/*
This is the core graphics library for all our displays, providing a common
set of graphics primitives (points, lines, circles, etc.).  It needs to be
paired with a hardware-specific library for each display device we carry
(to handle the lower-level functions).

Adafruit invests time and resources providing this open source code, please
support Adafruit & open-source hardware by purchasing products from Adafruit!
 
Copyright (c) 2013 Adafruit Industries.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

- Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*
* Modified the AdaFruit library to be a C library, changed the font and
* generally munged it in a variety of ways, creating a reasonably quick
* and dirty way to put something "interesting" on the LCD display.
* --Chuck McManis (2013, 2014)
*
*/

#include <stdint.h>
#include <math.h>
#include <stdlib.h>
#include "gfx.h"
#include "font-7x12.c"

#define pgm_read_byte(addr) (*(const unsigned char *)(addr))

struct gfx_state __gfx_state;

void
gfx_drawPixel(int x, int y, uint16_t color) {
    if ((x < 0) || (x >= __gfx_state._width) ||
        (y < 0) || (y >= __gfx_state._height)) {
        return; // off screen so don't draw it
    }
    (__gfx_state.drawpixel)(x, y, color);
}
#define true 1

void
gfx_init(void (*pixel_func)(int, int, uint16_t), int width, int height)
{
  __gfx_state._width    = width;
  __gfx_state._height   = height;
  __gfx_state.rotation  = 0;
  __gfx_state.cursor_y  = __gfx_state.cursor_x    = 0;
  __gfx_state.textsize  = 1;
  __gfx_state.textcolor = 0;
  __gfx_state.textbgcolor = 0xFFFF;
  __gfx_state.wrap      = true;
  __gfx_state.drawpixel = pixel_func;
}

// Draw a circle outline
void gfx_drawCircle(int16_t x0, int16_t y0, int16_t r,
    uint16_t color) {
  int16_t f = 1 - r;
  int16_t ddF_x = 1;
  int16_t ddF_y = -2 * r;
  int16_t x = 0;
  int16_t y = r;

  gfx_drawPixel(x0  , y0+r, color);
  gfx_drawPixel(x0  , y0-r, color);
  gfx_drawPixel(x0+r, y0  , color);
  gfx_drawPixel(x0-r, y0  , color);

  while (x<y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f += ddF_y;
    }
    x++;
    ddF_x += 2;
    f += ddF_x;

    gfx_drawPixel(x0 + x, y0 + y, color);
    gfx_drawPixel(x0 - x, y0 + y, color);
    gfx_drawPixel(x0 + x, y0 - y, color);
    gfx_drawPixel(x0 - x, y0 - y, color);
    gfx_drawPixel(x0 + y, y0 + x, color);
    gfx_drawPixel(x0 - y, y0 + x, color);
    gfx_drawPixel(x0 + y, y0 - x, color);
    gfx_drawPixel(x0 - y, y0 - x, color);
  }
}

void gfx_drawCircleHelper( int16_t x0, int16_t y0,
               int16_t r, uint8_t cornername, uint16_t color) {
  int16_t f     = 1 - r;
  int16_t ddF_x = 1;
  int16_t ddF_y = -2 * r;
  int16_t x     = 0;
  int16_t y     = r;

  while (x<y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f     += ddF_y;
    }
    x++;
    ddF_x += 2;
    f     += ddF_x;
    if (cornername & 0x4) {
      gfx_drawPixel(x0 + x, y0 + y, color);
      gfx_drawPixel(x0 + y, y0 + x, color);
    } 
    if (cornername & 0x2) {
      gfx_drawPixel(x0 + x, y0 - y, color);
      gfx_drawPixel(x0 + y, y0 - x, color);
    }
    if (cornername & 0x8) {
      gfx_drawPixel(x0 - y, y0 + x, color);
      gfx_drawPixel(x0 - x, y0 + y, color);
    }
    if (cornername & 0x1) {
      gfx_drawPixel(x0 - y, y0 - x, color);
      gfx_drawPixel(x0 - x, y0 - y, color);
    }
  }
}

void gfx_fillCircle(int16_t x0, int16_t y0, int16_t r,
			      uint16_t color) {
  gfx_drawFastVLine(x0, y0-r, 2*r+1, color);
  gfx_fillCircleHelper(x0, y0, r, 3, 0, color);
}

