#!/usr/bin/env zsh
emulate -L zsh
setopt PIPE_FAIL
export LC_ALL=C
typeset -F SECONDS
SRC="/Volumes/MicroSD-512"
DST="/Volumes/photos library iCloud"
AUDIT="$HOME/msd512-audit"
LEDGER="$AUDIT/ledger.tsv"
HN=$(cat "$AUDIT/hash.algo")
case "$HN" in
  blake3) HASH=(b3sum) ;;
  xxh128) HASH=(xxh128sum) ;;
  *)      HASH=(shasum -a 256) ;;
esac
hash_of() { "${HASH[@]}" < "$1" | awk '{print $1}'; }

[[ -d "$SRC" ]] || { print "FATAL: SRC not mounted"; exit 1; }
[[ -d "$DST" ]] || { print "FATAL: DST not mounted"; exit 1; }
[[ -s "$AUDIT/worklist.tsv" ]] || { print "FATAL: run phase1 first"; exit 1; }
mkdir -p "$AUDIT/tmp"
touch "$LEDGER"

# already-done set (resume) and dedup oracle in memory
typeset -A DONE HASHIDX INBUNDLE
while IFS=$'\t' read -r st h sz sp dp nt; do
  [[ "$st" == "ERROR" ]] && continue
  [[ -n "$sp" ]] && DONE[$sp]=1
  [[ -n "$h" && -n "$dp" ]] && HASHIDX[$h]="$dp"
done < "$LEDGER"
while IFS=$'\t' read -r h ib p; do
  [[ -n "$h" ]] && : ${HASHIDX[$h]::="$p"}
  [[ "$ib" == "1" ]] && INBUNDLE[$h]=1
done < "$AUDIT/dst.hashes.tsv"

t0=$SECONDS; nmig=0; ndup=0; nerr=0; ncon=0; bytes=0
total=$(wc -l < "$AUDIT/worklist.tsv" | tr -d ' ')
idx=0

while IFS=$'\t' read -r s t sz; do
  idx=$(( idx + 1 ))
  [[ -n "${DONE[$s]}" ]] && continue
  [[ -d "$SRC" ]] || { print "ABORT: SRC vanished at item $idx. Re-run to resume."; break; }
  [[ -r "$s" ]] || { printf 'ERROR\t\t%d\t%s\t\tunreadable\n' "$sz" "$s" >> "$LEDGER"; nerr=$(( nerr + 1 )); continue; }

  mkdir -p "${t:h}" 2>/dev/null
  part="$t.part"
  # SINGLE READ of SRC: tee writes DST, hash consumes the same stream
  h_src=$( cat -- "$s" | tee -- "$part" | "${HASH[@]}" | awk '{print $1}' )
  rc=$?
  if [[ $rc -ne 0 || -z "$h_src" ]]; then
    rm -f -- "$part"
    printf 'ERROR\t\t%d\t%s\t\tstream rc=%d\n' "$sz" "$s" "$rc" >> "$LEDGER"
    nerr=$(( nerr + 1 )); continue
  fi

  wsz=$(stat -f %z -- "$part" 2>/dev/null)
  h_dst=$(hash_of "$part")
  if [[ "$h_src" != "$h_dst" || "$wsz" != "$sz" ]]; then
    mkdir -p "$DST/_QUARANTINE/${${t#$DST/}:h}" 2>/dev/null
    mv -f -- "$part" "$DST/_QUARANTINE/${t#$DST/}" 2>/dev/null || rm -f -- "$part"
    printf 'ERROR\t%s\t%d\t%s\t\tverify-mismatch\n' "$h_src" "$sz" "$s" >> "$LEDGER"
    nerr=$(( nerr + 1 )); continue
  fi

  # zero-byte files never dedup by hash alone
  if [[ -n "${HASHIDX[$h_src]}" && "$sz" != "0" ]]; then
    ex="${HASHIDX[$h_src]}"
    rm -f -- "$part"
    if [[ -n "${INBUNDLE[$h_src]}" ]]; then
      printf 'DEDUP_BUNDLE\t%s\t%d\t%s\t%s\tbundle-only\n' "$h_src" "$sz" "$s" "$ex" >> "$LEDGER"
      printf '%s\t%s\n' "$s" "$ex" >> "$AUDIT/in-bundle-only.tsv"
    else
      printf 'DEDUP\t%s\t%d\t%s\t%s\talready-present\n' "$h_src" "$sz" "$s" "$ex" >> "$LEDGER"
    fi
    ndup=$(( ndup + 1 )); continue
  fi

  if [[ -e "$t" ]]; then
    if [[ "$(hash_of "$t")" == "$h_src" ]]; then
      rm -f -- "$part"
      printf 'DEDUP\t%s\t%d\t%s\t%s\tidentical-at-target\n' "$h_src" "$sz" "$s" "$t" >> "$LEDGER"
      ndup=$(( ndup + 1 )); continue
    fi
    c="$DST/_CONFLICTS/${t#$DST/}"
    mkdir -p "${c:h}" 2>/dev/null
    mv -f -- "$part" "$c"
    touch -r "$s" -- "$c" 2>/dev/null
    printf 'CONFLICT\t%s\t%d\t%s\t%s\tdifferent-content-same-path\n' "$h_src" "$sz" "$s" "$c" >> "$LEDGER"
    ncon=$(( ncon + 1 )); continue
  fi

  mv -f -- "$part" "$t"
  touch -r "$s" -- "$t" 2>/dev/null
  HASHIDX[$h_src]="$t"
  printf 'MIGRATED\t%s\t%d\t%s\t%s\t\n' "$h_src" "$sz" "$s" "$t" >> "$LEDGER"
  nmig=$(( nmig + 1 )); bytes=$(( bytes + sz ))

  if (( idx % 25 == 0 )); then
    el=$(( SECONDS - t0 + 0.001 ))
    printf '[%d/%d] mig=%d dup=%d err=%d %.1f GiB @ %.2f MiB/s\n' $idx $total $nmig $ndup $nerr $(( bytes/1073741824.0 )) $(( bytes/1048576.0/el )) >> "$AUDIT/phase3.progress"
  fi
done < "$AUDIT/worklist.tsv"

el=$(( SECONDS - t0 + 0.001 ))
print "===== PHASE3 ====="
printf 'processed=%d/%d migrated=%d dedup=%d conflict=%d error=%d\n' $idx $total $nmig $ndup $ncon $nerr
printf 'copied %.1f GiB in %.2f h => %.2f MiB/s\n' $(( bytes/1073741824.0 )) $(( el/3600 )) $(( bytes/1048576.0/el ))
awk -F'\t' '$1=="ERROR"{c[$6]++} END{for(k in c) printf "ERR %d\t%s\n", c[k], k}' "$LEDGER"
tail -3 "$AUDIT/phase3.progress" 2>/dev/null