//Copyright Paul Reiche, Fred Ford. 1992-2002

/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "ship.h"

#include "build.h"
#include "collide.h"
#include "colors.h"
#include "globdata.h"
#include "status.h"
#include "hyper.h"
#include "tactrans.h"
#include "pickship.h"
#include "intel.h"
#include "init.h"
#include "battle.h"
#include "supermelee/pickmele.h"
#include "races.h"
#include "setup.h"
#include "sounds.h"
#include "libs/mathlib.h"


void
animation_preprocess (ELEMENT *ElementPtr)
{
	if (ElementPtr->turn_wait > 0)
		--ElementPtr->turn_wait;
	else
	{
		ElementPtr->next.image.frame =
				IncFrameIndex (ElementPtr->current.image.frame);
		ElementPtr->state_flags |= CHANGING;

		ElementPtr->turn_wait = ElementPtr->next_turn;
	}
}


STATUS_FLAGS
inertial_thrust (ELEMENT *ElementPtr)
{
#define MAX_ALLOWED_SPEED     WORLD_TO_VELOCITY (DISPLAY_TO_WORLD (18))
#define MAX_ALLOWED_SPEED_SQR ((DWORD)MAX_ALLOWED_SPEED * MAX_ALLOWED_SPEED)

	COUNT CurrentAngle, TravelAngle;
	COUNT max_thrust, thrust_increment;
	VELOCITY_DESC *VelocityPtr;
	STARSHIP *StarShipPtr;

	VelocityPtr = &ElementPtr->velocity;

	GetElementStarShip (ElementPtr, &StarShipPtr);
	CurrentAngle = FACING_TO_ANGLE (StarShipPtr->ShipFacing);
	TravelAngle = GetVelocityTravelAngle (VelocityPtr);
	thrust_increment = StarShipPtr->RaceDescPtr->characteristics.thrust_increment;
	max_thrust = StarShipPtr->RaceDescPtr->characteristics.max_thrust;
	if (thrust_increment == max_thrust)
	{	// inertialess acceleration (Skiff)
		SetVelocityVector (VelocityPtr,
				max_thrust, StarShipPtr->ShipFacing);
		return (SHIP_AT_MAX_SPEED);
	}
	else if (TravelAngle == CurrentAngle
			&& (StarShipPtr->cur_status_flags
				& (SHIP_AT_MAX_SPEED | SHIP_BEYOND_MAX_SPEED))
			&& !(StarShipPtr->cur_status_flags & SHIP_IN_GRAVITY_WELL))
	{	// already maxed-out acceleration
		return (StarShipPtr->cur_status_flags
				& (SHIP_AT_MAX_SPEED | SHIP_BEYOND_MAX_SPEED));
	}
	else
	{
		SIZE delta_x, delta_y;
		SIZE cur_delta_x, cur_delta_y;
		DWORD desired_speed, max_speed;
		DWORD current_speed;

		thrust_increment = WORLD_TO_VELOCITY (thrust_increment);
		GetCurrentVelocityComponents (VelocityPtr, &cur_delta_x, &cur_delta_y);
		current_speed = VelocitySquared (cur_delta_x, cur_delta_y);
		delta_x = cur_delta_x + COSINE (CurrentAngle, thrust_increment);
		delta_y = cur_delta_y + SINE (CurrentAngle, thrust_increment);
		desired_speed = VelocitySquared (delta_x, delta_y);
		max_speed = VelocitySquared (WORLD_TO_VELOCITY (max_thrust), 0);
		
		if (desired_speed <= max_speed)
		{	// normal acceleration
			SetVelocityComponents (VelocityPtr, delta_x, delta_y);
		}
		else if (((StarShipPtr->cur_status_flags & SHIP_IN_GRAVITY_WELL)
				&& desired_speed <= MAX_ALLOWED_SPEED_SQR)
				|| desired_speed < current_speed)
		{	// acceleration in a gravity well within max allowed
			// deceleration after gravity whip
			SetVelocityComponents (VelocityPtr, delta_x, delta_y);
			return (SHIP_AT_MAX_SPEED | SHIP_BEYOND_MAX_SPEED);
		}
		else if (TravelAngle == CurrentAngle)
		{	// normal max acceleration, same vector
			if (current_speed <= max_speed)
				SetVelocityVector (VelocityPtr, max_thrust,
						StarShipPtr->ShipFacing);
			return (SHIP_AT_MAX_SPEED);
		}
		else
		{	// maxed-out acceleration at an angle to current travel vector
			// thrusting at an angle while at max velocity only changes
			// the travel vector, but does not really change the velocity

