#!/bin/bash
set -euo pipefail

DUMP_ROOT="${DUMP_ROOT:-/mnt/user/backups/borg/dumps/latest}"
REPORT_ROOT="${REPORT_ROOT:-/mnt/user/backups/restore-reports}"
MAX_DUMP_AGE_HOURS="${MAX_DUMP_AGE_HOURS:-26}"
MAX_REPORT_AGE_DAYS="${MAX_REPORT_AGE_DAYS:-45}"

now_epoch="$(date +%s)"
critical=()
warnings=()
info=()

check_file_age_hours() {
  local path="$1"
  local mtime
  mtime="$(stat -c %Y "$path")"
  echo $(( (now_epoch - mtime) / 3600 ))
}

check_file_age_days() {
  local path="$1"
  local mtime
  mtime="$(stat -c %Y "$path")"
  echo $(( (now_epoch - mtime) / 86400 ))
}

# pg_restore --list als billiger Header-Check fuer Custom-Format-Dumps;
# erkennt Korruption, die mit reinem "exists+nonempty" durchrutscht. Wir
# brauchen kein laufendes Postgres; der Check liest nur die Toc-Section.
PG_DUMPS="postgresql17-paperless.dump postgresql17-mailarchiver.dump postgresql17-authelia.dump mealie.dump immich.dump nextcloud.dump"
is_pg_custom_dump() {
  case " $PG_DUMPS " in *" $1 "*) return 0;; *) return 1;; esac
}

pg_header_ok() {
  local path="$1"
  if ! command -v pg_restore >/dev/null 2>&1; then
    # ohne Host-pg_restore: in laufendem Postgres-Container probieren
    if command -v docker >/dev/null 2>&1 && docker inspect postgresql17 >/dev/null 2>&1; then
      if docker exec -i postgresql17 pg_restore --list < "$path" >/dev/null 2>&1; then
        return 0  # Header valide
      else
        return 1  # Header korrupt
      fi
    fi
    return 2  # nicht pruefbar (kein pg_restore, kein Container)
  fi
  pg_restore --list "$path" >/dev/null 2>&1
}

check_pg_header() {
  local dump="$1"
  local path="$2"
  local age="$3"
  local missing_mode="${4:-critical}"

  if [ ! -f "$path" ]; then
    if [ "$missing_mode" = "optional" ]; then
      info+=("DUMP_OPTIONAL_MISSING $dump")
    else
      critical+=("DUMP_MISSING $dump")
    fi
    return
  fi
  if [ ! -s "$path" ]; then
    critical+=("DUMP_EMPTY $dump")
    return
  fi
  if [ "$age" -gt "$MAX_DUMP_AGE_HOURS" ]; then
    if [ "$missing_mode" = "optional" ]; then
      warnings+=("DUMP_OPTIONAL_STALE $dump age=${age}h")
    else
      critical+=("DUMP_STALE $dump age=${age}h")
    fi
    return
  fi

  if pg_header_ok "$path"; then
    rc=0
  else
    rc=$?
  fi
  case "$rc" in
    0) info+=("DUMP_OK $dump age=${age}h header=ok") ;;
    1) critical+=("DUMP_HEADER_INVALID $dump (pg_restore --list failed)") ;;
    2) info+=("DUMP_OK $dump age=${age}h header=unchecked") ;;
  esac
}

for dump in \
  postgresql17-paperless.dump \
  postgresql17-mailarchiver.dump \
  mealie.dump \
  immich.dump \
  nextcloud.dump \
  gitea.sqlite.dump \
  vaultwarden.sqlite.dump \
  speedtest-tracker.sqlite.dump \
  filebrowser.bolt.dump \
  unraid-flash-config.tar.gz; do
  path="$DUMP_ROOT/$dump"
  if [ ! -f "$path" ]; then
    critical+=("DUMP_MISSING $dump")
    continue
  fi
  if [ ! -s "$path" ]; then
    critical+=("DUMP_EMPTY $dump")
    continue
  fi
  age="$(check_file_age_hours "$path")"
  if [ "$age" -gt "$MAX_DUMP_AGE_HOURS" ]; then
    critical+=("DUMP_STALE $dump age=${age}h")
    continue
  fi

  if is_pg_custom_dump "$dump"; then
    check_pg_header "$dump" "$path" "$age"
  else
    info+=("DUMP_OK $dump age=${age}h")
  fi
done

optional_dump="postgresql17-authelia.dump"
optional_path="$DUMP_ROOT/$optional_dump"
optional_age=0
if [ -f "$optional_path" ]; then
  optional_age="$(check_file_age_hours "$optional_path")"
fi
check_pg_header "$optional_dump" "$optional_path" "$optional_age" optional

for service in vaultwarden gitea paperless; do
  if [ ! -d "$REPORT_ROOT" ]; then
    warnings+=("REPORT_ROOT_MISSING $REPORT_ROOT")
    break
  fi

  latest="$(find "$REPORT_ROOT" -maxdepth 1 -type f -name "$service-*.md" | sort | tail -n 1 || true)"
  if [ -z "$latest" ]; then
    warnings+=("REPORT_MISSING $service")
    continue
  fi
  age="$(check_file_age_days "$latest")"
  if [ "$age" -gt "$MAX_REPORT_AGE_DAYS" ]; then
    warnings+=("REPORT_STALE $service age=${age}d file=$(basename "$latest")")
  else
    info+=("REPORT_OK $service age=${age}d file=$(basename "$latest")")
  fi
done

echo "# Restore Freshness Check"
echo
echo "Timestamp: $(date '+%F %T')"
echo "Critical: ${#critical[@]}"
echo "Warnings: ${#warnings[@]}"
echo "Info: ${#info[@]}"
echo

if [ "${#critical[@]}" -gt 0 ]; then
  echo "## Critical"
  printf -- '- %s\n' "${critical[@]}"
  echo
fi

if [ "${#warnings[@]}" -gt 0 ]; then
  echo "## Warnings"
  printf -- '- %s\n' "${warnings[@]}"
  echo
fi

if [ "${#info[@]}" -gt 0 ]; then
  echo "## Info"
  printf -- '- %s\n' "${info[@]}"
fi

[ "${#critical[@]}" -eq 0 ]