esp32: wifi provisioning via AP captive portal

Replace compile-time env!() wifi/server config with NVS-based
runtime provisioning. Boot checks NVS — if no config, starts
AP mode (KFrame-Setup) with DNS responder + HTTP config form.
WiFi failure clears config and reboots into setup mode.

crates/client-esp32/src/hal/display.rs

@@ -2,8 +2,6 @@ use esp_idf_hal::delay::{Delay, Ets};
 use esp_idf_hal::gpio::{AnyIOPin, AnyOutputPin, PinDriver};
 use esp_idf_hal::spi::{SpiDeviceDriver, SpiDriver, SpiDriverConfig, SPI2, config::Config as SpiConfig};
 use mipidsi::{Builder, models::ILI9341Rgb565, options::{ColorOrder, Orientation, Rotation}, interface::SpiInterface};
-use embedded_graphics::pixelcolor::Rgb565;
-use embedded_graphics::prelude::*;
 use log::info;
 
 use crate::config::{self, SPI_BAUDRATE, SPI_BUFFER_SIZE};

crates/client-esp32/src/hal/wifi.rs

@@ -4,12 +4,16 @@ use esp_idf_hal::modem::Modem;
 use esp_idf_svc::eventloop::EspSystemEventLoop;
 use esp_idf_svc::nvs::EspDefaultNvsPartition;
 use esp_idf_svc::wifi::{
-    AuthMethod, BlockingWifi, ClientConfiguration, Configuration, EspWifi,
+    AccessPointConfiguration, AuthMethod, BlockingWifi, ClientConfiguration,
+    Configuration, EspWifi,
 };
 use log::{info, error};
 
 const MAX_RETRIES: u32 = 5;
 const RETRY_DELAY: Duration = Duration::from_secs(3);
+const AP_SSID: &str = "KFrame-Setup";
+const AP_CHANNEL: u8 = 1;
+const AP_MAX_CONNECTIONS: u16 = 4;
 
 pub fn init<'d>(
     modem: Modem<'d>,
@@ -54,3 +58,29 @@ pub fn init<'d>(
 
     Err(format!("WiFi failed after {MAX_RETRIES} attempts"))
 }
+
+pub fn init_ap<'d>(
+    modem: Modem<'d>,
+    sysloop: EspSystemEventLoop,
+    nvs: EspDefaultNvsPartition,
+) -> Result<BlockingWifi<EspWifi<'d>>, String> {
+    let esp_wifi = EspWifi::new(modem, sysloop.clone(), Some(nvs))
+        .map_err(|e| format!("wifi new: {e:?}"))?;
+
+    let mut wifi = BlockingWifi::wrap(esp_wifi, sysloop)
+        .map_err(|e| format!("wifi wrap: {e:?}"))?;
+
+    let config = Configuration::AccessPoint(AccessPointConfiguration {
+        ssid: AP_SSID.try_into().unwrap(),
+        auth_method: AuthMethod::None,
+        channel: AP_CHANNEL,
+        max_connections: AP_MAX_CONNECTIONS,
+        ..Default::default()
+    });
+
+    wifi.set_configuration(&config).map_err(|e| format!("wifi ap config: {e:?}"))?;
+    wifi.start().map_err(|e| format!("wifi ap start: {e:?}"))?;
+
+    info!("AP started: SSID={AP_SSID}");
+    Ok(wifi)
+}

crates/client-esp32/src/main.rs

@@ -2,6 +2,7 @@ mod adapters;
 mod boot;
 mod config;
 mod hal;
+mod provisioning;
 mod tasks;
 
 use std::sync::mpsc;
@@ -10,10 +11,6 @@ use esp_idf_svc::eventloop::EspSystemEventLoop;
 use esp_idf_svc::nvs::EspDefaultNvsPartition;
 use log::info;
 