			VELOCITY_DESC v = *VelocityPtr;

			DeltaVelocityComponents (&v,
					COSINE (CurrentAngle, thrust_increment >> 1)
					- COSINE (TravelAngle, thrust_increment),
					SINE (CurrentAngle, thrust_increment >> 1)
					- SINE (TravelAngle, thrust_increment));
			GetCurrentVelocityComponents (&v, &cur_delta_x, &cur_delta_y);
			desired_speed = VelocitySquared (cur_delta_x, cur_delta_y);
			if (desired_speed > max_speed)
			{
				if (desired_speed < current_speed)
					*VelocityPtr = v;
				return (SHIP_AT_MAX_SPEED | SHIP_BEYOND_MAX_SPEED);
			}

			*VelocityPtr = v;
		}

		return (0);
	}
}

void
ship_preprocess (ELEMENT *ElementPtr)
{
	STATUS_FLAGS cur_status_flags;
	STARSHIP *StarShipPtr;
	RACE_DESC *RDPtr;

	GetElementStarShip (ElementPtr, &StarShipPtr);
	RDPtr = StarShipPtr->RaceDescPtr;

	cur_status_flags =
			StarShipPtr->cur_status_flags
			& ~(LEFT | RIGHT | THRUST | WEAPON | SPECIAL);
	if (!(ElementPtr->state_flags & APPEARING))
	{
		cur_status_flags |= StarShipPtr->ship_input_state
				& (LEFT | RIGHT | THRUST | WEAPON | SPECIAL);
	}
	else
	{	// Preprocessing for the first time
		ElementPtr->crew_level = RDPtr->ship_info.crew_level;

		if (ElementPtr->playerNr == NPC_PLAYER_NUM
				&& LOBYTE (GLOBAL (CurrentActivity)) == IN_LAST_BATTLE)
		{	// Sa-Matra
			STAMP s;
			CONTEXT OldContext;

			OldContext = SetContext (StatusContext);
			s.origin.x = s.origin.y = 0;
			s.frame = RDPtr->ship_data.captain_control.background;
			DrawStamp (&s);
			DestroyDrawable (ReleaseDrawable (s.frame));
			RDPtr->ship_data.captain_control.background = 0;
			SetContext (OldContext);
		}
		else if (LOBYTE (GLOBAL (CurrentActivity)) <= IN_ENCOUNTER)
		{
			CONTEXT OldContext;

			InitShipStatus (&RDPtr->ship_info, StarShipPtr, NULL);
			OldContext = SetContext (StatusContext);
			DrawCaptainsWindow (StarShipPtr);
			SetContext (OldContext);
			if (RDPtr->preprocess_func)
				(*RDPtr->preprocess_func) (ElementPtr);

			// XXX: Hack: Pkunk sets hTarget!=0 when it reincarnates. In that
			//   case there is no ship_transition() but a Phoenix transition
			//   instead.
			if (ElementPtr->hTarget == 0)
			{
				ship_transition (ElementPtr);
			}
			else
			{
				ElementPtr->hTarget = 0;
				if (!PLRPlaying ((MUSIC_REF)~0) && OpponentAlive (StarShipPtr))
					BattleSong (TRUE);
			}
			return;
		}
		else
		{
			ElementPtr->current.location.x = LOG_SPACE_WIDTH >> 1;
			ElementPtr->current.location.y = LOG_SPACE_HEIGHT >> 1;
			ElementPtr->next.location = ElementPtr->current.location;
			InitIntersectStartPoint (ElementPtr);
			InitIntersectEndPoint (ElementPtr);

			if (hyper_transition (ElementPtr))
				return;
		}
	}
	StarShipPtr->cur_status_flags = cur_status_flags;

