#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;
static int mpilots = 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_shootWeapon(Pilot* p, PilotOutfit* w, const unsigned int t);
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) {
  // Binary search.
  int l, m, h;
  l = 0;
  h = pilots-1;
  while(l <= h) {
    m = (l+h)/2;
    if(pilot_stack[m]->id > id) h = m-1;
    else if(pilot_stack[m]->id < id) l = m+1;
    else break;
  }

  if(m == (pilots-1)) return PLAYER_ID;
  else return pilot_stack[m+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(!pilot_isDisabled(pilot_stack[i]) && ((!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) {
  if(id == PLAYER_ID) return player; // Special case player.

  // Binary search.
  int l, m, h;
  l = 0;
  h = pilots-1;
  while(l <= h) {
    m = (l+h)/2;
    if(pilot_stack[m]->id > id) h = m-1;
    else if(pilot_stack[m]->id < id) l = m+1;
    else return pilot_stack[m];
  }
  return NULL;
}

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

  if(!secondary) {
    // Primary weapons.
    for(i = 0; i < p->noutfits; i++)
      // Cycle through outfits to find primary weapons.
      if(!outfit_isProp(p->outfits[i].outfit, OUTFIT_PROP_WEAP_SECONDARY))
        pilot_shootWeapon(p, &p->outfits[i], target);
  } else {
    if(!p->secondary) return; // No secondary weapon.
    pilot_shootWeapon(p, p->secondary, target);
  }
}

static void pilot_shootWeapon(Pilot* p, PilotOutfit* w, const unsigned int t) {
  // WElll... Trying to shoot when you have no ammo?? FUUU
  int quantity = (outfit_isAmmo(w->outfit) && p->secondary) ?
        p->secondary->quantity : w->quantity;
  // Check to see if weapon is ready.
  if((SDL_GetTicks() - w->timer) < (w->outfit->delay / quantity)) return;

  // Regular weapons.
  if(outfit_isWeapon(w->outfit)) {
    // Different weapons.
    switch(w->outfit->type) {
      case OUTFIT_TYPE_BOLT:
        weapon_add(w->outfit, p->solid->dir, &p->solid->pos, &p->solid->vel, p->id, t);

        // Can't shoot for a while.
        w->timer = SDL_GetTicks();
        break;
      default:
        break;
    }
  }
  // Missile launchers.
  // Must be secondary weapon, Shootee can't be the target.
  else if(outfit_isLauncher(w->outfit) && (w == p->secondary) && (p->id != t)) {
    if(p->ammo && (p->ammo->quantity > 0)) {
      weapon_add(p->ammo->outfit, p->solid->dir, &p->solid->pos, &p->solid->vel, p->id, t);

      w->timer = SDL_GetTicks(); // Can't shoot for a while.
      p->ammo->quantity -= 1; // There's no getting this one back.
    }
  }
}

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

// Set the pilot's ammo based on their secondary weapon.
void pilot_setAmmo(Pilot* p) {
  int i;
  char* name;

  if((p->secondary == NULL) || !outfit_isLauncher(p->secondary->outfit)) {
    p->ammo = NULL;
    return;
  }

  name = p->secondary->outfit->ammo;

  for(i = 0; i < p->noutfits; i++)
    if(strcmp(p->outfits[i].outfit->name, name)==0) {
      p->ammo = p->outfits + i;
      return;
    }

  p->ammo = NULL;
}

// 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.x, p->solid->pos.y,  sx, sy, NULL);
}

// Update the pilot.
static void pilot_update(Pilot* pilot, const double dt) {
  if(pilot != player && pilot->armour < PILOT_DISABLED_ARMOUR * pilot->armour_max) { 
    // We are disabled.
    pilot_setFlag(pilot, PILOT_DISABLED);
    // Come to a halt slowly.
    vect_pset(&pilot->solid->vel, VMOD(pilot->solid->vel) * (1. - dt*0.10), VANGLE(pilot->solid->vel));
    vectnull(&pilot->solid->force);
    pilot->solid->dir_vel = 0.; // Stop it from turning.

    // Update the solid.
    pilot->solid->update(pilot->solid, dt);
    return;
  }
  // We are still alive.
  else if(pilot->armour < pilot->armour_max)
    pilot->armour += pilot->ship->armour_regen*dt;
  else
    pilot->shield += pilot->ship->shield_regen*dt;

  if(pilot->armour > pilot->armour_max) pilot->armour = pilot->armour_max;
  if(pilot->shield > pilot->shield_max) pilot->shield = pilot->shield_max;

  // 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));
  }
}

// ==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 armour.
  pilot->armour_max   = ship->armour;
  pilot->shield_max   = ship->shield;
  pilot->energy_max   = ship->energy;
  pilot->armour       = pilot->armour_max;
  pilot->shield       = pilot->shield_max;
  pilot->energy       = pilot->energy_max;


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

  // Outfits.
  pilot->outfits = NULL;
  pilot->secondary = NULL;
  pilot->ammo = 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;
      mpilots = 1;
    }
    pilot_stack[0] = dyn;
  } else {
    // Add to the stack.
    pilots++; // There is a new pilot.

    if(pilots >= mpilots) // Need to grow.
      pilot_stack = realloc(pilot_stack, ++mpilots*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);
  pilot_stack = NULL;
  pilots = 0;
}

// Clean up the pilots - Leaves the player.
void pilots_clean(void) {
  int i;
  for(i = 1; i < pilots; i++)
    pilot_free(pilot_stack[i]);
  pilots = 1;
}

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

// Render all the pilots.
void pilots_render(void) {
  int i;
  for(i = 1; i < pilots; i++)
    // Skip the player.
    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);
    fleet_stack = NULL;
  }
  nfleets = 0;
}