// --- Parameters ---
$fn = 100; // Smoothness of curves

// Dimensions
inlet_od = 40;
inlet_id = 35;
vertical_height = 10; // The "few mm" height before the turn
bend_radius = 20;    // Center-line radius of the elbow
horizontal_total = 70;

// Internal Taper specs
taper1_len = 10;
taper1_id_end = 30;
taper2_id_end = 32.1;
taper2_len = horizontal_total - taper1_len;

// Outer Taper specs
final_od = 36; // Ensures ~2-3mm wall thickness (36 - 32.1 = 3.9mm)

// --- Modules ---

// Helper to create a tapered cylinder (cone)
module tapered_cylinder(h, r1, r2) {
    cylinder(h = h, r1 = r1, r2 = r2);
}

module adapter() {
    difference() {
        // 1. OUTER SHELL
        union() {
            // Vertical section
            cylinder(h = vertical_height, d = inlet_od);
            
            // Elbow section
            translate([0, 0, vertical_height])
            rotate_extrude(angle = 90)
            translate([bend_radius, 0, 0])
            circle(d = inlet_od);
            
            // Horizontal sections (Outer Taper)
            translate([0, bend_radius, vertical_height + bend_radius])
            rotate([0, 90, 0]) {
                // Gradual OD taper from 40mm to final_od over the full 70mm
                tapered_cylinder(horizontal_total, inlet_od/2, final_od/2);
            }
        }

        // 2. INNER VOID (The Hole)
        union() {
            // Vertical void
            translate([0, 0, -1]) // slight offset for clean cut
            cylinder(h = vertical_height + 1, d = inlet_id);
            
            // Elbow void
            translate([0, 0, vertical_height])
            rotate_extrude(angle = 90)
            translate([bend_radius, 0, 0])
            circle(d = inlet_id);
            
            // Horizontal voids (Internal Tapers)
            translate([0, bend_radius, vertical_height + bend_radius])
            rotate([0, 90, 0]) {
                // First Taper: 35mm -> 30mm over 10mm
                tapered_cylinder(taper1_len, inlet_id/2, taper1_id_end/2);
                
                // Second Taper: 30mm -> 32.1mm over 60mm
                translate([0, 0, taper1_len])
                tapered_cylinder(taper2_len, taper1_id_end/2, taper2_id_end/2);
            }
        }
    }
}

// Execute
adapter();