/*
 * circle
 *
 *
 * Functions:
 *  libcircle_quarter and its alias libcircle_14
 *  libcircle_half and its alias libcircle_24 and libcircle_12
 *  libcircle_threequarter and its alias libcircle_34
 *
 * All functions take either r (radius) or d (diameter) as argument.
 * If both are given (for whatever reason you'd do this), radius is chosen over diameter.
 * Same applies for libcircle_degrees, however you also need to pass this module
 * the "degrees" argument which is pretty self-explanatory.
 */

module libcircle_14(r=0, d=0) {
    libcircle_quarter(r, d);
}

module libcircle_quarter(r=0, d=0) {
    diameter = __diameter_radius_conversion(r, d);
    intersection() {
        circle(d=diameter);
        square([radius, radius]);
    }
}

module libcircle_24(r=0, d=0) {
    libcircle_half(r, d);
}

module libcircle_12(r=0, d=0) {
    libcircle_half(r, d);
}

module libcircle_half(r=0, d=0) {
    diameter = __diameter_radius_conversion(r, d);
    intersection() {
        circle(d=diameter);
        translate([0, -diameter, 0])
        square([diameter, diameter*2]);
    }
}

module libcircle_34(r=0, d=0) {
    libcircle_threequarter(r, d);
}

module libcircle_threequarter(r=0, d=0) {
    diameter = __diameter_radius_conversion(r, d);
    difference() {
        circle(d=diameter);
        translate([-diameter, 0, 0])
        square([diameter, diameter]);
    }
}

module libcircle_degrees(r=0, d=0, degrees) {
    diameter = __diameter_radius_conversion(r, d);
    degrees = degrees % 360;

    if(degrees > 180) {
        __half_circle_degrees(diameter, 180);
        rotate([0, 0, 180])
        __half_circle_degrees(diameter, degrees-180);
    } else {
        __half_circle_degrees(diameter, degrees);
    }
}

module __half_circle_degrees(diameter, degrees) {
    // This is the most dirty hack I've pulled in a while.
    // But... Who cares? #sorrynotsorry ;)
    difference() {
        libcircle_half(d=diameter);
        rotate([0, 0, -degrees])
        translate([0, -diameter/2])
        square([diameter/2, diameter]);
    }
}

// https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/General#Scope_of_variables
// let's work our way around this... ;(
function __diameter_radius_conversion(r=0, d=0) = (r > 0) ? r*2 : d;