-const WIFI_SSID: &str = env!("KFRAME_WIFI_SSID");
-const WIFI_PASS: &str = env!("KFRAME_WIFI_PASS");
-const SERVER_ADDR: &str = env!("KFRAME_SERVER_ADDR");
-
 fn main() {
     esp_idf_svc::sys::link_patches();
     esp_idf_svc::log::EspLogger::initialize_default();
@@ -24,7 +21,7 @@ fn main() {
     let sysloop = EspSystemEventLoop::take().unwrap();
     let nvs = EspDefaultNvsPartition::take().unwrap();
 
-    let display = hal::display::init(hal::display::DisplayHardware {
+    let mut display = hal::display::init(hal::display::DisplayHardware {
         spi: peripherals.spi2,
         sclk: peripherals.pins.gpio18.into(),
         mosi: peripherals.pins.gpio23.into(),
@@ -34,11 +31,46 @@ fn main() {
     });
     info!("Display ready");
 
-    info!("Connecting WiFi...");
+    match provisioning::read_config(nvs.clone()) {
-    let _wifi = hal::wifi::init(peripherals.modem, sysloop, nvs, WIFI_SSID, WIFI_PASS)
+        Some(cfg) => run_station(peripherals.modem, sysloop, nvs, cfg, display),
-        .expect("WiFi init failed");
+        None => {
+            info!("No config found, entering setup mode");
+            run_setup(peripherals.modem, sysloop, nvs, &mut display);
+        }
+    }
+}
 
+fn run_station(
+    modem: esp_idf_hal::modem::Modem<'static>,
+    sysloop: EspSystemEventLoop,
+    nvs: EspDefaultNvsPartition,
+    cfg: provisioning::DeviceConfig,
+    display: adapters::display::Esp32DisplayAdapter,
+) {
+    info!("Connecting WiFi...");
+    match hal::wifi::init(modem, sysloop.clone(), nvs.clone(), &cfg.wifi_ssid, &cfg.wifi_pass) {
+        Ok(_wifi) => {
             let (tx, rx) = mpsc::channel();
-    tasks::network::spawn(SERVER_ADDR.into(), tx);
+            tasks::network::spawn(cfg.server_addr, tx);
             tasks::render::run(config::SCREEN, display, rx);
         }
+        Err(e) => {
+            info!("WiFi failed ({e}), clearing config and rebooting to setup mode");
+            provisioning::clear_config(nvs);
+            std::thread::sleep(std::time::Duration::from_secs(1));
+            unsafe { esp_idf_svc::sys::esp_restart(); }
+        }
+    }
+}
+
+fn run_setup(
+    modem: esp_idf_hal::modem::Modem<'static>,
+    sysloop: EspSystemEventLoop,
+    nvs: EspDefaultNvsPartition,
+    display: &mut adapters::display::Esp32DisplayAdapter,
+) {
+    let _wifi = hal::wifi::init_ap(modem, sysloop, nvs.clone())
+        .expect("AP mode failed");
+
+    provisioning::portal::run_captive_portal(nvs, display);
+}

