#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h> // We don't need this?

#include "main.h"
#include "log.h"
#include "weapon.h"
#include "pack.h"
#include "xml.h"
#include "pilot.h"

#define XML_ID    "Fleets" // XML section identifier.
#define XML_FLEET "fleet"

#define FLEET_DATA  "../dat/fleet.xml"

// Stack of pilot id's to assure uniqueness.
static unsigned int pilot_id = PLAYER_ID;

// Stack of pilots - yes, they come in stacks now.
Pilot** pilot_stack = NULL; // Not static, it is used in player.c and weapon.c and ai.c
int pilots = 0;
extern Pilot* player;

// Stack of fleets.
static Fleet* fleet_stack = NULL;
static int nfleets = 0;

// External.
extern void ai_destroy(Pilot* p); // Ai.
extern void ai_think(Pilot* pilot); // Ai.c
extern void player_think(Pilot* pilot); // Player.c
extern int gui_load(const char* name); // Player.c
// Internal.
static void pilot_update(Pilot* pilot, const double dt);
void pilot_render(Pilot* pilot);
static void pilot_free(Pilot* p);
static Fleet* fleet_parse(const xmlNodePtr parent);

// Get the next pilot based on id.
unsigned int pilot_getNext(const unsigned int id) {
  // Regular search.
  int i;
  for(i = 0; i < pilots; i++)
    if(pilot_stack[i]->id == id)
      break;

  if(i == pilots-1) return PLAYER_ID;

  return pilot_stack[i+1]->id;
}

// Get the nearest enemy to the pilot -- Tamir's (insightful) request.
unsigned int pilot_getNearest(const Pilot* p) {
  unsigned int tp;
  int i;
  double d, td;

  for(tp = 0, d = 0., i = 0; i < pilots; i++)
    if(areEnemies(p->faction, pilot_stack[i]->faction)) {
      td = vect_dist(&pilot_stack[i]->solid->pos, &p->solid->pos);
      if((!tp) || (td < d)) {
        d = td;
        tp = pilot_stack[i]->id;
      }
    }
  return tp;
}

// Get the nearest hostile enemy to the player.
unsigned pilot_getHostile(void) {
  unsigned int tp;
  int i;
  double d, td;
  for(tp = PLAYER_ID, d = 0., i = 0; i < pilots; i++)
    if(pilot_isFlag(pilot_stack[i], PILOT_HOSTILE)) {
      td = vect_dist(&pilot_stack[i]->solid->pos, &player->solid->pos);
      if((tp == PLAYER_ID) || (td < d)) {
        d = td;
        tp = pilot_stack[i]->id;
      }
    }
  return tp;
}

// Pull a pilot out of the pilot_stack based on id.
Pilot* pilot_get(const unsigned int id) {
  // Regular search.
  int i;
  for(i = 0; i < pilots; i++)
    if(pilot_stack[i]->id == id)
      return pilot_stack[i];
  return NULL;

  if(id == 0) return player;
#if 0
  // Dichotomical search.
  int i, n;
  for(i = 0, n = pilots/2; n > 0; n /= 2)
    i += (pilot_stack[i+n]->id > id) ? 0 : n;
  return (pilot_stack[i]->id == id) ? pilot_stack[i] : NULL;
#endif
}

// Mkay, this is how we shoot. Listen up.
void pilot_shoot(Pilot* p, const int secondary) {
  int i;
  if(!secondary) {
    // Primary weapons.
    if(!p->outfits) return; // No outfits.

    for(i = 0; i < p->noutfits; i++) // Cycle through outfits to find weapons.
      if(outfit_isWeapon(p->outfits[i].outfit) || // Is a weapon or launch?
            outfit_isLauncher(p->outfits[i].outfit))
        // Ready to shoot again.
        if((SDL_GetTicks()-p->outfits[i].timer) > (p->outfits[i].outfit->delay/p->outfits[i].quantity))
          // Different weapons have different behaviours.
          switch(p->outfits[i].outfit->type) {
            case OUTFIT_TYPE_BOLT:
              weapon_add(p->outfits[i].outfit, p->solid->dir, &p->solid->pos,
                    &p->solid->vel, p->id, (p==player) ? WEAPON_LAYER_FG : WEAPON_LAYER_BG);
              p->outfits[i].timer = SDL_GetTicks();
              break;
            default:
              break;
          }
  }
}

// Damage the pilot.
void pilot_hit(Pilot* p, const double damage_shield, const double damage_armor) {
  if(p->shield - damage_shield > 0.)
    p->shield -= damage_shield;
  else if(p->shield > 0.) {
    // Shields can take part of the blow.
    p->armor -= p->shield/damage_shield*damage_armor;
    p->shield = 0.;
  }
  else if(p->armor-damage_armor > 0.)
    p->armor -= damage_armor;
  else
    p->armor = 0.;
}

// Render the pilot.
void pilot_render(Pilot* p) {
  int sx, sy;

