/*
winnie - an experimental window system

Copyright (C) 2013 Eleni Maria Stea

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

Author: Eleni Maria Stea <elene.mst@gmail.com>
*/

#include <freetype/freetype.h>
#include <ft2build.h>
#include <stdint.h>
#include <stdlib.h>

#include "sdl/gfx.h"
#include "text.h"
#include "winnie.h"

#define DPI 72
#define FONT_PATH "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf"
#define FONT_SIZE 16

static int draw_glyph(Pixmap *pixmap, int x, int y, char c);

struct Text {
  FT_Library ft_lib;
  FT_Face ft_face;
  int text_x, text_y;
  int text_color[3];
};

static Text *text;

bool
init_text()
{
  if (!(text = (Text *) malloc(sizeof *text))) {
    return false;
  }

  if (FT_Init_FreeType(&text->ft_lib)) {
    fprintf(stderr, "Failed to initialize the FreeType library!\n");
    return false;
  }

  if (FT_New_Face(text->ft_lib, FONT_PATH, 0, &text->ft_face)) {
    fprintf(stderr, "Failed to load font: %s\n", FONT_PATH);
    return false;
  }

  if (FT_Set_Char_Size(text->ft_face, 0, FONT_SIZE * 64, DPI, DPI)) {
    fprintf(stderr, "Failed to set font size\n");
    return false;
  }

  set_text_color(255, 255, 255);

  return true;
}

void
destroy_text()
{
  free(text);
}

void
draw_text(const char *txt, Pixmap *pixmap)
{
  if (!pixmap) {
    pixmap = get_framebuffer_pixmap();
  }

  while (*txt != 0) {
    text->text_x += draw_glyph(pixmap, text->text_x, text->text_y, *txt);
    txt++;
  }
}

void
set_text_position(int x, int y)
{
  text->text_x = x;
  text->text_y = y;
}

void
set_text_color(int r, int g, int b)
{
  text->text_color[0] = r;
  text->text_color[1] = g;
  text->text_color[2] = b;
}

static int
draw_glyph(Pixmap *pixmap, int x, int y, char c)
{
  if (FT_Load_Char(text->ft_face, c, FT_LOAD_RENDER)) {
    return 0;
  }

  x += text->ft_face->glyph->bitmap_left;
  y -= text->ft_face->glyph->bitmap_top;

  FT_Bitmap *ft_bmp = &text->ft_face->glyph->bitmap;
  unsigned char *bmp_ptr = ft_bmp->buffer;
  unsigned char *pxm_ptr
      = pixmap->get_image() + (pixmap->get_width() * y + x) * 4;

  Rect clipping_rect = get_clipping_rect();

  for (unsigned int i = 0; i < ft_bmp->rows; i++) {
    int dest_y = i + y;
    if (dest_y >= clipping_rect.y + clipping_rect.height) {
      break;
    }

    if (dest_y >= clipping_rect.y) {
      for (unsigned int j = 0; j < ft_bmp->width; j++) {
        int dest_x = j + x;

        if (dest_x >= clipping_rect.x + clipping_rect.width) {
          break;
        }

        if (bmp_ptr[j] && dest_x >= clipping_rect.x) {
          int a = (int) bmp_ptr[j];
          pxm_ptr[4 * j]
              = (a * text->text_color[0] + pxm_ptr[4 * j] * (255 - a)) / 255;
          pxm_ptr[4 * j + 1]
              = (a * text->text_color[1] + pxm_ptr[4 * j + 1] * (255 - a))
                / 255;
          pxm_ptr[4 * j + 2]
              = (a * text->text_color[2] + pxm_ptr[4 * j + 2] * (255 - a))
                / 255;
        }
      }
    }

    pxm_ptr += 4 * pixmap->get_width();
    bmp_ptr += ft_bmp->pitch;
  }

  return text->ft_face->glyph->advance.x >> 6;
}