/*
   client/targets.cc
   This file is part of the Osirion project and is distributed under
   the terms of the GNU General Public License version 2
*/

#include <iostream>
#include <string>
#include <sstream>
#include <iomanip>

#include "audio/audio.h"
#include "audio/buffers.h"
#include "audio/sources.h"
#include "auxiliary/functions.h"
#include "audio/sources.h"
#include "client/client.h"
#include "client/input.h"
#include "client/soundext.h"
#include "client/video.h"
#include "core/application.h"
#include "core/entity.h"
#include "core/func.h"
#include "core/gameinterface.h"
#include "core/range.h"
#include "math/axis.h"
#include "math/vector3f.h"
#include "render/camera.h"
#include "render/state.h"

namespace client
{

namespace targets
{

const float TARGETBOXRADIUS = 0.025f;
unsigned int current_target_id = 0;
unsigned int current_hover = 0;

const core::Entity *current_target = 0;

bool is_valid_map_target(const core::Entity *entity)
{
	if (entity->serverside()) {
		return false;
	} else if (entity == core::localcontrol()) {
		return false;
	} else if (entity->has_flag(core::Entity::ShowOnMap)) {
		return true;
	} else 	if (entity == core::localplayer()->mission_target()) {
		return true;
	} else {
		return false;
	}
}

bool is_valid_hud_target(const core::Entity *entity)
{
	if (entity->serverside()) {
		return false;
	} else if (entity->type() == core::Entity::Projectile) {
		return false;
	} else if (entity == core::localcontrol()) {
		return false;
	} else if (entity->has_flag(core::Entity::ShowOnMap)) {
		return true;
	} else 	if (entity == core::localplayer()->mission_target()) {
		return true;
	} else if (!ext_render(entity)) {
		return false;
	} else {
		return ext_render(entity)->visible();
	}
}

const core::Entity* current()
{
	return current_target;
}

unsigned int current_id()
{
	return current_target_id;
}

unsigned int hover()
{
	return current_hover;
}

void set_target(const core::Entity *entity)
{
	current_target = entity;
	if (entity) {
		current_target_id = current_target->id();
		audio::play("ui/target");
	} else {
		current_target_id = 0;
	}
}

void set_target(unsigned int id)
{
	if (!core::localcontrol())
		return;
	core::Zone *zone = core::localcontrol()->zone();
	if (!zone)
		return;

	core::Entity *entity = zone->find_entity(id);

	if (entity && is_valid_hud_target(entity))
		set_target(entity);
}

void func_target_next(std::string const &args)
{
	if (!core::localcontrol())
		return;
	core::Zone *zone = core::localcontrol()->zone();
	if (!zone)
		return;

	if (!zone->content().size()) {
		current_target = 0;
		current_target_id = 0;
		return;
	}

	core::Zone::Content::iterator it = zone->content().begin();
	if (!current_target_id) {

		// first entity
		it = zone->content().begin();
		while (!is_valid_hud_target((*it)) && it != zone->content().end())
			it++;

	} else {
		// current entity
		while (it != zone->content().end() && ((*it)->id() != current_target_id))
			++it;

		// next legal entity
		if (it !=  zone->content().end())
			it++;
		if (it ==  zone->content().end()) {
			it =  zone->content().begin();
		}
		while (!is_valid_hud_target((*it))) {
			it++;
			if (it == zone->content().end())
				it = zone->content().begin();

			if ((*it)->id() == current_target_id) {
				current_target = (*it);
				return;
			}
		}
	}

	if (it !=  zone->content().end()) {
		set_target((*it));
	} else {
		current_target = 0;
		current_target_id = 0;

	}
}

void func_target_prev(std::string const &args)
{
	if (!core::localcontrol())
		return;
	core::Zone *zone = core::localcontrol()->zone();
	if (!zone)
		return;

	if (!zone->content().size()) {
		current_target = 0;
		current_target_id = 0;
		return;
	}

	core::Zone::Content::reverse_iterator rit = zone->content().rbegin();
	if (!current_target_id) {
		// last entity
		rit = zone->content().rbegin();
		while (!is_valid_hud_target((*rit)) && rit != zone->content().rend())
			rit++;
	} else {
		// current entity
		while (rit != zone->content().rend() && ((*rit)->id() != current_target_id))
			++rit;

		// previous legal entity
		if (rit !=  zone->content().rend())
			++rit;
		if (rit ==  zone->content().rend()) {
			rit =  zone->content().rbegin();
		}
		while (!is_valid_hud_target((*rit))) {
			++rit;
			if (rit == zone->content().rend())
				rit = zone->content().rbegin();

			if ((*rit)->id() == current_target_id) {
				current_target = (*rit);
				return;
			}
		}
	}

	if (rit != zone->content().rend()) {
		set_target((*rit));
	} else {
		current_target = 0;
		current_target_id = 0;
	}
}

void func_target_none(std::string const &args)
{
	current_target = 0;
	current_target_id = 0;
}

void func_target_center(std::string const &args)
{
	if (!core::localcontrol())
		return;