crates/client-esp32/src/provisioning/html.rs

@@ -0,0 +1,48 @@
+pub const SETUP_HTML: &str = r#"<!DOCTYPE html>
+<html>
+<head>
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<title>K-Frame Setup</title>
+<style>
+*{box-sizing:border-box;margin:0;padding:0}
+body{font-family:system-ui,sans-serif;background:#1a1a2e;color:#e0e0e0;display:flex;justify-content:center;align-items:center;min-height:100vh;padding:16px}
+.card{background:#16213e;border-radius:12px;padding:24px;width:100%;max-width:360px}
+h1{font-size:20px;text-align:center;margin-bottom:20px;color:#e94560}
+label{display:block;font-size:13px;margin-bottom:4px;color:#a0a0a0}
+input{width:100%;padding:10px;margin-bottom:14px;border:1px solid #333;border-radius:6px;background:#0f3460;color:#fff;font-size:15px}
+input:focus{outline:none;border-color:#e94560}
+button{width:100%;padding:12px;background:#e94560;color:#fff;border:none;border-radius:6px;font-size:16px;cursor:pointer}
+button:active{background:#c73650}
+.ok{text-align:center;color:#4ecca3;margin-top:16px;display:none}
+</style>
+</head>
+<body>
+<div class="card">
+<h1>K-Frame Setup</h1>
+<form id="f" method="POST" action="/save">
+<label for="s">WiFi SSID</label>
+<input id="s" name="ssid" required autocomplete="off">
+<label for="p">WiFi Password</label>
+<input id="p" name="pass" type="password">
+<label for="a">Server Address</label>
+<input id="a" name="server" placeholder="192.168.x.x:2699" required>
+<button type="submit">Save & Reboot</button>
+</form>
+<div class="ok" id="ok">Saved! Rebooting...</div>
+</div>
+<script>
+document.getElementById('f').onsubmit=function(e){
+e.preventDefault();
+var d=new FormData(this);
+var x=new XMLHttpRequest();
+x.open('POST','/save');
+x.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
+x.onload=function(){
+document.getElementById('f').style.display='none';
+document.getElementById('ok').style.display='block';
+};
+x.send('ssid='+encodeURIComponent(d.get('ssid'))+'&pass='+encodeURIComponent(d.get('pass'))+'&server='+encodeURIComponent(d.get('server')));
+}
+</script>
+</body>
+</html>"#;

crates/client-esp32/src/provisioning/mod.rs

@@ -0,0 +1,65 @@
+pub mod html;
+pub mod portal;
+
+use esp_idf_svc::nvs::{EspNvs, EspNvsPartition, NvsDefault};
+use log::{info, error};
+
+const NVS_NAMESPACE: &str = "kframe";
+const KEY_SSID: &str = "wifi_ssid";
+const KEY_PASS: &str = "wifi_pass";
+const KEY_SERVER: &str = "server_addr";
+
+pub struct DeviceConfig {
+    pub wifi_ssid: String,
+    pub wifi_pass: String,
+    pub server_addr: String,
+}
+
+pub fn read_config(nvs_partition: EspNvsPartition<NvsDefault>) -> Option<DeviceConfig> {
+    let nvs = EspNvs::new(nvs_partition, NVS_NAMESPACE, true).ok()?;
+
+    let ssid = read_string(&nvs, KEY_SSID)?;
+    let pass = read_string(&nvs, KEY_PASS)?;
+    let server = read_string(&nvs, KEY_SERVER)?;
+
+    if ssid.is_empty() {
+        return None;
+    }
+
+    info!("NVS config found: ssid={ssid}, server={server}");
+    Some(DeviceConfig {
+        wifi_ssid: ssid,
+        wifi_pass: pass,
+        server_addr: server,
+    })
+}
+
+pub fn save_config(nvs_partition: EspNvsPartition<NvsDefault>, config: &DeviceConfig) -> Result<(), String> {
+    let nvs = EspNvs::new(nvs_partition, NVS_NAMESPACE, true)
+        .map_err(|e| format!("nvs open: {e:?}"))?;
+
+    nvs.set_str(KEY_SSID, &config.wifi_ssid).map_err(|e| format!("nvs set ssid: {e:?}"))?;
+    nvs.set_str(KEY_PASS, &config.wifi_pass).map_err(|e| format!("nvs set pass: {e:?}"))?;
+    nvs.set_str(KEY_SERVER, &config.server_addr).map_err(|e| format!("nvs set server: {e:?}"))?;
+
+    info!("Config saved to NVS");
+    Ok(())
+}
+
+pub fn clear_config(nvs_partition: EspNvsPartition<NvsDefault>) {
+    match EspNvs::new(nvs_partition, NVS_NAMESPACE, true) {
+        Ok(nvs) => {
+            let _ = nvs.remove(KEY_SSID);
+            let _ = nvs.remove(KEY_PASS);
+            let _ = nvs.remove(KEY_SERVER);
+            info!("NVS config cleared");
+        }
+        Err(e) => error!("Failed to clear NVS: {e:?}"),
+    }
+}
+
+fn read_string(nvs: &EspNvs<NvsDefault>, key: &str) -> Option<String> {
+    let len = nvs.str_len(key).ok()??;
+    let mut buf = vec![0u8; len];
+    nvs.get_str(key, &mut buf).ok()?.map(|s| s.to_string())
+}

