/*
 * Author: KoffeinFlummi
 *
 * Calculates the offsets for all weapons needed to hit the current target.
 *
 * Arguments:
 * 0: The vehicle
 *
 * Return Value:
 * none
 */

#include "script_component.hpp"

private ["_ammoType", "_viewDiff", "_posArrival", "_airFriction", "_timeToLive", "_maxElev", "_vehicle", "_posTarget", "_distance", "_simulationStep", "_posX", "_velocityMagnitude", "_magazines", "_movingAzimuth", "_FCSElevation", "_velocityX", "_velocityY", "_weaponDirection", "_velocityTarget", "_FCSAzimuth", "_FCSMagazines", "_dirArrival", "_i", "_magazineType", "_angleTarget", "_offset", "_timeToTarget", "_initSpeed"];

_vehicle = _this select 0;
_distance = call FUNC(getRange);

if !(GVAR(enabled) && FUNC(canUseFCS)) exitWith {};

_magazines = magazines _vehicle;

if (_distance == 0) then {
    _distance = [
        getNumber (configFile >> "CfgVehicles" >> typeOf _vehicle >> QGVAR(DistanceInterval)),
        getNumber (configFile >> "CfgVehicles" >> typeOf _vehicle >> QGVAR(MaxDistance)),
        getNumber (configFile >> "CfgVehicles" >> typeOf _vehicle >> QGVAR(MinDistance))
    ] call EFUNC(common,getTargetDistance); // maximum distance: 5000m, 5m precision
};

_weaponDirection = _vehicle weaponDirection currentWeapon _vehicle;
_angleTarget = asin (_weaponDirection select 2);

if (count _this > 2) then {
    _distance = _this select 2;
};

if (!(isNil QGVAR(backgroundCalculation)) and {!(scriptDone GVAR(backgroundCalculation))}) then {
    terminate GVAR(backgroundCalculation);
};

// MOVING TARGETS
_movingAzimuth = 0;
if (time - GVAR(time) > 1 and GVAR(time) != -1 and count _this < 3) then {
    // calculate speed of target
    _posTarget = [
        (getPos _vehicle select 0) + _distance * (_weaponDirection select 0),
        (getPos _vehicle select 1) + _distance * (_weaponDirection select 1),
        (getPos _vehicle select 2) + _distance * (_weaponDirection select 2)
    ];
    _velocityTarget = [
        ((_posTarget select 0) - (GVAR(position) select 0)) / (time - GVAR(time)),
        ((_posTarget select 1) - (GVAR(position) select 1)) / (time - GVAR(time)),
        ((_posTarget select 2) - (GVAR(position) select 2)) / (time - GVAR(time))
    ];

    // estimate time to target
    _magazineType = currentMagazine _vehicle;
    _ammoType       = getText   (configFile >> "CfgMagazines" >> _magazineType >> "ammo");
    _initSpeed      = getNumber (configFile >> "CfgMagazines" >> _magazineType >> "initSpeed");
    _airFriction    = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "airFriction");
    _timeToLive     = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "timeToLive");
    _simulationStep = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "simulationStep");

    if (_simulationStep != 0) then {
        _posX = 0;
        _velocityX = _initSpeed;
        _velocityY = 0;
        _timeToTarget = 0;
        for "_i" from 1 to ((floor (_timeToLive / _simulationStep)) + 1) do {
            _posX = _posX + _velocityX * _simulationStep;
            if (_posX >= _distance) exitWith { // bullet passed the target
                _timeToTarget = _i * _simulationStep;
            };
            _velocityMagnitude = sqrt (_velocityX^2 + _velocityY^2);
            _velocityX = _velocityX + _velocityX * _velocityMagnitude * _airFriction * _simulationStep;
            _velocityY = _velocityY + _velocityY * _velocityMagnitude * _airFriction * _simulationStep - 9.81 * _simulationStep;
        };

        // calculate offsets
        _posArrival = [
            (_posTarget select 0) + (_velocityTarget select 0) * _timeToTarget,
            (_posTarget select 1) + (_velocityTarget select 1) * _timeToTarget,
            (_posTarget select 2) + (_velocityTarget select 2) * _timeToTarget
        ];
        _dirArrival = [
            ((_posArrival select 0) - (getPos _vehicle select 0)) / (_posArrival distance (getPos _vehicle)),
            ((_posArrival select 1) - (getPos _vehicle select 1)) / (_posArrival distance (getPos _vehicle)),
            ((_posArrival select 2) - (getPos _vehicle select 2)) / (_posArrival distance (getPos _vehicle))
        ];

