#!/usr/bin/env bash
# Retry docker/buildx commands on transient network/registry/cache failures.
# Usage: retry-docker-build.sh [max_attempts] [wait_seconds] -- <command...>
set -euo pipefail

MAX="${1:-3}"
WAIT="${2:-30}"
shift 2
[[ "${1:-}" == "--" ]] && shift

if [[ $# -eq 0 ]]; then
  echo "Usage: $0 [max_attempts] [wait_seconds] -- <command...>" >&2
  exit 2
fi

is_corrupt_cache() {
  grep -qiE 'crc32 mismatch|unpigz|corrupted|failed to compute cache key' <<<"$1"
}

purge_buildx_cache() {
  echo "== purge buildx cache (all + stale builders)"
  docker buildx prune -af >/dev/null 2>&1 || true
  docker builder prune -af >/dev/null 2>&1 || true
  docker ps -aq --filter "name=buildx_buildkit" --filter "status=exited" |
    xargs -r docker rm -f >/dev/null 2>&1 || true
  docker volume ls -q | grep -E '^buildx_buildkit_.*_state$' | while read -r vol; do
    if docker ps --filter "volume=${vol}" --format '{{.ID}}' | grep -q .; then
      continue
    fi
    echo "== remove volume ${vol}"
    docker volume rm -f "${vol}" >/dev/null 2>&1 || true
  done
}

attempt=1
corrupt_seen=0
while true; do
  cmd=("$@")
  # After a corrupt-cache failure, force a clean rebuild on the last attempt.
  if (( corrupt_seen == 1 && attempt == MAX )); then
    if [[ "${cmd[*]}" == *buildx\ build* ]] && [[ "${cmd[*]}" != *--no-cache* ]]; then
      echo "== last attempt: injecting --no-cache"
      cmd+=(--no-cache)
    fi
  fi
  echo "== docker build attempt ${attempt}/${MAX}: ${cmd[*]}"
  logf="$(mktemp)"
  set +e
  "${cmd[@]}" 2>&1 | tee "${logf}"
  code=${PIPESTATUS[0]}
  set -e
  if (( code == 0 )); then
    rm -f "${logf}"
    exit 0
  fi
  log="$(cat "${logf}" 2>/dev/null || true)"
  rm -f "${logf}"
  if (( attempt >= MAX )); then
    echo "== all ${MAX} attempts failed (last exit ${code})"
    exit "${code}"
  fi
  echo "== attempt ${attempt} failed (exit ${code}), retry in ${WAIT}s..."
  if is_corrupt_cache "${log}"; then
    corrupt_seen=1
    purge_buildx_cache
  else
    docker buildx prune -f >/dev/null 2>&1 || true
  fi
  sleep "${WAIT}"
  attempt=$((attempt + 1))
done