#!/bin/bash
set -Eeuo pipefail

ERROR_MSG=""
RESTORE_OK=0
DA_USER=""
DB_NAME=""
JOB_ID=""
LOG_FILE=""
RESTORE_MODE=""
SOURCE_DB_NAME=""
SOURCE_FILE=""
RESTORE_ROLLBACK_FILE=""
RESTORE_ROLLBACK_CREATED=0

JOB_FILE="${1:-}"
if [ -z "$JOB_FILE" ] || [ ! -f "$JOB_FILE" ]; then
  echo "mysql: missing job file" >&2
  exit 1
fi

PLUGIN_DIR="$(cd "$(dirname "$0")/.." && pwd)"
CONFIG_FILE="${PLUGIN_DIR}/plugin-settings.conf"
LOG_DIR="${PLUGIN_DIR}/data/logs"
COMMON_FILE="${PLUGIN_DIR}/scripts/setup/mysql_common.sh"
mkdir -p "$LOG_DIR"

urlencode() {
  local s="$1"
  local out=""
  local i c
  for ((i=0; i<${#s}; i++)); do
    c="${s:i:1}"
    case "$c" in
      [a-zA-Z0-9.~_-]) out+="$c" ;;
      ' ') out+='%20' ;;
      *) printf -v c '%%%02X' "'$c"; out+="$c" ;;
    esac
  done
  printf '%s' "$out"
}

notify_user() {
  local code="$1"
  if [ -z "${DA_USER:-}" ]; then
    return 0
  fi

  local subject message
  if [ "$code" -eq 0 ] && [ "$RESTORE_OK" -eq 1 ]; then
    subject="Przywracanie bazy MySQL zakończone pomyślnie"
    message="Przywracanie bazy ${DB_NAME} z pliku ${SOURCE_FILE:-nieznany} zakończone."
  else
    subject="Błąd przywracania bazy MySQL"
    if [ -n "$ERROR_MSG" ]; then
      message="Przywracanie bazy ${DB_NAME} nie powiodło się: ${ERROR_MSG}"
    else
      message="Przywracanie bazy ${DB_NAME} nie powiodło się. Sprawdź log zadania."
    fi
  fi

  local task_queue="/usr/local/directadmin/data/task.queue"
  local users="select1%3D$(urlencode "$DA_USER")"
  local line="action=notify&value=users&subject=$(urlencode "$subject")&message=$(urlencode "$message")&users=${users}"
  printf "%s\n" "$line" >> "$task_queue"
}

fail() {
  local msg="$1"
  ERROR_MSG="$msg"
  if [ -n "${LOG_FILE:-}" ]; then
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] ERROR: ${msg}" >> "$LOG_FILE"
  fi
}

log_unexpected_error() {
  local line_no="$1"
  local command="$2"
  local code="$3"
  if [ -z "${LOG_FILE:-}" ]; then
    return 0
  fi
  if [ -n "${ERROR_MSG:-}" ]; then
    return 0
  fi

  ERROR_MSG="Nieoczekiwany błąd wykonywania przywracania (kod ${code}, linia ${line_no})."
  echo "[$(date '+%Y-%m-%d %H:%M:%S')] ERROR: ${ERROR_MSG} CMD: ${command}" >> "$LOG_FILE"
}

load_plugin_settings() {
  if [ ! -f "$CONFIG_FILE" ]; then
    fail "Brak pliku konfiguracyjnego pluginu: $CONFIG_FILE"
    exit 1
  fi
  # shellcheck disable=SC1090
  source "$CONFIG_FILE"
}

sanitize_mysql_dump() {
  awk '
    function lower(s) { return tolower(s) }
    {
      line = $0
      l = lower(line)
      if (l ~ /^[[:space:]]*create[[:space:]]+database[[:space:]]+/) { next }
      if (l ~ /^[[:space:]]*drop[[:space:]]+database[[:space:]]+/) { next }
      if (l ~ /^[[:space:]]*use[[:space:]]+[`"]/ ) { next }
      if (l ~ /^[[:space:]]*use[[:space:]]+[a-z0-9_]+[[:space:]]*;/) { next }
      print line
    }
  '
}

preclean_database() {
  local db_name="$1"
  local current_charset=""
  local current_collation=""

