// ================================================================================
// ==      This file is a part of Turbo Badger. (C) 2011-2014, Emil Segerås      ==
// ==                     See tb_core.h for more information.                    ==
// ================================================================================

#include "tb_scroll_container.h"
#include "tb_system.h"
#include <assert.h>

namespace tb {

// == TBScrollBarVisibility ===================================

TBScrollBarVisibility TBScrollBarVisibility::Solve(SCROLL_MODE mode, int content_w, int content_h,
                                                   int available_w, int available_h,
                                                   int scrollbar_x_h, int scrollbar_y_w)
{
    TBScrollBarVisibility visibility;
    visibility.visible_w = available_w;
    visibility.visible_h = available_h;

    if (mode == SCROLL_MODE_X_Y)
    {
        visibility.y_on = true;
        visibility.x_on = true;
        visibility.visible_w -= scrollbar_y_w;
        visibility.visible_h -= scrollbar_x_h;
    }
    else if (mode == SCROLL_MODE_OFF)
    {
    }
    else if (mode == SCROLL_MODE_Y)
    {
        visibility.y_on = true;
        visibility.visible_w -= scrollbar_y_w;
    }
    else if (mode == SCROLL_MODE_Y_AUTO)
    {
        if (content_h > available_h)
        {
            visibility.y_on = true;
            visibility.visible_w -= scrollbar_y_w;
        }
    }
    else if (mode == SCROLL_MODE_X_AUTO_Y_AUTO)
    {
        if (content_w > visibility.visible_w)
        {
            visibility.x_on = true;
            visibility.visible_h = available_h - scrollbar_x_h;
        }
        if (content_h > visibility.visible_h)
        {
            visibility.y_on = true;
            visibility.visible_w = available_w - scrollbar_y_w;
        }
        if (content_w > visibility.visible_w)
        {
            visibility.x_on = true;
            visibility.visible_h = available_h - scrollbar_x_h;
        }
    }
    return visibility;
}

// == TBScrollContainerRoot ===================================

void TBScrollContainerRoot::OnPaintChildren(const PaintProps &paint_props)
{
    // We only want clipping in one axis (the overflowing one) so we
    // don't damage any expanded skins on the other axis. Add some fluff.
    const int fluff = 100;
    TBScrollContainer *sc = static_cast<TBScrollContainer *>(GetParent());
    TBRect clip_rect = GetPaddingRect().Expand(sc->m_scrollbar_x.CanScrollNegative() ? 0 : fluff,
                                               sc->m_scrollbar_y.CanScrollNegative() ? 0 : fluff,
                                               sc->m_scrollbar_x.CanScrollPositive() ? 0 : fluff,
                                               sc->m_scrollbar_y.CanScrollPositive() ? 0 : fluff);

    TBRect old_clip_rect = g_renderer->SetClipRect(clip_rect, true);

    TB_IF_DEBUG_SETTING(LAYOUT_CLIPPING, g_renderer->DrawRect(clip_rect, TBColor(255, 0, 0, 200)));

    TBWidget::OnPaintChildren(paint_props);

    g_renderer->SetClipRect(old_clip_rect, false);
}

void TBScrollContainerRoot::GetChildTranslation(int &x, int &y) const
{
    TBScrollContainer *sc = static_cast<TBScrollContainer *>(GetParent());
    x = (int) -sc->m_scrollbar_x.GetValue();
    y = (int) -sc->m_scrollbar_y.GetValue();
}

// == TBScrollContainer =======================================

TBScrollContainer::TBScrollContainer()
    : m_adapt_to_content_size(false)
    , m_adapt_content_size(false)
    , m_layout_is_invalid(false)
    , m_ignore_scroll_events(false)
    , m_mode(SCROLL_MODE_X_Y)
{
    AddChild(&m_scrollbar_x);
    AddChild(&m_scrollbar_y);
    AddChild(&m_root);
    m_scrollbar_y.SetAxis(AXIS_Y);
}