crates/client-esp32/src/provisioning/portal.rs

@@ -0,0 +1,201 @@
+use std::net::UdpSocket;
+use std::thread;
+use esp_idf_hal::io::Write;
+use esp_idf_svc::http::server::{Configuration as HttpConfig, EspHttpServer};
+use esp_idf_svc::nvs::{EspNvsPartition, NvsDefault};
+use client_domain::{BoundingBox, DisplayPort};
+use log::{info, error};
+
+use super::{DeviceConfig, save_config};
+use super::html::SETUP_HTML;
+
+const AP_IP: [u8; 4] = [192, 168, 4, 1];
+
+pub fn run_captive_portal<D: DisplayPort>(
+    nvs: EspNvsPartition<NvsDefault>,
+    display: &mut D,
+) {
+    draw_setup_screen(display);
+    spawn_dns_responder();
+
+    let nvs_clone = nvs.clone();
+    let mut server = EspHttpServer::new(&HttpConfig {
+        http_port: 80,
+        ..Default::default()
+    }).expect("HTTP server start failed");
+
+    server
+        .fn_handler::<esp_idf_svc::io::EspIOError, _>("/", esp_idf_svc::http::Method::Get, |req| {
+            req.into_ok_response()?
+                .write_all(SETUP_HTML.as_bytes())?;
+            Ok(())
+        })
+        .expect("GET / handler failed");
+
+    server
+        .fn_handler::<esp_idf_svc::io::EspIOError, _>("/save", esp_idf_svc::http::Method::Post, move |mut req| {
+            let mut body = vec![0u8; 512];
+            let len = req.read(&mut body).unwrap_or(0);
+            let body_str = std::str::from_utf8(&body[..len]).unwrap_or("");
+
+            let config = parse_form(body_str);
+            info!("Portal received config: ssid={}", config.wifi_ssid);
+
+            if let Err(e) = save_config(nvs_clone.clone(), &config) {
+                error!("Save failed: {e}");
+                req.into_ok_response()?.write_all(b"Error saving config")?;
+                return Ok(());
+            }
+
+            req.into_ok_response()?.write_all(b"OK")?;
+
+            thread::spawn(|| {
+                thread::sleep(std::time::Duration::from_secs(1));
+                unsafe { esp_idf_svc::sys::esp_restart(); }
+            });
+            Ok(())
+        })
+        .expect("POST /save handler failed");
+
+    server
+        .fn_handler::<esp_idf_svc::io::EspIOError, _>("/generate_204", esp_idf_svc::http::Method::Get, |req| {
+            redirect(req)
+        })
+        .expect("generate_204 handler failed");
+
+    server
+        .fn_handler::<esp_idf_svc::io::EspIOError, _>("/hotspot-detect.html", esp_idf_svc::http::Method::Get, |req| {
+            redirect(req)
+        })
+        .expect("hotspot-detect handler failed");
+
+    server
+        .fn_handler::<esp_idf_svc::io::EspIOError, _>("/canonical.html", esp_idf_svc::http::Method::Get, |req| {
+            redirect(req)
+        })
+        .expect("canonical handler failed");
+
+    info!("Captive portal running on http://192.168.4.1");
+
+    loop {
+        thread::sleep(std::time::Duration::from_secs(60));
+    }
+}
+
+fn redirect(req: esp_idf_svc::http::server::Request<&mut esp_idf_svc::http::server::EspHttpConnection>) -> Result<(), esp_idf_svc::io::EspIOError> {
+    let mut resp = req.into_response(302, None, &[("Location", "http://192.168.4.1/")])?;
+    resp.write_all(b"")?;
+    Ok(())
+}
+
+fn spawn_dns_responder() {
+    thread::Builder::new()
+        .stack_size(4096)
+        .name("dns".into())
+        .spawn(dns_responder)
+        .expect("DNS thread spawn failed");
+}
+
+fn dns_responder() {
+    let socket = match UdpSocket::bind("0.0.0.0:53") {