        _movingAzimuth = ((_dirArrival select 0) atan2 (_dirArrival select 1)) - ((_weaponDirection select 0) atan2 (_weaponDirection select 1));
        _angleTarget = asin (_dirArrival select 2);
        _distance = floor (_posArrival distance (getPos _vehicle));
    };
};
GVAR(enabled) = false;
GVAR(time) = -1;

// CALCULATE AZIMUTH CORRECTION
_viewDiff = _vehicle getVariable QGVAR(ViewDiff);
_FCSAzimuth = _movingAzimuth;
if (_viewDiff != 0) then {
    _FCSAzimuth = (atan (_distance / _viewDiff) - (abs _viewDiff / _viewDiff) * 90) + _movingAzimuth;
};

// CALCULATE OFFSET FOR CURRENT WEAPON
_FCSMagazines = [];
_FCSElevation = [];

_magazineType   = currentMagazine _vehicle;
_ammoType       = getText   (configFile >> "CfgMagazines" >> _magazineType >> "ammo");
if !(getText (configFile >> "CfgAmmo" >> _ammoType >> "simulation") == "shotMissile") then {
    _maxElev        = getNumber (configFile >> "CfgVehicles" >> typeOf _vehicle >> "Turrets" >> "MainTurret" >> "maxElev");
    _initSpeed      = getNumber (configFile >> "CfgMagazines" >> _magazineType >> "initSpeed");
    _airFriction    = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "airFriction");
    _timeToLive     = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "timeToLive");
    _simulationStep = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "simulationStep");

    _offset = [_distance, _angleTarget, _maxElev, _initSpeed, _airFriction, _timeToLive, _simulationStep] call FUNC(getAngle);

    _FCSMagazines = _FCSMagazines + [_magazineType];
    _FCSElevation = _FCSElevation + [_offset];
};

_vehicle setVariable [QGVAR(Distance),  _distance,     true];
_vehicle setVariable [QGVAR(Magazines), _FCSMagazines, true];
_vehicle setVariable [QGVAR(Elevation), _FCSElevation, true];
_vehicle setVariable [QGVAR(Azimuth),   _FCSAzimuth,   true];

// CALCULATE OFFSETS FOR OTHER WEAPONS IN THE BACKGROUND
GVAR(backgroundCalculation) = [_vehicle, _magazines, _distance, _angleTarget, _FCSMagazines, _FCSElevation] spawn {
    _vehicle      = _this select 0;
    _magazines    = _this select 1;
    _distance     = _this select 2;
    _angleTarget  = _this select 3;
    _FCSMagazines = _this select 4;
    _FCSElevation = _this select 5;

    {
        if !(_x in _FCSMagazines) then {
            _ammoType       = getText   (configFile >> "CfgMagazines" >> _x >> "ammo");
            if !(getText (configFile >> "CfgAmmo" >> _ammoType >> "simulation") == "shotMissile") then {
                _maxElev        = getNumber (configFile >> "CfgVehicles" >> typeOf _vehicle >> "Turrets" >> "MainTurret" >> "maxElev");
                _initSpeed      = getNumber (configFile >> "CfgMagazines" >> _x >> "initSpeed");
                _airFriction    = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "airFriction");
                _timeToLive     = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "timeToLive");
                _simulationStep = getNumber (configFile >> "CfgAmmo" >> _ammoType >> "simulationStep");

                _offset = [_distance, _angleTarget, _maxElev, _initSpeed, _airFriction, _timeToLive, _simulationStep] call FUNC(getAngle);

                _FCSMagazines = _FCSMagazines + [_x];
                _FCSElevation = _FCSElevation + [_offset];
            };
        };
    } forEach _magazines;

    _vehicle setVariable [QGVAR(Magazines), _FCSMagazines, true];
    _vehicle setVariable [QGVAR(Elevation), _FCSElevation, true];
};

[format ["%1: %2", localize "STR_ACE_FCS_ZeroedTo", _distance]] call EFUNC(common,displayTextStructured);