$fn = 64;

// --- Parameters ---
arm_length = 200;           // Length of the horizontal shelf support
wall_length = 150;          // Length of the vertical wall mount
width = 30;                 // Width of the bracket
thickness = 8;              // Thickness of the main arms
gusset_thickness = 6;       // Thickness of the center support brace
hole_dia = 5.5;             // Diameter of the screw holes
head_dia = 10.5;            // Diameter of the screw head (countersink)
countersink_depth = 4.5;    // Depth of the countersink

// --- Main Assembly ---
difference() {
    bracket_body();
    
    // Wall mounting holes (vertical arm)
    // Staggered bottom holes to allow easy screwdriver access past the gusset
    wall_hole(wall_length - 20, width / 2); // Top center
    wall_hole(35, 7);                       // Bottom offset 1
    wall_hole(35, width - 7);               // Bottom offset 2
    
    // Shelf mounting holes (horizontal arm)
    // Staggered back holes to allow easy screwdriver access past the gusset
    shelf_hole(arm_length - 20, width / 2); // Front center
    shelf_hole(45, 7);                      // Back offset 1
    shelf_hole(45, width - 7);              // Back offset 2
}

// --- Modules ---
module bracket_body() {
    union() {
        // Horizontal arm (shelf support)
        cube([arm_length - width/2, thickness, width]);
        translate([arm_length - width/2, 0, width/2])
            rotate([-90, 0, 0])
            cylinder(h = thickness, d = width);

        // Vertical arm (wall mount)
        cube([thickness, wall_length - width/2, width]);
        translate([0, wall_length - width/2, width/2])
            rotate([0, 90, 0])
            cylinder(h = thickness, d = width);

        // Inside corner reinforcement fillet
        translate([thickness - 0.1, thickness - 0.1, 0])
            difference() {
                cube([6.1, 6.1, width]);
                translate([6.1, 6.1, -1])
                    cylinder(h = width + 2, r = 6);
            }

        // Center diagonal brace (gusset)
        translate([0, 0, (width - gusset_thickness) / 2])
            linear_extrude(gusset_thickness)
            polygon([
                [thickness - 1, thickness - 1],
                [arm_length - width, thickness - 1],
                [thickness - 1, wall_length - width]
            ]);
    }
}

module wall_hole(y, z) {
    // Drills through the X axis (vertical arm) from inside out
    translate([thickness + 0.01, y, z])
        rotate([0, -90, 0]) {
            cylinder(h = thickness + 2, d = hole_dia);
            // Countersink for screw head
            cylinder(h = countersink_depth, d1 = head_dia, d2 = hole_dia);
        }
}

module shelf_hole(x, z) {
    // Drills through the Y axis (horizontal arm) from bottom up
    translate([x, -0.01, z])
        rotate([-90, 0, 0]) {
            cylinder(h = thickness + 2, d = hole_dia);
            // Countersink for screw head
            cylinder(h = countersink_depth, d1 = head_dia, d2 = hole_dia);
        }
}