$fn = 64;

// --- Parameters ---
// Cup Dimensions
cup_top_id = 80;        // Inner diameter at top (tapered for secure grip)
cup_bottom_id = 70;     // Inner diameter at bottom
holder_height = 60;     // Height of the cup holder
wall_thickness = 3;     // Wall thickness of the cup holder
base_thickness = 3;     // Thickness of the bottom base

// Rail Mount Dimensions (ArtArsenal / Generic Rail)
mount_width = 40;       // Width of the wall bracket
mount_height = 80;      // Total height of the wall bracket
plate_thickness = 5;    // Thickness of the main backplate
rail_gap = 5;           // Thickness of the rail lip (gap width)
hook_thick = 5;         // Thickness of the hook walls
hook_length = 15;       // How far the hook drops down behind the rail
standoff_height = 10;   // Height of the bottom wall standoff

// Structural
spine_thick = 15;       // Thickness of the connecting spine

// --- Derived Variables ---
cup_top_od = cup_top_id + wall_thickness * 2;
cup_bottom_od = cup_bottom_id + wall_thickness * 2;
overlap = 1;            
cup_y = -cup_top_od/2 + overlap;

// --- Modules ---
module rail_mount() {
    rotate([90, 0, 90])
    linear_extrude(height=mount_width, center=true)
    polygon([
        [0, 0], 
        [plate_thickness + rail_gap + hook_thick, 0], 
        [plate_thickness + rail_gap + hook_thick, standoff_height], 
        [plate_thickness, standoff_height + 5], 
        [plate_thickness, mount_height - hook_thick], 
        [plate_thickness + rail_gap, mount_height - hook_thick], 
        [plate_thickness + rail_gap, mount_height - hook_thick - hook_length], 
        [plate_thickness + rail_gap + hook_thick, mount_height - hook_thick - hook_length], 
        [plate_thickness + rail_gap + hook_thick, mount_height], 
        [0, mount_height] 
    ]);
}

// --- Main Assembly ---
difference() {
    union() {
        // Main Cup Holder Body
        translate([0, cup_y, 0])
            cylinder(d1=cup_bottom_od, d2=cup_top_od, h=holder_height);

        // Wall Rail Mount
        rail_mount();

        // Connecting Spine
        translate([-spine_thick/2, cup_y, 0])
            cube([spine_thick, abs(cup_y) + overlap, holder_height]);
    }

    // Inner Cup Cutout
    translate([0, cup_y, base_thickness])
        cylinder(d1=cup_bottom_id, d2=cup_top_id, h=holder_height + 1);

    // Top Chamfer for easy insertion
    translate([0, cup_y, holder_height - 2])
        cylinder(d1=cup_top_id, d2=cup_top_id + 4, h=2.1);

    // Bottom Drain Hole
    translate([0, cup_y, -1])
        cylinder(d=cup_bottom_id - 20, h=base_thickness + 2);
}