#!/bin/bash

#=================================================
# COMMON VARIABLES
#=================================================

pkg_dependencies="php-gd php-imagick imagemagick"

#=================================================
# FUTURE OFFICIAL HELPERS
#=================================================

# Create a dedicated fail2ban config (jail and filter conf files)
#
# usage 1: ynh_add_fail2ban_config --logpath=log_file --failregex=filter [--max_retry=max_retry] [--ports=ports]
# | arg: -l, --logpath=   - Log file to be checked by fail2ban
# | arg: -r, --failregex= - Failregex to be looked for by fail2ban
# | arg: -m, --max_retry= - Maximum number of retries allowed before banning IP address - default: 3
# | arg: -p, --ports=     - Ports blocked for a banned IP address - default: http,https
#
# -----------------------------------------------------------------------------
#
# usage 2: ynh_add_fail2ban_config --use_template [--others_var="list of others variables to replace"]
# | arg: -t, --use_template - Use this helper in template mode
# | arg: -v, --others_var=  - List of others variables to replace separeted by a space
# |                           for example : 'var_1 var_2 ...'
#
# This will use a template in ../conf/f2b_jail.conf and ../conf/f2b_filter.conf
#   __APP__      by  $app
#
#  You can dynamically replace others variables by example :
#   __VAR_1__    by $var_1
#   __VAR_2__    by $var_2
#
# Generally your template will look like that by example (for synapse):
#
# f2b_jail.conf:
#     [__APP__]
#     enabled = true
#     port = http,https
#     filter = __APP__
#     logpath = /var/log/__APP__/logfile.log
#     maxretry = 3
#
# f2b_filter.conf:
#     [INCLUDES]
#     before = common.conf
#     [Definition]
#
#     # Part of regex definition (just used to make more easy to make the global regex)
#     __synapse_start_line = .? \- synapse\..+ \-
#
#    # Regex definition.
#    failregex = ^%(__synapse_start_line)s INFO \- POST\-(\d+)\- <HOST> \- \d+ \- Received request\: POST /_matrix/client/r0/login\??<SKIPLINES>%(__synapse_start_line)s INFO \- POST\-\1\- Got login request with identifier: \{u'type': u'm.id.user', u'user'\: u'(.+?)'\}, medium\: None, address: None, user\: u'\5'<SKIPLINES>%(__synapse_start_line)s WARNING \- \- (Attempted to login as @\5\:.+ but they do not exist|Failed password login for user @\5\:.+)$
#
#     ignoreregex =
#
# -----------------------------------------------------------------------------
#
# Note about the "failregex" option:
#          regex to match the password failure messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>[\w\-.^_]+)
#
#          You can find some more explainations about how to make a regex here :
#          https://www.fail2ban.org/wiki/index.php/MANUAL_0_8#Filters
#
# Note that the logfile need to exist before to call this helper !!
#
# To validate your regex you can test with this command:
# fail2ban-regex /var/log/YOUR_LOG_FILE_PATH /etc/fail2ban/filter.d/YOUR_APP.conf
#
ynh_add_fail2ban_config () {
  # Declare an array to define the options of this helper.
  declare -Ar args_array=( [l]=logpath= [r]=failregex= [m]=max_retry= [p]=ports= [t]=use_template [v]=others_var=)
  local logpath
  local failregex
  local max_retry
  local ports
  local others_var
  local use_template
  # Manage arguments with getopts
  ynh_handle_getopts_args "$@"
  use_template="${use_template:-0}"
  max_retry=${max_retry:-3}
  ports=${ports:-http,https}

  finalfail2banjailconf="/etc/fail2ban/jail.d/$app.conf"
  finalfail2banfilterconf="/etc/fail2ban/filter.d/$app.conf"
  ynh_backup_if_checksum_is_different "$finalfail2banjailconf"
  ynh_backup_if_checksum_is_different "$finalfail2banfilterconf"

  if [ $use_template -eq 1 ]
  then
    # Usage 2, templates
    cp ../conf/f2b_jail.conf $finalfail2banjailconf
    cp ../conf/f2b_filter.conf $finalfail2banfilterconf

    if [ -n "${app:-}" ]
    then
      ynh_replace_string "__APP__" "$app" "$finalfail2banjailconf"
      ynh_replace_string "__APP__" "$app" "$finalfail2banfilterconf"
    fi

    # Replace all other variable given as arguments
    for var_to_replace in ${others_var:-}; do
      # ${var_to_replace^^} make the content of the variable on upper-cases
      # ${!var_to_replace} get the content of the variable named $var_to_replace
      ynh_replace_string "__${var_to_replace^^}__" "${!var_to_replace}" "$finalfail2banjailconf"
      ynh_replace_string "__${var_to_replace^^}__" "${!var_to_replace}" "$finalfail2banfilterconf"
    done

  else
    # Usage 1, no template. Build a config file from scratch.
    test -n "$logpath" || ynh_die "ynh_add_fail2ban_config expects a logfile path as first argument and received nothing."
    test -n "$failregex" || ynh_die "ynh_add_fail2ban_config expects a failure regex as second argument and received nothing."

    tee $finalfail2banjailconf <<EOF
[$app]
enabled = true
port = $ports
filter = $app
logpath = $logpath
maxretry = $max_retry
EOF

    tee $finalfail2banfilterconf <<EOF
[INCLUDES]
before = common.conf
[Definition]
failregex = $failregex
ignoreregex =
EOF
  fi

  # Common to usage 1 and 2.
  ynh_store_file_checksum "$finalfail2banjailconf"
  ynh_store_file_checksum "$finalfail2banfilterconf"

  systemctl try-reload-or-restart fail2ban

  local fail2ban_error="$(journalctl -u fail2ban | tail -n50 | grep "WARNING.*$app.*")"
  if [[ -n "$fail2ban_error" ]]; then
    ynh_print_err "Fail2ban failed to load the jail for $app"
    ynh_print_warn "${fail2ban_error#*WARNING}"
  fi
}

# Remove the dedicated fail2ban config (jail and filter conf files)
#
# usage: ynh_remove_fail2ban_config
ynh_remove_fail2ban_config () {
  ynh_secure_remove "/etc/fail2ban/jail.d/$app.conf"
  ynh_secure_remove "/etc/fail2ban/filter.d/$app.conf"
  systemctl try-reload-or-restart fail2ban
}

#=================================================

# Check available space before creating a temp directory.
#
# usage: ynh_smart_mktemp --min_size="Min size"
#
# | arg: -s, --min_size= - Minimal size needed for the temporary directory, in Mb
ynh_smart_mktemp () {
        # Declare an array to define the options of this helper.
        declare -Ar args_array=( [s]=min_size= )
        local min_size
        # Manage arguments with getopts
        ynh_handle_getopts_args "$@"

        min_size="${min_size:-300}"
        # Transform the minimum size from megabytes to kilobytes
        min_size=$(( $min_size * 1024 ))

        # Check if there's enough free space in a directory
        is_there_enough_space () {
                local free_space=$(df --output=avail "$1" | sed 1d)
                test $free_space -ge $min_size
        }

        if is_there_enough_space /tmp; then
                local tmpdir=/tmp
        elif is_there_enough_space /var; then
                local tmpdir=/var
        elif is_there_enough_space /; then
                local tmpdir=/   
        elif is_there_enough_space /home; then
                local tmpdir=/home
        else
                ynh_die "Insufficient free space to continue..."
        fi

        echo "$(sudo mktemp --directory --tmpdir="$tmpdir")"
}