//! \file Bitmap.hpp
//! Interface of the Bitmap class.

#pragma once

#include <Gosu/Fwd.hpp>
#include <Gosu/Color.hpp>
#include <Gosu/GraphicsBase.hpp>
#include <Gosu/Platform.hpp>
#include <string>
#include <vector>

namespace Gosu
{
    //! Rectangular area of pixels, each represented by a Color value. Provides
    //! minimal drawing functionality and serves as a temporary holder for
    //! graphical resources which are usually turned into Images later.
    //! Has (expensive) value semantics.
    class Bitmap
    {
        unsigned w, h;
        std::vector<Color> pixels;

    public:
        Bitmap()
        : w(0), h(0)
        {
        }
        
        Bitmap(unsigned w, unsigned h, Color c = Color::NONE)
        : w(w), h(h), pixels(w * h, c)
        {
        }
        
        unsigned width() const
        {
            return w;
        }
        
        unsigned height() const
        {
            return h;
        }

        void swap(Bitmap& other);

        void resize(unsigned width, unsigned height, Color c = Color::NONE);
        
        //! Returns the color at the specified position. x and y must be on the
        //! bitmap.
        Color get_pixel(unsigned x, unsigned y) const
        {
            return pixels[y * w + x];
        }

        //! Sets the pixel at the specified position to a color. x and y must
        //! be on the bitmap.
        void set_pixel(unsigned x, unsigned y, Color c)
        {
            pixels[y * w + x] = c;
        }

        //! Inserts a bitmap at the given position. Parts of the inserted
        //! bitmap that would be outside of the target bitmap will be
        //! clipped away.
        void insert(const Bitmap& source, int x, int y);

        //! Inserts a portion of a bitmap at the given position. Parts of the
        //! inserted bitmap that would be outside of the target bitmap will be
        //! clipped away.
        void insert(const Bitmap& source, int x, int y, unsigned src_x, unsigned src_y,
            unsigned src_width, unsigned src_height);

        //! Direct access to the array of color values. May be useful for optimized
        //! OpenGL operations.
        const Color* data() const
        {
            return &pixels[0];
        }
        
        Color* data()
        {
            return &pixels[0];
        }
    };
    
    //! Loads any supported image into a Bitmap.
    void load_image_file(Bitmap& bitmap, const std::string& filename);
    //! Loads any supported image into a Bitmap.
    void load_image_file(Bitmap& bitmap, Reader input);
    
    //! Saves a Bitmap to a file.
    void save_image_file(const Bitmap& bitmap, const std::string& filename);
    //! Saves a Bitmap to an arbitrary resource.
    void save_image_file(const Bitmap& bitmap, Writer writer,
        const std::string& format_hint = "png");

    //! Set the alpha value of all pixels which are equal to the color key
    //! to zero. Color values are adjusted so that no borders show up when
    //! the image is stretched or rotated.
    void apply_color_key(Bitmap& bitmap, Color key);
    
    //! The reverse of apply_color_key. Resets all fully transparent pixels by
    //! a background color, makes all other pixels fully opaque.
    void unapply_color_key(Bitmap& bitmap, Color background);
    
    void apply_border_flags(Bitmap& dest, const Bitmap& source, unsigned src_x, unsigned src_y,
        unsigned src_width, unsigned src_height, unsigned border_flags);
}