$fn = 64;

// --- Parameters ---
cols = 4;            // Number of columns
rows = 3;            // Number of rows
bat_diam = 15.2;     // AA battery diameter + clearance
bat_depth = 25;      // Depth of the slot
base = 3;            // Base thickness
spacing_x = 20;      // X spacing between slots
spacing_y = 23;      // Y spacing between slots (larger to fit labels)
wall_x = 5;          // Side wall thickness
wall_y = 7;          // Front/back wall thickness

// --- Calculated Dimensions ---
width = (cols - 1) * spacing_x + bat_diam + 2 * wall_x;
depth = (rows - 1) * spacing_y + bat_diam + 2 * wall_y;
height = base + bat_depth;

difference() {
    // Main body block
    cube([width, depth, height]);

    // Battery slots and individual labels
    for (c = [0 : cols - 1]) {
        for (r = [0 : rows - 1]) {
            slot_num = r * cols + c + 1;
            cx = wall_x + bat_diam/2 + c * spacing_x;
            cy = wall_y + bat_diam/2 + r * spacing_y;
            
            // Battery cylindrical cutout
            translate([cx, cy, base])
                cylinder(h = bat_depth + 1, d = bat_diam);
            
            // Slot number label (cut 0.6mm into top surface for clean 3D printing)
            translate([cx, cy - bat_diam/2 - 2.5, height - 0.6])
                linear_extrude(1.2)
                text(str(slot_num), size=4, halign="center", valign="center", font="Arial:style=Bold");
        }
    }

    // Front label "AA BATTERIES" (cut 0.6mm into front surface)
    translate([width/2, 0.6, height/2])
        rotate([90, 0, 0])
        linear_extrude(1.2)
        text("AA BATTERIES", size=height/3.5, halign="center", valign="center", font="Arial:style=Bold");
}