#include "externals.hh"
#include "camera.hh"
#include "utilities.hh"


/*= T_Camera =================================================================*/

T_Camera::T_Camera( ) noexcept
{
	cvtFov2Np( );
	cvtAnglesToVectors( );
}

/*----------------------------------------------------------------------------*/

void T_Camera::cvtAnglesToVectors( ) noexcept
{
	anglesToMatrix( &angles_.x , &rotMat_[ 0 ].x );
	dir_ = glm::vec3( 0 , 0 , -distance_ ) * rotMat_;
	up_ = glm::vec3( 0 , 1 , 0 ) * rotMat_;
	pos_ = lookAt_ - dir_;
}

void T_Camera::cvtVectorsToAngles( ) noexcept
{
#warning implement the fuck
}

/*------------------------------------------------------------------------------*/

void T_Camera::handleDND(
		ImVec2 const& move ,
		const bool hasCtrl ,
		const bool hasShift ,
		const bool lmb ) noexcept
{
	if ( move.x == 0 || move.y == 0 ) {
		return;
	}

	const float fdx( move.x * .1f * ( hasCtrl ? 1.f : .1f ) );
	const float fdy( move.y * .1f * ( hasCtrl ? 1.f : .1f ) );

	if ( lmb && hasShift ) {
		// Left mouse button, shift - move camera
		const auto side( glm::normalize( glm::cross( up_ , dir_ ) ) );
		lookAt_ += .1f * ( side * fdx + up_ * fdy );
	} else if ( lmb ) {
		// Left mouse button, no shift - change yaw/pitch
		updateAngle( angles_.y , fdx );
		updateAngle( angles_.x , fdy );
	} else {
		// Right mouse button - change roll
		updateAngle( angles_.z , fdx );
	}
	cvtAnglesToVectors( );
}

void T_Camera::handleWheel(
		const float wheel ,
		const bool hasCtrl ,
		const bool hasShift ) noexcept
{
	const float delta( wheel * ( hasCtrl ? 1.f : .1f) );
	if ( hasShift ) {
		fov_ = std::max( 1.f , std::min( 179.f , fov_ + delta ) );
		cvtFov2Np( );
	} else {
		distance_ = std::max( .01f , distance_ - delta );
		cvtAnglesToVectors( );
	}
}

/*----------------------------------------------------------------------------*/

void T_Camera::makeUI( ) noexcept
{
	using namespace ImGui;
	if ( !CollapsingHeader( "Camera" ) ) {
		return;
	}

	const bool changed[] = {
		DragFloat3( "Target" , &lookAt_.x ) ,
		DragFloat( "Distance" , &distance_ , .1f ,
				.1f , 1e8 , "%.1f" ) ,
		DragFloat3( "Angles" , &angles_.x , .01f , -180 , 180 ) ,

		DragFloat( "FoV" , &fov_ , .01f , .01f , 179.9f )
	};

	for ( unsigned i = 0 ; i < sizeof( changed ) / sizeof( bool ) ; i ++ ) {
		if ( changed[ i ] ) {
#warning fix this shit
			// FIXME update( );
			break;
		}
	}
}