// Face-Down Oval Zipper Pull Template
// Designed for face-down printing: text and border are channels in blue layer (printed first),
// then white backing fills the channels and covers the back.
// When flipped over, shows white text/border on blue background.

// Parameters - these can be overridden from command line
name = "NAME"; // Text to display on zipper pull
oval_width = 96; // Width of blue oval (mm) - total with border will be 100mm (96 + 2*2)
oval_height = 30; // Height of blue oval (mm) - total with border will be 34mm (30 + 2*2)
blue_thickness = 1; // Thickness of blue layer (mm) - this is the "show" side
white_thickness = 1.5; // Thickness of white backing layer (mm)
base_text_size = 13; // Base font size for medium names

// Dynamic font sizing based on name length (mimics Ford oval proportions)
// "Fred" (4 chars) at 13mm gives ~20% coverage - our target
name_length = len(name);
text_size = name_length <= 3 ? 18 :      // Short names (Zoe, Sam, Al) - larger (~21% coverage)
            name_length <= 5 ? 13 :      // Medium names (Fred, John, Mary) - standard (~20% coverage)
            name_length <= 8 ? 11 :      // Longer names (Michael, Jessica) - smaller (~25% coverage)
            11;                          // Very long names (Christopher) - increased to 11mm (~35% coverage)

// Border parameters
border_width = 2; // Width of the white border around the oval (mm)

// Hole parameters for zipper pull
hole_diameter = 4; // Diameter of the hole (mm)
hole_clearance = 4; // Minimum clearance from edge of outer border (mm)

// Total dimensions
total_width = oval_width + border_width*2;  // 100mm
total_height = oval_height + border_width*2; // 34mm

// Hole position - on LEFT side when viewed from show side
// Since we print face-down, hole appears on RIGHT during printing
// When flipped, it will be on the left as expected
hole_x = -(total_width/2) + (hole_diameter/2) + hole_clearance;

// Module to create an oval (ellipse)
module oval(width, height, depth) {
    scale([width/2, height/2, 1])
        cylinder(h=depth, r=1, $fn=100);
}

// Module for text with fake bold effect
module bold_text() {
    for (x = [-0.3, 0, 0.3]) {
        for (y = [-0.3, 0, 0.3]) {
            translate([x, y, 0])
                linear_extrude(height=blue_thickness + 0.1)
                    text(name,
                         size=text_size,
                         font="Fordscript",
                         halign="center",
                         valign="center");
        }
    }
}

// Blue layer with channels for text and border (prints first, face-down)
// The channels will be filled with white when the white layer is printed
module blue_layer() {
    color("RoyalBlue")
    difference() {
        // Full blue oval
        oval(total_width, total_height, blue_thickness);

        // Cut out the border ring channel (will be filled with white)
        translate([0, 0, -0.05])
            difference() {
                oval(total_width, total_height, blue_thickness + 0.1);
                oval(oval_width, oval_height, blue_thickness + 0.2);
            }

        // Cut out text channels (will be filled with white)
        translate([0, 0, -0.05])
            bold_text();

        // Cut out hole
        translate([hole_x, 0, -0.05])
            cylinder(h=blue_thickness + 0.1, d=hole_diameter, $fn=50);
    }
}

// White backing layer (prints second, on top of blue)
// Also fills the text and border channels
module white_layer() {
    color("white")
    difference() {
        union() {
            // Main backing layer on top of blue
            translate([0, 0, blue_thickness])
                oval(total_width, total_height, white_thickness);

            // Fill the border channel
            difference() {
                oval(total_width, total_height, blue_thickness);
                oval(oval_width, oval_height, blue_thickness + 0.1);
            }

            // Fill the text channels
            bold_text();
        }

        // Cut out hole through entire white layer
        translate([hole_x, 0, -0.05])
            cylinder(h=blue_thickness + white_thickness + 0.2, d=hole_diameter, $fn=50);
    }
}

// Main zipper pull assembly
module zipper_pull() {
    blue_layer();
    white_layer();
}

// Generate the zipper pull
zipper_pull();