/****************************************************************************
 * Mathematical_rb Copyright(c) 2014, Garen J. Torikian, All rights reserved.
 * --------------------------------------------------------------------------
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 ****************************************************************************/

#include "ruby.h"
#include <string.h>
#include <stdlib.h>
#include <lsm.h>
#include <lsmmathml.h>
#include <glib.h>
#include <glib/gi18n.h>
#include <glib/gprintf.h>
#include <gio/gio.h>
#include <cairo-pdf.h>
#include <cairo-svg.h>
#include <cairo-ps.h>
#include "itex2MML.h"

#define CSTR2SYM(str) ID2SYM(rb_intern(str))

static VALUE rb_mMathematical;
static VALUE rb_cMathematicalProcess;

// Raised when the contents could not be parsed
static VALUE rb_eParseError;
// Raised when the SVG document could not be created
static VALUE rb_eDocumentCreationError;
// Raised when the SVG document could not be read
static VALUE rb_eDocumentReadError;

char* readFile(const char* filename) {
  FILE* file = fopen(filename, "r");
  if (file == NULL) return NULL;

  fseek(file, 0, SEEK_END);
  long int size = ftell(file);
  rewind(file);

  char* content = calloc(size + 1, 1);

  fread(content, 1, size, file);

  fclose(file);
  unlink(file);

  return content;
}

static VALUE MATHEMATICAL_init(VALUE self, VALUE rb_Options) {
  Check_Type (rb_Options, T_HASH);
  VALUE ppi, zoom;

  ppi = rb_hash_aref(rb_Options, CSTR2SYM("ppi"));
  zoom = rb_hash_aref(rb_Options, CSTR2SYM("zoom"));

  Check_Type(ppi, T_FLOAT);
  Check_Type(zoom, T_FLOAT);

  rb_iv_set(self, "@ppi", ppi);
  rb_iv_set(self, "@zoom", zoom);

  return self;
}

static VALUE MATHEMATICAL_process(VALUE self, VALUE rb_LatexCode, VALUE rb_TempFile) {
  Check_Type (rb_LatexCode, T_STRING);
  Check_Type (rb_TempFile, T_STRING);

  const char *latex_code = StringValueCStr(rb_LatexCode);
  int latex_size = strlen(latex_code);

  const char *tempfile = StringValueCStr(rb_TempFile);

  g_type_init ();

  // convert the TeX math to MathML
  char * mathml = lsm_itex_to_mathml(latex_code, latex_size);

  if (mathml == NULL) rb_raise(rb_eParseError, "Failed to parse itex");

  int mathml_size = strlen(mathml);

  LsmDomDocument *document;
  document = lsm_dom_document_new_from_memory(mathml, mathml_size, NULL);

  lsm_itex_free_mathml_buffer (mathml);

  if (document == NULL) rb_raise(rb_eDocumentCreationError, "Failed to create document");

  LsmDomView *view;

  double ppi = NUM2DBL(rb_iv_get(self, "@ppi"));
  double zoom = NUM2DBL(rb_iv_get(self, "@zoom"));

  view = lsm_dom_document_create_view (document);
  lsm_dom_view_set_resolution (view, ppi);

  double width_pt = 2.0, height_pt = 2.0;
  unsigned int height, width;

  lsm_dom_view_get_size (view, &width_pt, &height_pt, NULL);
  lsm_dom_view_get_size_pixels (view, &width, &height, NULL);

  width_pt *= zoom;
  height_pt *= zoom;
  width *= zoom;
  height *= zoom;

  cairo_t *cairo;
  cairo_surface_t *surface;

  surface = cairo_svg_surface_create (tempfile, width_pt, height_pt);
  cairo = cairo_create (surface);
  cairo_surface_destroy (surface);
  cairo_scale (cairo, zoom, zoom);
  lsm_dom_view_render (view, cairo, 0, 0);

  cairo_destroy (cairo);
  g_object_unref (view);
  g_object_unref (document);

  char* svg_contents = readFile(tempfile);

  if (svg_contents == NULL) rb_raise(rb_eDocumentReadError, "Failed to read SVG contents");

  VALUE result_hash = rb_hash_new();

  rb_hash_aset (result_hash, rb_tainted_str_new2 ("width"),  INT2FIX(width_pt));
  rb_hash_aset (result_hash, rb_tainted_str_new2 ("height"), INT2FIX(height_pt));
  rb_hash_aset (result_hash, rb_tainted_str_new2 ("svg"),    rb_str_new2(svg_contents));

  return result_hash;
}

void Init_mathematical() {
  rb_mMathematical = rb_define_module("Mathematical");

  rb_cMathematicalProcess = rb_define_class_under(rb_mMathematical, "Process", rb_cObject);
  rb_eParseError = rb_define_class_under(rb_mMathematical, "ParseError", rb_eStandardError);
  rb_eDocumentCreationError = rb_define_class_under(rb_mMathematical, "DocumentCreationError", rb_eStandardError);
  rb_eDocumentReadError = rb_define_class_under(rb_mMathematical, "DocumentReadError", rb_eStandardError);

  rb_define_method(rb_cMathematicalProcess, "initialize", MATHEMATICAL_init, 1);
  rb_define_method(rb_cMathematicalProcess, "process", MATHEMATICAL_process, 2);
}