// Used to do circles and roundrects
void gfx_fillCircleHelper(int16_t x0, int16_t y0, int16_t r,
    uint8_t cornername, int16_t delta, uint16_t color) {

  int16_t f     = 1 - r;
  int16_t ddF_x = 1;
  int16_t ddF_y = -2 * r;
  int16_t x     = 0;
  int16_t y     = r;

  while (x<y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f     += ddF_y;
    }
    x++;
    ddF_x += 2;
    f     += ddF_x;

    if (cornername & 0x1) {
      gfx_drawFastVLine(x0+x, y0-y, 2*y+1+delta, color);
      gfx_drawFastVLine(x0+y, y0-x, 2*x+1+delta, color);
    }
    if (cornername & 0x2) {
      gfx_drawFastVLine(x0-x, y0-y, 2*y+1+delta, color);
      gfx_drawFastVLine(x0-y, y0-x, 2*x+1+delta, color);
    }
  }
}

// Bresenham's algorithm - thx wikpedia
void gfx_drawLine(int16_t x0, int16_t y0,
			    int16_t x1, int16_t y1,
			    uint16_t color) {
  int16_t steep = abs(y1 - y0) > abs(x1 - x0);
  if (steep) {
    swap(x0, y0);
    swap(x1, y1);
  }

  if (x0 > x1) {
    swap(x0, x1);
    swap(y0, y1);
  }

  int16_t dx, dy;
  dx = x1 - x0;
  dy = abs(y1 - y0);

  int16_t err = dx / 2;
  int16_t ystep;

  if (y0 < y1) {
    ystep = 1;
  } else {
    ystep = -1;
  }

  for (; x0<=x1; x0++) {
    if (steep) {
      gfx_drawPixel(y0, x0, color);
    } else {
      gfx_drawPixel(x0, y0, color);
    }
    err -= dy;
    if (err < 0) {
      y0 += ystep;
      err += dx;
    }
  }
}

// Draw a rectangle
void gfx_drawRect(int16_t x, int16_t y,
			    int16_t w, int16_t h,
			    uint16_t color) {
  gfx_drawFastHLine(x, y, w, color);
  gfx_drawFastHLine(x, y+h-1, w, color);
  gfx_drawFastVLine(x, y, h, color);
  gfx_drawFastVLine(x+w-1, y, h, color);
}

void gfx_drawFastVLine(int16_t x, int16_t y,
				 int16_t h, uint16_t color) {
  // Update in subclasses if desired!
  gfx_drawLine(x, y, x, y+h-1, color);
}

void gfx_drawFastHLine(int16_t x, int16_t y,
				 int16_t w, uint16_t color) {
  // Update in subclasses if desired!
  gfx_drawLine(x, y, x+w-1, y, color);
}

void gfx_fillRect(int16_t x, int16_t y, int16_t w, int16_t h,
			    uint16_t color) {
  // Update in subclasses if desired!
  int16_t i;
  for (i=x; i<x+w; i++) {
    gfx_drawFastVLine(i, y, h, color);
  }
}

void gfx_fillScreen(uint16_t color) {
  gfx_fillRect(0, 0, __gfx_state._width, __gfx_state._height, color);
}

// Draw a rounded rectangle
void gfx_drawRoundRect(int16_t x, int16_t y, int16_t w,
  int16_t h, int16_t r, uint16_t color) {
  // smarter version
  gfx_drawFastHLine(x+r  , y    , w-2*r, color); // Top
  gfx_drawFastHLine(x+r  , y+h-1, w-2*r, color); // Bottom
  gfx_drawFastVLine(x    , y+r  , h-2*r, color); // Left
  gfx_drawFastVLine(x+w-1, y+r  , h-2*r, color); // Right
  // draw four corners
  gfx_drawCircleHelper(x+r    , y+r    , r, 1, color);
  gfx_drawCircleHelper(x+w-r-1, y+r    , r, 2, color);
  gfx_drawCircleHelper(x+w-r-1, y+h-r-1, r, 4, color);
  gfx_drawCircleHelper(x+r    , y+h-r-1, r, 8, color);
}

