#include <libxml/parser.h>
#include <malloc.h>
#include <math.h>

#include "log.h"
#include "physics.h"
#include "opengl.h"
#include "rng.h"
#include "pilot.h"
#include "pack.h"
#include "space.h"

#define XML_NODE_START  1
#define XML_NODE_TEST   3

#define XML_PLANET_ID   "Planets"
#define XML_PLANET_TAG  "planet"

#define XML_SYSTEM_ID   "Systems"
#define XML_SYSTEM_TAG  "ssys"

#define PLANET_DATA     "../dat/planet.xml"
#define SYSTEM_DATA     "../dat/ssys.xml"

#define PLANET_GFX      "../gfx/planet/"

// Overcome warning due to zero value.

#define FLAG_XSET           (1<<0)
#define FLAG_YSET           (1<<1)
#define FLAG_ASTEROIDSSET    (1<<2)
#define FLAG_INTEFERENCESET (1<<3)

// Planet types. I didn't take them from Star Trek, I promise.
typedef enum {
  PLANET_CLASS_A, // Geothermal.
  PLANET_CLASS_B, // Geomorteus.
  PLANET_CLASS_C, // Geoinactive.
  PLANET_CLASS_D, // Asteroid/Moon.
  PLANET_CLASS_E, // Geoplastic.
  PLANET_CLASS_F, // Geometallic.
  PLANET_CLASS_G, // GroCrystaline.
  PLANET_CLASS_H, // Desert.
  PLANET_CLASS_I, // Gas Supergiant.
  PLANET_CLASS_J, // Gas Giant.
  PLANET_CLASS_K, // Adaptable.
  PLANET_CLASS_L, // Marginal.
  PLANET_CLASS_M, // Terrestrial.
  PLANET_CLASS_N, // Reducing.
  PLANET_CLASS_O, // Pelagic.
  PLANET_CLASS_P, // Glaciated.
  PLANET_CLASS_Q, // Variable.
  PLANET_CLASS_R, // Rogue.
  PLANET_CLASS_S, // Ultragiant.
  PLANET_CLASS_T, // Ultragiant.
  PLANET_CLASS_X, // Demon.
  PLANET_CLASS_Y, // Demon.
  PLANER_CLASS_Z  // Demon.
} PlanetClass;

typedef struct {
  char* name;
  Vec2 pos; // Position in star system.
  PlanetClass class;
  gl_texture* gfx_space; // Graphics in space.
} Planet;

typedef struct {
  char* name;
  Vec2 pos; // Position.
  int stars, asteroids; // Un numero!
  double interference; // Un uh.. Percentage.

  // Factions.
  Planet* planets; // Planets.
  int nplanets;

  // TODO: Throw some fleets here.
} StarSystem;

static StarSystem* systems = NULL;
static int nsystems = 0;
static StarSystem* cur_system = NULL; // Current star system.

#define STAR_BUF 100 // Area to leave around screen.
typedef struct {
  double x, y; // Position. It is simpler ligher to use two doubles than the physics.
  double brightness;
} Star;

static Star* stars = NULL; // Star array.
static int nstars = 0; // Total stars.

static Planet* planet_get(const char* name);
static StarSystem* system_parse(const xmlNodePtr parent);

// Init the system.
void space_init(const char* sysname) {
  int i;
  for(i = 0; i < nsystems; i++)
    if(strcmp(sysname, systems[i].name)==0)
      break;
  if(i == nsystems) ERR("System %s not found in stack", sysname);
  cur_system = systems+i;

  nstars = (cur_system->stars*gl_screen.w*gl_screen.h+STAR_BUF*STAR_BUF)/(800*640);
  stars = malloc(sizeof(Star)*nstars);
  for(i = 0; i < nstars; i++) {
    stars[i].brightness = (double)RNG(50, 200)/256.;
    stars[i].x = (double)RNG(-STAR_BUF, gl_screen.w + STAR_BUF);
    stars[i].y = (double)RNG(-STAR_BUF, gl_screen.h + STAR_BUF);
  }
}

