$fn=64;

// --- Parameters ---
jar_diameter = 90;      // Inner diameter for the treat jar
holder_depth = 50;      // Depth of the jar cup
wall_thickness = 4;     // Thickness of the walls
rail_width = 16;        // Thickness of the PetStation rail
rail_height = 25;       // Height of the rail
hook_width = 45;        // Width of the mounting hook
hook_drop = 15;         // Length of the hook's back prong
bottom_lip = 12;        // Width of the bottom lip (creates a hole to save plastic)

// --- Derived Variables ---
jar_od = jar_diameter + (wall_thickness * 2);
bracket_z_start = holder_depth - rail_height - wall_thickness;

module treat_jar_holder() {
    difference() {
        union() {
            // Main Cup
            cylinder(d=jar_od, h=holder_depth);

            // Rail Bracket Block (embedded into the cylinder wall)
            translate([-hook_width/2, jar_od/2 - wall_thickness*2, bracket_z_start])
                cube([hook_width, wall_thickness*3 + rail_width, rail_height + wall_thickness]);
            
            // Support Gusset (under the bracket for strength)
            hull() {
                translate([-hook_width/2, jar_od/2 - wall_thickness*2, bracket_z_start])
                    cube([hook_width, wall_thickness*2, 0.1]);
                translate([-hook_width/2, jar_od/2 - wall_thickness*2, wall_thickness])
                    cube([hook_width, 0.1, 0.1]);
            }
        }
        
        // Hollow out the cup interior
        translate([0, 0, wall_thickness])
            cylinder(d=jar_diameter, h=holder_depth + 1);
            
        // Bottom hole to save plastic and allow cleaning
        translate([0, 0, -1])
            cylinder(d=jar_diameter - (bottom_lip * 2), h=wall_thickness + 2);
            
        // Rail Slot Cutout (opens downwards)
        translate([-(hook_width+2)/2, jar_od/2, bracket_z_start - 1])
            cube([hook_width + 2, rail_width, rail_height + 1]);
            
        // Trim Outer Hook Prong to match desired hook_drop
        translate([-(hook_width+2)/2, jar_od/2 + rail_width - 0.1, -1])
            cube([hook_width + 2, wall_thickness + 2, holder_depth - wall_thickness - hook_drop + 1]);
    }
}

// Render the model
treat_jar_holder();