// =====================================================================
//  ESP32-S3-DevKitC-1 - two-part snap-fit case
//
//  BASE  : floor + walls. Board rests on 4 round posts, on the inner side of the pin slots, lined up in X with the first and last pin. Pin rows poke down into two floor slots, so Dupont connectors plug in from underneath.
//  LID   : cap with a skirt that clips over the base's inner "tongue". Has the two button holes. USB-C opening is split between both parts, so neither part needs a bridged (unsupported) cut-out.
//
//
//  !! Measure your board and check the values marked [CHECK] !!
//  Set show_board = true and part = "assembled" to preview the fit.
// =====================================================================

part       = "print";   // "print" | "base" | "lid" | "assembled"
show_board = true;      // ghost board in the "assembled" view
explode    = 0;         // mm - lifts the lid in the "assembled" view

$fn = 64;

/* ---------------- Board ---------------- */
pcb_l       = 63.74;  // [CHECK] PCB length (USB-C end -> antenna end)
pcb_w       = 28.35;   // [CHECK] PCB width
pcb_t       = 1.6;    // PCB thickness
pin_below   = 11;     // [CHECK] PCB underside -> pin tips (header + pin)
header_pins = 22;     // pins per row
pin_pitch   = 2.54;
row_dist    = 24.86;  // distance between the two pin rows
header_x0   = 2;  // [CHECK] first pin CENTRE, measured from the USB end
comp_h      = 3.5;    // tallest part above PCB top

/* ---------------- USB-C opening ---------------- */
usb_slot_w  = 24;     // one wide slot for both connectors + cable plug overmolds
usb_plug_h  = 6.5;    // slot height (plug overmold)
usb_axis_h  = 1.7;    // connector axis height above PCB top

/* ---------------- Buttons (lid holes) ---------------- */
// [CHECK] position of each button centre: [distance from USB end edge, offset from board centre line]
boot_pos    = [28, -5.68];
rst_pos     = [33, -5.68];
btn_d       = 3.4;    // hole diameter (use a pin / paper-clip / toothpick)

/* ---------------- Case / print tuning ---------------- */
wall        = 2.8;    // outer wall
tongue_t    = 1.6;    // inner lip of the base (the part that carries the snap groove)
tol         = 0.2;    // sliding clearance for PETG
clr         = 0.4;    // board-to-wall clearance
floor_t     = 2.0;
plate_t     = 2.0;    // lid top thickness
top_gap     = 0.6;    // clearance above the tallest component
overlap     = 6;      // how far the lid skirt slips over the base
snap_d      = 0.5;    // snap depth - raise to 0.6 for a firmer click
snap_len    = 12;     // length of each snap bump
r_in        = 1.0;    // inner corner radius

pin_win_w      = 3.0; // floor slot width under each pin row (Dupont housing ~2.6)
pin_win_margin = 2.0; // slot overhang beyond first/last pin
post_d      = 3;
post_y      = 8;      // post offset from centre line (inner side of the pin rows, between the header bodies)
// post X positions: in line with the first and last pin of the rows
post_x      = [header_x0, header_x0 + (header_pins-1)*pin_pitch];

/* ---------------- Derived ---------------- */
L_i       = pcb_l + 2*clr;
W_i       = pcb_w + 2*clr;
z_pcb_bot = pin_below + 0.5;       // pin tips end 0.5 mm above the print bed
z_pcb_top = z_pcb_bot + pcb_t;
z_split   = z_pcb_top + 2;         // joint between base and lid
z_ceil    = z_pcb_top + comp_h + top_gap;
z_top     = z_ceil + plate_t;
z_usb_bot = z_pcb_top + usb_axis_h - usb_plug_h/2;
z_usb_top = z_pcb_top + usb_axis_h + usb_plug_h/2;
z_snap    = z_split - 3.3;
ridge_d   = snap_d + tol - 0.1;
snap_x    = [0.27*L_i, 0.73*L_i];

/* ---------------- Helpers ---------------- */
module rr(x0, x1, y0, y1, r) {
    translate([x0+r, y0+r]) offset(r=r) square([x1-x0-2*r, y1-y0-2*r]);
}
module outline(d=0) { rr(-d, L_i+d, -W_i/2-d, W_i/2+d, r_in+d); }
module slab(d, z0, z1) { translate([0,0,z0]) linear_extrude(z1-z0) outline(d); }