  current_charset="$(mysql_exec mysql -Nse "SELECT DEFAULT_CHARACTER_SET_NAME FROM information_schema.SCHEMATA WHERE SCHEMA_NAME = '${db_name}'" 2>>"$LOG_FILE" || true)"
  current_collation="$(mysql_exec mysql -Nse "SELECT DEFAULT_COLLATION_NAME FROM information_schema.SCHEMATA WHERE SCHEMA_NAME = '${db_name}'" 2>>"$LOG_FILE" || true)"
  [ -n "$current_charset" ] || current_charset="utf8mb4"
  [ -n "$current_collation" ] || current_collation="utf8mb4_unicode_ci"

  echo "[$(date '+%Y-%m-%d %H:%M:%S')] Recreating database ${db_name} before restore" >> "$LOG_FILE"
  mysql_exec mysql -e "DROP DATABASE IF EXISTS $(mysql_quote_identifier "$db_name");" >> "$LOG_FILE" 2>&1
  mysql_exec mysql -e "CREATE DATABASE $(mysql_quote_identifier "$db_name") CHARACTER SET ${current_charset} COLLATE ${current_collation};" >> "$LOG_FILE" 2>&1
}

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

backup_alt_database_for_rollback() {
  local db_name="$1"
  RESTORE_ROLLBACK_FILE="$(mktemp)"
  RESTORE_ROLLBACK_CREATED=0

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

  echo "[$(date '+%Y-%m-%d %H:%M:%S')] Creating rollback dump for ${db_name}" >> "$LOG_FILE"
  if mysqldump_exec \
      --single-transaction \
      --quick \
      --skip-lock-tables \
      --routines \
      --triggers \
      --events \
      --default-character-set=utf8mb4 \
      "$db_name" > "$RESTORE_ROLLBACK_FILE" 2>>"$LOG_FILE"; then
    RESTORE_ROLLBACK_CREATED=1
    return 0
  fi

  rm -f "$RESTORE_ROLLBACK_FILE"
  RESTORE_ROLLBACK_FILE=""
  return 1
}

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

  echo "[$(date '+%Y-%m-%d %H:%M:%S')] Restoring rollback dump for ${db_name}" >> "$LOG_FILE"
  mysql_exec mysql -e "DROP DATABASE IF EXISTS $(mysql_quote_identifier "$db_name");" >> "$LOG_FILE" 2>&1 || true
  mysql_exec mysql -e "CREATE DATABASE $(mysql_quote_identifier "$db_name") CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;" >> "$LOG_FILE" 2>&1 || true
  mysql_exec "$db_name" < "$RESTORE_ROLLBACK_FILE" >> "$LOG_FILE" 2>&1 || {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] ERROR: rollback restore failed for ${db_name}" >> "$LOG_FILE"
    return 1
  }
}

quote_sh_value() {
  local value="$1"
  value="${value//\'/\'\\\'\'}"
  printf "'%s'" "$value"
}

set_job_var() {
  local key="$1"
  local value="$2"
  local tmp
  local owner_group=""
  if [ -f "$JOB_FILE" ]; then
    owner_group="$(stat -c '%u:%g' "$JOB_FILE" 2>/dev/null || stat -f '%u:%g' "$JOB_FILE" 2>/dev/null || true)"
  fi
  tmp="$(mktemp)"
  grep -v "^${key}=" "$JOB_FILE" > "$tmp" 2>/dev/null || true
  printf "%s=%s\n" "$key" "$(quote_sh_value "$value")" >> "$tmp"
  mv "$tmp" "$JOB_FILE"
  chmod 600 "$JOB_FILE" 2>/dev/null || true
  if [ "$(id -u)" -eq 0 ] && [ -n "$owner_group" ]; then
    chown "$owner_group" "$JOB_FILE" 2>/dev/null || true
  fi
}

on_exit() {
  local code="$1"
  if [ "$code" -ne 0 ] && [ -z "${ERROR_MSG:-}" ] && [ -n "${LOG_FILE:-}" ]; then
    ERROR_MSG="Zadanie przywracania zakończyło się błędem (kod ${code}) bez zarejestrowanego szczegółu."
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] ERROR: ${ERROR_MSG}" >> "$LOG_FILE"
  fi
  notify_user "$code"
}
trap 'log_unexpected_error "$LINENO" "$BASH_COMMAND" "$?"' ERR
trap cleanup_restore_rollback INT TERM
trap 'code=$?; cleanup_restore_rollback; on_exit "$code"' EXIT