// Fill a rounded rectangle
void gfx_fillRoundRect(int16_t x, int16_t y, int16_t w,
				 int16_t h, int16_t r, uint16_t color) {
  // smarter version
  gfx_fillRect(x+r, y, w-2*r, h, color);

  // draw four corners
  gfx_fillCircleHelper(x+w-r-1, y+r, r, 1, h-2*r-1, color);
  gfx_fillCircleHelper(x+r    , y+r, r, 2, h-2*r-1, color);
}

// Draw a triangle
void gfx_drawTriangle(int16_t x0, int16_t y0,
				int16_t x1, int16_t y1,
				int16_t x2, int16_t y2, uint16_t color) {
  gfx_drawLine(x0, y0, x1, y1, color);
  gfx_drawLine(x1, y1, x2, y2, color);
  gfx_drawLine(x2, y2, x0, y0, color);
}

// Fill a triangle
void gfx_fillTriangle ( int16_t x0, int16_t y0,
				  int16_t x1, int16_t y1,
				  int16_t x2, int16_t y2, uint16_t color) {

  int16_t a, b, y, last;

  // Sort coordinates by Y order (y2 >= y1 >= y0)
  if (y0 > y1) {
    swap(y0, y1); swap(x0, x1);
  }
  if (y1 > y2) {
    swap(y2, y1); swap(x2, x1);
  }
  if (y0 > y1) {
    swap(y0, y1); swap(x0, x1);
  }

  if(y0 == y2) { // Handle awkward all-on-same-line case as its own thing
    a = b = x0;
    if(x1 < a)      a = x1;
    else if(x1 > b) b = x1;
    if(x2 < a)      a = x2;
    else if(x2 > b) b = x2;
    gfx_drawFastHLine(a, y0, b-a+1, color);
    return;
  }

  int16_t
    dx01 = x1 - x0,
    dy01 = y1 - y0,
    dx02 = x2 - x0,
    dy02 = y2 - y0,
    dx12 = x2 - x1,
    dy12 = y2 - y1,
    sa   = 0,
    sb   = 0;

  // For upper part of triangle, find scanline crossings for segments
  // 0-1 and 0-2.  If y1=y2 (flat-bottomed triangle), the scanline y1
  // is included here (and second loop will be skipped, avoiding a /0
  // error there), otherwise scanline y1 is skipped here and handled
  // in the second loop...which also avoids a /0 error here if y0=y1
  // (flat-topped triangle).
  if(y1 == y2) last = y1;   // Include y1 scanline
  else         last = y1-1; // Skip it

  for(y=y0; y<=last; y++) {
    a   = x0 + sa / dy01;
    b   = x0 + sb / dy02;
    sa += dx01;
    sb += dx02;
    /* longhand:
    a = x0 + (x1 - x0) * (y - y0) / (y1 - y0);
    b = x0 + (x2 - x0) * (y - y0) / (y2 - y0);
    */
    if(a > b) swap(a,b);
    gfx_drawFastHLine(a, y, b-a+1, color);
  }