+        Ok(s) => s,
+        Err(e) => {
+            error!("DNS bind failed: {e}");
+            return;
+        }
+    };
+
+    info!("DNS responder started on :53");
+    let mut buf = [0u8; 512];
+
+    loop {
+        let (len, src) = match socket.recv_from(&mut buf) {
+            Ok(r) => r,
+            Err(_) => continue,
+        };
+        if len < 12 {
+            continue;
+        }
+
+        let mut resp = Vec::with_capacity(len + 16);
+
+        // Header: copy ID, set response flags
+        resp.extend_from_slice(&buf[0..2]);
+        resp.extend_from_slice(&[0x81, 0x80]);
+        resp.extend_from_slice(&buf[4..6]);
+        resp.extend_from_slice(&buf[4..6]);
+        resp.extend_from_slice(&[0, 0, 0, 0]);
+
+        // Copy question section
+        resp.extend_from_slice(&buf[12..len]);
+
+        // Answer: A record pointing to AP IP
+        resp.extend_from_slice(&[0xC0, 0x0C]); // Name pointer
+        resp.extend_from_slice(&[0, 1]); // Type A
+        resp.extend_from_slice(&[0, 1]); // Class IN
+        resp.extend_from_slice(&[0, 0, 0, 60]); // TTL 60s
+        resp.extend_from_slice(&[0, 4]); // Data length
+        resp.extend_from_slice(&AP_IP);
+
+        let _ = socket.send_to(&resp, src);
+    }
+}
+
+fn parse_form(body: &str) -> DeviceConfig {
+    let mut ssid = String::new();
+    let mut pass = String::new();
+    let mut server = String::new();
+
+    for pair in body.split('&') {
+        let mut parts = pair.splitn(2, '=');
+        let key = parts.next().unwrap_or("");
+        let val = url_decode(parts.next().unwrap_or(""));
+        match key {
+            "ssid" => ssid = val,
+            "pass" => pass = val,
+            "server" => server = val,
+            _ => {}
+        }
+    }
+
+    DeviceConfig { wifi_ssid: ssid, wifi_pass: pass, server_addr: server }
+}
+
+fn url_decode(s: &str) -> String {
+    let mut result = String::with_capacity(s.len());
+    let mut chars = s.bytes();
+    while let Some(b) = chars.next() {
+        match b {
+            b'+' => result.push(' '),
+            b'%' => {
+                let hi = chars.next().and_then(hex_val);
+                let lo = chars.next().and_then(hex_val);
+                if let (Some(h), Some(l)) = (hi, lo) {
+                    result.push((h << 4 | l) as char);
+                }
+            }
+            _ => result.push(b as char),
+        }
+    }
+    result
+}
+
+fn hex_val(b: u8) -> Option<u8> {
+    match b {
+        b'0'..=b'9' => Some(b - b'0'),
+        b'a'..=b'f' => Some(b - b'a' + 10),
+        b'A'..=b'F' => Some(b - b'A' + 10),
+        _ => None,
+    }
+}
+
+const FULL_SCREEN: BoundingBox = BoundingBox { x: 0, y: 0, width: 320, height: 240 };
+
+fn draw_setup_screen<D: DisplayPort>(display: &mut D) {
+    let _ = display.fill_background(FULL_SCREEN);
+    let _ = display.draw_text("K-Frame Setup", 0, 0, BoundingBox { x: 80, y: 50, width: 160, height: 20 });
+    let _ = display.draw_text("Connect to WiFi:", 0, 0, BoundingBox { x: 40, y: 90, width: 240, height: 14 });
+    let _ = display.draw_text("KFrame-Setup", 0, 0, BoundingBox { x: 80, y: 110, width: 160, height: 14 });
+    let _ = display.draw_text("Then open browser", 0, 0, BoundingBox { x: 40, y: 150, width: 240, height: 14 });
+    let _ = display.draw_text("to configure", 0, 0, BoundingBox { x: 60, y: 170, width: 200, height: 14 });
+}