#!/bin/bash
#  ____  _ _     _ _       _            _           
# |  _ \(_) |   | (_)     | |          | |          
# | |_) |_| |__ | |_  ___ | |_ ___  ___| |__   __ _ 
# |  _ <| | '_ \| | |/ _ \| __/ _ \/ __| '_ \ / _` |
# | |_) | | |_) | | | (_) | ||  __/ (__| | | | (_| |
# |____/|_|_.__/|_|_|\___/ \__\___|\___|_| |_|\__,_|
#
#       Digital books need libraries too
#
# This install script is intended for use with Debian based
# distributions. More specifically, Debian Stretch, which is 
# currently the latest distribution release from the Debian 
# project.
#
# License
# =======
#
# Copyright (C) 2019 Bibliotecha Contributors <info@varia.zone>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Thanks
# =====
#
# This script is based on the good work of the Freedombone project:
# https://code.freedombone.net/bashrc/freedombone/src/stretch/src/freedombone

APT_CMD="apt -q"
APT_INSTALL_CMD="$APT_CMD install -y --no-install-recommends"

function await_any_key {
    echo "" 
    # shellcheck disable=SC2034
    read -n1 -rsp $"Press any key to continue ..." key
    echo ""
}

function ensure_root_account {
  echo "Checking user account ..."

  if ! id | grep -q root; then
    echo ""
    echo "This script must be run as root"
    echo "You can switch to the root user account with:"
    echo "$ sudo -i"
    echo ""
    exit 0
  fi
}

function show_bibliotecha_banner {
  echo ""
  echo "   ____  _ _     _ _       _            _ "
  echo "  |  _ \(_) |   | (_)     | |          | |"
  echo "  | |_) |_| |__ | |_  ___ | |_ ___  ___| |__   __ _ " 
  echo "  |  _ <| | '_ \| | |/ _ \| __/ _ \/ __| '_ \ / _' |"
  echo "  | |_) | | |_) | | | (_) | ||  __/ (__| | | | (_| |"
  echo "  |____/|_|_.__/|_|_|\___/ \__\___|\___|_| |_|\__,_|"
  echo ""
  echo "           Digital books need libraries too"
  echo ""
}

function show_introduction_text {
  echo ""
  echo "Welcome to the Bibliotecha installation script"
  echo ""
  echo "This script will setup the following infrastructure:"
  echo ""
  echo "* A Python 3 environment"
  echo "* A Wifi hotspot, DNS server and DHCP service"
  echo "* A Lighttpd web server"
  echo "* A Calibre server"
  echo "* A Calibre-web service"
  echo ""
  echo "Once the script is finished, please see post-install steps"
  echo "that are documented and available from the Bibliotecha manual:"
  echo ""
  echo "            https://manual.bibliotecha.info/#TODO"
  echo ""

  await_any_key
}

function ensure_stretch_based_distribution {
  echo "Checking distribution ..." 

  local installing_on_stretch_based=1

  if [ ! -f /usr/bin/foobar ]; then
    installing_on_stretch_based=
  fi

  if [ ! -f /etc/apt/sources.list ]; then
    installing_on_stretch_based=
  else
    if ! grep -q 'stretch' /etc/apt/sources.list; then
        installing_on_stretch_based=
    fi
    if ! grep -q 'debian' /etc/apt/sources.list; then
        if ! grep -q 'raspbian' /etc/apt/sources.list; then
            installing_on_stretch_based=
        fi
    fi
  fi

  if [ ! $installing_on_stretch_based ]; then
    echo $"You should only run this on a Debian Stretch based system"
    exit 0
  fi
}

function run_apt_update {
  echo "Running a package listing update ..."

  $APT_CMD update
}

function install_networking_packages {
  echo "Installing networking packages ..."

