// Parametric Print-in-Place Hinge
// Modeled in the flat / open position for FDM printing

/* [Hinge Dimensions] */
hinge_length = 60;              // [30:5:150]
num_knuckles = 5;               // [3:2:9]
leaf_width = 20;                // [10:1:50]
leaf_thickness = 3.0;           // [1.5:0.5:6.0]
knuckle_diameter = 8.0;         // [5.0:0.5:14.0]
corner_radius = 3.0;            // [0:0.5:8]

/* [Print-in-Place Tolerances] */
pin_diameter = 4.0;             // [2.0:0.5:8.0]
clearance = 0.4;                // [0.2:0.05:0.8]
axial_clearance = 0.4;          // [0.2:0.05:0.8]

/* [Fasteners / Mounting Holes] */
screw_hole_diameter = 3.5;      // [2.0:0.1:6.0]
countersink_diameter = 7.0;     // [4.0:0.1:12.0]
screw_edge_offset = 15;         // [8:1:30]

/* [Colors] */
leaf_a_color = "#3A7CA5";       // [Color]
leaf_b_color = "#E07A5F";       // [Color]

/* [Quality] */
$fn = 64;

// Derived dimensions
knuckle_radius = knuckle_diameter / 2;
pin_radius = pin_diameter / 2;
knuckle_pitch = hinge_length / num_knuckles;
screw_x_pos = knuckle_radius + leaf_width / 2;

// Main assembly
module print_in_place_hinge() {
    color(leaf_a_color)
    leaf_a();

    color(leaf_b_color)
    leaf_b();
}

// Helper: 2D rounded rectangle for leaf flap
module leaf_plate_2d(w, l, r) {
    hull() {
        translate([0, 0]) square([w - r, l]);
        translate([w - r, r]) circle(r = r);
        translate([w - r, l - r]) circle(r = r);
    }
}

// Leaf A (Left Side, containing knuckles 0, 2, 4 and center pin)
module leaf_a() {
    difference() {
        union() {
            // Leaf plate extending left (-X)
            translate([-knuckle_radius, 0, 0])
            mirror([1, 0, 0])
            linear_extrude(height = leaf_thickness)
            leaf_plate_2d(leaf_width, hinge_length, corner_radius);

            // Knuckles for Leaf A (even indices) + bridge to leaf
            for (i = [0 : 2 : num_knuckles - 1]) {
                y0 = (i == 0) ? 0 : (i * knuckle_pitch + axial_clearance / 2);
                y1 = (i == num_knuckles - 1) ? hinge_length : ((i + 1) * knuckle_pitch - axial_clearance / 2);
                k_len = y1 - y0;

                translate([0, y0, knuckle_radius]) {
                    // Solid knuckle cylinder
                    rotate([-90, 0, 0])
                    cylinder(r = knuckle_radius, h = k_len);
                }

                // Bridge from leaf plate to knuckle cylinder
                translate([-knuckle_radius, y0, 0])
                cube([knuckle_radius, k_len, knuckle_radius]);
            }

            // Continuous hinge pin attached to Leaf A
            translate([0, 0, knuckle_radius])
            rotate([-90, 0, 0])
            cylinder(r = pin_radius, h = hinge_length);
        }

        // Cutouts on Leaf A side for Leaf B knuckles
        for (i = [1 : 2 : num_knuckles - 1]) {
            y_start = i * knuckle_pitch - axial_clearance / 2;
            k_len = knuckle_pitch + axial_clearance;
            translate([-(knuckle_radius + clearance), y_start, -0.5])
            cube([knuckle_radius + clearance + 0.1, k_len, knuckle_diameter + 1]);
        }

        // Countersunk screw holes on Leaf A
        countersink_hole(-screw_x_pos, screw_edge_offset);
        countersink_hole(-screw_x_pos, hinge_length - screw_edge_offset);
    }
}

// Leaf B (Right Side, containing knuckles 1, 3 with internal pin bore)
module leaf_b() {
    difference() {
        union() {
            // Leaf plate extending right (+X)
            translate([knuckle_radius, 0, 0])
            linear_extrude(height = leaf_thickness)
            leaf_plate_2d(leaf_width, hinge_length, corner_radius);

            // Knuckles for Leaf B (odd indices) + bridge to leaf
            for (i = [1 : 2 : num_knuckles - 1]) {
                y0 = i * knuckle_pitch + axial_clearance / 2;
                y1 = (i + 1) * knuckle_pitch - axial_clearance / 2;
                k_len = y1 - y0;

                translate([0, y0, knuckle_radius]) {
                    // Knuckle outer cylinder
                    rotate([-90, 0, 0])
                    cylinder(r = knuckle_radius, h = k_len);
                }

                // Bridge from leaf plate to knuckle cylinder
                translate([0, y0, 0])
                cube([knuckle_radius, k_len, knuckle_radius]);
            }
        }

        // Bore for hinge pin with radial clearance
        translate([0, -1, knuckle_radius])
        rotate([-90, 0, 0])
        cylinder(r = pin_radius + clearance, h = hinge_length + 2);

        // Cutouts on Leaf B side for Leaf A knuckles
        for (i = [0 : 2 : num_knuckles - 1]) {
            y0 = (i == 0) ? -0.1 : (i * knuckle_pitch - axial_clearance / 2);
            y1 = (i == num_knuckles - 1) ? (hinge_length + 0.1) : ((i + 1) * knuckle_pitch + axial_clearance / 2);
            k_len = y1 - y0;
            translate([-0.1, y0, -0.5])
            cube([knuckle_radius + clearance + 0.1, k_len, knuckle_diameter + 1]);
        }

        // Countersunk screw holes on Leaf B
        countersink_hole(screw_x_pos, screw_edge_offset);
        countersink_hole(screw_x_pos, hinge_length - screw_edge_offset);
    }
}

// Countersunk hole module (90 degree standard countersink)
module countersink_hole(x, y) {
    cs_depth = (countersink_diameter - screw_hole_diameter) / 2;
    translate([x, y, -1]) {
        // Through hole
        cylinder(d = screw_hole_diameter, h = leaf_thickness + 2);
        
        // Countersink cone
        translate([0, 0, leaf_thickness + 1 - cs_depth])
        cylinder(d1 = screw_hole_diameter, d2 = countersink_diameter, h = cs_depth + 0.01);
        
        // Upper clearance opening
        translate([0, 0, leaf_thickness + 1])
        cylinder(d = countersink_diameter, h = 2);
    }
}

print_in_place_hinge();