#!/usr/bin/env zsh
emulate -L zsh
export LC_ALL=C
AUDIT="$HOME/msd512-audit"
LEDGER="$AUDIT/ledger.tsv"
SM="$AUDIT/src.manifest.tsv"

src_total=$(wc -l < "$SM" | tr -d ' ')
awk -F'\t' '{c[$1]++} END{for(k in c) printf "%s\t%d\n", k, c[k]}' "$LEDGER" | sort > "$AUDIT/status.counts.tsv"
acct=$(awk -F'\t' '{print $4}' "$LEDGER" | sort -u | wc -l | tr -d ' ')

cut -f4 "$LEDGER" | sort -u > "$AUDIT/accounted.txt"
cut -f3 "$SM" | sort -u > "$AUDIT/all.src.txt"
comm -23 "$AUDIT/all.src.txt" "$AUDIT/accounted.txt" > "$AUDIT/unaccounted.tsv"

# integrity spot check: re-hash 1% of migrated files at DST
HN=$(cat "$AUDIT/hash.algo")
case "$HN" in blake3) HASH=(b3sum);; xxh128) HASH=(xxh128sum);; *) HASH=(shasum -a 256);; esac
awk -F'\t' '$1=="MIGRATED"{print $2"\t"$5}' "$LEDGER" | awk 'NR%100==1' > "$AUDIT/spot.list"
bad=0; n=0
while IFS=$'\t' read -r h p; do
  n=$(( n + 1 ))
  a=$("${HASH[@]}" < "$p" 2>/dev/null | awk '{print $1}')
  [[ "$a" == "$h" ]] || { bad=$(( bad + 1 )); print "SPOTFAIL\t$p" >> "$AUDIT/spot.fail.tsv"; }
done < "$AUDIT/spot.list"

# delete candidates: SRC files with a verified DST twin (REVIEW ONLY, never executed)
awk -F'\t' '$1=="MIGRATED"||$1=="DEDUP"{printf "%s\t%s\t%s\n", $4, $5, $2}' "$LEDGER" > "$AUDIT/delete-candidates.tsv"

print "===== PHASE4 ====="
printf 'src files=%d accounted=%d unaccounted=%d\n' $src_total $acct "$(wc -l < "$AUDIT/unaccounted.tsv" | tr -d ' ')"
cat "$AUDIT/status.counts.tsv"
printf 'spot-check: %d re-hashed, %d mismatches\n' $n $bad
awk -F'\t' '$1=="MIGRATED"{b+=$3} END{printf "migrated bytes: %.1f GiB\n", b/1073741824}' "$LEDGER"
printf 'delete-candidates: %s files (REVIEW ONLY)\n' "$(wc -l < "$AUDIT/delete-candidates.tsv" | tr -d ' ')"
head -5 "$AUDIT/unaccounted.tsv"