	// this is essentialy the hover algorithm with the cursor in the center
	const core::Entity *new_target = 0;
	math::Vector3f center = render::Camera::eye() + render::Camera::axis().forward() * (render::FRUSTUMFRONT + 0.001);
	float smallest_d = -1;

	for (core::Zone::Content::const_iterator it = core::localcontrol()->zone()->content().begin(); it != core::localcontrol()->zone()->content().end(); it++) {
		const core::Entity *entity = (*it);

		math::Vector3f v(entity->location() - render::Camera::eye());
		v.normalize();

		if (is_valid_hud_target(entity) && math::dotproduct(render::Camera::axis().forward(), v) > 0.85) {

			// calculate the distance from entity location to the line [eye - cursor]
			float d = math::Vector3f::length(math::crossproduct((center - render::Camera::eye()) , (render::Camera::eye() - entity->location()))) / math::Vector3f::length(center - render::Camera::eye());

			// the entity closer to the center beam
			if (smallest_d < 0 || d < smallest_d) {
				new_target = entity;
				smallest_d = d;
			}
		}
	}

	if (new_target)
		set_target(new_target);
}

void reset()
{
	current_target = 0;
	current_target_id = 0;
	current_hover = 0;

}

void init()
{
	core::Func *func = 0;

	func = core::Func::add("target_next", func_target_next);
	func->set_info("select next target");

	core::Func::add("target_prev", func_target_prev);
	func->set_info("select previous target");

	core::Func::add("target_none", func_target_none);
	func->set_info("deselect current target");

	core::Func::add("target_center", func_target_center);
	func->set_info("select target near center");

	reset();
}

void shutdown()
{
	reset();

	core::Func::remove("target_next");
	core::Func::remove("target_prev");
	core::Func::remove("target_none");
	core::Func::remove("target_center");
}

// render targets and sounds (in world coordinates)
void frame()
{
	core::Zone *zone = core::localplayer()->zone();
	if (!zone)
		return;

	/* Notes
		http://en.wikipedia.org/wiki/Line-plane_intersection
		http://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html
	*/
	using math::Vector3f;

	render_listener_sound();

	current_target = 0;
	current_hover = 0;

	float z = -1;

	// mouse cursor location in 3d world space
	float x = 0;
	float y = 0;

	if ((input::joystick_lastmoved_time() > input::mouse_lastmoved_time()) && (render::Camera::mode() == render::Camera::Cockpit || render::Camera::mode() == render::Camera::Track)) {
		x = 0;
		y = 0;
	} else {
		x = (float)(input::mouse_position_x() - render::State::width() / 2) / (float)render::State::width();
		y = (float)(input::mouse_position_y() - render::State::height() / 2) / (float)render::State::height() / render::State::aspect();
	}

	Vector3f cursor = render::Camera::eye() + render::Camera::axis().forward() * (render::FRUSTUMFRONT + 0.001);
	cursor -= render::Camera::axis().left() * x;
	cursor -= render::Camera::axis().up() * y;
	
	// set aim
	if (core::localcontrol()) {
		core::localcontrol()->set_target_aim(cursor);
	}

	//math::Vector3f center = render::Camera::eye() + (render::Camera::axis().forward() * (render::FRUSTUMFRONT + 0.001f));
	for (core::Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); it++) {
		core::Entity *entity = (*it);

		// render entity sound
		if ((entity->type() == core::Entity::Controlable) || (entity->model() && entity->model()->sounds().size())) {
			render_entity_sound(entity);
		}

		// find the current target
		if (!core::localplayer()->view() && core::localcontrol() && (is_valid_hud_target(entity) || is_valid_map_target(entity))) {

			if (entity->id() == current_target_id) {
				current_target = entity;
			}

			// check if the mouse is hovering the entity
			Vector3f v(entity->location() - render::Camera::eye());
			v.normalize();

			if (math::dotproduct(render::Camera::axis().forward(), v) > 0.75) {

				// calculate the distance from entity location to the line [eye - cursor]
				float d = math::Vector3f::length(math::crossproduct((cursor - render::Camera::eye()) , (render::Camera::eye() - entity->location()))) / math::Vector3f::length(cursor - render::Camera::eye());

				float r = entity->radius() * 0.5f;

				if (ext_render(entity)->distance() > 512.0f)
					math::clamp(r, 8.0f, r);
				else if (ext_render(entity)->distance() > 256.0f)
					math::clamp(r, 4.0f, r);
				else if (ext_render(entity)->distance() > 128.0f)
					math::clamp(r, 2.0f, r);

				// if the cursor-beam hits the entity sphere
				if (d < r) {
					float myz = math::distance(cursor, entity->location());
					if (z < 0 || myz < z) {
						current_hover = entity->id();
						z = myz;
					}
				}
			}


		}
	}

	if (!current_target) {
		current_target_id = 0;
	} else {
		current_target_id  = current_target->id();


	}
}

}

}