#!/bin/sh
set -eu

log() {
  printf '%s\n' "[workspace-spaces-sync] $*"
}

fail() {
  log "ERROR: $*" >&2
  exit 1
}

DATA_ROOT="${DATA_ROOT:-/data}"
S3CMD_BIN="${S3CMD_BIN:-s3cmd}"
SPACES_BUCKET="${SPACES_BUCKET-}"
SPACES_ENDPOINT="${SPACES_ENDPOINT-}"
SPACES_SYNC_INTERVAL_SECONDS="${SPACES_SYNC_INTERVAL_SECONDS:-60}"

# An unset bucket disables synchronization on platforms that provide their own
# persistent volume, including HF Spaces and suitably configured Cloud Run.
if [ -z "${SPACES_BUCKET}" ]; then
  exit 0
fi

[ -n "${SPACES_ENDPOINT}" ] || fail "SPACES_ENDPOINT is required"
[ -n "${AWS_ACCESS_KEY_ID-}" ] || fail "AWS_ACCESS_KEY_ID is required"
[ -n "${AWS_SECRET_ACCESS_KEY-}" ] || fail "AWS_SECRET_ACCESS_KEY is required"
command -v "${S3CMD_BIN}" >/dev/null 2>&1 || fail "s3cmd is not installed"

endpoint="${SPACES_ENDPOINT#https://}"
endpoint="${endpoint#http://}"
endpoint="${endpoint%/}"

case "${endpoint}" in
  ''|*[!A-Za-z0-9.-]*) fail "SPACES_ENDPOINT must be a regional hostname" ;;
esac

case "${SPACES_BUCKET}" in
  *[!a-z0-9.-]*|'') fail "SPACES_BUCKET contains unsupported characters" ;;
esac

case "${SPACES_SYNC_INTERVAL_SECONDS}" in
  ''|*[!0-9]*) fail "SPACES_SYNC_INTERVAL_SECONDS must be an integer" ;;
esac

if [ "${SPACES_SYNC_INTERVAL_SECONDS}" -lt 30 ]; then
  fail "SPACES_SYNC_INTERVAL_SECONDS must be at least 30"
fi

umask 077
config_file="$(mktemp /tmp/workspace-spaces-config.XXXXXX)"
temporary_file=''

cleanup() {
  rm -f "${config_file}"
  if [ -n "${temporary_file}" ]; then
    rm -f "${temporary_file}"
  fi
}

trap cleanup EXIT

{
  printf '%s\n' '[default]'
  printf '%s\n' 'access_key ='
  printf '%s\n' 'secret_key ='
  printf '%s\n' 'bucket_location = US'
  printf '%s\n' "host_base = ${endpoint}"
  printf '%s\n' "host_bucket = %(bucket)s.${endpoint}"
  printf '%s\n' 'use_https = True'
  printf '%s\n' 'check_ssl_certificate = True'
  printf '%s\n' 'check_ssl_hostname = True'
} > "${config_file}"

s3cmd_run() {
  "${S3CMD_BIN}" --config="${config_file}" --no-progress "$@"
}

workspace_dir="${DATA_ROOT}/workspace"
claude_dir="${DATA_ROOT}/claude"
remote_uri="s3://${SPACES_BUCKET}/latest.tar.gz"

restore_snapshot() {
  listing="$(s3cmd_run ls "${remote_uri}")" \
    || fail "Unable to check ${remote_uri}"

  if [ -z "${listing}" ]; then
    log "No existing snapshot found in ${SPACES_BUCKET}"
    return 0
  fi

  temporary_file="$(mktemp /tmp/workspace-restore.XXXXXX)"
  s3cmd_run get --force "${remote_uri}" "${temporary_file}" \
    || fail "Unable to download ${remote_uri}"

  tar -tzf "${temporary_file}" >/dev/null \
    || fail "Downloaded workspace snapshot is not a valid gzip archive"

  invalid_member="$(
    tar -tzf "${temporary_file}" \
      | awk '
          /(^|\/)\.\.($|\/)/ {
            print
            exit
          }
          $0 == "workspace" || $0 ~ /^workspace\// {
            next
          }
          $0 == "claude/projects" || $0 ~ /^claude\/projects\// {
            next
          }
          $0 == "claude/history.jsonl" {
            next
          }
          {
            print
            exit
          }
        '
  )"
  [ -z "${invalid_member}" ] \
    || fail "Workspace snapshot contains an invalid path: ${invalid_member}"

  tar --touch -C "${DATA_ROOT}" -xzf "${temporary_file}"
  rm -f "${temporary_file}"
  temporary_file=''
  log "Restored candidate snapshot from ${SPACES_BUCKET}"
}

upload_snapshot() {
  [ -d "${workspace_dir}" ] || return 0

  temporary_file="$(mktemp /tmp/workspace-snapshot.XXXXXX)"

  # Preserve the candidate's code and the minimum Claude Code state needed to
  # inspect/resume conversations. Do not archive Claude credentials, settings,
  # plugins, caches, or other reusable user configuration.
  set -- workspace
  if [ -d "${claude_dir}/projects" ]; then
    set -- "$@" claude/projects
  fi
  if [ -f "${claude_dir}/history.jsonl" ]; then
    set -- "$@" claude/history.jsonl
  fi

  if ! tar -C "${DATA_ROOT}" -czf "${temporary_file}" \
    --exclude='workspace/.venv' \
    --exclude='workspace/__pycache__' \
    --exclude='workspace/.pytest_cache' \
    --exclude='workspace/.mypy_cache' \
    --exclude='workspace/.ruff_cache' \
    --exclude='workspace/.env' \
    --exclude='workspace/.env.*' \
    --exclude='workspace/.claude' \
    --exclude='workspace/.claude.json' \
    --exclude='workspace/.openrouter' \
    --exclude='workspace/openrouter.env' \
    --exclude='workspace/.git/index.lock' \
    "$@"
  then
    log "WARNING: Workspace changed during snapshot; retrying later" >&2
    rm -f "${temporary_file}"
    temporary_file=''
    return 1
  fi

  if ! s3cmd_run put "${temporary_file}" "${remote_uri}"; then
    log "WARNING: Unable to upload workspace snapshot; retrying later" >&2
    rm -f "${temporary_file}"
    temporary_file=''
    return 1
  fi

  rm -f "${temporary_file}"
  temporary_file=''
  log "Uploaded candidate workspace and Claude transcript snapshot to ${SPACES_BUCKET}"
}

watch_snapshots() {
  stop_requested=0
  trap 'stop_requested=1' INT TERM HUP

  while [ "${stop_requested}" -eq 0 ]; do
    upload_snapshot || true

    if [ "${stop_requested}" -eq 0 ]; then
      sleep "${SPACES_SYNC_INTERVAL_SECONDS}" &
      wait "$!" || true
    fi
  done

  log "Shutdown requested; uploading final workspace snapshot"
  upload_snapshot || true
}

case "${1:-}" in
  validate)
    log "Spaces synchronization configured for candidate bucket ${SPACES_BUCKET}"
    ;;
  restore)
    restore_snapshot
    ;;
  snapshot)
    upload_snapshot
    ;;
  watch)
    watch_snapshots
    ;;
  *)
    fail "Usage: $0 {validate|restore|snapshot|watch}"
    ;;
esac