#!/bin/bash
set -Eeuo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PLUGIN_DIR="$(cd "$SCRIPT_DIR/../.." && pwd)"
COMMON_FILE="$PLUGIN_DIR/scripts/setup/mysql_common.sh"
SETTINGS_FILE="${DA_ALT_MYSQL_SETTINGS_FILE:-$PLUGIN_DIR/plugin-settings.conf}"
LOG_FILE="${DA_ALT_MYSQL_RESTORE_LOG:-$PLUGIN_DIR/data/logs/da-restore.log}"
DA_USER=""
PAYLOAD_DIR=""
OVERWRITE_POLICY=""
RESTORE_ROLLBACK_FILE=""
RESTORE_ROLLBACK_CREATED=0

mkdir -p "$(dirname "$LOG_FILE")"

log() {
  printf '[%s] %s\n' "$(date '+%Y-%m-%d %H:%M:%S')" "$*" >> "$LOG_FILE"
}

die() {
  log "ERROR: $*"
  printf 'alt-mysql restore payload: %s\n' "$*" >&2
  exit 1
}

usage() {
  cat >&2 <<'EOF'
Usage: alt_mysql_restore_payload.sh --user DA_USER --payload /path/to/backup/alt_mysql [--overwrite allow|deny]
EOF
  exit 2
}

while [ "$#" -gt 0 ]; do
  case "$1" in
    --user) DA_USER="${2:-}"; shift 2 ;;
    --payload) PAYLOAD_DIR="${2:-}"; shift 2 ;;
    --overwrite) OVERWRITE_POLICY="${2:-}"; shift 2 ;;
    *) usage ;;
  esac
done

[ -n "$DA_USER" ] || usage
[ -n "$PAYLOAD_DIR" ] || usage
[[ "$DA_USER" =~ ^[A-Za-z0-9_][A-Za-z0-9_.-]*$ ]] || die "unsafe DirectAdmin username: $DA_USER"
[ -d "$PAYLOAD_DIR" ] || die "payload directory does not exist: $PAYLOAD_DIR"
[ -r "$COMMON_FILE" ] || die "missing helper: $COMMON_FILE"
# shellcheck source=../setup/mysql_common.sh
source "$COMMON_FILE"
mysql_load_plugin_settings_file "$SETTINGS_FILE"

read_plugin_setting() {
  local key="$1"
  local default="$2"
  local line value
  [ -r "$SETTINGS_FILE" ] || {
    printf '%s\n' "$default"
    return 0
  }
  line="$(grep -E "^${key}=" "$SETTINGS_FILE" | tail -n 1 || true)"
  [ -n "$line" ] || {
    printf '%s\n' "$default"
    return 0
  }
  value="${line#*=}"
  value="${value%%#*}"
  value="${value%\"}"
  value="${value#\"}"
  value="${value%\'}"
  value="${value#\'}"
  value="$(printf '%s' "$value" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')"
  printf '%s\n' "${value:-$default}"
}

sha256_file() {
  local file="$1"
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$file" | awk '{print $1}'
    return 0
  fi
  if command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$file" | awk '{print $1}'
    return 0
  fi
  die "missing sha256sum/shasum"
}

require_php_cli() {
  command -v php >/dev/null 2>&1 || die "php CLI is required to parse manifest.json"
}

manifest_database_rows() {
  local manifest="$1"
  php -r '
    $manifest = $argv[1];
    $data = json_decode(file_get_contents($manifest), true);
    if (!is_array($data) || ($data["format"] ?? "") !== "da-alt-mysql-v1") {
        fwrite(STDERR, "invalid manifest\n");
        exit(3);
    }
    foreach (($data["databases"] ?? []) as $db) {
        $name = (string)($db["name"] ?? "");
        $file = (string)($db["file"] ?? "");
        $sha = (string)($db["sha256"] ?? "");
        if ($name === "" || $file === "" || $sha === "") {
            fwrite(STDERR, "invalid database entry\n");
            exit(4);
        }
        echo $name, "\t", $file, "\t", $sha, "\n";
    }
  ' "$manifest"
}

safe_database_name() {
  local db="$1"
  [[ "$db" =~ ^[A-Za-z0-9_]+$ ]] || die "unsafe database name in payload: $db"
  printf '%s\n' "$db"
}

