$fn = 64;

// --- Parameters ---
// Base grid dimensions (2x2 tile)
grid_unit = 20; 
tile_x = grid_unit * 2;
tile_y = grid_unit * 2;

// Heights and thicknesses
base_height = 3;
sidewalk_width = 3;
sidewalk_height = 1;
entrance_width = 14;

// Parking space dimensions
spot_depth = 11;
spot_width = 7.5;
num_spots = 4;
line_w = 0.8; // Extrusion width for 3D printing
line_h = 0.4; // 2 layers at 0.2mm for visible lines

// --- Geometry ---
union() {
    // 1. Main solid base
    cube([tile_x, tile_y, base_height]);

    // 2. Raised sidewalk border
    translate([0, 0, base_height])
    difference() {
        cube([tile_x, tile_y, sidewalk_height]);

        // Inner cutout for the parking lot surface
        translate([sidewalk_width, sidewalk_width, -0.1])
            cube([tile_x - sidewalk_width*2, tile_y - sidewalk_width*2, sidewalk_height + 0.2]);

        // Cutout for the entrance/exit (front edge)
        translate([(tile_x - entrance_width)/2, -0.1, -0.1])
            cube([entrance_width, sidewalk_width + 0.2, sidewalk_height + 0.2]);
    }

    // 3. Raised parking lines (painted lines)
    translate([0, 0, base_height]) {
        // Calculate starting Y to center the parking spots vertically
        y_start = (tile_y - (num_spots * spot_width)) / 2;

        // Left side parking spots
        for (i = [0 : num_spots]) {
            translate([sidewalk_width, y_start + (i * spot_width), 0])
                cube([spot_depth, line_w, line_h]);
        }
        // Left dividing line
        translate([sidewalk_width + spot_depth, y_start, 0])
            cube([line_w, (num_spots * spot_width) + line_w, line_h]);

        // Right side parking spots
        for (i = [0 : num_spots]) {
            translate([tile_x - sidewalk_width - spot_depth, y_start + (i * spot_width), 0])
                cube([spot_depth, line_w, line_h]);
        }
        // Right dividing line
        translate([tile_x - sidewalk_width - spot_depth - line_w, y_start, 0])
            cube([line_w, (num_spots * spot_width) + line_w, line_h]);
            
        // Entrance dividing line (center dashed line)
        translate([(tile_x - line_w)/2, sidewalk_width + 2, 0])
            cube([line_w, 4, line_h]);
        translate([(tile_x - line_w)/2, sidewalk_width + 8, 0])
            cube([line_w, 4, line_h]);
    }
}