  // Get the sprite corresponding to the direction facing.
  gl_getSpriteFromDir(&sx, &sy, p->ship->gfx_space, p->solid->dir);

  gl_blitSprite(p->ship->gfx_space, &p->solid->pos, sx, sy, NULL);
}

// Update the pilot.
static void pilot_update(Pilot* pilot, const double dt) {
  // Regeneration.
  if(pilot->armor < pilot->armor_max)
    pilot->armor += pilot->ship->armor_regen*dt;
  else
    pilot->shield += pilot->ship->shield_regen*dt;

  if(pilot->armor > pilot->armor_max) pilot->armor = pilot->armor_max;
  if(pilot->shield > pilot->shield_max) pilot->shield = pilot->shield_max;

  if((pilot->solid->dir > 2.*M_PI) || (pilot->solid->dir < 0.0))
    pilot->solid->dir = fmod(pilot->solid->dir, 2.*M_PI);

  // Update the solid.
  pilot->solid->update(pilot->solid, dt);
  
  if(VMOD(pilot->solid->vel) > pilot->ship->speed) {
    // Should not go faster.
    vect_pset(&pilot->solid->vel, pilot->ship->speed, VANGLE(pilot->solid->vel));
  }

  pilot_render(pilot);
}

// ==Init pilot.===========================================
// ship  : Ship pilot is flying.
// name  : Pilot's name, if NULL, ships name will be used.
// dir   : Initial facing direction. (radians)
// vel   : Initial velocity.
// pos   : Initial position.
// flags : Tweaking the pilot.
// ========================================================
void pilot_init(Pilot* pilot, Ship* ship, char* name, Faction* faction, AI_Profile* ai,
      const double dir, const Vec2* pos, const Vec2* vel, const int flags) {

  if(flags & PILOT_PLAYER) // Player is ID 0
    pilot->id = PLAYER_ID;
  else
    pilot->id = ++pilot_id; // New unique pilot id based on pilot_id, Can't be 0.
  
  pilot->ship = ship;  
  pilot->name = strdup((name == NULL) ? ship->name : name);

  // Faction.
  pilot->faction = faction;

  // AI.
  pilot->ai       = ai;
  pilot->tcontrol = 0;
  pilot->flags    = 0;

  // Solid.
  pilot->solid = solid_create(ship->mass, dir, pos, vel);

  // Max shields armor.
  pilot->armor_max  = ship->armor;
  pilot->shield_max = ship->shield;
  pilot->energy_max = ship->energy;
  pilot->armor      = pilot->armor_max;
  pilot->shield     = pilot->shield_max;
  pilot->energy     = pilot->energy_max;


  // Initially idle.
  pilot->task = NULL;

  // Outfits.
  pilot->outfits = NULL;
  ShipOutfit* so;
  if(ship->outfit) {
    pilot->noutfits = 0;
    for(so = ship->outfit; so; so = so->next) {
      pilot->outfits = realloc(pilot->outfits, (pilot->noutfits+1)*sizeof(PilotOutfit));
      pilot->outfits[pilot->noutfits].outfit = so->data;
      pilot->outfits[pilot->noutfits].quantity = so->quantity;
      pilot->outfits[pilot->noutfits].timer = 0;
      (pilot->noutfits)++;
    }
  }

  if(flags & PILOT_PLAYER) {
    pilot->think = player_think; // Players don't need to thing! :P
    pilot->render = NULL;
    pilot_setFlag(pilot, PILOT_PLAYER); // It's a player!
    player = pilot;
    gui_load(pilot->ship->gui); // Load the GUI.
  } else {
    pilot->think = ai_think;
    pilot->render = pilot_render;
  }
  pilot->update = pilot_update;

}

// Create a new pilot - Params are same as pilot_init. Return pilot's id.
unsigned int pilot_create(Ship* ship, char* name, Faction* faction, AI_Profile* ai,  const double dir,
      const Vec2* pos, const Vec2* vel, const int flags) {
  Pilot* dyn = MALLOC_L(Pilot);
  if(dyn == NULL) {
    WARN("Unable to allocate memory.");
    return 0;
  }
  pilot_init(dyn, ship, name, faction, ai, dir, pos, vel, flags);

  if(flags & PILOT_PLAYER) {
    // Player.
    if(!pilot_stack) {
      pilot_stack = MALLOC_L(Pilot*);
      pilots = 1;
    }
    pilot_stack[0] = dyn;
  } else {
    // Add to the stack.
    pilot_stack = realloc(pilot_stack, ++pilots*sizeof(Pilot*));
    pilot_stack[pilots-1] = dyn;
  }
  return dyn->id;
}

// Frees and cleans up a pilot.
static void pilot_free(Pilot* p) {
  solid_free(p->solid);
  free(p->outfits);
  free(p->name);
  ai_destroy(p);
  free(p);
}

// Destroy pilot from stack.
void pilot_destroy(Pilot* p) {
  int i;
  for(i = 0; i < pilots; i++)
    if(pilot_stack[i] == p)
      break;
  while(i < pilots) {
    pilot_stack[i] = pilot_stack[i+1];
    i++;
  }
  pilot_free(p);
}

