#!/bin/bash
set -Eeuo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PLUGIN_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
COMMON_FILE="$SCRIPT_DIR/mysql_common.sh"

NATIVE_MY_CNF="${NATIVE_MY_CNF:-/etc/my.cnf}"
NATIVE_MY_CNF_D="${NATIVE_MY_CNF_D:-/etc/my.cnf.d}"
NATIVE_MYSQL_CONF="${NATIVE_MYSQL_CONF:-/usr/local/directadmin/conf/mysql.conf}"
CUSTOMBUILD_OPTIONS_CONF="${CUSTOMBUILD_OPTIONS_CONF:-/usr/local/directadmin/custombuild/options.conf}"
NEW_NATIVE_PORT="${NEW_NATIVE_PORT:-3307}"
DA_CLI_BIN="${DA_CLI_BIN:-da}"
OS_RELEASE_FILE="${OS_RELEASE_FILE:-/etc/os-release}"

LOG_FILE="${NATIVE_TAKEOVER_LOG:-$PLUGIN_DIR/data/logs/native-port-takeover.log}"
mkdir -p "$(dirname "$LOG_FILE")" 2>/dev/null || true

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

die() {
  log "ERROR: $*"
  printf '[BŁĄD] %s\n' "$*" >&2
  exit 1
}

# --- state populated by the detection functions, consumed by later steps ---
NATIVE_CURRENT_PORT=""
NATIVE_CURRENT_SOCKET=""
NATIVE_CURRENT_HOST=""
NATIVE_CURRENT_USER=""
NATIVE_CURRENT_PASS=""
NATIVE_CURRENT_MYSQL_INST=""

require_root() {
  [ "$(id -u)" -eq 0 ] || die "Ten skrypt musi zostać uruchomiony jako root."
}

check_os_guard() {
  [ -r "$OS_RELEASE_FILE" ] || die "Nie można odczytać $OS_RELEASE_FILE."
  local os_id="" os_version=""
  os_id="$(awk -F= '$1=="ID"{gsub(/"/,"",$2); print $2}' "$OS_RELEASE_FILE")"
  os_version="$(awk -F= '$1=="VERSION_ID"{gsub(/"/,"",$2); print $2}' "$OS_RELEASE_FILE")"

  [ "$os_id" = "almalinux" ] || die "Ten skrypt obsługuje wyłącznie AlmaLinux 8/9 (wykryto: ${os_id:-nieznany})."
  case "$os_version" in
    8*|9*) ;;
    *) die "Ten skrypt obsługuje wyłącznie AlmaLinux 8/9 (wykryto wersję: ${os_version:-nieznana})." ;;
  esac
  log "Wykryto obsługiwany system: AlmaLinux $os_version."
}

read_native_mysql_conf() {
  [ -r "$NATIVE_MYSQL_CONF" ] || die "Nie znaleziono pliku $NATIVE_MYSQL_CONF."
  NATIVE_CURRENT_USER="$(mysql_read_key_value "$NATIVE_MYSQL_CONF" user || true)"
  NATIVE_CURRENT_PASS="$(mysql_read_key_value "$NATIVE_MYSQL_CONF" passwd || true)"
  NATIVE_CURRENT_PORT="$(mysql_read_key_value "$NATIVE_MYSQL_CONF" port || true)"
  NATIVE_CURRENT_SOCKET="$(mysql_read_key_value "$NATIVE_MYSQL_CONF" socket || true)"
  NATIVE_CURRENT_HOST="$(mysql_read_key_value "$NATIVE_MYSQL_CONF" host || true)"
  [ -n "$NATIVE_CURRENT_USER" ] || die "Nie udało się odczytać pola user z $NATIVE_MYSQL_CONF."
  [ -n "$NATIVE_CURRENT_PORT" ] || die "Nie udało się odczytać pola port z $NATIVE_MYSQL_CONF."
}

