#!/bin/sh
# wifi-band-verify.sh — LOG-ONLY diagnostic. Compares UCI labels against the
# PHYSICAL band each netdev is on and records the verdict to logread.
# NEVER writes UCI: with ra0/rax0 ↔ dat binding random per boot (and band-content
# invariant keeping physical always correct), mutating UCI oscillates across
# wifi reloads. Logging the mismatch is enough — LuCI display patch (wireless.js
# getActiveSSID) makes the UI match iwinfo truth regardless of UCI labels.
# Triggered by rc.local at boot and mtwifi_cfg dispatcher tail.
# Commit-only would still be loop-safe, but useless: detection is non-deterministic
# across reloads, so any commit causes oscillation. Log-only is structurally stable.

LOCK=/tmp/wifi-band-verify.lock
NOW=$(date +%s)
if [ -f "$LOCK" ]; then
	LAST=$(cat "$LOCK" 2>/dev/null)
	[ -n "$LAST" ] && [ $((NOW - LAST)) -lt 120 ] && exit 0
fi
echo "$NOW" > "$LOCK"

log() { logger -t wifi-band-verify -- "$*"; }

get_ch()   { iwinfo "$1" info 2>/dev/null | awk '/Channel:/ {print $4}'; }
get_essid(){ iwinfo "$1" info 2>/dev/null | awk -F"\x22" '/ESSID:/ {print $2}'; }

# Phase 1: wait until both radios report identical channels on two consecutive
# 10s probes (guards against mid-init transient reads; max 18 rounds = 3min).
ra0ch=""; rax0ch=""; stable=0; i=0
while [ $i -lt 18 ]; do
	c1=$(get_ch ra0); c2=$(get_ch rax0)
	case "$c1" in ""|*[!0-9]*) c1="" ;; esac
	case "$c2" in ""|*[!0-9]*) c2="" ;; esac
	if [ -n "$c1" ] && [ -n "$c2" ] && [ "$c1" = "$ra0ch" ] && [ "$c2" = "$rax0ch" ]; then
		stable=1; break
	fi
	ra0ch=$c1; rax0ch=$c2
	i=$((i+1)); sleep 10
done
[ $stable -eq 1 ] || { log "radios not stable after 3min; skipped"; exit 0; }

# Phase 2: physical band from channel (2g ≤14, 5g ≥36)
band_of() { [ "$1" -le 14 ] && echo 2g || echo 5g; }
ra0band=$(band_of "$ra0ch"); rax0band=$(band_of "$rax0ch")
[ "$ra0band" = "$rax0band" ] && { log "both radios on $ra0band ch$ra0ch/$rax0ch; abnormal"; exit 0; }

# Phase 3: read UCI labels and live ESSIDs, log verdict — NO mutation.
uci -q get wireless.MT7981_1_1 >/dev/null || exit 0
uci -q get wireless.MT7981_1_2 >/dev/null || exit 0
u1=$(uci -q get wireless.MT7981_1_1.band)
u2=$(uci -q get wireless.MT7981_1_2.band)
s1=$(uci -q get wireless.default_MT7981_1_1.ssid)
s2=$(uci -q get wireless.default_MT7981_1_2.ssid)
e1=$(get_essid ra0); e2=$(get_essid rax0)

if [ "$u1" = "$ra0band" ] && [ "$u2" = "$rax0band" ] && [ "$s1" = "$e1" ] && [ "$s2" = "$e2" ]; then
	log "consistent: ra0=$ra0band ch$ra0ch [$e1], rax0=$rax0band ch$rax0ch [$e2]; uci=$u1/$u2"
else
	log "MISMATCH (no-op): ra0=$ra0band ch$ra0ch [$e1], rax0=$rax0band ch$rax0ch [$e2]; uci=$u1/$u2 ssid=$s1/$s2"
fi
exit 0