$fn = 64;

// --- Parameters ---
// Width of the attachment (Z-axis when printed flat)
part_width = 20;

// Base plate dimensions
plate_thickness = 10;
plate_height = 65;
corner_radius = 2;

// Rail cutout dimensions (French cleat style for PetStation/generic rails)
rail_cut_depth = 5;
rail_cut_bottom = 10;
rail_cut_top = 55;
rail_angle_drop = 6;

// Hook dimensions
hook_thickness = 12;
hook_extension = 35;
hook_upward = 25;
hook_y_offset = 25;
hook_knob_dia = 18;

// --- Module ---
module leash_hook() {
    // Extrude the 2D profile to make it 3D
    // Designed to print flat on its side for maximum layer adhesion and strength
    linear_extrude(height = part_width, center = false) {
        difference() {
            union() {
                // Main backplate with rounded front edges
                hull() {
                    translate([0, 0]) square([0.1, plate_height]);
                    translate([plate_thickness - corner_radius, corner_radius]) circle(r=corner_radius);
                    translate([plate_thickness - corner_radius, plate_height - corner_radius]) circle(r=corner_radius);
                }

                // Hook horizontal shaft
                hull() {
                    translate([plate_thickness - 0.1, hook_y_offset - hook_thickness/2]) square([0.1, hook_thickness]);
                    translate([plate_thickness + hook_extension, hook_y_offset]) circle(d=hook_thickness);
                }

                // Hook upward curve
                hull() {
                    translate([plate_thickness + hook_extension, hook_y_offset]) circle(d=hook_thickness);
                    translate([plate_thickness + hook_extension, hook_y_offset + hook_upward]) circle(d=hook_thickness);
                }

                // Hook end knob to prevent leash from slipping off
                translate([plate_thickness + hook_extension, hook_y_offset + hook_upward]) circle(d=hook_knob_dia);
            }

            // Rail groove cutout (subtracted from the back)
            // Creates a downward-pointing lip to hang securely on a wall rail
            polygon([
                [-0.1, rail_cut_bottom - 2], // Slight lead-in chamfer for easy insertion
                [rail_cut_depth, rail_cut_bottom],
                [rail_cut_depth, rail_cut_top],
                [-0.1, rail_cut_top - rail_angle_drop]
            ]);
        }
    }
}

// Render the part
leash_hook();