read_current_mysql_inst() {
  [ -r "$CUSTOMBUILD_OPTIONS_CONF" ] || die "Nie znaleziono pliku $CUSTOMBUILD_OPTIONS_CONF."
  NATIVE_CURRENT_MYSQL_INST="$(mysql_read_key_value "$CUSTOMBUILD_OPTIONS_CONF" mysql_inst || true)"
  [ -n "$NATIVE_CURRENT_MYSQL_INST" ] || die "Nie udało się odczytać mysql_inst z $CUSTOMBUILD_OPTIONS_CONF."
  log "Bieżąca wartość mysql_inst: $NATIVE_CURRENT_MYSQL_INST."
}

already_migrated() {
  [ "$NATIVE_CURRENT_PORT" != "3306" ]
}

check_native_reachable() {
  local bin
  bin="$(mysql_detect_binary mysql)" || die "Nie znaleziono klienta mysql/mariadb do sprawdzenia natywnej instancji."
  MYSQL_PWD="$NATIVE_CURRENT_PASS" "$bin" \
    --user="$NATIVE_CURRENT_USER" \
    --protocol=TCP --host=127.0.0.1 --port="$NATIVE_CURRENT_PORT" \
    -e "SELECT 1" >/dev/null 2>>"$LOG_FILE" \
    || die "Natywna instancja MariaDB nie odpowiada na porcie $NATIVE_CURRENT_PORT z bieżącymi poświadczeniami."
  log "Natywna instancja MariaDB odpowiada na porcie $NATIVE_CURRENT_PORT."
}

port_is_listening() {
  local port="$1"
  if command -v ss >/dev/null 2>&1; then
    ss -ltn "( sport = :$port )" 2>/dev/null | awk 'NR > 1 { found=1 } END { exit !found }'
    return $?
  fi
  if command -v lsof >/dev/null 2>&1; then
    lsof -nP -iTCP:"$port" -sTCP:LISTEN >/dev/null 2>&1
    return $?
  fi
  log "Nie znaleziono ss ani lsof - zakładam, że port $port jest wolny."
  return 1
}

preflight_new_port_free() {
  if port_is_listening "$NEW_NATIVE_PORT"; then
    die "Port $NEW_NATIVE_PORT jest już zajęty. Zmień NEW_NATIVE_PORT i spróbuj ponownie."
  fi
  log "Port docelowy $NEW_NATIVE_PORT jest wolny."
}

DID_SET_MYSQL_INST_NO=0
CONFIG_BACKUPS=()

disable_custombuild_mysql_management() {
  if [ "$NATIVE_CURRENT_MYSQL_INST" = "no" ]; then
    log "mysql_inst jest już ustawione na 'no' - pomijam."
    return 0
  fi
  "$DA_CLI_BIN" build set mysql_inst no >>"$LOG_FILE" 2>&1 \
    || die "Nie udało się ustawić mysql_inst=no przez '$DA_CLI_BIN build set mysql_inst no'."
  DID_SET_MYSQL_INST_NO=1
  log "Ustawiono mysql_inst=no przez CustomBuild."
}

restore_custombuild_mysql_management() {
  [ "$DID_SET_MYSQL_INST_NO" -eq 1 ] || return 0
  "$DA_CLI_BIN" build set mysql_inst "$NATIVE_CURRENT_MYSQL_INST" >>"$LOG_FILE" 2>&1 \
    || log "OSTRZEŻENIE: nie udało się przywrócić mysql_inst=$NATIVE_CURRENT_MYSQL_INST."
  log "Przywrócono mysql_inst=$NATIVE_CURRENT_MYSQL_INST."
}

backup_config_file() {
  local file="$1"
  local backup
  backup="${file}.bak.$(date +%Y%m%d%H%M%S)"
  cp -a "$file" "$backup"
  CONFIG_BACKUPS+=("$file:$backup")
  log "Utworzono kopię zapasową $file jako $backup."
}

rewrite_port_in_file() {
  local file="$1" new_port="$2"
  local tmp changed=0

  [ -r "$file" ] || return 1
  tmp="$(mktemp)"

  awk -v new_port="$new_port" '
    BEGIN { in_section = 0; changed = 0 }
    /^[[:space:]]*\[[^]]+\][[:space:]]*$/ {
      section = tolower($0)
      gsub(/^[[:space:]]*\[[[:space:]]*/, "", section)
      gsub(/[[:space:]]*\][[:space:]]*$/, "", section)
      in_section = (section == "mysqld" || section == "mariadb" || section == "server")
      print
      next
    }
    in_section && /^[[:space:]]*port[[:space:]]*=/ {
      print "port=" new_port
      changed = 1
      next
    }
    { print }
    END { if (changed) exit 0; else exit 1 }
  ' "$file" > "$tmp"
  local awk_status=$?