TBScrollContainer::~TBScrollContainer()
{
    RemoveChild(&m_root);
    RemoveChild(&m_scrollbar_y);
    RemoveChild(&m_scrollbar_x);
}

void TBScrollContainer::SetAdaptToContentSize(bool adapt)
{
    if (m_adapt_to_content_size == adapt)
        return;
    InvalidateLayout(INVALIDATE_LAYOUT_RECURSIVE);
    m_adapt_to_content_size = adapt;
    InvalidateLayout(INVALIDATE_LAYOUT_RECURSIVE);
}

void TBScrollContainer::SetAdaptContentSize(bool adapt)
{
    if (m_adapt_content_size == adapt)
        return;
    m_adapt_content_size = adapt;
    InvalidateLayout(INVALIDATE_LAYOUT_TARGET_ONLY);
}

void TBScrollContainer::SetScrollMode(SCROLL_MODE mode)
{
    if (mode == m_mode)
        return;
    m_mode = mode;
    InvalidateLayout(INVALIDATE_LAYOUT_TARGET_ONLY);
}

void TBScrollContainer::ScrollTo(int x, int y)
{
    int old_x = m_scrollbar_x.GetValue();
    int old_y = m_scrollbar_y.GetValue();
    m_scrollbar_x.SetValue(x);
    m_scrollbar_y.SetValue(y);
    if (old_x != m_scrollbar_x.GetValue() ||
            old_y != m_scrollbar_y.GetValue())
        Invalidate();
}

TBWidget::ScrollInfo TBScrollContainer::GetScrollInfo()
{
    ScrollInfo info;
    info.min_x = static_cast<int>(m_scrollbar_x.GetMinValue());
    info.min_y = static_cast<int>(m_scrollbar_y.GetMinValue());
    info.max_x = static_cast<int>(m_scrollbar_x.GetMaxValue());
    info.max_y = static_cast<int>(m_scrollbar_y.GetMaxValue());
    info.x = m_scrollbar_x.GetValue();
    info.y = m_scrollbar_y.GetValue();
    return info;
}

void TBScrollContainer::InvalidateLayout(INVALIDATE_LAYOUT il)
{
    m_layout_is_invalid = true;
    // No recursion up to parents here unless we adapt to content size.
    if (m_adapt_to_content_size)
        TBWidget::InvalidateLayout(il);
}

TBRect TBScrollContainer::GetPaddingRect()
{
    int visible_w = GetRect().w;
    int visible_h = GetRect().h;
    if (m_scrollbar_x.GetOpacity())
        visible_h -= m_scrollbar_x.GetPreferredSize().pref_h;
    if (m_scrollbar_y.GetOpacity())
        visible_w -= m_scrollbar_y.GetPreferredSize().pref_w;
    return TBRect(0, 0, visible_w, visible_h);
}

PreferredSize TBScrollContainer::OnCalculatePreferredContentSize(const SizeConstraints &constraints)
{
    PreferredSize ps;
    ps.pref_w = ps.pref_h = 100;
    ps.min_w = ps.min_h = 50;
    if (m_adapt_to_content_size)
    {
        if (TBWidget *content_child = m_root.GetFirstChild())
        {
            ps = content_child->GetPreferredSize(constraints);
            int scrollbar_y_w = m_scrollbar_y.GetPreferredSize().pref_w;
            int scrollbar_x_h = m_scrollbar_x.GetPreferredSize().pref_h;

            ps.pref_w += scrollbar_y_w;
            ps.max_w += scrollbar_y_w;

            if (m_mode == SCROLL_MODE_X_Y ||
                    m_mode == SCROLL_MODE_X_AUTO_Y_AUTO)
            {
                ps.pref_h += scrollbar_x_h;
                ps.max_h += scrollbar_x_h;
            }
        }
    }
    return ps;
}

