// 2020 Extrusion Insert
// Configurable 3D printable insert for 2020 aluminum extrusion

// Import PCIe holder functionality
include <holder.scad>;

// Import hexagon functionality for M3 nut holes
include <hexagon.scad>;

// Trapezium module - creates a centralized trapezoid shape (2D)
// Parameters:
//   base_width: width of the bottom edge
//   top_width: width of the top edge  
//   height: height of the trapezium
module trapezium_2d(base_width, top_width, height) {
    // Create the trapezoid points (centered)
    points = [
        [-base_width/2, -height/2],  // bottom left
        [base_width/2, -height/2],   // bottom right
        [top_width/2, height/2],     // top right
        [-top_width/2, height/2]     // top left
    ];
    
    polygon(points);
}

// Rectangle module - creates a rectangle extending from base (2D)
// Parameters:
//   width: width of the rectangle
//   height: height of the rectangle
//   offset_y: vertical offset from origin (default 0)
module rectangle_2d(width, height, offset_y = 0) {
    translate([0, offset_y])
        square([width, height], center = true);
}

// Combined module - joins trapezium and rectangle together
// Parameters:
//   trap_base_width: trapezium base width
//   trap_top_width: trapezium top width
//   trap_height: trapezium height
//   rect_width: rectangle width
//   rect_height: rectangle height
//   rect_offset: vertical offset for rectangle from trapezium base
module trapezium_with_rectangle_2d(
    trap_base_width, 
    trap_top_width, 
    trap_height,
    rect_width,
    rect_height,
    rect_offset = 0
) {
    union() {
        // Main trapezium
        trapezium_2d(trap_base_width, trap_top_width, trap_height);
        
        // Rectangle extending from base
        translate([0, -trap_height/2 + rect_offset])
            rectangle_2d(rect_width, rect_height);
    }
}

// Example usage (uncomment to test):
// Individual shapes:
//trapezium_2d(base_width = 20, top_width = 10, height = 15);
//translate([30, 0]) rectangle_2d(width = 8, height = 5);

// Combined shape extruded to 3D with M3 nut hole:
rect_height_val = 1.7;
extrude_height = 10;

difference() {
    // Main extruded shape
    linear_extrude(height = extrude_height) {
        trapezium_with_rectangle_2d(
            trap_base_width = 10.95, 
            trap_top_width = 5.5, 
            trap_height = 4.0,
            rect_width = 6.3,
            rect_height = rect_height_val,
            rect_offset = -rect_height_val/2 + 0.01  // Small overlap for clean union
        );
    }
    
    // M3 nut hole on top face of trapezium (extended outward for clean cut)
    translate([0, 4.0/2 + (m3_nut_height + 2)/2, extrude_height/2]) {
        rotate([90, 0, 0]) {
            hexagon_3d(m3_nut_width, m3_nut_height + 2);  // Extra height for clean cut
        }
    }
    
    // M3 bolt hole through entire trapezium
    translate([0, 4.0/2, extrude_height/2]) {
        rotate([90, 0, 0]) {
            cylinder(h = rect_height_val + 20, d = 3.2, center = true, $fn = 32);  // Long M3 clearance hole
        }
    }
}