Wi-Fi Tools: scan logging to CSV, plus sort and filter

- lib/wifi (host-tested): scan_log (CSV field quoting, header/row, a
  once-per-interval throttle) and network_list_view (sort by signal /
  channel / name, filter open-only / hide-hidden / strong-only)
- ScanEntry moved to lib/wifi so both are testable on the PC
- Wi-Fi Tools networks view: s sort, o/h/w filters, l toggles logging
  to /wifi/scans/<date>.csv (header + one row per AP per logged scan,
  throttled 30 s, needs the clock for timestamps); foreground-only
- Wi-Fi scan logs replace probe-request logs as a clean-up category
- Serial: cat <path>, and key <char> injects a character

Verified on the device: CSV written with header, timestamps, BSSID,
channel, RSSI, security and SSID; hidden networks marked.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

lib/wifi/src/network_list_view.cpp

@@ -0,0 +1,59 @@
+#include "network_list_view.h"
+
+#include <algorithm>
+#include <cctype>
+
+namespace roro {
+
+namespace {
+std::string lower(std::string s) {
+    for (auto& c : s) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+    return s;
+}
+}  // namespace
+
+std::vector<int> orderNetworks(const std::vector<ScanEntry>& entries, WifiSort sort, const NetworkFilter& filter) {
+    std::vector<int> idx;
+    for (int i = 0; i < static_cast<int>(entries.size()); i++) {
+        const ScanEntry& e = entries[i];
+        if (filter.openOnly && !e.open) continue;
+        if (filter.hideHidden && e.ssid.empty()) continue;
+        if (e.rssi < filter.minRssi) continue;
+        idx.push_back(i);
+    }
+    std::stable_sort(idx.begin(), idx.end(), [&](int a, int b) {
+        const ScanEntry& x = entries[a];
+        const ScanEntry& y = entries[b];
+        switch (sort) {
+            case WifiSort::Signal: return x.rssi > y.rssi;  // strongest first
+            case WifiSort::Channel: return x.channel != y.channel ? x.channel < y.channel : x.rssi > y.rssi;
+            case WifiSort::Name: {
+                // Hidden networks (no name) sort to the end.
+                if (x.ssid.empty() != y.ssid.empty()) return y.ssid.empty();
+                return lower(x.ssid) < lower(y.ssid);
+            }
+        }
+        return false;
+    });
+    return idx;
+}
+
+const char* sortName(WifiSort sort) {
+    switch (sort) {
+        case WifiSort::Signal: return "signal";
+        case WifiSort::Channel: return "channel";
+        case WifiSort::Name: return "name";
+    }
+    return "";
+}
+
+WifiSort nextSort(WifiSort sort) {
+    switch (sort) {
+        case WifiSort::Signal: return WifiSort::Channel;
+        case WifiSort::Channel: return WifiSort::Name;
+        case WifiSort::Name: return WifiSort::Signal;
+    }
+    return WifiSort::Signal;
+}
+
+}  // namespace roro

lib/wifi/src/network_list_view.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "scan_entry.h"
+
+namespace roro {
+
+enum class WifiSort { Signal, Channel, Name };
+
+struct NetworkFilter {
+    bool openOnly = false;
+    bool hideHidden = false;
+    int minRssi = -100;  // drop anything weaker
+};
+
+// The order and selection the network list shows: indices into `entries`, sorted and filtered.
+// Stable, so equal rows keep their scan order.
+std::vector<int> orderNetworks(const std::vector<ScanEntry>& entries, WifiSort sort, const NetworkFilter& filter);
+
+const char* sortName(WifiSort sort);
+WifiSort nextSort(WifiSort sort);
+
+}  // namespace roro

lib/wifi/src/scan_entry.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <string>
+
+namespace roro {
+
+// One access point an ordinary Wi-Fi scan reported (a network announcing itself). No client or
+// monitor-mode data: just what a beacon broadcasts.
+struct ScanEntry {
+    std::string ssid;   // empty for a hidden network
+    std::string bssid;  // the access point's own address, from its beacon
+    int channel;
+    int rssi;
+    bool open;
+    std::string security;  // "open", "WPA2", "WPA3"...
+};
+
+}  // namespace roro

lib/wifi/src/scan_log.cpp

@@ -0,0 +1,27 @@
+#include "scan_log.h"
+
+namespace roro::scanlog {
+
+std::string csvField(const std::string& value) {
+    bool needsQuote = false;
+    for (char c : value)
+        if (c == ',' || c == '"' || c == '\n' || c == '\r') needsQuote = true;
+    if (!needsQuote) return value;
+    std::string out = "\"";
+    for (char c : value) {
+        if (c == '"') out += '"';  // escape by doubling
+        out += c;
+    }
+    out += '"';
+    return out;
+}
+
+std::string header() { return "time,bssid,channel,rssi,security,ssid"; }
+
+std::string row(const std::string& timestamp, const ScanEntry& ap) {
+    return csvField(timestamp) + "," + csvField(ap.bssid) + "," + std::to_string(ap.channel) + "," +
+           std::to_string(ap.rssi) + "," + csvField(ap.security) + "," +
+           csvField(ap.ssid.empty() ? "(hidden)" : ap.ssid);
+}
+
+}  // namespace roro::scanlog

lib/wifi/src/scan_log.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "scan_entry.h"
+
+namespace roro {
+
+// Writes what Wi-Fi Tools already sees (access points, channel, signal) to a CSV Log, so the user
+// can track their own Wi-Fi environment over time. One row per access point per logged scan.
+namespace scanlog {
+
+// A CSV field, quoted when it contains a comma, quote or newline.
+std::string csvField(const std::string& value);
+
+// The header row (no trailing newline).
+std::string header();
+
+// One data row for an access point seen at `timestamp` (a preformatted local time string).
+std::string row(const std::string& timestamp, const ScanEntry& ap);
+
+}  // namespace scanlog
+
+// Decides when to write a scan to the Log: at most once per interval.
+class ScanLogThrottle {
+   public:
+    explicit ScanLogThrottle(uint32_t intervalMs) : intervalMs_(intervalMs) {}
+    bool due(uint32_t nowMs) const { return !logged_ || nowMs - lastMs_ >= intervalMs_; }
+    void logged(uint32_t nowMs) {
+        lastMs_ = nowMs;
+        logged_ = true;
+    }
+    void reset() { logged_ = false; }
+
+   private:
+    uint32_t intervalMs_;
+    uint32_t lastMs_ = 0;
+    bool logged_ = false;
+};
+
+}  // namespace roro