#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>

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

// Stack of pilot id's to assure uniqueness.
static unsigned int pilot_id = 0;

// Stack of pilots - yes, they come in stacks now.
Pilot** pilot_stack;
int pilots = 0;
extern Pilot* player;

// External.
extern void ai_destroy(Pilot* p); // Ai.
extern void player_think(Pilot* pilot); // Player.c
extern void ai_think(Pilot* pilot); // Ai.c
// Internal.
static void pilot_update(Pilot* pilot, const double dt);
void pilot_render(Pilot* pilot);
static void pilot_free(Pilot* p);

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

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

    for(i = 0; p->outfits[i].outfit; 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, double damage_shield, 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 sprite;
  gl_texture* t = p->ship->gfx_space;

  // Get the sprite corresponding to the direction facing.
  sprite = (int)(p->solid->dir / (2.0*M_PI / (t->sy * t->sx)));

  gl_blitSprite(t, &p->solid->pos, sprite % (int)t->sx, sprite / (int)t->sy);
}

// 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->armor > pilot->armor_max) pilot->armor = pilot->armor_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, const double dir, const Vec2* pos, 
      const Vec2* vel, const int flags) {

  if(flags & PILOT_PLAYER) // Player is ID 0
    pilot->id = 0;
  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);

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

  if(flags & PILOT_PLAYER) {
    pilot->think = player_think; // Players don't need to thing! :P
    pilot->render = NULL;
    pilot->properties |= PILOT_PLAYER;
    player = pilot;
  } 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, 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, 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]);
  }
}