$fn=64;

// --- Parameters ---
// Backplate dimensions
plate_width = 60;
plate_height = 75;
plate_thick = 8;
corner_radius = 5;

// Mounting holes (Vertical alignment for single wall stud)
hole_spacing = 50;
hole_dia = 5.2;
screw_head_dia = 10.5;

// Hook arms
arm_gap = 32;         // Gap for hammer handle
arm_width = 14;       // Horizontal thickness of each arm
arm_length = 50;      // Protrusion from wall
arm_base_height = 25; // Vertical thickness at the wall
arm_tip_height = 12;  // Vertical thickness at the tip
lip_height = 10;      // Height of the retaining lip
arm_slope = 3;        // Upward slope of the arms

// --- Main Assembly ---
// Rotated to lay flat on the backplate for support-free 3D printing
rotate([-90, 0, 0]) {
    difference() {
        union() {
            backplate();
            
            // Left Arm
            translate([-(arm_gap/2 + arm_width/2), plate_thick, 0])
                arm();
                
            // Right Arm
            translate([(arm_gap/2 + arm_width/2), plate_thick, 0])
                arm();
        }
        holes();
    }
}

// --- Modules ---
module backplate() {
    // Positioned so the back is at Y=0 and front is at Y=plate_thick
    translate([0, plate_thick/2, 0])
    rotate([90, 0, 0])
    hull() {
        for (x = [-plate_width/2 + corner_radius, plate_width/2 - corner_radius]) {
            for (z = [-plate_height/2 + corner_radius, plate_height/2 - corner_radius]) {
                translate([x, z, -plate_thick/2])
                    cylinder(r=corner_radius, h=plate_thick);
            }
        }
    }
}

module arm() {
    tip_z = (arm_base_height - arm_tip_height) / 2 + arm_slope; 
    tip_y = arm_length - arm_tip_height/2;
    
    // Main arm protrusion
    hull() {
        // Base at the backplate
        translate([0, 0, 0])
            cube([arm_width, 0.1, arm_base_height], center=true);
        
        // Tip of the arm
        translate([0, tip_y, tip_z])
            rotate([0, 90, 0])
            cylinder(d=arm_tip_height, h=arm_width, center=true);
    }
    
    // Retaining lip at the end
    // Angled at 45 degrees to allow support-free 3D printing
    hull() {
        // Tip of the arm
        translate([0, tip_y, tip_z])
            rotate([0, 90, 0])
            cylinder(d=arm_tip_height, h=arm_width, center=true);
        
        // Upward and forward lip
        translate([0, tip_y + lip_height, tip_z + lip_height])
            rotate([0, 90, 0])
            cylinder(d=arm_tip_height * 0.5, h=arm_width, center=true);
    }
}

module holes() {
    // Vertical mounting holes with countersinks
    for (z = [-hole_spacing/2, hole_spacing/2]) {
        // Thru hole
        translate([0, -1, z])
            rotate([-90, 0, 0])
            cylinder(d=hole_dia, h=plate_thick + 2);
        
        // Countersink
        translate([0, plate_thick - 3, z])
            rotate([-90, 0, 0])
            cylinder(d1=hole_dia, d2=screw_head_dia, h=3.1);
    }
}