// Ring Solar Charger — Vinyl Siding Adapter Plate
// Mounts the integrated Ring Solar Charger on horizontal beaded vinyl lap siding.
// Units: millimeters. Vanilla OpenSCAD only.
//
// Rear profile (y=0 bottom, y=plate_height top):
//   TOP    — bead coping cavity scooped into rear face (concave semicircle)
//   MID    — flat rear shelf continues downward
//   BOTTOM — slow taper outward toward siding projection
//
// Backup (flat + taper only): ring-solar-siding-adapter.backup.scad

/* [Plate] */
plate_width = 93.1;
plate_height = 171.45;
min_wall_thickness = 5.0;
edge_round = 0;

/* [Siding Profile] */
siding_projection = 27.0;
face_inset_depth = 8.0;
bead_coping_radius = 10.00;      // Semicircle radius for bead groove (measured on siding)
bead_coping_offset_top = 11.00;  // Distance from plate top to groove center (tune on wall)
flat_upper_ratio = 0.55;         // Fraction of plate height that stays flat at the top
bottom_taper_depth_ratio = 1.6;  // Rear depth at plate bottom = min_wall_thickness * this (outward from flat shelf)
rear_extension = 7.5;            // Extra depth toward wall; front face + bead groove stay fixed vs front/top
course_pitch = 165.1;
profile_segments = 8;
profile_mode = "curved"; // [curved, stepped]
rear_clearance = 0.2;

/* [Mounting Holes] */
mount_hole_offset_top = 50.0;
mount_hole_offset_bottom = 44.7;
mount_hole_dia = 4.5;
mount_hole_x = 0;

/* [Export] */
part_mode = "full"; // [full, profile_strip, front_slice]
profile_strip_width = 20;
front_slice_depth = 3.5; // [2:0.5:8]

/* [Hidden] */
$fn = 64;
epsilon = 0.01;

// ---------------------------------------------------------------------------
// Siding rear-profile geometry
// OpenSCAD 2D polygon uses [plate_Y, plate_Z]; linear_extrude() goes along +Z (width).
// OpenSCAD 3D: X = plate height (y), Y = depth (z), Z = plate width.
// Lower depth Y = toward wall (back). Higher depth Y = toward Ring (front).
// ---------------------------------------------------------------------------

function projection_z() = siding_projection - rear_clearance;

function face_inset_z() = projection_z() - face_inset_depth;

// Flat rear shelf shifted toward the wall; bead groove keeps absolute depth at face_inset_z.
function flat_rear_z() = face_inset_z() - rear_extension;

function bead_coping_y_center() = plate_height - bead_coping_offset_top;

// Bottom of flat rear shelf (flat_upper_ratio measured from plate top downward).
function face_y_flat_end() = plate_height * (1 - flat_upper_ratio);

// Rear depth where the bottom taper ends (outward from flat shelf, in wall-thickness units).
function bottom_rear_z() =
    flat_rear_z() + min_wall_thickness * bottom_taper_depth_ratio;

// Slow taper from bottom_rear_z at the plate bottom up to the flat rear shelf.
function lower_curve_z(y) =
    let(
        y1 = face_y_flat_end(),
        t = y / max(y1, epsilon),
        ease = pow(sin(t * 90), 1.4),
        z_bottom = bottom_rear_z(),
        z_top = flat_rear_z()
    )
    z_top + (z_bottom - z_top) * (1 - ease);

function stepped_rear_z(y) =
    y >= face_y_flat_end() ? flat_rear_z() : bottom_rear_z();

// Bead coping: fixed depth vs front/top. Flat chord at face_inset_z; arc scoops into plate.
function bead_coping_rear_z(y) =
    let(
        r = bead_coping_radius,
        shelf = face_inset_z(),
        dy = y - bead_coping_y_center(),
        disc = r * r - dy * dy
    )
    disc >= 0 ? shelf + sqrt(disc) : flat_rear_z();

// Flat top shelf + bead cavity + lower taper.
function rear_z_at(y) =
    y >= face_y_flat_end() ? bead_coping_rear_z(y)
    : profile_mode == "stepped" ? stepped_rear_z(y)
    : lower_curve_z(y);

function rear_profile_points() =
    let(
        step = plate_height / max(profile_segments * 12, 24),
        yc = bead_coping_y_center(),
        r = bead_coping_radius,
        arc_step = r / 16
    )
    concat(
        [for (y = [0 : step : max(yc - r - epsilon, 0)]) [y, rear_z_at(y)]],
        [for (y = [yc - r : arc_step : yc + r]) [y, rear_z_at(y)]],
        [for (y = [min(yc + r + step, plate_height) : step : plate_height]) [y, rear_z_at(y)]]
    );

function max_rear_z() =
    let(pts = rear_profile_points())
    max([for (p = pts) p[1]]);

// Front face anchored to bead groove + min wall (independent of rear_extension).
function front_z() =
    face_inset_z() + bead_coping_radius + min_wall_thickness;

function rear_y_min() =
    min([for (p = rear_profile_points()) p[1]]);

function minkowski_active() =
    edge_round > 0 && min_wall_thickness >= 2 * edge_round + 1;

function hole_y_min() =
    rear_y_min() - (minkowski_active() ? edge_round : 0) - epsilon;

function hole_y_max() =
    front_z() + (minkowski_active() ? edge_round : 0) + epsilon;

function cross_section_polygon() =
    let(
        rear_pts = rear_profile_points(),
        fz = front_z()
    )
    [
        for (p = rear_pts) p,
        [plate_height, fz],
        [0, fz]
    ];

// ---------------------------------------------------------------------------
// Modules
// ---------------------------------------------------------------------------

module cross_section_2d() {
    polygon(cross_section_polygon());
}

module adapter_body(width) {
    linear_extrude(width, center = true)
        cross_section_2d();
}

module mount_holes() {
    y_min = hole_y_min();
    y_max = hole_y_max();
    hole_depth = y_max - y_min;
    center_y = (y_min + y_max) / 2;
    for (y_pos = [plate_height - mount_hole_offset_top, mount_hole_offset_bottom]) {
        translate([y_pos, center_y, mount_hole_x])
            rotate([90, 0, 0])
                cylinder(h = hole_depth, d = mount_hole_dia, center = true);
    }
}

module rounded_body(width) {
    if (minkowski_active()) {
        minkowski() {
            adapter_body(max(width - 2 * edge_round, 1));
            sphere(r = edge_round);
        }
    } else {
        adapter_body(width);
    }
}

// Keep only the front face cap for fit-checking width, height, and hole placement.
module front_slice_mask(width) {
    fz = front_z();
    translate([plate_height / 2, fz - front_slice_depth / 2, 0])
        cube(
            [plate_height + 2 * epsilon, front_slice_depth + 2 * epsilon, width + 2 * epsilon],
            center = true
        );
}

module adapter_plate() {
    width = part_mode == "profile_strip" ? profile_strip_width : plate_width;
    if (part_mode == "full") {
        difference() {
            rounded_body(width);
            mount_holes();
        }
    } else if (part_mode == "front_slice") {
        intersection() {
            difference() {
                rounded_body(width);
                mount_holes();
            }
            front_slice_mask(width);
        }
    } else {
        rounded_body(width);
    }
}

adapter_plate();