database_allowed_for_user() {
  local db="$1"
  [[ "$db" == "${DA_USER}_"* ]]
}

import_gzip_sql() {
  local database="$1"
  local file="$2"
  if [[ "$file" == *.gz ]]; then
    gunzip -c "$file" | mysql_exec "$database"
    return "${PIPESTATUS[1]}"
  fi
  mysql_exec "$database" < "$file"
}

cleanup_restore_rollback() {
  if [ -n "${RESTORE_ROLLBACK_FILE:-}" ] && [ -f "$RESTORE_ROLLBACK_FILE" ]; then
    rm -f "$RESTORE_ROLLBACK_FILE"
  fi
  RESTORE_ROLLBACK_FILE=""
  RESTORE_ROLLBACK_CREATED=0
}

backup_alt_database_for_rollback() {
  local db="$1"
  cleanup_restore_rollback
  RESTORE_ROLLBACK_FILE="$(mktemp)"

  if [ -z "$(mysql_exec mysql -Nse "SELECT 1 FROM information_schema.SCHEMATA WHERE SCHEMA_NAME='$(mysql_escape_literal "$db")' LIMIT 1" 2>>"$LOG_FILE" || true)" ]; then
    cleanup_restore_rollback
    return 0
  fi

  log "creating rollback dump: $db"
  if mysqldump_exec \
      --single-transaction \
      --quick \
      --skip-lock-tables \
      --routines \
      --triggers \
      --events \
      --default-character-set=utf8mb4 \
      "$db" > "$RESTORE_ROLLBACK_FILE" 2>>"$LOG_FILE"; then
    RESTORE_ROLLBACK_CREATED=1
    return 0
  fi

  cleanup_restore_rollback
  return 1
}

restore_alt_database_from_rollback() {
  local db="$1"
  if [ "$RESTORE_ROLLBACK_CREATED" -ne 1 ] || [ -z "${RESTORE_ROLLBACK_FILE:-}" ] || [ ! -r "$RESTORE_ROLLBACK_FILE" ]; then
    return 0
  fi

  log "restoring rollback dump: $db"
  mysql_exec mysql -e "DROP DATABASE IF EXISTS $(mysql_quote_identifier "$db");" >> "$LOG_FILE" 2>&1 || true
  mysql_exec mysql -e "CREATE DATABASE $(mysql_quote_identifier "$db") CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;" >> "$LOG_FILE" 2>&1 || true
  mysql_exec "$db" < "$RESTORE_ROLLBACK_FILE" >> "$LOG_FILE" 2>&1 || {
    log "ERROR: rollback restore failed for $db"
    return 1
  }
}

trap cleanup_restore_rollback INT TERM EXIT

metadata_cleanup_for_user() {
  local escaped_user
  escaped_user="$(mysql_escape_literal "$DA_USER")"
  mysql_exec mysql -e "DELETE FROM da_plugin_access_hosts WHERE da_user='${escaped_user}' OR role_name LIKE '${escaped_user}\\_%';"
  mysql_exec mysql -e "DELETE FROM da_plugin_grant_profiles WHERE db_name LIKE '${escaped_user}\\_%' OR role_name LIKE '${escaped_user}\\_%';"
  mysql_exec mysql -e "DELETE FROM da_plugin_database_owners WHERE db_name LIKE '${escaped_user}\\_%' OR role_name LIKE '${escaped_user}\\_%';"
}

verify_database_exists() {
  local db="$1"
  local escaped_db
  escaped_db="$(mysql_escape_literal "$db")"
  [ -n "$(mysql_exec mysql -Nse "SELECT 1 FROM information_schema.SCHEMATA WHERE SCHEMA_NAME='${escaped_db}' LIMIT 1")" ] \
    || die "database was not restored: $db"
}

sync_remote_hosts_if_enabled() {
  local allow sync_script
  allow="$(read_plugin_setting allow_remote_hosts 0)"
  [ "$allow" = "1" ] || return 0
  sync_script="$(read_plugin_setting MYSQL_PLUGIN_SUDO_SYNC_HOSTS /usr/local/directadmin/plugins/alt-mysql/scripts/setup/mysql_host_sync.sh)"
  if [ -x "$sync_script" ]; then
    "$sync_script" >> "$LOG_FILE" 2>&1 || log "WARNING: host sync failed after restore"
  fi
}