  // For lower part of triangle, find scanline crossings for segments
  // 0-2 and 1-2.  This loop is skipped if y1=y2.
  sa = dx12 * (y - y1);
  sb = dx02 * (y - y0);
  for(; y<=y2; y++) {
    a   = x1 + sa / dy12;
    b   = x0 + sb / dy02;
    sa += dx12;
    sb += dx02;
    /* longhand:
    a = x1 + (x2 - x1) * (y - y1) / (y2 - y1);
    b = x0 + (x2 - x0) * (y - y0) / (y2 - y0);
    */
    if(a > b) swap(a,b);
    gfx_drawFastHLine(a, y, b-a+1, color);
  }
}

void gfx_drawBitmap(int16_t x, int16_t y,
			      const uint8_t *bitmap, int16_t w, int16_t h,
			      uint16_t color) {

  int16_t i, j, byteWidth = (w + 7) / 8;

  for(j=0; j<h; j++) {
    for(i=0; i<w; i++ ) {
      if(pgm_read_byte(bitmap + j * byteWidth + i / 8) & (128 >> (i & 7))) {
	gfx_drawPixel(x+i, y+j, color);
      }
    }
  }
}

void gfx_write(uint8_t c) {
  if (c == '\n') {
    __gfx_state.cursor_y += __gfx_state.textsize*12;
    __gfx_state.cursor_x  = 0;
  } else if (c == '\r') {
    // skip em
  } else {
    gfx_drawChar(__gfx_state.cursor_x, __gfx_state.cursor_y, 
                c, __gfx_state.textcolor, __gfx_state.textbgcolor,
                 __gfx_state.textsize);
    __gfx_state.cursor_x += __gfx_state.textsize*8;
    if (__gfx_state.wrap && (__gfx_state.cursor_x > (__gfx_state._width - __gfx_state.textsize*8))) {
      __gfx_state.cursor_y += __gfx_state.textsize*12;
      __gfx_state.cursor_x = 0;
    }
  }
}

void gfx_puts(char *s) {
    while (*s) {
        gfx_write(*s);
        s++;
    }
}

// Draw a character
void gfx_drawChar(int16_t x, int16_t y, unsigned char c,
			    uint16_t color, uint16_t bg, uint8_t size) {

  int8_t i, j, line;
  int8_t descender;
  unsigned const char *glyph;

  glyph = &mcm_font[(c & 0x7f) * 9];

  descender = (*glyph & 0x80) != 0;

  for (i=0; i<12; i++ ) {
    line = 0x00;
    if ( descender ) {
        if (i > 2) {
          line = *(glyph + (i - 3));
        }
    } else {
        if (i < 9) {
            line = *(glyph + i);
        }
    }
    line &= 0x7f;
    for (j = 0; j<8; j++) {
      if (line & 0x80) {
        if (size == 1) // default size
          gfx_drawPixel(x+j, y+i, color);
        else {  // big size
          gfx_fillRect(x+(j*size), y+(i*size), size, size, color);
        } 
      } else if (bg != color) {
        if (size == 1) // default size
          gfx_drawPixel(x+j, y+i, bg);
        else {  // big size
          gfx_fillRect(x+j*size, y+i*size, size, size, bg);
        }
      }
      line <<= 1;
    }
  }
}

void gfx_setCursor(int16_t x, int16_t y) {
  __gfx_state.cursor_x = x;
  __gfx_state.cursor_y = y;
}

void gfx_setTextSize(uint8_t s) {
  __gfx_state.textsize = (s > 0) ? s : 1;
}

void gfx_setTextColor(uint16_t c, uint16_t b) {
  __gfx_state.textcolor   = c;
  __gfx_state.textbgcolor = b; 
}

void gfx_setTextWrap(uint8_t w) {
  __gfx_state.wrap = w;
}

uint8_t gfx_getRotation(void) {
  return __gfx_state.rotation;
}

void gfx_setRotation(uint8_t x) {
  __gfx_state.rotation = (x & 3);
  switch(__gfx_state.rotation) {
   case 0:
   case 2:
    __gfx_state._width  = GFX_WIDTH;
    __gfx_state._height = GFX_HEIGHT;
    break;
   case 1:
   case 3:
    __gfx_state._width  = GFX_HEIGHT;
    __gfx_state._height = GFX_WIDTH;
    break;
  }
}

// Return the size of the display (per current rotation)
uint16_t gfx_width(void) {
  return __gfx_state._width;
}
 
uint16_t gfx_height(void) {
  return __gfx_state._height;
}