#!/usr/bin/env bash
set -euo pipefail
export LC_ALL=C

script_dir=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
compose_args=(-f "$script_dir/docker-compose.prod.yml")
if (($#)); then
  env_file=$1
  set -a
  source "$env_file"
  set +a
  compose_args=(--env-file "$env_file" "${compose_args[@]}")
fi

required=(GOCHAT_IMAGE_REF SHANGWUTONG_IMAGE_REF GOCHAT_DATABASE_DSN GOCHAT_REDIS_DSN MEILI_MASTER_KEY GOCHAT_JWT_SECRET GOCHAT_BACKUP_OFFSITE_DIR GOCHAT_BACKUP_OFFSITE_SOURCE GOCHAT_BACKUP_OFFSITE_FSTYPE)
for name in "${required[@]}"; do
  value=${!name:-}
  if [[ -z $value || ${value^^} == *CHANGE_ME* ]]; then
    echo "$name is required and must not contain CHANGE_ME" >&2
    exit 1
  fi
done

if [[ $GOCHAT_BACKUP_OFFSITE_DIR != /* ]] || [[ ! -d $GOCHAT_BACKUP_OFFSITE_DIR ]]; then
  echo "GOCHAT_BACKUP_OFFSITE_DIR must be an existing external mount point" >&2
  exit 1
fi
offsite_dir=$(realpath -e -- "$GOCHAT_BACKUP_OFFSITE_DIR")
if [[ $offsite_dir == / ]]; then
  echo "GOCHAT_BACKUP_OFFSITE_DIR must not be /" >&2
  exit 1
fi
if ! offsite_info=$(findmnt -M "$offsite_dir" -n -o SOURCE,FSTYPE,MAJ:MIN); then
  echo "GOCHAT_BACKUP_OFFSITE_DIR must be an existing external mount point" >&2
  exit 1
fi
read -r offsite_source offsite_type offsite_device <<< "$offsite_info"
if [[ $offsite_source != "$GOCHAT_BACKUP_OFFSITE_SOURCE" || $offsite_type != "$GOCHAT_BACKUP_OFFSITE_FSTYPE" ]]; then
  echo "GOCHAT_BACKUP_OFFSITE_DIR mount source/type does not match the approved values" >&2
  exit 1
fi
case $offsite_type in
  tmpfs | devtmpfs | ramfs)
    echo "GOCHAT_BACKUP_OFFSITE_DIR must not use an in-memory filesystem" >&2
    exit 1
    ;;
esac

local_probe=${GOCHAT_BACKUP_DIR:-./backups/local}
if [[ $local_probe != /* ]]; then
  local_probe=$script_dir/$local_probe
fi
while [[ ! -e $local_probe && $local_probe != / ]]; do
  local_probe=$(dirname -- "$local_probe")
done
read -r local_source local_device < <(findmnt -T "$local_probe" -n -o SOURCE,MAJ:MIN)
if [[ $offsite_source == "$local_source" || $offsite_device == "$local_device" ]]; then
  echo "GOCHAT_BACKUP_OFFSITE_DIR must use a different source/device than GOCHAT_BACKUP_DIR" >&2
  exit 1
fi

if ((${#GOCHAT_JWT_SECRET} < 32)); then
  echo "GOCHAT_JWT_SECRET must be at least 32 characters" >&2
  exit 1
fi
if ((${#MEILI_MASTER_KEY} < 16)); then
  echo "MEILI_MASTER_KEY must be at least 16 bytes" >&2
  exit 1
fi
alertmanager_webhook_file=${ALERTMANAGER_WEBHOOK_URL_FILE:-../../.secrets/alertmanager-webhook-url}
if [[ $alertmanager_webhook_file != /* ]]; then
  alertmanager_webhook_file=$script_dir/$alertmanager_webhook_file
fi
if [[ ! -r $alertmanager_webhook_file ]] || ! IFS= read -r alertmanager_webhook_url <"$alertmanager_webhook_file" || [[ ! $alertmanager_webhook_url =~ ^https://[^[:space:]]+$ ]]; then
  echo "ALERTMANAGER_WEBHOOK_URL_FILE must contain one HTTPS URL" >&2
  exit 1
fi
if [[ -n ${GOCHAT_DATABASE_DSN:-} ]]; then
  "$script_dir/database_client_entrypoint.sh" --preflight
  if [[ $GOCHAT_DATABASE_DSN == *sslrootcert=* ]]; then
    tls_gid=${GOCHAT_DATABASE_TLS_GID:-}
    if [[ ! $tls_gid =~ ^[1-9][0-9]*$ ]]; then
      echo "GOCHAT_DATABASE_TLS_GID must be set to a positive numeric group ID" >&2
      exit 1
    fi
    for name in GOCHAT_DATABASE_TLS_CA_FILE GOCHAT_DATABASE_TLS_CLIENT_CERT_FILE GOCHAT_DATABASE_TLS_CLIENT_KEY_FILE; do
      host_file=${!name:-}
      if [[ -z $host_file ]]; then
        echo "$name must be set when the database DSN uses certificate files" >&2
        exit 1
      fi
      if [[ $host_file != /* ]]; then
        host_file=$script_dir/$host_file
      fi
      if [[ ! -f $host_file ]]; then
        echo "$name must point to an existing regular file" >&2
        exit 1
      fi
      file_gid=$(stat -c %g -- "$host_file")
      file_mode=$(stat -c %a -- "$host_file")
      group_digit=${file_mode: -2:1}
      if [[ $file_gid != "$tls_gid" ]] || (((8#$group_digit & 4) == 0)); then
        echo "$name must be readable by GOCHAT_DATABASE_TLS_GID" >&2
        exit 1
      fi
    done
  fi
fi

images=$(docker compose "${compose_args[@]}" config --images)
while IFS= read -r image; do
  if [[ $image =~ @sha256:[0-9a-fA-F]{64}$ ]]; then
    continue
  fi
  echo "production image must be pinned to a sha256 digest: $image" >&2
  exit 1
done <<< "$images"
echo "production preflight passed"