeTrackingView::slotUpdateSummaries);

    setFocusProxy(m_taskSelector);
    setFocusPolicy(Qt::StrongFocus);
}

void TimeTrackingView::populateEditMenu(QMenu *menu)
{
    m_taskSelector->populateEditMenu(menu);
}

void TimeTrackingView::PaintAttributes::initialize(const QPalette &palette)
{
    headerBrush = palette.mid();
    taskBrushEven = palette.light();
    taskBrushOdd = palette.midlight();
    totalsRowBrush = headerBrush;
    totalsRowEvenDayBrush = QBrush(taskBrushEven.color().darker(125));
    headerEvenDayBrush = totalsRowEvenDayBrush;
    QColor dimHighlight = palette.highlight().color();
    dim = 0.25;
    dimHighlight.setAlphaF(dim * dimHighlight.alphaF());
    runningTaskColor = palette.highlight().color();
}

QSize TimeTrackingView::sizeHint() const
{
    if (!m_cachedSizeHint.isValid()) {
        // the sizeHint is like the minimum size hint, only it allows
        // for more text in the task name column
        const QFontMetrics narrowFontMetrics = QFontMetrics(m_narrowFont);
        const QRect textRect
            = narrowFontMetrics.boundingRect(tr("moremoremoremoremore"));
        const int widthHint = minimumSizeHint().width() + textRect.width();
        m_cachedSizeHint = QSize(widthHint, minimumSizeHint().height());
    }
    return m_cachedSizeHint;
}

QSize TimeTrackingView::minimumSizeHint() const
{
    if (!m_cachedMinimumSizeHint.isValid()) {
        // the header row, task rows, and totals row are all of the same height
        const QFontMetrics fixedFontMetrics(m_fixedFont);
        const QFontMetrics narrowFontMetrics(m_narrowFont);
        const QRect totalsColumnFieldRect(
            fixedFontMetrics.boundingRect(QStringLiteral("100:00"))
            .adjusted(0, 0, 2 * Margin, 2 * Margin));
        const int dayWidth = fixedFontMetrics.width(QStringLiteral("00:00")) + 2 * Margin;
        const int fieldHeight = qMax(fixedFontMetrics.lineSpacing(),
                                     narrowFontMetrics.lineSpacing())
                                + 2 * Margin;
        const QRect taskColumnFieldRect = narrowFontMetrics.boundingRect(
            tr("KDABStuffngy"))
                                          .adjusted(0, 0, 2 * Margin, 2 * Margin);
        // the tracking row needs to accommodate the task selector widget
        const QSize taskSelectorSizeHint = m_taskSelector->sizeHint();
        const int trackingRowHeight = qMax(fieldHeight, taskSelectorSizeHint.height() + 2 * Margin);

        const int minimumWidth
            = totalsColumnFieldRect.width()
              + 7 * dayWidth
              + taskColumnFieldRect.width();
        const int minimumHeight = (rowCount() - 1) * fieldHeight + trackingRowHeight;
        m_cachedMinimumSizeHint = QSize(minimumWidth, minimumHeight);
        m_cachedTotalsFieldRect = QRect(0, 0, totalsColumnFieldRect.width(), fieldHeight);
        m_cachedDayFieldRect = QRect(0, 0, dayWidth, fieldHeight);
    }
    return m_cachedMinimumSizeHint;
}

QMenu *TimeTrackingView::menu() const
{
    return m_taskSelector->menu();
}

void TimeTrackingView::paintEvent(QPaintEvent *e)
{
    m_activeFieldRects.clear();
    const int FieldHeight = m_cachedTotalsFieldRect.height();
    QPainter painter(this);
    // all attributes are determined in data(), we just paint the rects:
    for (int row = 0; row < rowCount() - 1; ++row) {
        for (int column = 0; column < columnCount(); ++column) {
            // get the rectangle of the field that will be drawn
            QRect fieldRect;
            const int y = row * FieldHeight;
            if (column == columnCount() - 1) {   // totals column
                fieldRect = QRect(width() - m_cachedTotalsFieldRect.width(), y,
                                  m_cachedTotalsFieldRect.width(), FieldHeight);
            } else if (column == 0) {   // task column
                fieldRect = QRect(0, y, taskColumnWidth(), FieldHeight);
            } else if (column > 0) {   //  a task
                fieldRect = QRect(width() - m_cachedTotalsFieldRect.width()
                                  - 8 * m_cachedDayFieldRect.width()
                                  + column * m_cachedDayFieldRect.width(), y,
                                  m_cachedDayFieldRect.width(), FieldHeight);
            }
            // paint the field, if it is in the dirty region
            if (e->rect().contains(fieldRect)) {
                DataField field = m_defaultField;
                data(field, column, row);
                int alignment = Qt::AlignRight | Qt::AlignVCenter;
                if (row == 0) {
                    alignment = Qt::AlignCenter | Qt::AlignVCenter;
                } else if (column == 0 && row < rowCount() - 1) {
                    alignment = Qt::AlignLeft | Qt::AlignVCenter;
                }
                if (column == 0)    // task column
                    field.text = elidedText(field.text, field.font, fieldRect.width() - 2*Margin);
                if (field.storeAsActive) m_activeFieldRects << fieldRect;
                const QRect textRect = fieldRect.adjusted(Margin, Margin, -Margin, -Margin);
                if (field.hasHighlight) {
                    painter.setBrush(field.highlight);
                    painter.setPen(Qt::NoPen);
                    painter.drawRect(fieldRect);
                } else {
                    painter.setBrush(field.background);
                    painter.setPen(Qt::NoPen);
                    painter.drawRect(fieldRect);
                }
                painter.setPen(palette().text().color());
                painter.setFont(field.font);
                painter.drawText(textRect, alignment, field.text);
            }
        }
    }
    // paint the tracking row
    const int top = (rowCount() - 1) * FieldHeight;
    const QRect fieldRect(0, top, width(), height() - top);
    if (e->rect().contains(fieldRect)) {
        DataField field = m_defaultField;
        data(field, 0, rowCount() - 1);
        painter.setBrush(field.background);
        painter.setPen(Qt::NoPen);
        painter.drawRect(fieldRect);
    }
}