// Free the prisoned pilot!
void pilots_free(void) {
  int i;
  for(i = 0; i < pilots; i++)
    pilot_free(pilot_stack[i]);
  free(pilot_stack);
}

// Update all pilots.
void pilots_update(double dt) {
  int i;
  for(i = 0; i < pilots; i++) {
    if(pilot_stack[i]->think)
      pilot_stack[i]->think(pilot_stack[i]);
    if(pilot_stack[i]->update)
      pilot_stack[i]->update(pilot_stack[i], dt);
    if(pilot_stack[i]->render)
      pilot_stack[i]->render(pilot_stack[i]);
  }
}

// Return the fleet based on 'name'
Fleet* fleet_get(const char* name) {
  int i;
  for(i = 0; i < nfleets; i++)
    if(strcmp(name, fleet_stack[i].name)==0)
      return fleet_stack+i;

  return NULL;
}

// Parse the fleet node.
static Fleet* fleet_parse(const xmlNodePtr parent) {
  xmlNodePtr cur, node;
  FleetPilot* pilot;
  char* c;
  node = parent->xmlChildrenNode;

  Fleet* tmp = CALLOC_L(Fleet);

  tmp->name = (char*)xmlGetProp(parent, (xmlChar*)"name"); // Already mallocs.
  if(tmp->name == NULL) WARN("Fleet in "FLEET_DATA" has invalid or no name");
  
  do {
    // Load all the data.
    if(strcmp((char*)node->name, "faction")==0)
      tmp->faction = faction_get((char*)node->children->content);
    else if(strcmp((char*)node->name, "ai")==0)
      tmp->ai = ai_getProfile((char*)node->children->content);
    else if(strcmp((char*)node->name, "pilots")==0) {
      cur = node->children;
      do {
        if(strcmp((char*)cur->name, "pilot")==0) {
          tmp->npilots++; // Pilot count.
          pilot = MALLOC_L(FleetPilot);

          // Name is not obligatory. Will only override ship name.
          c = (char*)xmlGetProp(cur, (xmlChar*)"name"); // Mallocs.
          pilot->name = c; // No need to free here however.

          pilot->ship = ship_get((char*)cur->children->content);
          if(pilot->ship == NULL)
            WARN("Pilot %s in Fleet %s has null ship", pilot->name, tmp->name);

          c = (char*)xmlGetProp(cur, (xmlChar*)"chance"); // Mallocs.
          pilot->chance = atoi(c);
          if(pilot->chance == 0)
            WARN("Pilot %s in Fleet %s has 0%% chance of appearing", pilot->name, tmp->name);
          if(c) free(c); // Free the external malloc.

          tmp->pilots = realloc(tmp->pilots, sizeof(FleetPilot)*tmp->npilots);
          memcpy(tmp->pilots+(tmp->npilots-1), pilot, sizeof(FleetPilot));
          free(pilot);
        }
      } while((cur = cur->next));
    }
  } while((node = node->next));
#define MELEMENT(o,s) if((o) == NULL) WARN("Fleet '%s' missing '"s"' element", tmp->name)
  MELEMENT(tmp->ai,       "ai");
  MELEMENT(tmp->faction,  "faction");
  MELEMENT(tmp->pilots,   "pilots");
  #undef MELEMENT

  return tmp;
}

// Load the fleets.
int fleet_load(void) {
  uint32_t bufsize;
  char* buf = pack_readfile(DATA, FLEET_DATA, &bufsize);

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

  Fleet* tmp = NULL;

  node = doc->xmlChildrenNode; // Ships node.
  if(strcmp((char*)node->name, XML_ID)) {
    ERR("Malformed "FLEET_DATA" file: missing root element '"XML_ID"'");
    return -1;
  }
  node = node->xmlChildrenNode; // First ship node.
  if(node == NULL) {
    ERR("Malformed "FLEET_DATA" file: does not contain elements");
    return -1;
  }

  do {
    if(node->type == XML_NODE_START && strcmp((char*)node->name, XML_FLEET)==0) {
      tmp = fleet_parse(node);
      fleet_stack = realloc(fleet_stack, sizeof(Fleet)*(++nfleets));
      memcpy(fleet_stack+nfleets-1, tmp, sizeof(Fleet));
      free(tmp);
    }
  } while((node = node->next));

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

  DEBUG("Loaded %d fleet%c", nfleets, (nfleets==1)?' ':'s');

  return 0;
}

// Free the fleets.
void fleet_free(void) {
  int i, j;
  if(fleet_stack != NULL) {
    for(i = 0; i < nfleets; i++) {
      for(j = 0; j < fleet_stack[i].npilots; j++)
        if(fleet_stack[i].pilots[j].name)
          free(fleet_stack[i].pilots[j].name);
      free(fleet_stack[i].name);
      free(fleet_stack[i].pilots);
    }
    free(fleet_stack);
  }
  nfleets = 0;
}