$fn=64;

// --- Parameters ---
columns = 5;
rows = 3;

// USB Type-A dimensions (with clearance for easy insertion)
slot_width = 13.5;
slot_thickness = 5.0;
slot_depth = 12.0;

// Layout spacing
spacing_x = 22.0;
spacing_y = 16.0;
base_height = 18.0;
corner_radius = 4.0;

// --- Calculated Dimensions ---
length = (columns - 1) * spacing_x + slot_width + 12;
width = (rows - 1) * spacing_y + slot_thickness + 12;

// --- Modules ---
module base_block() {
    hull() {
        translate([corner_radius, corner_radius, 0]) 
            cylinder(r=corner_radius, h=base_height);
        translate([length - corner_radius, corner_radius, 0]) 
            cylinder(r=corner_radius, h=base_height);
        translate([corner_radius, width - corner_radius, 0]) 
            cylinder(r=corner_radius, h=base_height);
        translate([length - corner_radius, width - corner_radius, 0]) 
            cylinder(r=corner_radius, h=base_height);
    }
}

// --- Main Assembly ---
difference() {
    // Main body
    base_block();
    
    // Cut out the USB slots
    for (c = [0 : columns - 1]) {
        for (r = [0 : rows - 1]) {
            
            // Center the array of slots within the block
            x_pos = (length - ((columns - 1) * spacing_x)) / 2 + c * spacing_x;
            y_pos = (width - ((rows - 1) * spacing_y)) / 2 + r * spacing_y;
            
            translate([x_pos, y_pos, base_height - slot_depth]) {
                
                // Main rectangular slot cavity
                translate([-slot_width/2, -slot_thickness/2, 0])
                    cube([slot_width, slot_thickness, slot_depth]);
                
                // Chamfered opening at the top for easier insertion
                hull() {
                    translate([-slot_width/2, -slot_thickness/2, slot_depth - 1.5])
                        cube([slot_width, slot_thickness, 0.1]);
                    
                    translate([-(slot_width+3)/2, -(slot_thickness+3)/2, slot_depth + 1])
                        cube([slot_width+3, slot_thickness+3, 0.1]);
                }
            }
        }
    }
}