package allegro5

// #include <allegro5/allegro.h>
// #include <stdlib.h>
import "C"

import (
  "fmt"
  "unsafe"
)

// Bitmap represents an in memory bitmap
type Bitmap struct {
  bitmap *C.ALLEGRO_BITMAP
  width int
  height int
}

type DrawOptions struct {
  Center bool
  Scale *Scale
  Tint *Color
}

type Scale struct {
  Horizontal float32
  Vertical float32  
}

// NewBitmap creates a new bitmap of given width and height
func NewBitmap(width, height int) (*Bitmap, error) {
  b := C.al_create_bitmap(C.int(width), C.int(height))
  if nil == b {
    return nil, fmt.Errorf("Error creating bitmap")
  }
  return &Bitmap{b, width, height}, nil
}

// LoadBitmap tries to load the image at the specified path as a bitmap 
func LoadBitmap(path string) (*Bitmap, error) {
  p := C.CString(path)
  defer C.free(unsafe.Pointer(p))
  b := C.al_load_bitmap(p)
  if nil == b {
    return nil, fmt.Errorf("Error loading bitmap")
  }
  width := int(C.al_get_bitmap_width(b))
  height := int(C.al_get_bitmap_height(b))
  return &Bitmap{b, width, height}, nil
}

// Draw draws the bitmap at the given location
func (b *Bitmap) Draw(left, top float32) {
  C.al_draw_bitmap(b.bitmap, C.float(left), C.float(top), 0)
}

func (b *Bitmap) DrawOptions(left, top float32, options DrawOptions) {
  width := float32(b.width)
  height := float32(b.height)

  scale := nil != options.Scale
  if scale {
    width *= options.Scale.Horizontal
    height *= options.Scale.Vertical
  }
  if options.Center {
    left -= width * 0.5
    top -= height * 0.5 
  }
  
  if scale {
    if nil == options.Tint {
      C.al_draw_scaled_bitmap(b.bitmap, 0, 0, C.float(b.width), C.float(b.height), C.float(left), C.float(top), C.float(width), C.float(height), 0)
    } else {
      C.al_draw_tinted_scaled_bitmap(b.bitmap, options.Tint.color, 0, 0, C.float(b.width), C.float(b.height), C.float(left), C.float(top), C.float(width), C.float(height), 0)
    }
  } else {
    if nil == options.Tint {
      C.al_draw_bitmap(b.bitmap, C.float(left), C.float(top), 0)
    } else {
      C.al_draw_tinted_bitmap(b.bitmap, options.Tint.color, C.float(left), C.float(top), 0)
    }
  }
}

func (b *Bitmap) Width() int {
  return b.width
}

func (b *Bitmap) Height() int {
  return b.height
}

// Destroy destroys the bitmap
func (b *Bitmap) Destroy() {
  C.al_destroy_bitmap(b.bitmap)
}