#include <math.h>
#include <malloc.h>
#include <string.h>

#include "outfit.h"
#include "physics.h"
#include "main.h"
#include "log.h"
#include "rng.h"
#include "pilot.h"
#include "collision.h"
#include "player.h"
#include "weapon.h"

#define weapon_isSmart(w) (w->think)

// Some stuff from pilot.
extern Pilot** pilot_stack;
extern int pilots;

// Ai stuff.
extern void ai_attacked(Pilot* attacked, const unsigned int attacker);

typedef struct Weapon {
  Solid* solid; // Actually has its own solid. :D

  unsigned int parent; // The pilot that just shot at you!
  unsigned int target; // Target to hit. Only used by seeking stuff.
  const Outfit* outfit; // Related outfit that fired.
  unsigned int timer; // Mainly used to see when the weapon was fired.

  // Update position and render.
  void(*update)(struct Weapon*, const double, WeaponLayer); // Position update and render.
  void(*think)(struct Weapon*); // Some missiles need to be inteligent.
} Weapon;

// Behind Pilot layer.
static Weapon** wbackLayer = NULL; // Behind pilots.
static int nwbackLayer     = 0;    // Number of elements.
static int mwbackLayer     = 0;    // Allocated memory size.
// Behind player layer.
static Weapon** wfrontLayer = NULL;  // Behind pilots.
static int nwfrontLayer    = 0;    // Number of elements.
static int mwfrontLayer    = 0;    // Allocated memory size.


static Weapon* weapon_create(const Outfit* outfit, const double dir,
      const Vec2* pos, const Vec2* vel, const unsigned int parent, 
      const unsigned int target);

static void weapon_render(const Weapon* w);
static void weapons_updateLayer(const double dt, const WeaponLayer layer);
static void weapon_update(Weapon* w, const double dt, WeaponLayer layer);
static void weapon_hit(Weapon* w, Pilot* p, WeaponLayer layer);
static void weapon_destroy(Weapon* w, WeaponLayer layer);
static void weapon_free(Weapon* w);
// Think.
static void think_seeker(Weapon* w);

// Draw the minimap weapons (player.c).
#define PIXEL(x,y) if((shape == RADAR_RECT && ABS(x) < w/2. && ABS(y)<h/2.) || \
      (shape == RADAR_CIRCLE && (((x)*(x)+(y)*(y))<rc))) glVertex2i((x),(y))
void weapon_minimap(const double res, const double w, const double h, const RadarShape shape) {
  int i, rc;
  double x, y;

  if(shape == RADAR_CIRCLE) rc = (int)(w*w);

  for(i = 0; i < nwbackLayer; i++) {
    x = (wbackLayer[i]->solid->pos.x - player->solid->pos.x) / res;
    y = (wbackLayer[i]->solid->pos.y - player->solid->pos.y) / res;
    PIXEL(x,y);
  }
  
  for(i = 0; i < nwfrontLayer; i++) {
    x = (wfrontLayer[i]->solid->pos.x - player->solid->pos.x) / res;
    y = (wfrontLayer[i]->solid->pos.y - player->solid->pos.y) / res;
    PIXEL(x,y);
  }
}
#undef PIXEL

// Pause/Unpause the weapon system.
void weapons_pause(void) {
  int i;
  unsigned int t = SDL_GetTicks();
  for(i = 0; i < nwbackLayer; i++)
    wbackLayer[i]->timer -= t;
  for(i = 0; i < nwfrontLayer; i++)
    wfrontLayer[i]->timer -= t;
}


void weapons_unpause(void) {
  int i;
  unsigned int t = SDL_GetTicks();
  for(i = 0; i < nwbackLayer; i++)
    wbackLayer[i]->timer += t;
  for(i = 0; i < nwfrontLayer; i++)
    wfrontLayer[i]->timer += t;
}

static void think_seeker(Weapon* w) {
  if(w->target == w->parent) return; // HEY! Self harm is not allowed.