void TimeTrackingView::resizeEvent(QResizeEvent *)
{
    sizeHint(); // make sure cached values are updated
    m_taskSelector->resize(width() - 2*Margin, m_taskSelector->sizeHint().height());
    m_taskSelector->move(Margin, height() - Margin - m_taskSelector->height());
    m_elidedTexts.clear();
}

void TimeTrackingView::mousePressEvent(QMouseEvent *event)
{
    const int position = getSummaryAt(event->pos());
    if (position < 0)
        return;
    const TaskId id = m_summaries.at(position).task;

    if (!taskIsValidAndTrackable(id))
        return;

    if (!isTracking()) {
        if (position >= 0 && position < m_summaries.size())
            m_taskSelector->taskSelected(m_summaries.at(position));
    }
}

void TimeTrackingView::mouseDoubleClickEvent(QMouseEvent *event)
{   // we rely on the mouse press event that was received before the doubleclick!
    // start tracking
    const int position = getSummaryAt(event->pos());
    if (position < 0)
        return;

    const TaskId id = m_summaries.at(position).task;

    if (!taskIsValidAndTrackable(id))
        return;

    if (!DATAMODEL->isTaskActive(id)) {
        emit stopEvents();
        emit startEvent(id);
    } else {
        emit stopEvents();
    }
}

int TimeTrackingView::getSummaryAt(const QPoint &position)
{
    const int left = 0;
    const int right = taskColumnWidth();
    const int fieldIndex = position.y() / m_cachedTotalsFieldRect.height();
    const int taskIndex = fieldIndex - 1;
    if (taskIndex < 0 || taskIndex >= m_summaries.count())
        return -1;
    if (position.x() < left || position.x() > right)
        return -1;
    return taskIndex;
}

int TimeTrackingView::taskColumnWidth() const
{
    return width() - m_cachedTotalsFieldRect.width() - 7 * m_cachedDayFieldRect.width();
}

void TimeTrackingView::data(DataField &field, int column, int row) const
{
    const int HeaderRow = 0;
    const int TotalsRow = rowCount() - 2;
    const int TrackingRow = rowCount() - 1;
    const int TaskColumn = 0;
    const int TotalsColumn = columnCount() - 1;
    const int Day = column - 1;

