Math.radians = function (degrees) {
    return degrees * Math.PI / 180;
};

Math.degrees = function (radians) {
    return radians * 180 / Math.PI;
};

function calculateSquishInfo(data) {
    //data = bore, stroke, conrod, rpm, exhtiming, compratio, sqarearatio, sqangle, sqclear
    const boreMeters = data[0] / 1000; // input is in mm, so /1000 gives meters
    const strokeMeters = data[1] / 1000; // input is in mm, so /1000 gives meters
    const conrodMeters = data[2] / 1000; // input is in mm, so /1000 gives meters
    const RPM = data[3];
    const exhTiming = data[4]; // in degrees after tdc
    const compratio = data[5];
    const squish_area_ratio = data[6] / 100; // ratio of areas, NOT diameters/radii (% -> ratio)
    const squish_angle = data[7]; // in degrees
    const squish_clearance = data[8] / 1000; // input is in mm, so /1000 gives meters

    // calculate further info from the input
    const piston_area = Math.PI * (boreMeters ** 2) / 4; // piston top face area in m^2
    const swept_vol = piston_area * strokeMeters; // cylinder swept volume in m^3

    function pistonPosition(crank_angle)
    // crank angle in degrees, return piston position in meters
   {  
        ct = strokeMeters / 2;
        alpha = Math.degrees(Math.asin(ct * Math.sin(Math.radians(crank_angle)) / conrodMeters))
        x = conrodMeters + ct - Math.cos(Math.radians(alpha)) * conrodMeters - Math.cos(Math.radians(crank_angle)) * ct;
        return x;
    }

    exh_opens_a = pistonPosition(exhTiming);
    trapped_swept_vol = piston_area * exh_opens_a;
    clearance_vol = trapped_swept_vol / (compratio - 1)
    squish_area = squish_area_ratio * piston_area; // area perpendicular to piston face, independent of squish angle
    bowl_area = piston_area - squish_area; // the rest of piston face area in the head is the bowl
    bowl_diam = Math.sqrt(4 * bowl_area / Math.PI);

    squish_radial_radius = (boreMeters - bowl_diam) / 2; // Inner radius of squish band measured perpendicular to piston face
    squish_cone_height = Math.tan(Math.radians(squish_angle)) * squish_radial_radius;
    squish_cone_vol = 1 / 3 * Math.PI * Math.pow(squish_radial_radius, 2) * squish_cone_height; // approximating the squish band is a perfect cone
    squish_bowl_vol = squish_clearance * bowl_area; // volume in the bowl area at the height of sq clearance above piston

    squish_vol = squish_clearance * squish_area; // band volume, symmetry of a ring (cone vol caused by squish angle not included)
    if (squish_angle > 0) {
        squish_vol += squish_cone_vol; // add the cone volume if a cone is present (sq angle > 0)
    }

    bowl_vol = clearance_vol - squish_vol - squish_bowl_vol; // the rest of the volume is the "bowl" of the head

    // Setting the initial conditions for the calculation:
    pressure_trap = 101325; // using ambient 20 C air as reference (to be altered in future versions?)
    temp_trap = 293.15; // using ambient 20 C air as reference
    R = 287.058 // gas constant
    G = 1.401 // Gamma constant
    step = 0.1; // Size of one time step in deg

    vol_sq_a = exh_opens_a * squish_area + squish_vol; // starting sq vol = hollow cylinder of height exh_opens_a with squish area + squish vol itself
    vol_bowl_a = exh_opens_a * bowl_area + bowl_vol + squish_bowl_vol; // starting bowl vol = cylinder of height exh_opens_a with bowl area + squish bowl vol itself
    vol_cyl_a = exh_opens_a * piston_area + clearance_vol; // starting cyl vol = cylinder of height exh_opens_a with piston area + clearance volume
    vol_trap = vol_cyl_a; // trapped volume is the cylinder volume at which exh port closes

    mass_trap = pressure_trap * vol_trap / (R * temp_trap);

    // Initially every component of the system is at the same equal pressure (p_trap / p_cyl_a in this case)
    p_cyl_a = pressure_trap;
    p_sq_a = p_cyl_a;
    p_bowl_a = p_cyl_a;

    mass_sq_a = mass_trap * vol_sq_a / vol_cyl_a;
    dt = step / (6 * RPM) // delta t

    angleDown = (360 - exhTiming)

    sq_v_array = [];
    crank_angle_array = [];
    energy_array = [];
    max_sq_v = 0;
    max_crank_angle = 0;
    p_max = 0;

    while (angleDown <= 360) {
        exh_opens_b = pistonPosition(angleDown);
        dh = exh_opens_a - exh_opens_b; // delta h

        // New values
        vol_sq_b = exh_opens_b * squish_area + squish_vol;
        vol_bowl_b = exh_opens_b * bowl_area + squish_bowl_vol + bowl_vol;
        vol_cyl_b = exh_opens_b * piston_area + clearance_vol;

        p_cyl_b = pressure_trap * Math.pow((pressure_trap / vol_cyl_b), G);
        temp_cyl_b = p_cyl_b * vol_cyl_b / (mass_trap * R);
        rho_cyl_b = p_cyl_b / (R * temp_cyl_b);

        p_sq_b = p_sq_a * Math.pow((vol_sq_a / vol_sq_b), G);
        p_bowl_b = p_bowl_a * Math.pow((vol_bowl_a / vol_bowl_b), G);

        mass_sq_b = mass_trap * vol_sq_b / vol_cyl_b;

        dmsq = mass_sq_a - mass_sq_b; // delta mass_squish
        sq_height = exh_opens_a + squish_clearance - 0.5 * dh + squish_cone_height;
        sq_v_circle = Math.PI * bowl_diam; // ring with radius of the bowl radius ("ID of the squishband")
        sq_v_area = sq_height * sq_v_circle;
        sq_v = dmsq / (rho_cyl_b * sq_v_area * dt);

        sq_v_array.push(sq_v);
        crank_angle_array.push(360 - angleDown);
        if (sq_v > max_sq_v) {
            max_sq_v = sq_v;
            max_crank_angle = 360 - angleDown;
        }

        p_ratio = p_sq_b / p_bowl_b;
        if (p_ratio > p_max) p_max = p_ratio;

        k_e = 0.5 * dmsq * Math.pow(sq_v, 2); // KE = 1/2 * m * v^2 (kinetic energy)
        energy_array.push(k_e * 1000);

        exh_opens_a = exh_opens_b;
        vol_sq_a = vol_sq_b;
        mass_sq_a = mass_sq_b;
        p_sq_a = p_sq_b;
        p_bowl_a = p_bowl_b;

        angleDown += step;

    }

    dataArray = [max_sq_v, max_crank_angle, sq_v_array, crank_angle_array, p_max, energy_array]; // output data
    mainWindow.webContents.send('calculatedData', dataArray);
}