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

#include <cmath>

#include "core/application.h"
#include "core/gameinterface.h"
#include "math/mathlib.h"
#include "math/matrix4f.h"
#include "render/camera.h"
#include "render/gl.h"
#include "render/state.h"
#include "sys/sys.h"

using math::degrees360f;
using math::degrees180f;

namespace render
{

const float 		MIN_DELTA = 10e-10;
const float 		COS_PI_4  = sqrt(2.0f) * 0.5f;

const float		pitch_free = -30.0f;
const float 		pitch_track = -5.0f;
const float 		pitch_overview = -5.0f;

math::Vector3f 		Camera::camera_eye;
math::Vector3f 		Camera::camera_target;
math::Axis 		Camera::camera_axis;
Camera::Mode 		Camera::camera_mode;
Camera::Mode		Camera::camera_previous_mode;

// current and target yaw angle in XZ plane, positive is looking left
float Camera::direction_current;
float Camera::direction_target;
float Camera::target_direction;

// current and target pitch angle in XY, positive is looking up
float Camera::pitch_current;
float Camera::pitch_target;
float Camera::target_pitch;

float Camera::distance;
float Camera::camera_zoom;

void Camera::init()
{
	direction_current = 0;
	direction_target = 0;

	pitch_current = pitch_track * 2;
	pitch_target = pitch_track;

	target_pitch = 0.0f;
	target_direction = 0.0f;

	distance = 0.4f;
	camera_zoom = 2.0f;

	camera_mode = Overview;
	camera_previous_mode = Track;
	set_mode(Track);

	camera_axis.clear();
	camera_eye.clear();
	camera_target.clear();

}

void Camera::shutdown()
{
}

void Camera::set_mode(Mode newmode)
{

	direction_target = 0;
	direction_current = direction_target;
	pitch_target = pitch_track;
	pitch_current = pitch_target;

	target_direction = 0.0f;
	target_pitch = 0.0f;
	distance = 0.4f;

	camera_axis.clear();

	if (camera_mode != Overview)
		camera_previous_mode = camera_mode;

	switch (newmode) {
		case Track:
			// switch camera to Track mode
			camera_mode = Track;
			if (core::localcontrol()) {
				camera_axis.assign(core::localcontrol()->axis());
			}
			break;

		case Free:
			// switch camera to Free mode
			camera_mode = Free;
			pitch_target = pitch_free;
			pitch_current = pitch_target;
			break;

		case Cockpit:
			camera_mode = Cockpit;
			break;

		case Overview:
			// switch camera to Overview mode
			camera_mode = Overview;

		default:
			break;
	}

}

void Camera::view_next()
{

	if (!core::localcontrol()) {
		set_mode(Overview);
		return;
	}

	switch (camera_mode) {
		case Free:
			// switch camera to Track mode
			set_mode(Track);
			//con_print << "view: track" << std::endl;
			core::application()->notify_message(core::Message::Info, std::string("view: track"));
			break;

		case Track:
			// switch camera to Cockpit mode
			set_mode(Cockpit);
			//con_print << "view: cockpit" << std::endl;
			core::application()->notify_message(core::Message::Info, std::string("view: cockpit"));
			break;

		case Cockpit:
			// switch camera to Free mode
			set_mode(Free);
			//con_print << "view: free" << std::endl;
			core::application()->notify_message(core::Message::Info, std::string("view: free"));
			break;

		default:
			break;
	}
}

void Camera::view_previous()
{

	if (!core::localcontrol()) {
		set_mode(Overview);
		return;
	}

	switch (camera_mode) {
		case Cockpit:
			// switch camera to Track mode
			set_mode(Track);
			//con_print << "view: track" << std::endl;
			core::application()->notify_message(core::Message::Info, std::string("view: track"));
			break;

		case Free:
			// switch camera to Cockpit mode
			set_mode(Cockpit);
			//con_print << "view: cockpit" << std::endl;
			core::application()->notify_message(core::Message::Info, std::string("view: cockpit"));
			break;

		case Track:
			// switch camera to Free mode
			set_mode(Free);
			//con_print << "view: free" << std::endl;
			core::application()->notify_message(core::Message::Info, std::string("view: free"));
			break;

		default:
			break;
	}
}

void Camera::set_zoom(float zoom)
{
	camera_zoom += zoom;
	math::clamp(camera_zoom, 1.0f, 10.0f);
}

