$fn = 64;

// --- PARAMETERS ---
shield_width = 120;
shield_height = 150;
shield_thickness = 5;

rim_width = 6;
rim_height = 3;

cross_width = 16;
cross_height = 90;
cross_thickness = 3;
cross_y_offset = 10;

spool_diameter = 40;
spool_depth = 25;

flange_width = 60;
flange_height = 100;
flange_thickness = 5;

// Z-height calculations for stacking
z_flange = 0;
z_core = flange_thickness;
z_shield = flange_thickness + spool_depth;
z_details = z_shield + shield_thickness;

// --- MAIN ASSEMBLY ---
union() {
    // 1. Back Flange with Keyholes (Wall Mount)
    difference() {
        translate([0, 0, z_flange])
            linear_extrude(flange_thickness)
                rounded_rect(flange_width, flange_height, 8);
        
        translate([0, 30, z_flange]) keyhole_cutout();
        translate([0, -30, z_flange]) keyhole_cutout();
    }

    // 2. Spool Core (Cable Holder Stand-off)
    translate([0, 0, z_core])
        cylinder(d=spool_diameter, h=spool_depth);

    // 3. Shield Base
    translate([0, 0, z_shield])
        linear_extrude(shield_thickness)
            shield_2d(shield_width, shield_height);

    // 4. Shield Details (Rim & Cross)
    translate([0, 0, z_details]) {
        // Raised Rim
        linear_extrude(rim_height)
            difference() {
                shield_2d(shield_width, shield_height);
                offset(r=-rim_width) shield_2d(shield_width, shield_height);
            }
        
        // Central Cross
        translate([0, cross_y_offset, 0])
            linear_extrude(cross_thickness) {
                square([cross_width, cross_height], center=true);
                square([cross_height, cross_width], center=true);
            }
    }
}

// --- MODULES ---

// Generates the classic curved heater shield 2D profile
module shield_2d(w, h) {
    cx = w/4 - (h*h)/w;
    cy = h/2;
    r = sqrt(cx*cx + h*h);
    
    intersection() {
        // Flat top boundary
        translate([-w, -h]) square([w*2, h + h/2]);
        // Curved right side
        translate([cx, cy]) circle(r=r);
        // Curved left side
        translate([-cx, cy]) circle(r=r);
    }
}

// Generates a 2D rectangle with rounded corners
module rounded_rect(w, h, r) {
    hull() {
        translate([-w/2 + r, h/2 - r]) circle(r=r);
        translate([w/2 - r, h/2 - r]) circle(r=r);
        translate([-w/2 + r, -h/2 + r]) circle(r=r);
        translate([w/2 - r, -h/2 + r]) circle(r=r);
    }
}

// Generates the negative space for a wall-mounting keyhole slot
module keyhole_cutout() {
    // Narrow slot for the screw shaft
    translate([0, 0, -1])
    linear_extrude(flange_thickness + 2) {
        circle(d=8);
        translate([-2.5, 0]) square([5, 12]);
        translate([0, 12]) circle(d=5);
    }
    // Wider recess for the screw head to slide into
    translate([0, 0, 2.5])
    linear_extrude(flange_thickness + spool_depth) {
        circle(d=14);
        translate([-4.5, 0]) square([9, 12]);
        translate([0, 12]) circle(d=9);
    }
}