/*
   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/sources.h"
#include "client/input.h"
#include "client/view.h"
#include "client/video.h"
#include "core/application.h"
#include "core/entity.h"
#include "core/func.h"
#include "core/gameinterface.h"
#include "math/vector3f.h"
#include "render/gl.h"
#include "render/render.h"
#include "render/text.h"

namespace client {

namespace targets {

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

core::Entity *current_target = 0;
core::Cvar *snd_engines = 0;


bool is_legal_target(core::Entity *entity)
{
	if (entity->id() == core::localcontrol()->id())
		return false;
	else
		return true;
}

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

unsigned int current_id()
{
	return current_target_id;
}

unsigned int hover()
{
	return current_hover;
}

void select_target(core::Entity *entity)
{
	current_target = entity;
	current_target_id = current_target->id();
	core::application()->notify_sound("ui/target");
}

void select_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)
		select_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_legal_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_legal_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()) {
		select_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_legal_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_legal_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()) {
		select_target((*rit));
	} else {
		current_target = 0;
		current_target_id = 0;
	}
}

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

void init()
{
	snd_engines = core::Cvar::get("snd_engines", "1", core::Cvar::Archive);
	snd_engines->set_info("[bool] enable or disable engine sounds");

	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");

	reset();
}

void shutdown()
{
	reset();

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

void render_listener_sound()
{
	if (!(snd_engines && snd_engines->value()))
		return;

	math::Vector3f velocity(0, 0 ,0);
	if (core::localcontrol()) {
		velocity.assign(core::localcontrol()->state()->axis().forward() * core::localcontrol()->speed());
	}

	audio::update_listener(render::Camera::eye(), render::Camera::axis(), velocity);
}

void render_entity_sound(core::Entity *entity)
{
	if (!(entity->type() == core::Entity::Controlable))
		return;

	if (!(snd_engines && snd_engines->value())) {
		entity->state()->clearsound();
		return;
	}

	core::EntityControlable *entitycontrolable = (core::EntityControlable *) entity;
	core::ClientState *state = entity->state();

	if (entity->model() && state->detailvisible() && entitycontrolable->thrust() > 0 ) {

		float speed = entitycontrolable->speed();
		float pitch = 0.2f + entitycontrolable->thrust() * 0.8f;
		
		if (!state->state_enginesound) {
			if ((state->state_enginesound = audio::Sources::get()) > 0 ) {

				size_t enginesound = 0;
				if (entity->model())
					enginesound = entity->model()->enginesound();
				
				std::stringstream soundname;
				soundname << "engines/loop" << std::setfill('0') << std::setw(2) << enginesound;
				audio::loop(state->state_enginesound, soundname.str().c_str(), pitch, 0);
			}
		}

		if (state->state_enginesound) {
			audio::update_source(state->state_enginesound,
				state->location() - state->axis().forward() * entity->model()->maxbbox().y , state->axis().forward() * speed, pitch);
		}
	} else {
		entity->state()->clearsound();
	}
}

// render client targets
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 = (float)(input::mouse_position_x() - video::width /2) / (float)video::width;
	float y = (float)(input::mouse_position_y() - video::height /2) / (float)video::height / render::Camera::aspect();

	Vector3f cursor = render::Camera::eye() + render::Camera::axis().forward() * (render::Camera::frustum_front() + 0.001);
	cursor -= render::Camera::axis().left() * x;
	cursor -= render::Camera::axis().up() * y;

	math::Vector3f center = render::Camera::eye() + (render::Camera::axis().forward() * (render::Camera::frustum_front() +0.01f));
	for (core::Zone::Content::iterator it=zone->content().begin(); it != zone->content().end(); it++) {
		core::Entity *entity = (*it);
		
		// render entity sound
		render_entity_sound(entity);

		// find the current target
		if (entity->id() == current_target_id) {
			current_target = entity;
		}
		
		// check if the mouse is hovering the entity
		if (core::localcontrol() && entity->state()->visible()) {
			Vector3f v(entity->state()->location() - render::Camera::eye());
			v.normalize();

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

				// caculate 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());
	
				// if the cursor-beam hits the entity sphere
				if (d < entity->radius() * 0.5f) {
					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();
	}
}

void draw_target()
{
	using math::Vector3f;

	if (!current_target)
		return;

	core::Entity *entity = current_target;

	// if target is in visible space
	Vector3f v(entity->state()->location() - render::Camera::eye());
	v.normalize();
	if (math::dotproduct(render::Camera::axis().forward(), v) > 0.75 ) {

		// find the intersection of the line [ eye - target ] in the frustum front plane
		Vector3f const &plane_normal = render::Camera::axis().forward();
		Vector3f const &plane_point = render::Camera::eye() + render::Camera::axis().forward() * (render::Camera::frustum_front() + 0.001);

		float d = (plane_normal.x * plane_point.x + plane_normal.y * plane_point.y + plane_normal.z * plane_point.z);
		float t = d - plane_normal.x * render::Camera::eye().x 
			- plane_normal.y * render::Camera::eye().y
			- plane_normal.z * render::Camera::eye().z;
		t /= plane_normal.x * (entity->state()->location().x - render::Camera::eye().x)
			+ plane_normal.y * (entity->state()->location().y - render::Camera::eye().y)
			+ plane_normal.z * (entity->state()->location().z - render::Camera::eye().z);

		Vector3f intersection = render::Camera::eye() + (entity->state()->location() - render::Camera::eye()) * t;

		// draw the target cursor in the frustum front plane, but in real world coordinates
		const float r = 0.05;
		render::gl::color(1, 1, 1, 1);
		render::gl::begin(render::gl::LineLoop);
		render::gl::vertex(intersection + render::Camera::axis().up() * r);
		render::gl::vertex(intersection + render::Camera::axis().left() * r);
		render::gl::vertex(intersection - render::Camera::axis().up() * r);
		render::gl::vertex(intersection - render::Camera::axis().left() * r);
		render::gl::end();
	}
}

}

}