main() {
  local manifest users_file grants_file metadata_file db file rel_file expected_sha actual_sha overwrite
  manifest="$PAYLOAD_DIR/manifest.json"
  users_file="$PAYLOAD_DIR/grants/users.sql.gz"
  grants_file="$PAYLOAD_DIR/grants/grants.sql.gz"
  [ -r "$manifest" ] || die "missing manifest: $manifest"
  [ -r "$users_file" ] || die "missing users payload: $users_file"
  [ -r "$grants_file" ] || die "missing grants payload: $grants_file"

  require_php_cli
  mysql_load_alt_credentials
  mysql_ensure_metadata_schema

  overwrite="${OVERWRITE_POLICY:-$(read_plugin_setting DA_ALT_MYSQL_RESTORE_OVERWRITE allow)}"
  case "$overwrite" in
    allow|deny) ;;
    prompt) overwrite="deny" ;;
    *) overwrite="deny" ;;
  esac

  log "restore payload start: user=$DA_USER payload=$PAYLOAD_DIR overwrite=$overwrite"
  manifest_database_rows "$manifest" >/dev/null

  while IFS=$'\t' read -r db rel_file expected_sha; do
    db="$(safe_database_name "$db")"
    database_allowed_for_user "$db" || die "database $db does not match target user prefix $DA_USER"
    file="$PAYLOAD_DIR/$rel_file"
    [ -r "$file" ] || die "missing database dump: $file"
    actual_sha="$(sha256_file "$file")"
    [ "$actual_sha" = "$expected_sha" ] || die "checksum mismatch for $db"
    if [ "$overwrite" = "deny" ] && [ -n "$(mysql_exec mysql -Nse "SELECT 1 FROM information_schema.SCHEMATA WHERE SCHEMA_NAME='$(mysql_escape_literal "$db")' LIMIT 1")" ]; then
      die "target database exists and overwrite is denied: $db"
    fi
  done < <(manifest_database_rows "$manifest")

  log "restoring user definitions"
  import_gzip_sql mysql "$users_file" >> "$LOG_FILE" 2>&1 || die "cannot restore MySQL users from payload"

  metadata_cleanup_for_user

  while IFS=$'\t' read -r db rel_file expected_sha; do
    db="$(safe_database_name "$db")"
    file="$PAYLOAD_DIR/$rel_file"
    log "restoring database: $db"
    backup_alt_database_for_rollback "$db" || die "cannot create rollback dump before restoring database: $db"
    if ! mysql_exec mysql -e "DROP DATABASE IF EXISTS $(mysql_quote_identifier "$db");" >> "$LOG_FILE" 2>&1; then
      restore_alt_database_from_rollback "$db" || true
      die "cannot drop database before restore: $db"
    fi
    if ! mysql_exec mysql -e "CREATE DATABASE $(mysql_quote_identifier "$db") CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;" >> "$LOG_FILE" 2>&1; then
      restore_alt_database_from_rollback "$db" || true
      die "cannot create database before restore: $db"
    fi
    if ! import_gzip_sql "$db" "$file" >> "$LOG_FILE" 2>&1; then
      restore_alt_database_from_rollback "$db" || true
      die "cannot import database dump: $db"
    fi
    cleanup_restore_rollback
    verify_database_exists "$db"
  done < <(manifest_database_rows "$manifest")

  for metadata_file in \
    "$PAYLOAD_DIR/metadata/da_plugin_database_owners.sql.gz" \
    "$PAYLOAD_DIR/metadata/da_plugin_grant_profiles.sql.gz" \
    "$PAYLOAD_DIR/metadata/da_plugin_access_hosts.sql.gz"; do
    if [ -r "$metadata_file" ]; then
      log "restoring metadata: ${metadata_file##*/}"
      import_gzip_sql mysql "$metadata_file" >> "$LOG_FILE" 2>&1 || die "cannot restore metadata: $metadata_file"
    fi
  done

  log "restoring grants"
  import_gzip_sql mysql "$grants_file" >> "$LOG_FILE" 2>&1 || die "cannot restore grants from payload"
  mysql_exec mysql -e "FLUSH PRIVILEGES;" >> "$LOG_FILE" 2>&1 || true
  sync_remote_hosts_if_enabled

  log "restore payload completed: user=$DA_USER"
}

main "$@"