[ -f "$COMMON_FILE" ] || {
  echo "Brak helpera MySQL: $COMMON_FILE" >&2
  exit 1
}
# shellcheck disable=SC1090
source "$COMMON_FILE"

# shellcheck disable=SC1090
source "$JOB_FILE"

JOB_ID="${JOB_ID:-$(basename "$JOB_FILE" .env)}"
DA_USER="${DA_USER:-}"
DB_NAME="${DB_NAME:-}"
RESTORE_MODE="${RESTORE_MODE:-overwrite}"
SOURCE_DB_NAME="${SOURCE_DB_NAME:-}"
SOURCE_FILE="${SOURCE_FILE:-}"

LOG_FILE="${LOG_DIR}/${JOB_ID}.log"
echo "[$(date '+%Y-%m-%d %H:%M:%S')] Start restore job ${JOB_ID}" > "$LOG_FILE"

if [ -z "$DA_USER" ] || [ -z "$DB_NAME" ] || [ -z "$SOURCE_FILE" ]; then
  fail "Brak DA_USER, DB_NAME lub SOURCE_FILE w pliku zadania."
  exit 1
fi

if [[ "$DB_NAME" != "${DA_USER}_"* ]]; then
  fail "Baza ${DB_NAME} nie należy do użytkownika ${DA_USER}."
  exit 1
fi

if [ ! -r "$SOURCE_FILE" ]; then
  fail "Nie można odczytać pliku źródłowego: ${SOURCE_FILE}"
  exit 1
fi

load_plugin_settings
mysql_load_alt_credentials
MYSQL_BIN="$(mysql_alt_binary mysql)" || {
  fail "Brak binarium mysql."
  exit 1
}

if [ -z "$(mysql_exec mysql -Nse "SELECT 1 FROM information_schema.SCHEMATA WHERE SCHEMA_NAME = '${DB_NAME}'" 2>>"$LOG_FILE" || true)" ]; then
  fail "Docelowa baza danych nie istnieje: ${DB_NAME}"
  exit 1
fi

if ! backup_alt_database_for_rollback "$DB_NAME"; then
  fail "Nie udało się utworzyć kopii rollback przed przywracaniem bazy ${DB_NAME}."
  exit 1
fi

if ! preclean_database "$DB_NAME"; then
  restore_alt_database_from_rollback "$DB_NAME" || true
  fail "Nie udało się przygotować bazy ${DB_NAME} do importu; przywrócono kopię rollback, jeśli była dostępna."
  exit 1
fi

echo "[$(date '+%Y-%m-%d %H:%M:%S')] Restore source file: ${SOURCE_FILE}" >> "$LOG_FILE"
if [ -n "$SOURCE_DB_NAME" ]; then
  echo "[$(date '+%Y-%m-%d %H:%M:%S')] Restore source DB label: ${SOURCE_DB_NAME}" >> "$LOG_FILE"
fi
echo "[$(date '+%Y-%m-%d %H:%M:%S')] Restore target DB: ${DB_NAME}" >> "$LOG_FILE"

set +e
if [[ "$SOURCE_FILE" == *.gz ]]; then
  gunzip -c "$SOURCE_FILE" | sanitize_mysql_dump | mysql_exec "$DB_NAME" >> "$LOG_FILE" 2>&1
  RC=${PIPESTATUS[2]}
else
  sanitize_mysql_dump < "$SOURCE_FILE" | mysql_exec "$DB_NAME" >> "$LOG_FILE" 2>&1
  RC=${PIPESTATUS[1]}
fi
set -e

if [ "$RC" -ne 0 ]; then
  restore_alt_database_from_rollback "$DB_NAME" || true
  fail "Import pliku ${SOURCE_FILE} do bazy ${DB_NAME} zakończył się błędem."
  exit 1
fi

set_job_var "END_TS" "$(date +%s)"
echo "[$(date '+%Y-%m-%d %H:%M:%S')] Restore completed successfully." >> "$LOG_FILE"
RESTORE_OK=1
exit 0