#include <stdio.h>
#include <assert.h>
#include <GL/gl.h>

#include "mesh.h"
#include "edge.h"
#include "vertex.h"
#include "triangle.h"
#include "vertex_parent.h"
#include "glCanvas.h"

#define INITIAL_VERTEX 10000
#define INITIAL_EDGE 10000
#define INITIAL_TRIANGLE 10000



// =======================================================================
// CONSTRUCTORS & DESTRUCTORS
// =======================================================================

Mesh::Mesh() {
  vertices = new Array<Vertex*>(INITIAL_VERTEX);
  edges = new Bag<Edge*>(INITIAL_EDGE,Edge::extract_func);
  triangles = new Bag<Triangle*>(INITIAL_TRIANGLE,Triangle::extract_func);
  vertex_parents = new Bag<VertexParent*>(INITIAL_VERTEX, VertexParent::extract_func);
  bbox = NULL;
}

Mesh::~Mesh() {
  delete vertices;  
  vertices = NULL;
  delete edges;
  edges = NULL;
  delete triangles;
  triangles = NULL;
  delete bbox;
  bbox = NULL;
}

// =======================================================================
// MODIFIERS:   ADD & REMOVE
// =======================================================================

Vertex* Mesh::addVertex(const Vec3f &position) {
  int index = numVertices();
  Vertex *v = new Vertex(index, position);
  vertices->Add(v);
  if (bbox == NULL) 
    bbox = new BoundingBox(position,position);
  else 
    bbox->Extend(position);
  return v;
}

void Mesh::addTriangle(Vertex *a, Vertex *b, Vertex *c) {

  // create the triangle
  Triangle *t = new Triangle();

  // create the edges
  Edge *ea = new Edge(a,t);
  Edge *eb = new Edge(b,t);
  Edge *ec = new Edge(c,t);

  // point the triangle to one of its edges
  t->setEdge(ea);

  // connect the edges to each other
  ea->setNext(ec);
  eb->setNext(ea);
  ec->setNext(eb);

  // add them to the master list
  edges->Add(ea);
  edges->Add(eb);
  edges->Add(ec);

  // connect up with opposite edges (if they exist)
  Edge *ea_op = getEdge((*ea)[1],(*ea)[0]);
  Edge *eb_op = getEdge((*eb)[1],(*eb)[0]);
  Edge *ec_op = getEdge((*ec)[1],(*ec)[0]);  
  if (ea_op != NULL) { ea_op->setOpposite(ea); }
  if (eb_op != NULL) { eb_op->setOpposite(eb); }
  if (ec_op != NULL) { ec_op->setOpposite(ec); }

  // add the triangle to the master list
  triangles->Add(t); 
}

void Mesh::removeTriangle(Triangle *t) {

  Edge *ea = t->getEdge();
  Edge *eb = ea->getNext();
  Edge *ec = eb->getNext();
  assert (ec->getNext() == ea);

  // remove elements from master lists
  edges->Remove(ea);
  edges->Remove(eb);
  edges->Remove(ec);
  triangles->Remove(t);

  // clean up memory
  delete ea;
  delete eb;
  delete ec;
  delete t;
}

Edge* Mesh::getEdge(Vertex *a, Vertex *b) const {
  assert (edges != NULL);
  return edges->Get(a->getIndex(),b->getIndex());
}

Vertex* Mesh::getChildVertex(Vertex *p1, Vertex *p2) const {
  VertexParent *vp = vertex_parents->GetReorder(p1->getIndex(), p2->getIndex());
  if (vp == NULL) return NULL;
  return vp->get();
}

void Mesh::setParentsChild(Vertex *p1, Vertex *p2, Vertex *child) {
  vertex_parents->Add(new VertexParent(p1,p2,child));
}

// =======================================================================
// the load function parses very simple .obj files
// the basic format has been extended to allow the specification 
// of crease weights on the edges.
// =======================================================================

void Mesh::Load(const char *input_file) {
  
  FILE *objfile = fopen(input_file,"r");
  if (objfile == NULL) {
    printf ("ERROR! CANNOT OPEN '%s'\n",input_file);
    return;
  }

  char line[200];
  char token[100];
  char atoken[100];
  char btoken[100];
  char ctoken[100];
  char dtoken[100];
  char etoken[100];
  float x,y,z;
  int a,b,c,d,e;
  
  int index = 0;
  int vert_count = 0;
  int vert_index = 1;
  
  while (fgets(line, 200, objfile)) {   
    
    if (line[strlen(line)-2] == '\\') {
      fgets(token, 100, objfile);	
      int tmp = strlen(line)-2;
      strncpy(&line[tmp],token,100);
    }
    int token_count = sscanf (line, "%s\n",token);
    if (token_count == -1) continue;
    a = b = c = d = e = -1;
    if (!strcmp(token,"usemtl") ||
	!strcmp(token,"g")) {
      vert_index = 1; //vert_count + 1;
      index++;
    } else if (!strcmp(token,"v")) {
      vert_count++;
      sscanf (line, "%s %f %f %f\n",token,&x,&y,&z);
      addVertex(Vec3f(x,y,z));
    } else if (!strcmp(token,"f")) {
      int num = sscanf (line, "%s %s %s %s %s %s\n",token,
			atoken,btoken,ctoken,dtoken,etoken);
      sscanf (atoken,"%d",&a);
      sscanf (btoken,"%d",&b);
      sscanf (ctoken,"%d",&c);
      if (num > 4) sscanf (dtoken,"%d",&d);
      if (num > 5) sscanf (etoken,"%d",&e);
      a -= vert_index;
      b -= vert_index;
      c -= vert_index;
      if (d >= 0) d -= vert_index;
      if (e >= 0) e -= vert_index;
      assert (a >= 0 && a < numVertices());
      assert (b >= 0 && b < numVertices());
      assert (c >= 0 && c < numVertices());