  Pilot* p = pilot_get(w->target);
  if(p == NULL) return; // Can't do anything with no pilots.

  double diff = angle_diff(w->solid->dir, vect_angle(&w->solid->pos, &p->solid->pos));
  w->solid->dir_vel = 10 * diff * w->outfit->turn;
  // Face the target.
  if(w->solid->dir_vel > w->outfit->turn) w->solid->dir_vel = w->outfit->turn;
  else if(w->solid->dir_vel < -w->outfit->turn) w->solid->dir_vel = -w->outfit->turn;

  vect_pset(&w->solid->force, w->outfit->thrust, w->solid->dir);

  if(VMOD(w->solid->vel) > w->outfit->speed)
    // We should not go any faster.
    vect_pset(&w->solid->vel, w->outfit->speed, VANGLE(w->solid->vel));
}

// Update all the weapon layers.
void weapons_update(const double dt) {
  weapons_updateLayer(dt, WEAPON_LAYER_BG);
  weapons_updateLayer(dt, WEAPON_LAYER_FG);
}

// Update all weapons in the layer.
static void weapons_updateLayer(const double dt, const WeaponLayer layer) {
  Weapon** wlayer;
  int* nlayer;

  switch(layer) {
    case WEAPON_LAYER_BG:
      wlayer = wbackLayer;
      nlayer = &nwbackLayer;
      break;
    case WEAPON_LAYER_FG:
      wlayer = wfrontLayer;
      nlayer = &nwfrontLayer;
      break;
  }
  int i;
  Weapon* w;
  for(i = 0; i < (*nlayer); i++) {
    w = wlayer[i];
    switch(wlayer[i]->outfit->type) {
      case OUTFIT_TYPE_MISSILE_SEEK_AMMO:
        if(SDL_GetTicks() > (wlayer[i]->timer + wlayer[i]->outfit->duration)) {
          weapon_destroy(wlayer[i], layer);
          continue;
        }
        break;
      default:
        // Check see if it exceeds distance.
        if(SDL_GetTicks() > (wlayer[i]->timer + 1000*(unsigned int)
              wlayer[i]->outfit->range/wlayer[i]->outfit->speed)) {
          weapon_destroy(wlayer[i],layer);
          continue;
        }
        break;
    }
    weapon_update(wlayer[i], dt, layer);
    // If the weapon has been deleted we are going to have to hold back one.
    if(w != wlayer[i]) i--;
  }
}

// Render all the weapons.
void weapons_render(const WeaponLayer layer) {
  Weapon** wlayer;
  int* nlayer;
  int i;

  switch(layer) {
    case WEAPON_LAYER_BG:
      wlayer = wbackLayer;
      nlayer = &nwbackLayer;
      break;
    case WEAPON_LAYER_FG:
      wlayer = wfrontLayer;
      nlayer = &nwfrontLayer;
      break;
  }
  for(i = 0; i < (*nlayer); i++)
    weapon_render(wlayer[i]);
}

// Render the weapons.
static void weapon_render(const Weapon* w) {
  int sx, sy;

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

  gl_blitSprite(w->outfit->gfx_space, w->solid->pos.x, w->solid->pos.y, sx, sy, NULL);
}

// Update the weapon.
static void weapon_update(Weapon* w, const double dt, WeaponLayer layer) {
  int i, wsx, wsy, psx, psy;
  gl_getSpriteFromDir(&wsx, &wsy, w->outfit->gfx_space, w->solid->dir);

  for(i = 0; i < pilots; i++) {
    gl_getSpriteFromDir(&psx, &psy, pilot_stack[i]->ship->gfx_space,
          pilot_stack[i]->solid->dir);
    if(w->parent == pilot_stack[i]->id) continue; // Hey! That's you.

    if((weapon_isSmart(w)) && (pilot_stack[i]->id == w->target) &&
          CollideSprite(w->outfit->gfx_space, wsx, wsy, &w->solid->pos,
                pilot_stack[i]->ship->gfx_space, psx, psy, &pilot_stack[i]->solid->pos)) {
      weapon_hit(w, pilot_stack[i], layer);
      return;
    }
    else if(!weapon_isSmart(w) &&
          !areAllies(pilot_get(w->parent)->faction, pilot_stack[i]->faction) &&
          CollideSprite(w->outfit->gfx_space, wsx, wsy, &w->solid->pos,
                pilot_stack[i]->ship->gfx_space, psx, psy, &pilot_stack[i]->solid->pos)) {
      weapon_hit(w, pilot_stack[i], layer);
      return;
    }
  }
  if(weapon_isSmart(w)) (*w->think)(w);
  (*w->solid->update)(w->solid, dt);
}

// Good shot.
static void weapon_hit(Weapon* w, Pilot* p, WeaponLayer layer) {
  // Someone should let the ai know it's been attacked.
  if(!pilot_isPlayer(p))
    ai_attacked(p, w->parent);
  if(w->parent == PLAYER_ID)
    // Make hostile to player.
    pilot_setFlag(p, PILOT_HOSTILE);