	if (StarShipPtr->energy_counter)
		--StarShipPtr->energy_counter;
	else if (RDPtr->ship_info.energy_level < (BYTE)RDPtr->ship_info.max_energy
			|| (SBYTE)RDPtr->characteristics.energy_regeneration < 0)
		DeltaEnergy (ElementPtr,
				(SBYTE)RDPtr->characteristics.energy_regeneration);

	if (RDPtr->preprocess_func)
	{
		(*RDPtr->preprocess_func) (ElementPtr);
		cur_status_flags = StarShipPtr->cur_status_flags;
	}

	if (ElementPtr->turn_wait)
		--ElementPtr->turn_wait;
	else if (cur_status_flags & (LEFT | RIGHT))
	{
		if (cur_status_flags & LEFT)
			StarShipPtr->ShipFacing =
					NORMALIZE_FACING (StarShipPtr->ShipFacing - 1);
		else
			StarShipPtr->ShipFacing =
					NORMALIZE_FACING (StarShipPtr->ShipFacing + 1);
		ElementPtr->next.image.frame =
				SetAbsFrameIndex (ElementPtr->next.image.frame,
				StarShipPtr->ShipFacing);
		ElementPtr->state_flags |= CHANGING;

		ElementPtr->turn_wait = RDPtr->characteristics.turn_wait;
	}

	if (ElementPtr->thrust_wait)
		--ElementPtr->thrust_wait;
	else if (cur_status_flags & THRUST)
	{
		STATUS_FLAGS thrust_status;

		thrust_status = inertial_thrust (ElementPtr);
		StarShipPtr->cur_status_flags &=
				~(SHIP_AT_MAX_SPEED
				| SHIP_BEYOND_MAX_SPEED
				| SHIP_IN_GRAVITY_WELL);
		StarShipPtr->cur_status_flags |= thrust_status;

		ElementPtr->thrust_wait = RDPtr->characteristics.thrust_wait;

		if (!OBJECT_CLOAKED (ElementPtr)
				&& LOBYTE (GLOBAL (CurrentActivity)) <= IN_ENCOUNTER)
		{
			spawn_ion_trail (ElementPtr);
		}
	}

	if (LOBYTE (GLOBAL (CurrentActivity)) <= IN_ENCOUNTER)
		PreProcessStatus (ElementPtr);
}

void
ship_postprocess (ELEMENT *ElementPtr)
{
	STARSHIP *StarShipPtr;
	RACE_DESC *RDPtr;

	if (ElementPtr->crew_level == 0)
		return;

	GetElementStarShip (ElementPtr, &StarShipPtr);
	RDPtr = StarShipPtr->RaceDescPtr;

	if (StarShipPtr->weapon_counter)
		--StarShipPtr->weapon_counter;
	else if ((StarShipPtr->cur_status_flags
			& WEAPON) && DeltaEnergy (ElementPtr,
			-RDPtr->characteristics.weapon_energy_cost))
	{
		COUNT num_weapons;
		HELEMENT Weapon[6];

		num_weapons = (*RDPtr->init_weapon_func) (ElementPtr, Weapon);

		if (num_weapons)
		{
			HELEMENT *WeaponPtr;
			STARSHIP *StarShipPtr;
			BOOLEAN played_sfx = FALSE;

			GetElementStarShip (ElementPtr, &StarShipPtr);
			WeaponPtr = &Weapon[0];
			do
			{
				HELEMENT w;
				w = *WeaponPtr++;
				if (w)
				{
					ELEMENT *EPtr;

					LockElement (w, &EPtr);
					SetElementStarShip (EPtr, StarShipPtr);
					if (!played_sfx)
					{
						ProcessSound (RDPtr->ship_data.ship_sounds, EPtr);
						played_sfx = TRUE;
					}
					UnlockElement (w);

					PutElement (w);
				}
			} while (--num_weapons);
			
			if (!played_sfx)
				ProcessSound (RDPtr->ship_data.ship_sounds, ElementPtr);
		}

