/*
This Source Code Form is subject to the
terms of the Mozilla Public License, v.
2.0. If a copy of the MPL was not
distributed with this file, You can
obtain one at
http://mozilla.org/MPL/2.0/.
*/

#include "stdafx.h"
#include "vehicle/Camera.h"

#include "utilities/Globals.h"
#include "utilities/utilities.h"
#include "utilities/glmHelpers.h"
#include "Console.h"
#include "utilities/Timer.h"
#include "vehicle/Driver.h"
#include "vehicle/DynObj.h"
#include "MOVER.h"

//---------------------------------------------------------------------------

void TCamera::Init(glm::dvec3 const &NPos, glm::dvec3 const &NAngle /*, TCameraType const NType*/, TDynamicObject *Owner)
{

    vUp = { 0, 1, 0 };
    Velocity = { 0, 0, 0 };
    Angle = NAngle;
    Pos = NPos;

    m_owner = Owner;
};

void TCamera::Reset() {

    Angle = {};
    m_rotationoffsets = {};
};


void TCamera::OnCursorMove(double x, double y) {
    m_rotationoffsets.x += y;
    m_rotationoffsets.y += x;
}

static double ComputeAxisSpeed(double param, double walkspeed, double maxspeed, double threshold) {
    double absval = std::abs(param);
    // 2/3rd of the stick range lerps walk speed, past that we lerp between max walk and run speed
    double walk = walkspeed * std::min(absval / threshold, 1.0);
    double run  = std::max(0.0, absval - threshold) / (1.0 - threshold) * std::max(0.0, maxspeed - walkspeed);
    return (param >= 0.0 ? 1.0 : -1.0) * (walk + run);
}


bool
TCamera::OnCommand( command_data const &Command ) {

    auto const walkspeed { 1.0 };
    auto const runspeed { 10.0 };

	// threshold position on stick between walk lerp and walk/run lerp
	auto const stickthreshold = 2.0 / 3.0;

    bool iscameracommand { true };
    switch( Command.command ) {

        case user_command::viewturn: {

            OnCursorMove(
                Command.param1 *  0.005 * Global.fMouseXScale / Global.ZoomFactor,
                Command.param2 *  0.01  * Global.fMouseYScale / Global.ZoomFactor );
            break;
        }

        case user_command::movehorizontal:
        case user_command::movehorizontalfast: {

            auto const movespeed = m_owner == nullptr ?       runspeed : // free roam
                false == FreeFlyModeFlag ? walkspeed : // vehicle cab
                0.0; // vehicle external

//            if( movespeed == 0.0 ) { break; } // enable to fix external cameras in place

            auto const speedmultiplier = true == FreeFlyModeFlag && Command.command == user_command::movehorizontalfast ? m_owner == nullptr ? 30.0 : 5.0 : 1.0;

            // left-right
            m_moverate.x = ComputeAxisSpeed(Command.param1, walkspeed, movespeed, stickthreshold) * speedmultiplier;
            // forward-back
            m_moverate.z = -ComputeAxisSpeed(Command.param2, walkspeed, movespeed, stickthreshold) * speedmultiplier;

            break;
        }

        case user_command::movevertical:
        case user_command::moveverticalfast: {

            auto const movespeed = m_owner == nullptr ?       runspeed * 0.5 : // free roam
                false == FreeFlyModeFlag ? walkspeed : // vehicle cab
                0.0; // vehicle external

//            if( movespeed == 0.0 ) { break; } // enable to fix external cameras in place

            auto const speedmultiplier = true == FreeFlyModeFlag && Command.command == user_command::moveverticalfast ? m_owner == nullptr ? 10.0 : 3.0 : 1.0;
            // up-down
            m_moverate.y = ComputeAxisSpeed(Command.param1, walkspeed, movespeed, stickthreshold) * speedmultiplier;

            break;
        }

        default: {

            iscameracommand = false;
            break;
        }
    } // switch

    return iscameracommand;
}

static void UpdateVelocityAxis(double& velocity, double moverate, double deltatime)
{
    velocity = std::clamp(velocity + moverate * 10.0 * deltatime, -std::abs(moverate), std::abs(moverate));
}


void TCamera::Update()
{
    // check for sent user commands
    // NOTE: this is a temporary arrangement, for the transition period from old command setup to the new one
    // ultimately we'll need to track position of camera/driver for all human entities present in the scenario
    command_data command;
    // NOTE: currently we're only storing commands for local entity and there's no id system in place,
    // so we're supplying 'default' entity id of 0
	while( simulation::Commands.pop( command, static_cast<std::size_t>( command_target::entity ) | 0 ) ) {