  // Let the ship know that is should take some kind of damage.
  pilot_hit(p, w->outfit->damage_shield, w->outfit->damage_armour);
  // We don't need the weapon particle any longer.
  weapon_destroy(w, layer);
}

static Weapon* weapon_create(const Outfit* outfit, const double dir, const Vec2* pos,
      const Vec2* vel, unsigned int parent, const unsigned int target) {
  Vec2 v;
  double mass = 1; // Presumer lasers have a mass of 1.
  double rdir = dir; // Real direction (accuracy).
  Weapon* w = MALLOC_L(Weapon);
  w->parent = parent; // Non-Changeable.
  w->target = target; // Non-Changeable.
  w->outfit = outfit; // Non-Changeable.
  w->update = weapon_update;
  w->timer = SDL_GetTicks();
  w->think = NULL;

  switch(outfit->type) {
    case OUTFIT_TYPE_BOLT:
      // Need accuracy and speed based on player. -- Another contribution from VLack.
      rdir += RNG(-outfit->accuracy/2., outfit->accuracy/2.)/180.*M_PI;
      if((rdir > 2.*M_PI) || (rdir < 0.)) rdir = fmod(rdir, 2.*M_PI);
      vectcpy(&v, vel);
      vect_cadd(&v, outfit->speed*cos(rdir), outfit->speed*sin(rdir));
      w->solid = solid_create(mass, rdir, pos, &v);
      break;
    case OUTFIT_TYPE_MISSILE_SEEK_AMMO:
      mass = w->outfit->mass;
      w->solid = solid_create(mass, dir, pos, vel);
      w->think = think_seeker; // Eeek!!!
      break;
    default:
      // Just dump it where the player is.
      w->solid = solid_create(mass, dir, pos, vel);
      break;
  }
  return w;
}

// Add a new weapon.
void weapon_add(const Outfit* outfit, const double dir, const Vec2* pos, const Vec2* vel,
      unsigned int parent, unsigned int target) {
  
  if(!outfit_isWeapon(outfit) && !outfit_isAmmo(outfit)) {
    ERR("Trying to create a weapon from a non-Weapon type Outfit");
    return;
  }

  WeaponLayer layer = (parent == PLAYER_ID) ? WEAPON_LAYER_FG : WEAPON_LAYER_BG;
  Weapon* w = weapon_create(outfit, dir, pos, vel, parent, target);

  // Set the propper layer.
  Weapon** curLayer = NULL;
  int* mLayer = NULL;
  int* nLayer = NULL;
  switch(layer) {
    case WEAPON_LAYER_BG:
      curLayer = wbackLayer;
      nLayer = &nwbackLayer;
      mLayer = &mwbackLayer;
      break;
    case WEAPON_LAYER_FG:
      curLayer = wfrontLayer;
      nLayer = &nwfrontLayer;
      mLayer = &mwfrontLayer;
      break;
    default:
      ERR("Invalid WEAPON_LAYER specified.");
      return;
  }
  if(*mLayer > *nLayer) // More memory allocated than what we need.
    curLayer[(*nLayer)++] = w;
  else { // Need to allocate more memory.
    switch(layer) {
      case WEAPON_LAYER_BG:
        curLayer = wbackLayer = realloc(curLayer, (++(*mLayer))*sizeof(Weapon*));
        break;
      case WEAPON_LAYER_FG:
        curLayer = wfrontLayer = realloc(curLayer, (++(*mLayer))*sizeof(Weapon*));
        break;
    }
    curLayer[(*nLayer)++] = w;
  }
}

// Destroy the weapon.
static void weapon_destroy(Weapon* w, WeaponLayer layer) {
  int i;
  Weapon** wlayer;
  int* nlayer;
  switch(layer) {
    case WEAPON_LAYER_BG:
      wlayer = wbackLayer;
      nlayer = &nwbackLayer;
      break;
    case WEAPON_LAYER_FG:
      wlayer = wfrontLayer;
      nlayer = &nwfrontLayer;
      break;
  }
  for(i = 0; wlayer[i] != w; i++); // Get us to the current posision.
  weapon_free(wlayer[i]);
  wlayer[i] = NULL;
  (*nlayer)--;
  
  for(; i < (*nlayer); i++)
    wlayer[i] = wlayer[i+1];
}

// Clear the weapon.
static void weapon_free(Weapon* w) {
  solid_free(w->solid);
  free(w);
}

// Clear all the weapons, do not free the layers.
void weapon_clear(void) {
  int i;
  for(i = 0; i < nwbackLayer; i++)
    weapon_free(wbackLayer[i]);
  nwbackLayer = 0;
  for(i = 0; i < nwfrontLayer; i++)
    weapon_free(wfrontLayer[i]);
  nwfrontLayer = 0;
}

void weapon_exit(void) {
  weapon_clear();
  free(wbackLayer);
  free(wfrontLayer);
}