$fn = 64;

// --- Parameters ---
pot_diameter = 76.2;      // 3 inch inner diameter
ring_wall = 4;            // Wall thickness of the ring
ring_height = 12;         // Height of the ring

arm_length = 15;          // Length of the connection arm
arm_width = 12;           // Width of the connection arm

twist_shaft_dia = 12;     // Diameter of the twist-lock shaft
twist_shaft_len = 8;      // Length of the twist-lock shaft
twist_tab_width = 22;     // Total width of the locking tabs across
twist_tab_depth = 6;      // Width of the tabs (perpendicular to twist)
twist_tab_thickness = 3;  // Thickness of the tabs in the insertion direction

// --- Main Object ---
union() {
    // Main Pot Ring
    difference() {
        cylinder(d=pot_diameter + (ring_wall * 2), h=ring_height);
        // Inner cutout (extended to ensure clean manifold subtraction)
        translate([0, 0, -1])
            cylinder(d=pot_diameter, h=ring_height + 2);
    }

    // Connection Arm
    // Overlaps the ring by 1mm and the shaft by 1mm to ensure it is watertight
    translate([pot_diameter/2 - 1, -arm_width/2, 0])
        cube([arm_length + 2, arm_width, ring_height]);

    // Twist-Lock Connector
    translate([pot_diameter/2 + arm_length, 0, ring_height/2])
        twist_lock_male();
}

// --- Modules ---
module twist_lock_male() {
    rotate([0, 90, 0]) {
        // Shaft
        cylinder(d=twist_shaft_dia, h=twist_shaft_len, center=false);
        
        // Locking Tabs
        translate([0, 0, twist_shaft_len]) {
            union() {
                // Central hub of the tab to keep it completely circular in the middle
                cylinder(d=twist_shaft_dia, h=twist_tab_thickness, center=false);
                // The extended locking flanges
                translate([0, 0, twist_tab_thickness/2])
                    cube([twist_tab_width, twist_tab_depth, twist_tab_thickness], center=true);
            }
        }
    }
}