bool TBScrollContainer::OnEvent(const TBWidgetEvent &ev)
{
    if (ev.type == EVENT_TYPE_CHANGED && (ev.target == &m_scrollbar_x || ev.target == &m_scrollbar_y))
    {
        Invalidate();
        OnScroll(m_scrollbar_x.GetValue(), m_scrollbar_y.GetValue());
        return true;
    }
    else if (ev.type == EVENT_TYPE_WHEEL && ev.modifierkeys == TB_MODIFIER_NONE && !m_ignore_scroll_events)
    {
        double old_val_y = m_scrollbar_y.GetValueDouble();
        m_scrollbar_y.SetValueDouble(old_val_y + ev.delta_y * TBSystem::GetPixelsPerLine());
        double old_val_x = m_scrollbar_x.GetValueDouble();
        m_scrollbar_x.SetValueDouble(old_val_x + ev.delta_x * TBSystem::GetPixelsPerLine());
        return (m_scrollbar_x.GetValueDouble() != old_val_x || m_scrollbar_y.GetValueDouble() != old_val_y);
    }
    else if (ev.type == EVENT_TYPE_KEY_DOWN && !m_ignore_scroll_events)
    {
        // ATOMIC: Disabling arrow key scroll
        /*
        if (ev.special_key == TB_KEY_LEFT && m_scrollbar_x.CanScrollNegative())
            ScrollBySmooth(-TBSystem::GetPixelsPerLine(), 0);
        else if (ev.special_key == TB_KEY_RIGHT && m_scrollbar_x.CanScrollPositive())
            ScrollBySmooth(TBSystem::GetPixelsPerLine(), 0);
        else if (ev.special_key == TB_KEY_UP && m_scrollbar_y.CanScrollNegative())
            ScrollBySmooth(0, -TBSystem::GetPixelsPerLine());
        else if (ev.special_key == TB_KEY_DOWN && m_scrollbar_y.CanScrollPositive())
            ScrollBySmooth(0, TBSystem::GetPixelsPerLine());
        else*/ if (ev.special_key == TB_KEY_PAGE_UP && m_scrollbar_y.CanScrollNegative())
            ScrollBySmooth(0, -GetPaddingRect().h);
        else if (ev.special_key == TB_KEY_PAGE_DOWN && m_scrollbar_y.CanScrollPositive())
            ScrollBySmooth(0, GetPaddingRect().h);
        else if (ev.special_key == TB_KEY_HOME)
            ScrollToSmooth(m_scrollbar_x.GetValue(), 0);
        else if (ev.special_key == TB_KEY_END)
            ScrollToSmooth(m_scrollbar_x.GetValue(), (int)m_scrollbar_y.GetMaxValue());
        else
            return false;
        return true;
    }
    return false;
}

void TBScrollContainer::OnProcess()
{
    SizeConstraints sc(GetRect().w, GetRect().h);
    ValidateLayout(sc);
}

void TBScrollContainer::ValidateLayout(const SizeConstraints &constraints)
{
    if (!m_layout_is_invalid)
        return;
    m_layout_is_invalid = false;

    // Layout scrollbars (no matter if they are visible or not)
    int scrollbar_y_w = m_scrollbar_y.GetPreferredSize().pref_w;
    int scrollbar_x_h = m_scrollbar_x.GetPreferredSize().pref_h;
    m_scrollbar_x.SetRect(TBRect(0, GetRect().h - scrollbar_x_h, GetRect().w - scrollbar_y_w, scrollbar_x_h));
    m_scrollbar_y.SetRect(TBRect(GetRect().w - scrollbar_y_w, 0, scrollbar_y_w, GetRect().h));

    if (TBWidget *content_child = m_root.GetFirstChild())
    {
        int horizontal_padding = TBScrollBarVisibility::IsAlwaysOnY(m_mode) ? scrollbar_y_w : 0;
        int vertical_padding = TBScrollBarVisibility::IsAlwaysOnX(m_mode) ? scrollbar_x_h : 0;

        SizeConstraints inner_sc = constraints.ConstrainByPadding(horizontal_padding, vertical_padding);

        PreferredSize ps = content_child->GetPreferredSize(inner_sc);

        TBScrollBarVisibility visibility = TBScrollBarVisibility::Solve(m_mode, ps.pref_w, ps.pref_h,
                                                                        GetRect().w, GetRect().h,
                                                                        scrollbar_x_h, scrollbar_y_w);
        m_scrollbar_x.SetOpacity(visibility.x_on ? 1.f : 0.f);
        m_scrollbar_y.SetOpacity(visibility.y_on ? 1.f : 0.f);
        m_root.SetRect(TBRect(0, 0, visibility.visible_w, visibility.visible_h));

        int content_w, content_h;
        if (m_adapt_content_size)
        {
            content_w = MAX(ps.pref_w, m_root.GetRect().w);
            content_h = MAX(ps.pref_h, m_root.GetRect().h);
            if (!visibility.x_on && m_root.GetRect().w < ps.pref_w)
                content_w = MIN(ps.pref_w, m_root.GetRect().w);
        }
        else
        {
            content_w = ps.pref_w;
            content_h = ps.pref_h;
        }

        content_child->SetRect(TBRect(0, 0, content_w, content_h));
        double limit_max_w = MAX(0, content_w - m_root.GetRect().w);
        double limit_max_h = MAX(0, content_h - m_root.GetRect().h);
        m_scrollbar_x.SetLimits(0, limit_max_w, m_root.GetRect().w);
        m_scrollbar_y.SetLimits(0, limit_max_h, m_root.GetRect().h);
    }
}

void TBScrollContainer::OnResized(int old_w, int old_h)
{
    InvalidateLayout(INVALIDATE_LAYOUT_TARGET_ONLY);
    SizeConstraints sc(GetRect().w, GetRect().h);
    ValidateLayout(sc);
}

}; // namespace tb