// 45-degree triangular prism along X; apex points toward -Y (into the case)
module wedge(len, d) {
    rotate([90,0,90]) linear_extrude(len, center=true)
        polygon([[-d,0],[0.3,d+0.3],[0.3,-d-0.3]]);
}
// all snap positions: two per long side + one on the far end wall
module snap_set(off, d) {
    for (xc = snap_x, s = [-1,1])
        translate([xc, s*(W_i/2 + tongue_t + off), z_snap])
            mirror([0, s<0 ? 1 : 0, 0]) wedge(snap_len, d);
    translate([L_i + tongue_t + off, 0, z_snap])
        rotate([0,0,-90]) wedge(snap_len, d);
}

/* ---------------- BASE ---------------- */
module base() {
    difference() {
        union() {
            difference() {
                slab(wall, 0, z_split);
                slab(0, floor_t, z_split+1);                       // pocket
                translate([0,0,z_split-overlap])                   // rebate -> leaves the tongue
                    linear_extrude(overlap+1)
                        difference() { outline(wall+1); outline(tongue_t); }
                snap_set(0, snap_d);                               // snap grooves
            }
            for (px = post_x, s = [-1,1])                          // PCB support posts (in line with first / last pin)
                translate([clr+px, s*post_y, floor_t-0.01])
                    cylinder(d=post_d, h=z_pcb_bot-floor_t+0.01);
        }
        // pin-row slots through the floor
        for (s = [-1,1])
            translate([clr + header_x0 - pin_win_margin, s*row_dist/2 - pin_win_w/2, -1])
                cube([(header_pins-1)*pin_pitch + 2*pin_win_margin, pin_win_w, floor_t+2]);
        // lower half of the USB-C opening (open at the top -> no bridging)
        translate([-wall-1, -usb_slot_w/2, z_usb_bot])
            cube([wall+1, usb_slot_w, z_split+1-z_usb_bot]);
    }
}

/* ---------------- LID (modelled in assembled position) ---------------- */
module lid() {
    difference() {
        union() {
            slab(wall, z_split, z_top);                            // cap
            translate([0,0,z_split-overlap+0.3])                   // skirt over the tongue
                linear_extrude(overlap-0.3+0.01)
                    difference() { outline(wall); outline(tongue_t+tol); }
            snap_set(tol, ridge_d);                                // snap ridges
        }
        slab(0, z_split-1, z_ceil);                                // cavity
        // upper half of the USB-C opening (open at the skirt edge -> no bridging)
        translate([-wall-1, -usb_slot_w/2, z_split-overlap-1])
            cube([wall+1, usb_slot_w, z_usb_top-(z_split-overlap-1)]);
        // BOOT / RST holes
        for (p = [boot_pos, rst_pos])
            translate([clr+p[0], p[1], z_ceil-1]) cylinder(d=btn_d, h=plate_t+2);
    }
}
module lid_for_print() { translate([0,0,z_top]) rotate([180,0,0]) lid(); }

/* ---------------- Preview ghost (approximate) ---------------- */
module ghost() {
    color("seagreen", 0.6) {
        translate([clr, -pcb_w/2, z_pcb_bot]) cube([pcb_l, pcb_w, pcb_t]);
        for (s=[-1,1]) translate([clr+header_x0-1.27, s*row_dist/2-1.27, z_pcb_bot-2.5])
            cube([(header_pins-1)*pin_pitch+2.54, 2.54, 2.5]);
        for (s=[-1,1]) for (i=[0:header_pins-1])
            translate([clr+header_x0+i*pin_pitch-0.32, s*row_dist/2-0.32, z_pcb_bot-pin_below])
                cube([0.64,0.64,pin_below]);
    }
    color("silver", 0.8) {
        for (s=[-1,1]) translate([clr-0.5, s*6.5-4.47, z_pcb_top]) cube([7.3, 8.94, 3.2]); // USB-C (approx. y)
        translate([clr+pcb_l-25.5, -9, z_pcb_top]) cube([25.5, 18, 3.2]);                    // module
    }
    color("black", 0.8) for (p=[boot_pos, rst_pos])
        translate([clr+p[0], p[1], z_pcb_top]) cylinder(d=3, h=3.5);
}

/* ---------------- Output ---------------- */
if (part == "base")           base();
else if (part == "lid")       lid_for_print();
else if (part == "assembled") { base(); translate([0,0,explode]) lid(); if (show_board) ghost(); }
else { base(); translate([0, -(W_i + 2*wall + 10), 0]) lid_for_print(); }