$fn = 64;

// --- PARAMETERS ---
rail_length = 400;      // Total length of the mounting rail
tolerance = 0.4;        // Clearance for sliding fit of attachments
wall_thickness = 5;     // Thickness of the attachment walls

// --- LAYOUT ---
// Main Wall Rail
rail();

// Modular Attachment 1: Leash/Collar Hook
translate([60, -40, 0])
hook_attachment();

// Modular Attachment 2: Treat/Bag Bin
translate([60, 40, 0])
bin_attachment();

// --- MODULES ---

// 2D Profile of the dovetail rail
// Designed with 45-degree angles for support-free 3D printing
module rail_2d() {
    polygon([
        [0, 0],     // Bottom against wall
        [40, 0],    // Top against wall
        [30, 10],   // Top overhang
        [25, 15],   // Top flat
        [15, 15],   // Bottom flat
        [10, 10]    // Bottom overhang
    ]);
}

// 3D Extrusion of the rail
module rail_3d(length) {
    rotate([90, 0, 0])
    linear_extrude(length, center=true)
    rail_2d();
}

// The complete printable rail with mounting holes
module rail() {
    difference() {
        rail_3d(rail_length);
        
        // Countersunk mounting holes spaced every 80mm
        for (y = [-160 : 80 : 160]) {
            translate([20, y, 0]) {
                // Shaft for 5mm screw
                cylinder(h=50, d=5, center=true);
                // Cutout for screw head (leaves 5mm of plastic against wall)
                translate([0, 0, 10]) 
                cylinder(h=10, d=10, center=true);
            }
        }
    }
}

// Universal sliding base for all modular attachments
module attachment_base(length) {
    difference() {
        // Outer block
        translate([20, 0, 12.5])
        cube([50, length, 25], center=true);

        // Rail Cutout (expanded by tolerance for sliding fit)
        rotate([90, 0, 0])
        linear_extrude(length + 2, center=true)
        offset(r=tolerance) rail_2d();

        // Trim bottom to ensure it sits perfectly flush against the wall
        translate([20, 0, -5])
        cube([60, length + 2, 10], center=true);
    }
}

// 2D Profile for the J-hook
module hook_profile() {
    difference() {
        offset(r=2) offset(r=-2) // Round the sharp edges slightly
        polygon([
            [-12, 0],
            [12, 0],
            [10, 15],
            [20, 25],
            [20, 40],
            [10, 40],
            [10, 30],
            [0, 20],
            [-12, 20]
        ]);
        // Keep bottom perfectly flat for union
        translate([-20, -10]) square([40, 10]);
    }
}

// Complete hook attachment module
module hook_attachment() {
    union() {
        attachment_base(30);
        
        // Hook protruding from the front face
        translate([20, 0, 25])
        rotate([90, 0, 0])
        linear_extrude(15, center=true)
        hook_profile();
    }
}

// Complete storage bin attachment module
module bin_attachment() {
    union() {
        attachment_base(60);
        
        // Bin protruding from the front face
        translate([20, 0, 25])
        difference() {
            // Outer bin shell
            translate([0, 0, 20])
            cube([40, 50, 40], center=true);
            
            // Inner hollow space (2mm walls and floor)
            translate([0, 0, 22])
            cube([36, 46, 40], center=true);
        }
    }
}