#!/bin/sh
# fptrial.sh -- a labelled verification protocol against fingerprintd.
#
#   fptrial.sh [correct_presses] [wrong_presses]   defaults 15 and 0
#
# Runs fprintd-verify once per press and tells you which finger to use before
# each one. The daemon's transcript records every frame; THIS records the label
# and the wall-clock time from "press now" to the client seeing a result, which
# is the latency a user feels. Unlabelled runs cannot be turned into a rate.
#
# HOLD, DO NOT TAP -- and this script said the opposite for its whole life,
# which quietly made every rate this project has ever quoted a worst case.
#
# Jorijn, 2026-09-05: "press and LIFT (quick tap) is wrong, holding the sensor
# until it gives the result is a 100% success rate." The logs agree and say why.
# Same template, same session, learning off, only the technique differing:
#
#   tapped   4/15 and 3/15
#   held    15/15 and 15/15
#
# The mechanism is in the frame metrics. A tap is caught while the finger is
# still arriving or already leaving, and such a frame matched 0 times in 53;
# with the rescan budget at 0 that rejection is terminal and ends the press. A
# held finger yields a full-contact frame, and those match.
#
# It is also what a real user does: nobody taps a phone's fingerprint sensor and
# walks away, they rest a finger until it unlocks. Measuring taps was measuring
# a case the product does not have.
C=${1:-15}; W=${2:-0}
OUT=/tmp/fptrial-$(date +%Y%m%d-%H%M%S).log
now() { awk '{gsub(/\./,""); print $1 "0000000"}' /proc/uptime; }
run() {  # $1 = label
    printf '\n>>> %s -- press and HOLD until it answers ... ' "$1"
    t0=$(now)
    res=$(timeout 20 fprintd-verify user 2>&1 | grep -E 'Verify result' | tail -1)
    t1=$(now)
    ms=$(( (t1 - t0) / 1000000 ))
    verdict=$(printf '%s' "$res" | grep -oE 'verify-(match|no-match|unknown-error)' || echo timeout)
    printf '%s  (%d ms)\n' "$verdict" "$ms"
    printf '%s %s %d\n' "$1" "$verdict" "$ms" >> "$OUT"
    sleep 1
}
echo "labelled trial -> $OUT"
i=1; while [ $i -le $C ]; do run "CORRECT $i/$C"; i=$((i+1)); done
# The wrong-finger half is skippable, and skipping it is the right default once
# the question it answers is settled. Across every run this project has made the
# wrong finger has matched ZERO times out of forty-odd taps; the open question
# is the FALSE NEGATIVE rate, and each wrong-finger tap spends a press that
# could have measured that instead. Pass a count to put the control back.
if [ "$W" -gt 0 ]; then
    echo; echo "===== now switch to a DIFFERENT finger ====="; sleep 3
    i=1; while [ $i -le $W ]; do run "WRONG $i/$W"; i=$((i+1)); done
fi
echo
echo "===== summary ====="
awk '$1=="CORRECT"{c++; if($3=="verify-match")cm++; ct+=$4}
     $1=="WRONG"  {w++; if($3=="verify-match")wm++; wt+=$4}
     END{printf "  correct finger: %d/%d matched  (false negatives %d)  mean %d ms\n", cm,c,c-cm,(c?ct/c:0);
         if (w) printf "  wrong finger:   %d/%d matched  (false ACCEPTS %d)   mean %d ms\n", wm,w,wm,wt/w;
         else   printf "  wrong finger:   not run this trial\n"}' "$OUT"
echo "  per-tap log: $OUT"