void Camera::frame(float seconds)
{
	math::Axis target_axis;
	float d = 0;

	if (core::localplayer()->view()) {
		if (camera_mode != Overview) {
			set_mode(Overview);
		}
	} else if (core::localcontrol()) {
		if (camera_mode == Overview) {
			set_mode(camera_previous_mode);
		}
	} else {
		if (camera_mode != Overview) {
			set_mode(Overview);
		}
	}

	if (mode() == Overview) {
		camera_eye.clear();

		if (core::localplayer()->view()) {
			// player view entity

			camera_axis.assign(core::localplayer()->view()->axis());
			if (core::localplayer()->view() == core::localcontrol()) {
				camera_axis.change_pitch(pitch_free);
				camera_target.assign(core::localplayer()->view()->location());
				distance = math::max(core::localplayer()->view()->radius(), 1.0f) * 2.0f;
			} else {
				distance = math::max(core::localplayer()->view()->radius(), 1.0f) * 3.0f;
				camera_axis.change_direction(180.0f);
				camera_target.assign(core::localplayer()->view()->location() - core::localplayer()->view()->axis().left()*(math::max(core::localplayer()->view()->radius(), 1.0f)*0.5f));
			}

			/*
					} else if (core::localplayer()->zone()->default_view()) {
						// default zone view entity
						camera_target.assign(core::localplayer()->zone()->default_view()->location());
						camera_axis.assign(core::localplayer()->zone()->default_view()->axis());
						camera_axis.change_direction(180.0f);
						distance = math::max(core::localplayer()->zone()->default_view()->radius(), 1.0f) * 2.0f;
			*/
		} else {
			// default location (0,0,0)
			camera_target.clear();
			camera_axis.clear();
			pitch_current = pitch_overview;
			camera_axis.change_pitch(pitch_current);
			distance = 8.0f;
		}
	} else {

		camera_target.assign(core::localcontrol()->location());
		target_axis.assign(core::localcontrol()->axis());
		distance = core::localcontrol()->radius();

		if (mode() == Track) {

			float cosangle;		// cosine of an angle
			float angle;		// angle in radians
			math::Vector3f n;	// normal of a plane

			n.assign(math::crossproduct(camera_axis.forward(), target_axis.forward()));
			if (!(n.length() < MIN_DELTA)) {
				n.normalize();
				cosangle = math::dotproduct(camera_axis.forward(), target_axis.forward());
				angle = acos(cosangle) * seconds; // * 180.0f / M_PI;
				if (angle > MIN_DELTA)
					camera_axis.rotate(n, -angle);
			}

			n.assign(math::crossproduct(camera_axis.left(), target_axis.left()));
			if (!(n.length() < MIN_DELTA)) {
				n.normalize();
				cosangle = math::dotproduct(camera_axis.left(), target_axis.left());
				angle = acos(cosangle) * seconds; // * 180.0f / M_PI;
				if (angle > MIN_DELTA)
					camera_axis.rotate(n, -angle);
			}

			n.assign(math::crossproduct(camera_axis.up(), target_axis.up()));
			if (!(n.length() < MIN_DELTA)) {
				n.normalize();
				cosangle = math::dotproduct(camera_axis.up(), target_axis.up());
				angle = acos(cosangle) * seconds; // * 180.0f / M_PI;
				if (angle > MIN_DELTA)
					camera_axis.rotate(n, -angle);
			}

			if (core::localcontrol()->model()) {
				camera_target -= camera_axis.forward() * math::max(FRUSTUMFRONT / WORLDSCALE, core::localcontrol()->model()->maxbbox().x());
				camera_target += camera_axis.up() * math::max(FRUSTUMFRONT / WORLDSCALE, core::localcontrol()->model()->maxbbox().z() * 2.0f);
			} else {
				camera_target -= camera_axis.forward() * math::max(FRUSTUMFRONT / WORLDSCALE, FRUSTUMFRONT / WORLDSCALE + core::localcontrol()->radius());
				camera_target += camera_axis.up() * math::max(FRUSTUMFRONT / WORLDSCALE, FRUSTUMFRONT / WORLDSCALE + core::localcontrol()->radius());
			}

			distance = math::max(FRUSTUMFRONT / WORLDSCALE, FRUSTUMFRONT / WORLDSCALE + camera_zoom * core::localcontrol()->radius()) + 0.001f;