      addTriangle(getVertex(a),getVertex(b),getVertex(c));
      if (d > -1) { assert (d < numVertices()); addTriangle(getVertex(a),getVertex(c),getVertex(d)); }
      if (e > -1) { assert (e < numVertices()); addTriangle(getVertex(a),getVertex(d),getVertex(e)); }
    } else if (!strcmp(token,"e")) {
      int num = sscanf (line, "%s %s %s %s\n",token,atoken,btoken,ctoken);
      assert (num == 4);
      sscanf (atoken,"%d",&a);
      sscanf (btoken,"%d",&b);
      if (!strcmp(ctoken,"inf")) x = 1000000; // this is close to infinity...
      else sscanf (ctoken,"%f",&x);
      Vertex *va = getVertex(a);
      Vertex *vb = getVertex(b);
      Edge *ab = getEdge(va,vb);
      Edge *ba = getEdge(vb,va);
      assert (ab != NULL);
      assert (ba != NULL);
      ab->setCrease(x);
      ba->setCrease(x);
    } else if (!strcmp(token,"vt")) {
    } else if (!strcmp(token,"vn")) {
    } else if (token[0] == '#') {
    } else {
      printf ("LINE: '%s'",line);
    }
  }
}

// =======================================================================
// PAINT
// =======================================================================

Vec3f ComputeNormal(const Vec3f &p1, const Vec3f &p2, const Vec3f &p3) {
  Vec3f v12 = p2;
  v12 -= p1;
  Vec3f v23 = p3;
  v23 -= p2;
  Vec3f normal;
  Vec3f::Cross3(normal,v12,v23);
  normal.Normalize();
  return normal;
}

void InsertNormal(const Vec3f &p1, const Vec3f &p2, const Vec3f &p3) {
  Vec3f normal = ComputeNormal(p1,p2,p3);
  glNormal3f(normal.x(), normal.y(), normal.z());
}

void Mesh::Paint(ArgParser *args) {

  // scale it so it fits in the window
  Vec3f center; bbox->getCenter(center);
  float s = 1/bbox->maxDim();
  glScalef(s,s,s);
  glTranslatef(-center.x(),-center.y(),-center.z());

  // this offset prevents "z-fighting" bewteen the edges and faces
  // the edges will always win.
  glEnable(GL_POLYGON_OFFSET_FILL);
  glPolygonOffset(1.1,4.0);

  // draw the triangles
  glColor3f(1,1,1);
  Iterator<Triangle*> *iter = triangles->StartIteration();
  glBegin (GL_TRIANGLES);
  while (Triangle *t = iter->GetNext()) {
    Vec3f a = (*t)[0]->get();
    Vec3f b = (*t)[1]->get();
    Vec3f c = (*t)[2]->get();
    InsertNormal(a,b,c); 
    glVertex3f(a.x(),a.y(),a.z());
    glVertex3f(b.x(),b.y(),b.z());
    glVertex3f(c.x(),c.y(),c.z());
  }
  triangles->EndIteration(iter);
  glEnd();

  glDisable(GL_POLYGON_OFFSET_FILL); 
 
  if (args->wireframe) {
    glDisable(GL_LIGHTING);

    // draw all the interior, non-crease edges
    glLineWidth(1);
    glColor3f(0,0,0);
    glBegin (GL_LINES);
    Iterator<Edge*> *iter = edges->StartIteration();
    while (Edge *e = iter->GetNext()) {
      if (e->getOpposite() == NULL || e->getCrease() > 0) continue;
      Vec3f a = (*e)[0]->get();
      Vec3f b = (*e)[1]->get();
      glVertex3f(a.x(),a.y(),a.z());
      glVertex3f(b.x(),b.y(),b.z());
    }
    edges->EndIteration(iter);
    glEnd();

    // draw all the interior, crease edges
    glLineWidth(3);
    glColor3f(1,1,0);
    glBegin (GL_LINES);
    iter = edges->StartIteration();
    while (Edge *e = iter->GetNext()) {
      if (e->getOpposite() == NULL || e->getCrease() == 0) continue;
      Vec3f a = (*e)[0]->get();
      Vec3f b = (*e)[1]->get();
      glVertex3f(a.x(),a.y(),a.z());
      glVertex3f(b.x(),b.y(),b.z());
    }
    edges->EndIteration(iter);
    glEnd();

    // draw all the boundary edges
    glLineWidth(3);
    glColor3f(1,0,0);
    glBegin (GL_LINES);
    iter = edges->StartIteration();
    while (Edge *e = iter->GetNext()) {
      if (e->getOpposite() != NULL) continue;
      assert (e->getCrease() == 0);
      Vec3f a = (*e)[0]->get();
      Vec3f b = (*e)[1]->get();
      glVertex3f(a.x(),a.y(),a.z());
      glVertex3f(b.x(),b.y(),b.z());
    }
    edges->EndIteration(iter);
    glEnd();

    glEnable(GL_LIGHTING);
  }
  
  HandleGLError(); 
}

// =================================================================
// SUBDIVISION
// =================================================================

void Mesh::LoopSubdivision() {
  printf ("Subdivide the mesh!\n");
}

// =================================================================
// SIMPLIFICATION
// =================================================================

void Mesh::Simplification(int target_tri_count) {
  printf ("Simplify the mesh! %d -> %d\n", numTriangles(), target_tri_count);
}

// =================================================================