		StarShipPtr->weapon_counter =
				RDPtr->characteristics.weapon_wait;
	}

	if (StarShipPtr->special_counter)
		--StarShipPtr->special_counter;

	if (RDPtr->postprocess_func)
		(*RDPtr->postprocess_func) (ElementPtr);

	if (LOBYTE (GLOBAL (CurrentActivity)) <= IN_ENCOUNTER)
		PostProcessStatus (ElementPtr);
}

void
collision (ELEMENT *ElementPtr0, POINT *pPt0,
		ELEMENT *ElementPtr1, POINT *pPt1)
{
	if (!(ElementPtr1->state_flags & FINITE_LIFE))
	{
		ElementPtr0->state_flags |= COLLISION;
		if (GRAVITY_MASS (ElementPtr1->mass_points))
		{
			// Collision with a planet.
			SIZE damage;

			damage = ElementPtr0->hit_points >> 2;
			if (damage == 0)
				damage = 1;
			do_damage (ElementPtr0, damage);

			damage = TARGET_DAMAGED_FOR_1_PT + (damage >> 1);
			if (damage > TARGET_DAMAGED_FOR_6_PLUS_PT)
				damage = TARGET_DAMAGED_FOR_6_PLUS_PT;
			ProcessSound (SetAbsSoundIndex (GameSounds, damage), ElementPtr0);
		}
	}
	(void) pPt0;  /* Satisfying compiler (unused parameter) */
	(void) pPt1;  /* Satisfying compiler (unused parameter) */
}

static BOOLEAN
spawn_ship (STARSHIP *StarShipPtr)
{
	HELEMENT hShip;
	RACE_DESC *RDPtr;

	RDPtr = load_ship (StarShipPtr->SpeciesID, TRUE);
	if (!RDPtr)
		return FALSE;

	StarShipPtr->RaceDescPtr = RDPtr;

	StarShipPtr->ship_input_state = 0;
	StarShipPtr->cur_status_flags = 0;
	StarShipPtr->old_status_flags = 0;

	if (LOBYTE (GLOBAL (CurrentActivity)) == IN_ENCOUNTER
			|| LOBYTE (GLOBAL (CurrentActivity)) == IN_LAST_BATTLE)
	{
		if (StarShipPtr->crew_level == 0)
		{
			// SIS, already handled from sis_ship.c.
			// RDPtr->ship_info.crew_level = GLOBAL_SIS (CrewEnlisted);
		}
		else
			RDPtr->ship_info.crew_level = StarShipPtr->crew_level;

		if (RDPtr->ship_info.crew_level > RDPtr->ship_info.max_crew)
			RDPtr->ship_info.crew_level = RDPtr->ship_info.max_crew;
	}

	StarShipPtr->energy_counter = 0;
	StarShipPtr->weapon_counter = 0;
	StarShipPtr->special_counter = 0;

	hShip = StarShipPtr->hShip;
	if (hShip == 0)
	{
		hShip = AllocElement ();
		if (hShip != 0)
			InsertElement (hShip, GetHeadElement ());
	}

	StarShipPtr->hShip = hShip;
	if (StarShipPtr->hShip != 0)
	{
		// Construct an ELEMENT for the STARSHIP
		ELEMENT *ShipElementPtr;

		LockElement (hShip, &ShipElementPtr);

		ShipElementPtr->playerNr = StarShipPtr->playerNr;
		ShipElementPtr->crew_level = 0;
		ShipElementPtr->mass_points = RDPtr->characteristics.ship_mass;
		ShipElementPtr->state_flags = APPEARING | PLAYER_SHIP | IGNORE_SIMILAR;
		ShipElementPtr->turn_wait = 0;
		ShipElementPtr->thrust_wait = 0;
		ShipElementPtr->life_span = NORMAL_LIFE;
		ShipElementPtr->colorCycleIndex = 0;

