#!/bin/bash

set -o pipefail

CASSANDRA_CONF_DIR="/etc/cassandra/"
CASSANDRA_CONF_FILE="cassandra.yaml"

HOSTNAME=$(cat /proc/sys/kernel/hostname)
#IP_ADDRESS=$(cat /etc/hosts | grep $HOSTNAME | awk '{print $1}' | head -n 1)

# update cassandra config file (cassandra.yaml) based on the environment varibales
# set by the user
function save_env_config_vars() {
  # check whether the user mounted in his own config file
  CONFIG_OWNER=$(ls -l "$CASSANDRA_CONF_DIR" | grep "$CASSANDRA_CONF_FILE" | awk '{print $3}')

  if [ "$CONFIG_OWNER" == "cassandra" ]; then
    # set the seeds for succesfull gossip initialization
    # if the seeds were not set as the environment variable
    if [ -z "$CASSANDRA_SEEDS" ]; then
      # get the ip-address that the cassandra server is going to run on
      #CASSANDRA_SEEDS=$(cassandra -f 2>/dev/null | grep :7000 | cut -d'/' -f2 | cut -d':' -f1)

      # get the hostname of the machine that the cassandra server is going to run on
      CASSANDRA_SEEDS="$HOSTNAME"
    fi

    # alter the seeds in the config file
    sed -ri 's/(- seeds:).*/\1 "'"$CASSANDRA_SEEDS"'"/' "$CASSANDRA_CONF_DIR$CASSANDRA_CONF_FILE"

    for yaml in \
      cluster_name \
      disk_optimization_strategy \
      endpoint_snitch \
      num_tokens \
      rpc_address \
      key_cache_size_in_mb \
      concurrent_reads \
      concurrent_writes \
      memtable_allocation_type \
      memtable_cleanup_threshold \
      memtable_flush_writers \
      concurrent_compactors \
      compaction_throughput_mb_per_sec \
      counter_cache_size_in_mb \
      internode_compression \
      gc_warn_threshold_in_ms \
    ; do
      var="CASSANDRA_${yaml^^}"
      val="${!var}"
      if [ "$val" ]; then
        sed -ri 's/^(# )?('"$yaml"':).*/\2 '"$val"'/' "$CASSANDRA_CONF_DIR$CASSANDRA_CONF_FILE"
      fi
    done

    # hidden viariable (not originaly in config file)
    CASSANDRA_AUTO_BOOTSTRAP="${CASSANDRA_AUTO_BOOTSTRAP:-false}"

    echo "auto_bootstrap: ${CASSANDRA_AUTO_BOOTSTRAP}" >> "$CASSANDRA_CONF_DIR$CASSANDRA_CONF_FILE"
  fi
}

# wait until the cassandra server accepts cqlsh connections
function wait_for_cql_listener_up() {
  PORT=$(cat "$CASSANDRA_CONF_DIR$CASSANDRA_CONF_FILE" | grep native_transport_port | head -1 | cut -d' ' -f2)
  while ! nc -z $HOSTNAME $PORT; do
    sleep 1
  done
}

# create an 'admin' user with password set by CASSANDRA_ADMIN_PASSWORD environmnet variable
function create_admin_user() {
  # change the config
  sed -ri 's/(^authenticator:).*/\1 PasswordAuthenticator/' "$CASSANDRA_CONF_DIR$CASSANDRA_CONF_FILE"
#  echo config changed
 
  # start cassandra with authentication
  cassandra >/dev/null &
#  echo starting server

  # add admin super user with CASSANDRA_ADMIN_PASSWORD via the default super user
  while ! cqlsh $HOSTNAME -u cassandra -p cassandra <<< "CREATE ROLE admin WITH PASSWORD = '$CASSANDRA_ADMIN_PASSWORD' \
    AND SUPERUSER = true \
    AND LOGIN = true;" >/dev/null 2>/dev/null; do
      sleep 1
  done
#  echo admin super user created

  # login as admin and drop the default super user 
  cqlsh $HOSTNAME -u admin -p "$CASSANDRA_ADMIN_PASSWORD" <<< "DROP ROLE cassandra;" >/dev/null
#  echo cassandra super user dropped

  # shut the cassandra down
  nodetool stopdaemon 2>/dev/null
#  echo server stopped

  # hide the admin password
  unset CASSANDRA_ADMIN_PASSWORD
#  echo password var dropped

}