        OnCommand( command );
    }

    auto const deltatime { Timer::GetDeltaRenderTime() }; // czas bez pauzy

    // update rotation
    auto const rotationfactor { std::min( 1.0, 20 * deltatime ) };

    Angle.y -= m_rotationoffsets.y * rotationfactor;
    m_rotationoffsets.y *= 1.0 - rotationfactor;
    Angle.y = std::remainder(Angle.y, 2.0 * M_PI);

    // Limit the camera pitch to +/- 90°.
    Angle.x = std::clamp(Angle.x - m_rotationoffsets.x * rotationfactor, -M_PI_2, M_PI_2);
    m_rotationoffsets.x *= 1.0 - rotationfactor;

    // update position
    if( m_owner == nullptr
     || true == FreeFlyModeFlag
     || false == Global.ctrlState
     || true == DebugCameraFlag ) {
        // ctrl is used for mirror view, so we ignore the controls when in vehicle if ctrl is pressed
        // McZapkie-170402: poruszanie i rozgladanie we free takie samo jak w follow
        UpdateVelocityAxis(Velocity.x, m_moverate.x, deltatime);
        UpdateVelocityAxis(Velocity.y, m_moverate.y, deltatime);
        UpdateVelocityAxis(Velocity.z, m_moverate.z, deltatime);
    }
    if( m_owner == nullptr
     || true == DebugCameraFlag ) {
        // free movement position update
        auto movement { Velocity };
		movement = RotateY(movement, (double)Angle.y);
        Pos += movement * 5.0 * deltatime;
    }
    else {
        // attached movement position update
        auto movement { Velocity * -2.0 };
        movement.y = -movement.y;
        auto const *owner { (
            m_owner->Mechanik ?
                m_owner->Mechanik :
                m_owner->ctOwner ) };
        if( owner && owner->Occupied()
         && owner->Occupied()->CabOccupied < 0 ) { 
            movement *= -1.f;
            movement.y = -movement.y;
        }
/*
        if( ( m_owner->ctOwner )
         && ( m_owner->ctOwner->Vehicle()->DirectionGet() != m_owner->DirectionGet() ) ) {
            movement *= -1.f;
            movement.y = -movement.y;
        }
*/
		movement = RotateY(movement, (double)Angle.y);

        m_owneroffset += movement * deltatime;
    }
}

bool TCamera::SetMatrix( glm::dmat4 &Matrix ) {

    Matrix = glm::rotate(Matrix, -(double)Angle.x, glm::dvec3(1, 0, 0));
	Matrix = glm::rotate(Matrix, -(double)Angle.y, glm::dvec3(0, 1, 0)); // w zewnętrznym widoku: kierunek patrzenia
	Matrix = glm::rotate(Matrix, -(double)Angle.z, glm::dvec3(0, 0, 1)); // po wyłączeniu tego kręci się pojazd, a sceneria nie

    if( m_owner != nullptr && false == DebugCameraFlag ) {

        Matrix *= glm::lookAt(Pos, LookAt, glm::dvec3{ vUp } );
    }
    else {
        Matrix = glm::translate( Matrix, -Pos ); // nie zmienia kierunku patrzenia
    }

    return true;
}

void TCamera::RaLook()
{ // zmiana kierunku patrzenia - przelicza Yaw
    auto where = LookAt - Pos /*+ Math3D::vector3(0, 3, 0)*/; // trochę w górę od szyn
    if( where.x != 0.0 || where.z != 0.0 ) {
        Angle.y = atan2( -where.x, -where.z ); // kąt horyzontalny
        m_rotationoffsets.y = 0.0;
    }
    double l = glm::length(where);
    if( l > 0.0 ) {
        Angle.x = asin( where.y / l ); // kąt w pionie
        m_rotationoffsets.x = 0.0;
    }
};