$fn=64;

// Parameters
length = 100;           // Total length of the raceway
width = 30;             // Outer width of the base
height = 20;            // Height of the base
wall_thickness = 2;     // Thickness of the walls
tolerance = 0.2;        // Tolerance for the snap fit
snap_depth = 0.8;       // Depth of the snap ridges

// Layout parts side-by-side, oriented flat for 3D printing
translate([-width/2 - 5, 0, 0])
    rotate([-90, 0, 0])
        raceway_base();

translate([width/2 + 5, 0, 0])
    rotate([-90, 0, 0])
        raceway_lid();

module raceway_base() {
    linear_extrude(height = length) {
        union() {
            // Main U-channel
            difference() {
                translate([-width/2, 0]) 
                    square([width, height]);
                translate([-width/2 + wall_thickness, wall_thickness]) 
                    square([width - 2*wall_thickness, height]);
            }
            // Left snap ridge (with 0.1mm overlap for manifold union)
            translate([-width/2 + 0.1, height - 4]) 
                polygon([[0,0], [-snap_depth - 0.1, 1], [0, 2]]);
            // Right snap ridge
            translate([width/2 - 0.1, height - 4]) 
                polygon([[0,0], [snap_depth + 0.1, 1], [0, 2]]);
        }
    }
}

module raceway_lid() {
    lid_inner_w = width + 2*tolerance;
    lid_outer_w = lid_inner_w + 2*wall_thickness;
    lid_leg_h = 6;
    
    linear_extrude(height = length) {
        union() {
            // Main lid body
            difference() {
                translate([-lid_outer_w/2, 0]) 
                    square([lid_outer_w, lid_leg_h + wall_thickness]);
                // Hollow out the inside of the lid
                translate([-lid_inner_w/2, wall_thickness]) 
                    square([lid_inner_w, lid_leg_h + 1]);
            }
            // Left snap catch (with 0.1mm overlap for manifold union)
            translate([-lid_inner_w/2 - 0.1, wall_thickness + 2 + tolerance]) 
                polygon([[0,0], [snap_depth + 0.1, 1], [0, 2]]);
            // Right snap catch
            translate([lid_inner_w/2 + 0.1, wall_thickness + 2 + tolerance]) 
                polygon([[0,0], [-snap_depth - 0.1, 1], [0, 2]]);
        }
    }
}