// Load the planets of name 'name'.
static Planet* planet_get(const char* name) {
  Planet* tmp = NULL;

  char str[PATH_MAX] = "\0";
  char* tstr;

  uint32_t flags = 0;

  uint32_t bufsize;
  char* buf = pack_readfile(DATA, PLANET_DATA, &bufsize);

  xmlNodePtr node, cur;
  xmlDocPtr doc = xmlParseMemory(buf, bufsize);

  node = doc->xmlChildrenNode;
  if(strcmp((char*)node->name, XML_PLANET_ID)) {
    ERR("Malformed "PLANET_DATA" file: missing root element '"XML_PLANET_ID"'");
    return NULL;
  }

  node = node->xmlChildrenNode; // First system node.
  if(node == NULL) {
    ERR("Malformed "PLANET_DATA" file: does not contain elements");
    return NULL;
  }

  do {
    if(node->type == XML_NODE_START && strcmp((char*)node->name, XML_PLANET_TAG)==0) {
      tstr = (char*)xmlGetProp(node, (xmlChar*)"name");
      if(strcmp(tstr, name)==0) { // Found.
        tmp = CALLOC_L(Planet);
        tmp->name = tstr;

        node = node->xmlChildrenNode;

        while((node = node->next)) {
          if(strcmp((char*)node->name, "GFX")==0) {
            cur = node->children;
            if(strcmp((char*)cur->name, "text")==0) {
              snprintf(str, strlen((char*)cur->content)+sizeof(PLANET_GFX),
                    PLANET_GFX"%s", (char*)cur->content);
              tmp->gfx_space = gl_newSprite(str, 1, 1);
            }
          }
          else if(strcmp((char*)node->name, "pos")==0) {
            cur = node->children;
            while((cur = cur->next)) {
              if(strcmp((char*)cur->name, "x")==0) {
                flags |= FLAG_XSET;
                tmp->pos.x = atof((char*)cur->children->content);
              }
              else if(strcmp((char*)cur->name, "y")==0) {
                flags |= FLAG_YSET;
                tmp->pos.y = atof((char*)cur->children->content);
              }
            }
          }
          else if(strcmp((char*)node->name, "general")==0) {
            cur = node->children;
            while((cur = cur->next)) {
              if(strcmp((char*)cur->name, "class")==0)
                tmp->class = atoi((char*)cur->children->content);
            }
          }
        }
        break;
      } else
        free(tstr); // xmlGetProp mallocs the string.
    }
  } while((node = node->next));

  xmlFreeDoc(doc);
  free(buf);
  xmlCleanupParser();

  // Check elements.
  if(tmp) {
#define MELEMENT(o,s) if((o) == 0) WARN("Planet '%s' missing '"s"' element", tmp->name)
    MELEMENT(flags&FLAG_XSET, "x");
    MELEMENT(flags&FLAG_YSET, "y");
    MELEMENT(tmp->class, "class");
#undef MELEMENT
  } else
    WARN("No planet found matching name '%s'", name);

  return tmp;
}

// Parse node 'parent' which should be the node of a system.
// Return the StarSystem fully loaded.
static StarSystem* system_parse(const xmlNodePtr parent) {
  Planet* planet = NULL;
  StarSystem* tmp = CALLOC_L(StarSystem);
  xmlNodePtr cur, node;

  uint32_t flags;

  tmp->name = (char*)xmlGetProp(parent, (xmlChar*)"name"); // Already mallocs.

  node = parent->xmlChildrenNode;

  while((node = node->next)) {
    // Load all the things!
    if(strcmp((char*)node->name, "pos")==0) {
      cur = node->children;
      while((cur = cur->next)) {
        if(strcmp((char*)cur->name, "x")==0) {
          flags |= FLAG_XSET;
          tmp->pos.x = atof((char*)cur->children->content);
        }
        if(strcmp((char*)cur->name, "y")==0) {
          flags |= FLAG_YSET;
          tmp->pos.y = atof((char*)cur->children->content);
        }
      }
    }
    else if(strcmp((char*)node->name, "general")==0) {
      cur = node->children;
      while((cur = cur->next)) {
        if(strcmp((char*)cur->name, "stars")==0) // Non-zero.
          tmp->stars = atoi((char*)cur->children->content);
        else if(strcmp((char*)cur->name, "asteroids")==0) {
          flags |= FLAG_ASTEROIDSSET;
          tmp->asteroids = atoi((char*)cur->children->content);
        }
        else if(strcmp((char*)cur->name, "interference")==0) {
          flags |= FLAG_INTEFERENCESET;
          tmp->interference = atof((char*)cur->children->content);
        }
      }
    }
    else if(strcmp((char*)node->name, "planets")==0) {
      cur = node->children;
      while((cur = cur->next)) {
        if(strcmp((char*)cur->name, "planet")==0) {
          planet = planet_get((const char*)cur->children->content);
          tmp->planets = realloc(tmp->planets, sizeof(Planet)*(++tmp->nplanets));
          memcpy(tmp->planets+tmp->nplanets-1, planet, sizeof(Planet));
          free(planet);
        }
      }
    }
  }
  // Check elements.
#define MELEMENT(o,s) if((o) == 0) WARN("Star System '%s' missing '"s"' element", tmp->name)
  MELEMENT(flags&FLAG_XSET, "x");
  MELEMENT(flags&FLAG_YSET, "y");
  MELEMENT(tmp->stars, "stars");
  MELEMENT(flags&FLAG_ASTEROIDSSET, "asteroids"); // Can be 0.
  MELEMENT(flags&FLAG_INTEFERENCESET, "inteference");
#undef MELEMENT
  DEBUG("Loaded Star System '%s' with %d Planets%s", tmp->name, tmp->nplanets, (tmp->nplanets > 1) ? "s" : "");

