// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/views/layout/box_layout.h"

#include "ui/gfx/insets.h"
#include "ui/gfx/rect.h"
#include "ui/views/view.h"

namespace views {

BoxLayout::BoxLayout(BoxLayout::Orientation orientation,
                     int inside_border_horizontal_spacing,
                     int inside_border_vertical_spacing,
                     int between_child_spacing)
    : orientation_(orientation),
      inside_border_horizontal_spacing_(inside_border_horizontal_spacing),
      inside_border_vertical_spacing_(inside_border_vertical_spacing),
      between_child_spacing_(between_child_spacing),
      spread_blank_space_(false) {
}

BoxLayout::~BoxLayout() {
}

void BoxLayout::Layout(View* host) {
  gfx::Rect child_area(host->GetLocalBounds());
  child_area.Inset(host->GetInsets());
  child_area.Inset(inside_border_horizontal_spacing_,
                   inside_border_vertical_spacing_);
  int x = child_area.x();
  int y = child_area.y();

  int padding = 0;
  if (spread_blank_space_) {
    int total = 0;
    int visible = 0;
    for (int i = 0; i < host->child_count(); ++i) {
      View* child = host->child_at(i);
      if (!child->visible())
        continue;
      if (orientation_ == kHorizontal)
        total += child->GetPreferredSize().width() + between_child_spacing_;
      else
        total += child->GetPreferredSize().height() + between_child_spacing_;
      ++visible;
    }

    if (visible) {
      total -= between_child_spacing_;
      if (orientation_ == kHorizontal)
        padding = (child_area.width() - total) / visible;
      else
        padding = (child_area.height() - total) / visible;

      if (padding < 0)
        padding = 0;
    }
  }

  for (int i = 0; i < host->child_count(); ++i) {
    View* child = host->child_at(i);
    if (child->visible()) {
      gfx::Rect bounds(x, y, child_area.width(), child_area.height());
      gfx::Size size(child->GetPreferredSize());
      if (orientation_ == kHorizontal) {
        bounds.set_width(size.width() + padding);
        x += size.width() + between_child_spacing_ + padding;
      } else {
        bounds.set_height(size.height() + padding);
        y += size.height() + between_child_spacing_ + padding;
      }
      // Clamp child view bounds to |child_area|.
      bounds.Intersect(child_area);
      child->SetBoundsRect(bounds);
    }
  }
}

gfx::Size BoxLayout::GetPreferredSize(View* host) {
  gfx::Rect bounds;
  int position = 0;
  for (int i = 0; i < host->child_count(); ++i) {
    View* child = host->child_at(i);
    if (child->visible()) {
      gfx::Size size(child->GetPreferredSize());
      if (orientation_ == kHorizontal) {
        gfx::Rect child_bounds(position, 0, size.width(), size.height());
        bounds.Union(child_bounds);
        position += size.width();
      } else {
        gfx::Rect child_bounds(0, position, size.width(), size.height());
        bounds.Union(child_bounds);
        position += size.height();
      }
      position += between_child_spacing_;
    }
  }
  gfx::Insets insets(host->GetInsets());
  return gfx::Size(
      bounds.width() + insets.width() + 2 * inside_border_horizontal_spacing_,
      bounds.height() + insets.height() + 2 * inside_border_vertical_spacing_);
}

} // namespace views