		SetPrimType (&DisplayArray[ShipElementPtr->PrimIndex], STAMP_PRIM);
		ShipElementPtr->current.image.farray = RDPtr->ship_data.ship;

		if (ShipElementPtr->playerNr == NPC_PLAYER_NUM
				&& LOBYTE (GLOBAL (CurrentActivity)) == IN_LAST_BATTLE)
		{
			// This is the Sa-Matra
			StarShipPtr->ShipFacing = 0;
			ShipElementPtr->current.image.frame =
					SetAbsFrameIndex (RDPtr->ship_data.ship[0],
					StarShipPtr->ShipFacing);
			ShipElementPtr->current.location.x = LOG_SPACE_WIDTH >> 1;
			ShipElementPtr->current.location.y = LOG_SPACE_HEIGHT >> 1;
			++ShipElementPtr->life_span;
		}
		else
		{
			StarShipPtr->ShipFacing = NORMALIZE_FACING (TFB_Random ());
			if (inHQSpace ())
			{	// Only one ship is ever spawned in HyperSpace -- flagship
				COUNT facing = GLOBAL (ShipFacing);
				// XXX: Solar system reentry test depends on ShipFacing != 0
				if (facing > 0)
					--facing;

				// XXX: This appears to set the facing to a random value
				//   for when the ship returns from an encounter back
				//   to HyperSpace. However, it is overwritten later
				//   in sis.c. See also r1614.
				//GLOBAL (ShipFacing) = StarShipPtr->ShipFacing + 1;
				StarShipPtr->ShipFacing = facing;
			}
			ShipElementPtr->current.image.frame =
					SetAbsFrameIndex (RDPtr->ship_data.ship[0],
					StarShipPtr->ShipFacing);
			do
			{
				ShipElementPtr->current.location.x =
						WRAP_X (DISPLAY_ALIGN_X (TFB_Random ()));
				ShipElementPtr->current.location.y =
						WRAP_Y (DISPLAY_ALIGN_Y (TFB_Random ()));
			} while (CalculateGravity (ShipElementPtr)
					|| TimeSpaceMatterConflict (ShipElementPtr));
		}

		ShipElementPtr->preprocess_func = ship_preprocess;
		ShipElementPtr->postprocess_func = ship_postprocess;
		ShipElementPtr->death_func = ship_death;
		ShipElementPtr->collision_func = collision;
		ZeroVelocityComponents (&ShipElementPtr->velocity);

		SetElementStarShip (ShipElementPtr, StarShipPtr);
		ShipElementPtr->hTarget = 0;

		UnlockElement (hShip);
	}

	return (hShip != 0);
}

// Select a new ship and spawn it.
BOOLEAN
GetNextStarShip (STARSHIP *LastStarShipPtr, COUNT which_side)
{
	HSTARSHIP hBattleShip;

	hBattleShip = GetEncounterStarShip (LastStarShipPtr, which_side);
	if (hBattleShip)
	{
		STARSHIP *StarShipPtr;

		StarShipPtr = LockStarShip (&race_q[which_side], hBattleShip);
		if (LastStarShipPtr)
		{
			if (StarShipPtr == LastStarShipPtr)
			{
				// Ship has been recycled (on infinite ship worlds).
				LastStarShipPtr = 0;
			}
			else
				StarShipPtr->hShip = LastStarShipPtr->hShip;
		}

		if (!spawn_ship (StarShipPtr))
		{
			UnlockStarShip (&race_q[which_side], hBattleShip);
			return (FALSE);
		}
		UnlockStarShip (&race_q[which_side], hBattleShip);
	}

	if (LastStarShipPtr)
		LastStarShipPtr->hShip = 0;

	return (hBattleShip != 0);
}

BOOLEAN
GetInitialStarShips (void)
{
	if (LOBYTE (GLOBAL (CurrentActivity)) == SUPER_MELEE)
	{
		HSTARSHIP ships[NUM_PLAYERS];
		COUNT i;
		
		if (!GetInitialMeleeStarShips (ships))
			return FALSE;

		for (i = 0; i < NUM_PLAYERS; i++)
		{
			STARSHIP *StarShipPtr;
			COUNT playerI = GetPlayerOrder (i);

			StarShipPtr = LockStarShip (&race_q[playerI], ships[playerI]);
			if (!spawn_ship (StarShipPtr))
			{
				UnlockStarShip (&race_q[playerI], ships[playerI]);
				return FALSE;
			}
			UnlockStarShip (&race_q[playerI], ships[playerI]);
		}
		return TRUE;
	}
	else
	{
		int i;
		
		for (i = NUM_PLAYERS; i > 0; --i)
		{
			if (!GetNextStarShip (NULL, i - 1))
				return FALSE;
		}
		return TRUE;
	}
}