$fn = 64;

// --- Parameters ---

// Backplate dimensions
plate_width = 240;
plate_height = 80;
plate_thickness = 5;
corner_radius = 6;

// Harness pegs (larger, top row)
harness_peg_len = 45;
harness_peg_r = 7;

// Collar pegs (smaller, bottom row)
collar_peg_len = 25;
collar_peg_r = 4;

// Mounting holes
screw_hole_r = 2.5;
screw_head_r = 5;
hole_margin = 15;

// --- Modules ---

// Print-in-place friendly peg with a chamfered stopper
module peg(len, r) {
    // Main shaft
    cylinder(h=len, r=r);
    // Stopper (angles are >45 degrees for easy printing without supports)
    translate([0, 0, len]) 
        cylinder(h=r*1.2, r1=r, r2=r*1.6);
    translate([0, 0, len+r*1.2]) 
        cylinder(h=r*1.2, r1=r*1.6, r2=r);
}

module backplate() {
    difference() {
        // Main rounded rectangle body
        hull() {
            translate([corner_radius, corner_radius, 0]) 
                cylinder(r=corner_radius, h=plate_thickness);
            translate([plate_width-corner_radius, corner_radius, 0]) 
                cylinder(r=corner_radius, h=plate_thickness);
            translate([plate_width-corner_radius, plate_height-corner_radius, 0]) 
                cylinder(r=corner_radius, h=plate_thickness);
            translate([corner_radius, plate_height-corner_radius, 0]) 
                cylinder(r=corner_radius, h=plate_thickness);
        }

        // Countersunk mounting holes in the corners
        for(x = [hole_margin, plate_width-hole_margin]) {
            for(y = [hole_margin, plate_height-hole_margin]) {
                translate([x, y, -1]) {
                    // Screw shaft hole
                    cylinder(r=screw_hole_r, h=plate_thickness+2);
                    // Countersink for screw head
                    translate([0, 0, plate_thickness - 2 + 1])
                        cylinder(r1=screw_hole_r, r2=screw_head_r, h=2.1);
                }
            }
        }
    }
}

// --- Assembly ---

union() {
    backplate();

    // Top Row: 3 Heavy-duty pegs for harnesses
    for(i = [1 : 3]) {
        x_pos = i * (plate_width / 4);
        // Embed slightly into the plate to ensure a manifold mesh
        translate([x_pos, plate_height - 25, plate_thickness - 0.1])
            peg(harness_peg_len, harness_peg_r);
    }

    // Bottom Row: 4 Standard pegs for collars/leashes
    for(i = [1 : 4]) {
        x_pos = (i - 0.5) * (plate_width / 4);
        translate([x_pos, 25, plate_thickness - 0.1])
            peg(collar_peg_len, collar_peg_r);
    }
}