// Copyright 2010 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.

#ifndef CC_BASE_TILING_DATA_H_
#define CC_BASE_TILING_DATA_H_

#include <utility>

#include "base/basictypes.h"
#include "base/logging.h"
#include "cc/base/cc_export.h"
#include "ui/gfx/rect.h"
#include "ui/gfx/size.h"

namespace gfx {
class Vector2d;
}

namespace cc {

class CC_EXPORT TilingData {
 public:
  TilingData();
  TilingData(const gfx::Size& max_texture_size,
             const gfx::Rect& tiling_rect,
             bool has_border_texels);
  TilingData(const gfx::Size& max_texture_size,
             const gfx::Rect& tiling_rect,
             int border_texels);

  gfx::Rect tiling_rect() const { return tiling_rect_; }
  void SetTilingRect(const gfx::Rect& tiling_rect);

  gfx::Size max_texture_size() const { return max_texture_size_; }
  void SetMaxTextureSize(const gfx::Size& max_texture_size);

  int border_texels() const { return border_texels_; }
  void SetHasBorderTexels(bool has_border_texels);
  void SetBorderTexels(int border_texels);

  bool has_empty_bounds() const { return !num_tiles_x_ || !num_tiles_y_; }
  int num_tiles_x() const { return num_tiles_x_; }
  int num_tiles_y() const { return num_tiles_y_; }
  // Return the tile index whose non-border texels include src_position.
  int TileXIndexFromSrcCoord(int src_position) const;
  int TileYIndexFromSrcCoord(int src_position) const;
  // Return the lowest tile index whose border texels include src_position.
  int FirstBorderTileXIndexFromSrcCoord(int src_position) const;
  int FirstBorderTileYIndexFromSrcCoord(int src_position) const;
  // Return the highest tile index whose border texels include src_position.
  int LastBorderTileXIndexFromSrcCoord(int src_position) const;
  int LastBorderTileYIndexFromSrcCoord(int src_position) const;

  gfx::Rect ExpandRectToTileBoundsWithBorders(const gfx::Rect& rect) const;
  gfx::Rect ExpandRectToTileBounds(const gfx::Rect& rect) const;

  gfx::Rect TileBounds(int i, int j) const;
  gfx::Rect TileBoundsWithBorder(int i, int j) const;
  int TilePositionX(int x_index) const;
  int TilePositionY(int y_index) const;
  int TileSizeX(int x_index) const;
  int TileSizeY(int y_index) const;

  // Difference between TileBound's and TileBoundWithBorder's origin().
  gfx::Vector2d TextureOffset(int x_index, int y_index) const;

  class CC_EXPORT BaseIterator {
   public:
    operator bool() const { return index_x_ != -1 && index_y_ != -1; }

    int index_x() const { return index_x_; }
    int index_y() const { return index_y_; }
    std::pair<int, int> index() const {
     return std::make_pair(index_x_, index_y_);
    }

   protected:
    explicit BaseIterator(const TilingData* tiling_data);
    void done() {
      index_x_ = -1;
      index_y_ = -1;
    }

    const TilingData* tiling_data_;
    int index_x_;
    int index_y_;
  };

  // Iterate through tiles whose bounds + optional border intersect with |rect|.
  class CC_EXPORT Iterator : public BaseIterator {
   public:
    Iterator();
    Iterator(const TilingData* tiling_data,
             const gfx::Rect& tiling_rect,
             bool include_borders);
    Iterator& operator++();

   private:
    int left_;
    int right_;
    int bottom_;
  };

  // Iterate through all indices whose bounds + border intersect with
  // |consider| but which also do not intersect with |ignore|.
  class CC_EXPORT DifferenceIterator : public BaseIterator {
   public:
    DifferenceIterator(
      const TilingData* tiling_data,
      const gfx::Rect& consider_rect,
      const gfx::Rect& ignore_rect);
    DifferenceIterator& operator++();

   private:
    bool in_ignore_rect() const {
     return index_x_ >= ignore_left_ && index_x_ <= ignore_right_ &&
       index_y_ >= ignore_top_ && index_y_ <= ignore_bottom_;
    }

    int consider_left_;
    int consider_top_;
    int consider_right_;
    int consider_bottom_;
    int ignore_left_;
    int ignore_top_;
    int ignore_right_;
    int ignore_bottom_;
  };

  // Iterate through all indices whose bounds + border intersect with
  // |consider| but which also do not intersect with |ignore|. The iterator
  // order is a counterclockwise spiral around the given center.
  class CC_EXPORT SpiralDifferenceIterator : public BaseIterator {
   public:
    SpiralDifferenceIterator();
    SpiralDifferenceIterator(const TilingData* tiling_data,
                             const gfx::Rect& consider_rect,
                             const gfx::Rect& ignore_rect,
                             const gfx::Rect& center_rect);
    SpiralDifferenceIterator& operator++();

   private:
    bool in_consider_rect() const {
      return index_x_ >= consider_left_ && index_x_ <= consider_right_ &&
             index_y_ >= consider_top_ && index_y_ <= consider_bottom_;
    }
    bool in_ignore_rect() const {
      return index_x_ >= ignore_left_ && index_x_ <= ignore_right_ &&
             index_y_ >= ignore_top_ && index_y_ <= ignore_bottom_;
    }
    bool valid_column() const {
      return index_x_ >= consider_left_ && index_x_ <= consider_right_;
    }
    bool valid_row() const {
      return index_y_ >= consider_top_ && index_y_ <= consider_bottom_;
    }

    int current_step_count() const {
      return (direction_ == UP || direction_ == DOWN) ? vertical_step_count_
                                                      : horizontal_step_count_;
    }

    bool needs_direction_switch() const;
    void switch_direction();

    int consider_left_;
    int consider_top_;
    int consider_right_;
    int consider_bottom_;
    int ignore_left_;
    int ignore_top_;
    int ignore_right_;
    int ignore_bottom_;

    enum Direction { UP, LEFT, DOWN, RIGHT };

    Direction direction_;
    int delta_x_;
    int delta_y_;
    int current_step_;
    int horizontal_step_count_;
    int vertical_step_count_;
  };

 private:
  void AssertTile(int i, int j) const {
    DCHECK_GE(i,  0);
    DCHECK_LT(i, num_tiles_x_);
    DCHECK_GE(j, 0);
    DCHECK_LT(j, num_tiles_y_);
  }

  void RecomputeNumTiles();

  gfx::Size max_texture_size_;
  gfx::Rect tiling_rect_;
  int border_texels_;

  // These are computed values.
  int num_tiles_x_;
  int num_tiles_y_;
};

}  // namespace cc

#endif  // CC_BASE_TILING_DATA_H_