  return tmp;
}

// Load the ENTIRE universe into RAM. -- WOAH! -- Wasn't that bad. :P
int space_load(void) {
  uint32_t bufsize;
  char* buf = pack_readfile(DATA, SYSTEM_DATA, &bufsize);

  StarSystem* tmp;

  xmlNodePtr node;
  xmlDocPtr doc = xmlParseMemory(buf, bufsize);

  node = doc->xmlChildrenNode;
  if(strcmp((char*)node->name, XML_SYSTEM_ID)) {
    ERR("Malformed "SYSTEM_DATA" file: missing root element '"XML_SYSTEM_ID"'");
    return -1;
  }
  node = node->xmlChildrenNode; // First system node.
  if(node == NULL) {
    ERR("Malformed "SYSTEM_DATA" file: does not contain elements");
    return -1;
  }
  do {
    if(node->type == XML_NODE_START && strcmp((char*)node->name, XML_SYSTEM_TAG)==0) {
      tmp = system_parse(node);
      systems = realloc(systems, sizeof(StarSystem)*(++nsystems));
      memcpy(systems+nsystems-1, tmp, sizeof(StarSystem));
      free(tmp);
    }
  } while((node = node->next));

  xmlFreeDoc(doc);
  free(buf);
  xmlCleanupParser();

  return 0;
}

// Render the system. -- Just playing god now.
void space_render(double dt) {
  int i;
  glMatrixMode(GL_PROJECTION);
  glPushMatrix(); // Projection translation matrix.
  glTranslated(-(double)gl_screen.w/2., -(double)gl_screen.h/2., 0.);
  glBegin(GL_POINTS);
  for(i = 0; i < nstars; i++) {
    // Update the position.
    stars[i].x -= VX(player->solid->vel)/(15.-10.*stars[i].brightness)*dt;
    stars[i].y -= VY(player->solid->vel)/(15.-10.*stars[i].brightness)*dt;
    // Scroll those stars bitch!
    if(stars[i].x > gl_screen.w + STAR_BUF) stars[i].x = -STAR_BUF;
    else if(stars[i].x < -STAR_BUF) stars[i].x = gl_screen.w + STAR_BUF;
    if(stars[i].y > gl_screen.h + STAR_BUF) stars[i].y = -STAR_BUF;
    else if(stars[i].y < -STAR_BUF) stars[i].y = gl_screen.h + STAR_BUF;
    // Render.
    glColor4d(1., 1., 1., stars[i].brightness);
    glVertex2d(stars[i].x, stars[i].y);
  }
  glEnd();
  glPopMatrix(); // Projection translation matrix.
}

// Render the planets.
void planets_render(void) {
  int i;
  for(i = 0; i < cur_system->nplanets; i++)
    gl_blitSprite(cur_system->planets[i].gfx_space, &cur_system->planets[i].pos, 0, 0);
}

// Clean up the system.
void space_exit(void) {
  int i,j;
  for(i = 0; i < nsystems; i++) {
    free(systems[i].name);
    for(j = 0; j < systems[i].nplanets; j++) {
      free(systems[i].planets[j].name);
      if(systems[i].planets[j].gfx_space)
        gl_freeTexture(systems[i].planets[j].gfx_space);
    }
    free(systems[i].planets);
  }
  free(systems);
  if(stars) free(stars);
}