  if [ "$awk_status" -eq 0 ]; then
    cp "$tmp" "$file"
    changed=1
  fi
  rm -f "$tmp"
  [ "$changed" -eq 1 ]
}

find_and_rewrite_native_port_configs() {
  local any_changed=0
  local f

  for f in "$NATIVE_MY_CNF" "$NATIVE_MY_CNF_D"/*.cnf; do
    [ -f "$f" ] || continue
    if grep -Eq '^[[:space:]]*port[[:space:]]*=[[:space:]]*3306[[:space:]]*$' "$f"; then
      backup_config_file "$f"
      if rewrite_port_in_file "$f" "$NEW_NATIVE_PORT"; then
        any_changed=1
        log "Zaktualizowano port w $f."
      fi
    fi
  done

  if [ "$any_changed" -eq 0 ]; then
    backup_config_file "$NATIVE_MY_CNF"
    if grep -Eq '^[[:space:]]*\[mysqld\][[:space:]]*$' "$NATIVE_MY_CNF"; then
      awk -v new_port="$NEW_NATIVE_PORT" '
        { print }
        /^[[:space:]]*\[mysqld\][[:space:]]*$/ && !done { print "port=" new_port; done=1 }
      ' "$NATIVE_MY_CNF" > "${NATIVE_MY_CNF}.tmp" && mv "${NATIVE_MY_CNF}.tmp" "$NATIVE_MY_CNF"
    else
      printf '\n[mysqld]\nport=%s\n' "$NEW_NATIVE_PORT" >> "$NATIVE_MY_CNF"
    fi
    log "Brak istniejącej dyrektywy port= w sekcji serwera - dodano port=$NEW_NATIVE_PORT do $NATIVE_MY_CNF."
  fi
}

update_native_mysql_conf_port() {
  local target_port="$1"
  local tmp
  tmp="$(mktemp)"
  awk -v new_port="$target_port" '
    BEGIN { done = 0 }
    /^[[:space:]]*port[[:space:]]*=/ { print "port=" new_port; done=1; next }
    { print }
    END { if (!done) print "port=" new_port }
  ' "$NATIVE_MYSQL_CONF" > "$tmp"
  cp "$tmp" "$NATIVE_MYSQL_CONF"
  rm -f "$tmp"
}

apply_config_mutations() {
  backup_config_file "$NATIVE_MYSQL_CONF"
  find_and_rewrite_native_port_configs
  update_native_mysql_conf_port "$NEW_NATIVE_PORT"
  log "Zaktualizowano $NATIVE_MYSQL_CONF na port $NEW_NATIVE_PORT."
}

rollback_config_changes() {
  local pair file backup
  for pair in "${CONFIG_BACKUPS[@]}"; do
    file="${pair%%:*}"
    backup="${pair#*:}"
    if [ -r "$backup" ]; then
      cp -a "$backup" "$file"
      log "Przywrócono $file z kopii zapasowej $backup."
    fi
  done
}