		} else if (mode() == Free) {

			camera_axis.assign(target_axis);

			direction_target =  direction_current - 90 * target_direction;
			pitch_target = pitch_current - 90 * target_pitch;

			// adjust direction
			d = degrees180f(direction_current - direction_target);
			direction_current = degrees360f(direction_current -  d * seconds);
			camera_axis.change_direction(direction_current);

			// adjust pitch
			d = degrees180f(pitch_current - pitch_target);
			pitch_current = degrees360f(pitch_current -  d * seconds);
			camera_axis.change_pitch(pitch_current);

			distance = math::max(FRUSTUMFRONT / WORLDSCALE, FRUSTUMFRONT / WORLDSCALE + camera_zoom * core::localcontrol()->radius()) + 0.001f;

		} else if (mode() == Cockpit) {

			camera_axis.assign(target_axis);

			if (core::localcontrol()->model()) {
				camera_target += (core::localcontrol()->model()->maxbbox().x()) *
						 core::localcontrol()->axis().forward();
			} else  {
				camera_target += (core::localcontrol()->radius()) *
						 core::localcontrol()->axis().forward();
			}
			distance = (FRUSTUMFRONT / WORLDSCALE) - 0.001f;
		}
	}

	// calculate eye position
	camera_eye = camera_target - (distance * camera_axis.forward());
}

void Camera::frustum()
{
	// Change to the projection matrix and set our viewing volume large enough for the skysphere
	gl::matrixmode(GL_PROJECTION);
	gl::loadidentity();

	gl::frustum(-FRUSTUMSIZE, FRUSTUMSIZE, -FRUSTUMSIZE / State::aspect(), FRUSTUMSIZE / State::aspect(), FRUSTUMFRONT, core::range::maxdistance * WORLDSCALE);
	gl::matrixmode(GL_MODELVIEW);
	gl::loadidentity();

	// map world coordinates to opengl coordinates
	gl::rotate(90.0f, 0.0f, 1.0f, 0.0f);
	gl::rotate(-90.0f, 1.0f , 0.0f, 0.0f);

	// apply the transpose of the axis transformation (the axis is orhtonormal)
	math::Matrix4f matrix;
	matrix.assign(camera_axis);
	gl::multmatrix(matrix.transpose());

	gl::scale(4.0f, 4.0f, 4.0f);

	gl::translate(-1.0f * camera_eye);

}

void Camera::frustum_default(float distance, float cx, float cy)
{
	// Change to the projection matrix and set our viewing volume large enough for the skysphere
	gl::matrixmode(GL_PROJECTION);
	gl::loadidentity();

	// move eye to (cx, cy)
	// note: the factor 2.0f probably has to be 1.0f/frustum_size
	gl::translate(2.0f*(-State::width() * 0.5f + cx) / State::width() , 2.0f*(State::height() * 0.5f - cy) / State::height(), 0.0f);

	gl::frustum(-FRUSTUMSIZE, FRUSTUMSIZE, -FRUSTUMSIZE / State::aspect(), FRUSTUMSIZE / State::aspect(), FRUSTUMFRONT, 1023.0f);

	gl::matrixmode(GL_MODELVIEW);
	gl::loadidentity();

	// map world coordinates to opengl coordinates
	gl::rotate(90.0f, 0.0f, 1.0f, 0.0f);
	gl::rotate(-90.0f, 1.0f , 0.0f, 0.0f);

	gl::translate(distance + 1.0f, 0.0f, 0.0f);

	// extra model rotation
	gl::rotate(-core::application()->time() / 8.0f *360.0f , 0.0f, 0.0f, 1.0f);
}

void Camera::ortho()
{
	// switch to orthographic projection
	gl::matrixmode(GL_PROJECTION);
	gl::loadidentity();
	glOrtho(0, State::width(), State::height(), 0, -16.0f, 16.0f);

	gl::matrixmode(GL_MODELVIEW);
	gl::loadidentity();
}

void Camera::set_direction(float direction)
{
	target_direction = direction;
	math::clamp(target_direction, -1.0f, 1.0f);
}

void Camera::set_pitch(float pitch)
{
	target_pitch = pitch;
	math::clamp(target_pitch, -1.0f, 1.0f);
}

void Camera::reset()
{
	set_mode(camera_mode);
}

}