$fn = 64;

// --- Parameters ---
projection = 75;            // Total distance from wall to tip
base_width = 25;            // Width of the wall plate
base_thickness = 5;         // Thickness of the wall plate
top_hole_z = 20;            // Z position of top screw hole
bottom_hole_z = -25;        // Z position of bottom screw hole
hole_dia = 4.5;             // Screw shaft diameter
cs_dia = 9;                 // Countersink head diameter
cs_depth = 3;               // Countersink depth

// Hook arm profile points [Y, Z, Diameter]
// Designed to ensure exactly 75mm projection and hold >2kg
p1 = [5, -5, 14];           // Base connection
p2 = [35, -5, 12];          // Straight outward section
p3 = [55, 5, 10];           // Upward curve
p4 = [69, 25, 12];          // Tip (69 + 12/2 = 75mm max projection)

// --- Modules ---
module base_plate() {
    hull() {
        translate([0, base_thickness, top_hole_z])
            rotate([90, 0, 0])
            cylinder(h=base_thickness, d=base_width);
            
        translate([0, base_thickness, bottom_hole_z])
            rotate([90, 0, 0])
            cylinder(h=base_thickness, d=base_width);
    }
}

module hook_arm() {
    hull() {
        translate([0, p1[0], p1[1]]) sphere(d=p1[2]);
        translate([0, p2[0], p2[1]]) sphere(d=p2[2]);
    }
    hull() {
        translate([0, p2[0], p2[1]]) sphere(d=p2[2]);
        translate([0, p3[0], p3[1]]) sphere(d=p3[2]);
    }
    hull() {
        translate([0, p3[0], p3[1]]) sphere(d=p3[2]);
        translate([0, p4[0], p4[1]]) sphere(d=p4[2]);
    }
}

module screw_hole(z_pos) {
    translate([0, base_thickness + 0.1, z_pos])
    rotate([90, 0, 0]) {
        // Countersink cone
        cylinder(h=cs_depth + 0.1, d1=cs_dia, d2=hole_dia);
        // Screw shaft
        translate([0, 0, cs_depth])
            cylinder(h=base_thickness + 2, d=hole_dia);
    }
}

// --- Main Geometry ---
difference() {
    union() {
        base_plate();
        hook_arm();
    }
    
    // Subtractions for mounting hardware
    screw_hole(top_hole_z);
    screw_hole(bottom_hole_z);
    
    // Clean flush cut at the back (wall face) to ensure printability
    translate([-base_width, -50, bottom_hole_z - base_width])
        cube([base_width * 2, 50, (top_hole_z - bottom_hole_z) + base_width * 2 + 50]);
}