NATIVE_SERVICE_NAME=""
DID_RESTART_NATIVE=0
DID_RESTART_DA=0
# Guards rollback_service_state so it only acts while wired via the EXIT trap
# below. NOTE: this is intentionally an EXIT trap, not an ERR trap - see the
# comment above the trap installation in main() for why.
ROLLBACK_ARMED=0

detect_native_service_name() {
  NATIVE_SERVICE_NAME="$(mysql_service_name)"
  log "Wykryta usługa natywnej MariaDB: $NATIVE_SERVICE_NAME."
}

restart_native_service() {
  systemctl restart "$NATIVE_SERVICE_NAME" || die "Nie udało się zrestartować usługi $NATIVE_SERVICE_NAME."
  DID_RESTART_NATIVE=1
}

verify_native_listening_new_port() {
  local i
  for i in $(seq 1 30); do
    if port_is_listening "$NEW_NATIVE_PORT" && ! port_is_listening 3306; then
      log "Natywna instancja nasłuchuje na porcie $NEW_NATIVE_PORT, port 3306 wolny."
      return 0
    fi
    sleep 1
  done
  die "Natywna instancja nie nasłuchuje na porcie $NEW_NATIVE_PORT po restarcie (lub port 3306 wciąż zajęty)."
}

restart_directadmin_service() {
  systemctl restart directadmin || die "Nie udało się zrestartować usługi directadmin."
  DID_RESTART_DA=1
}

verify_da_connectivity_new_port() {
  local bin
  bin="$(mysql_detect_binary mysql)" || die "Nie znaleziono klienta mysql/mariadb do weryfikacji łączności DA."
  MYSQL_PWD="$NATIVE_CURRENT_PASS" "$bin" \
    --user="$NATIVE_CURRENT_USER" \
    --protocol=TCP --host=127.0.0.1 --port="$NEW_NATIVE_PORT" \
    -e "SELECT 1" >/dev/null 2>>"$LOG_FILE" \
    || die "DirectAdmin nie może połączyć się z natywną instancją na nowym porcie $NEW_NATIVE_PORT."
  log "Potwierdzono łączność DirectAdmina z natywną instancją na porcie $NEW_NATIVE_PORT."
}

rollback_service_state() {
  [ "$ROLLBACK_ARMED" -eq 1 ] || return 0
  rollback_config_changes
  restore_custombuild_mysql_management
  if [ -n "$NATIVE_SERVICE_NAME" ]; then
    systemctl restart "$NATIVE_SERVICE_NAME" \
      || log "OSTRZEŻENIE: nie udało się zrestartować $NATIVE_SERVICE_NAME podczas wycofywania zmian."
  fi
  if [ "$DID_RESTART_DA" -eq 1 ]; then
    systemctl restart directadmin \
      || log "OSTRZEŻENIE: nie udało się zrestartować directadmin podczas wycofywania zmian."
  fi
  log "Wycofano zmiany przejęcia portu natywnej instancji MariaDB."
}

main() {
  require_root
  check_os_guard
  read_native_mysql_conf
  read_current_mysql_inst

  if already_migrated; then
    log "Natywna instancja już działa na porcie $NATIVE_CURRENT_PORT (nie 3306) - pomijam przejęcie."
    exit 0
  fi

  check_native_reachable
  preflight_new_port_free
  detect_native_service_name

  # NOTE: deliberately an EXIT trap, not an ERR trap as originally planned.
  # die() (used by every failure path below) calls `exit` directly, and bash's
  # ERR trap does not fire for a function that terminates via an explicit
  # `exit` call - it only fires when a command's non-zero status propagates
  # through normal control flow. An EXIT trap fires on *any* shell exit
  # (explicit exit, errexit-triggered exit, or falling off the end of the
  # script), which is what "any failure from this point on triggers
  # rollback" actually requires here. ROLLBACK_ARMED guards it so it is a
  # no-op before this point and after a successful run.
  ROLLBACK_ARMED=1
  trap 'rollback_service_state' EXIT

  disable_custombuild_mysql_management
  apply_config_mutations
  restart_native_service
  verify_native_listening_new_port
  restart_directadmin_service
  verify_da_connectivity_new_port

  ROLLBACK_ARMED=0
  trap - EXIT
  log "Przejęcie portu natywnej instancji MariaDB zakończone powodzeniem: $NATIVE_CURRENT_PORT -> $NEW_NATIVE_PORT."
}

[ -r "$COMMON_FILE" ] || die "missing helper: $COMMON_FILE"
# shellcheck source=./mysql_common.sh
source "$COMMON_FILE"

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
  main "$@"
fi