    field.font = m_fixedFont;
    if (row == HeaderRow) {
        field.font = m_narrowFont;
        if (column == TaskColumn) {
            field.text = tr("Task");
        } else if (column == TotalsColumn) {
            field.text = tr("Total");
        } else {
            field.text = m_shortDayNames[ column - 1 ];
        }
        field.background = (Day % 2)
                           ? m_paintAttributes.headerBrush
                           : m_paintAttributes.headerEvenDayBrush;
    } else if (row == TotalsRow) {
        field.background = m_paintAttributes.totalsRowBrush;
        if (column == TaskColumn) {
            // field.text = tr( "Total" );
        } else if (column == TotalsColumn) {
            int total = 0;
            Q_FOREACH (const WeeklySummary &s, m_summaries)
                total += std::accumulate(s.durations.begin(), s.durations.end(), 0);
            field.text = hoursAndMinutes(total);
        } else {
            int total = 0;
            Q_FOREACH (const WeeklySummary &s, m_summaries)
                total += s.durations[Day];
            field.text = hoursAndMinutes(total);
            field.background = (Day % 2)
                               ? m_paintAttributes.totalsRowBrush
                               : m_paintAttributes.totalsRowEvenDayBrush;
        }
    } else if (row == TrackingRow) {
        // we only return one value, the paint method will treat this
        // column as a special case
        field.background = m_paintAttributes.taskBrushOdd;
        // field.text = tr( " 00:45 2345 KDAB/HR/Project Time Bookkeeping" );
    } else { // a task row
        field.background = row % 2 ? m_paintAttributes.taskBrushEven
                           : m_paintAttributes.taskBrushOdd;
        if (m_summaries.size() > row - 1) {
            const int index = row - 1; // index into summaries
            const bool active = DATAMODEL->isTaskActive(m_summaries[index].task);
            if (active) {
                field.hasHighlight = true;
                field.highlight = m_paintAttributes.halfHighlight;
            }
            int day = column - 1;
            if (column == TaskColumn) {
                field.text = DATAMODEL->taskIdAndSmartNameString(m_summaries[index].task);
                field.font = m_narrowFont;
            } else if (column == TotalsColumn) {
                const QVector<int> &durations = m_summaries[index].durations;
                const int total = std::accumulate(durations.begin(), durations.end(), 0);
                field.text = hoursAndMinutes(total);
            } else {
                int duration = m_summaries[index].durations[day];
                field.text = duration > 0 ? hoursAndMinutes(duration) : QString();
                // highlight today as well, with the half highlight:
                if (day == m_dayOfWeek -1) {
                    field.hasHighlight = true;
                    field.storeAsActive = active;
                    field.highlight
                        = active ? QBrush(m_paintAttributes.runningTaskColor) : m_paintAttributes.
                          halfHighlight;
                }
            }
        }
    }
}

void TimeTrackingView::setSummaries(const QVector<WeeklySummary> &summaries)
{
    m_activeFieldRects.clear();
    m_summaries = summaries;
    m_cachedMinimumSizeHint = QSize();
    m_cachedSizeHint = QSize();
    m_dayOfWeek = QDate::currentDate().dayOfWeek();
    m_elidedTexts.clear();
    updateGeometry();
    update();
    // populate menu:
    m_taskSelector->populate(m_summaries);
    // FIXME maybe remember last selected task
    handleActiveEvents();
    emit taskMenuChanged();
}

bool TimeTrackingView::isTracking() const
{
    return DATAMODEL->activeEventCount() > 0;
}

void TimeTrackingView::configurationChanged()
{
    m_fixedFont = font();
#ifdef Q_OS_OSX
    m_fixedFont.setFamily(QStringLiteral("Andale Mono"));
    m_fixedFont.setPointSize(11);
#endif

    switch (CONFIGURATION.timeTrackerFontSize) {
    case Configuration::TimeTrackerFont_Small:
        m_fixedFont.setPointSizeF(0.9 * m_fixedFont.pointSize());
        break;
    case Configuration::TimeTrackerFont_Regular:
        break;
    case Configuration::TimeTrackerFont_Large:
        m_fixedFont.setPointSizeF(1.2 * m_fixedFont.pointSize());
        break;
    }

    // re-populate menu:
    m_taskSelector->populate(m_summaries);
    emit taskMenuChanged();

    m_narrowFont = font(); // stay with the desktop
    m_narrowFont.setPointSize(m_fixedFont.pointSize());

    /* invalidate cache and force recalc */
    m_cachedSizeHint = QSize();
    m_cachedMinimumSizeHint = QSize();
    updateGeometry();
    sizeHint();

    /* force repaint */
    repaint();
}

void TimeTrackingView::handleActiveEvents()
{
    m_activeFieldRects.clear();
    Q_ASSERT(DATAMODEL->activeEventCount() >= 0);

    m_taskSelector->handleActiveEvents();
}

QString TimeTrackingView::elidedText(const QString &text, const QFont &font, int width)
{
    if (!m_elidedTexts.contains(text))
        m_elidedTexts.insert(text, Charm::elidedTaskName(text, font, width));
    Q_ASSERT(m_elidedTexts.contains(text));
    return m_elidedTexts.value(text);
}

void TimeTrackingView::slotUpdateSummaries()
{
    setSummaries(m_summaries);
}

bool TimeTrackingView::taskIsValidAndTrackable(int taskId)
{
    const Task &task = DATAMODEL->getTask(taskId);

    bool expired = !task.isCurrentlyValid();
    bool trackable = task.trackable();
    bool notTrackableAndExpired = (!trackable && expired);
    const auto id = QString::number(task.id());
    const QString name = task.name();
    QString expirationDate = QLocale::system().toString(task.validUntil(), QLocale::ShortFormat);

    if (!trackable || expired) {
        QString message = notTrackableAndExpired ? tr(
            "The task %1 (%2) is not trackable and expired since %3").arg(id, name, expirationDate)
                          : expired ? tr("The task %1 (%2) is expired since %3").arg(id, name,
                                                                                     expirationDate)
                          : tr("The task %1 (%2) is not trackable").arg(id, name);

        QMessageBox::information(this, tr("Please choose another task"), message);
        return false;
    }
    return true;
}