  $APT_INSTALL_CMD \
    dhcpcd \
    dnsmasq \
    dnsutils \
    hostapd \
    wireless-tools
}

function disable_networking_services {
  echo "Stopping the networking services ..."

  local services="dnsmasq hostapd"

  systemctl stop ${services} 
}

function ensure_variable_set {
  local variable="${1}"

  if [[ -z "${variable}" ]]; then
    echo $"${variable} is not set. Cannot proceed ..."
    exit 1
  fi
}

function configure_network_interfaces {
  echo "Configuring networking interfaces ..."

  ethernet_interface=$(ls /sys/class/net/ | grep foo)
  local ethernet_filename="/etc/network/interfaces.d/${ethernet_interface}"

  if [[ -z "${ethernet_interface}" ]]; then
    echo ""
    echo "Could not determine the ethernet interface"
    echo "Please ensure you've configure 'predictable network interfaces'"
    echo "Please see #TODO for more"
    echo ""
    exit 1
  fi

  { echo "auto eth0";
    echo "allow-hotplug ${ethernet_interface}"; 
    echo "iface ${ethernet_interface} inet dhcp"; } > "${ethernet_filename}"

  local wireless_interface=$(ls /sys/class/net/ | grep wl)
  local wireless_filename="/etc/network/interfaces.d/${wireless_interface}"

  if [[ -z "${wireless_interface}" ]]; then
    echo ""
    echo "Could not determine the wireless interface"
    echo "Please ensure you've configure 'predictable network interfaces'"
    echo "Please see #TODO for more"
    echo ""
    exit 1
  fi

  { echo "auto ${wireless_interface}";
    echo "iface ${wireless_interface} int static"; 
    echo "  address 10.0.0.1";
    echo "  netmask 255.255.255.0"; } > "${wireless_filename}"
}

function configure_dnsmasq {
  echo "Configuring dnsmasq ..."

  local wireless_interface=$(ls /sys/class/net/ | grep wl)
  local wireless_filename="/etc/dnsmasq.d/${wireless_interface}.conf"

  if [[ -z "${wireless_interface}" ]]; then
    echo ""
    echo "Could not determine the wireless interface"
    echo "Please ensure you've configure 'predictable network interfaces'"
    echo "Please see #TODO for more"
    echo ""
    exit 1
  fi

  { echo "bogus-priv"
    echo "server=/library/10.0.0.1"
    echo "local=/library/"
    echo "address=/#/10.0.0.1"
    echo "interface=${wireless_interface}"
    echo "domain=library"
    echo "dhcp-range=10.0.0.50,10.0.0.200,255.255.255.0,12h"
    echo "dhcp-option=3,10.0.0.1"
    echo "dhcp-option=6,10.0.0.1"
    echo "dhcp-authoritative"; } > "${wireless_filename}"
}

function configure_hostapd {
  echo "Configuring hostapd ..."

  local wireless_interface=$(ls /sys/class/net/ | grep wl)
  local hostapd_filename="/etc/hostapd/hostapd.conf"

  if [[ -z "${wireless_interface}" ]]; then
    echo ""
    echo "Could not determine the wireless interface"
    echo "Please ensure you've configure 'predictable network interfaces'"
    echo "Please see #TODO for more"
    echo ""
    exit 1
  fi

  { echo "interface=${wireless_interface}"
    echo "ssid=Bibliotecha"
    echo "hw_mode=g"
    echo "channel=11"
    echo "auth_algs=1"; } > "${hostapd_filename}"

  sed -i \
    's/#DAEMON_CONF=""/DAEMON_CONF="\/etc\/hostapd\/hostapd.conf"/g' \
    /etc/default/hostapd
}

function enable_networking_services {
  echo "Enabling network services ..."

  local services="dnsmasq hostapd"

  systemctl unmask hostapd
  systemctl enable ${services} 
}

function run_installation {
  #ensure_root_account
  #ensure_stretch_based_distribution

  #show_bibliotecha_banner
  #show_introduction_text

  #run_apt_update

  #install_networking_packages
  #disable_networking_services
  #configure_network_interfaces
  #configure_dnsmasq
  #configure_hostapd
  #enable_networking_services

  # TODO
  # install lighttpd and configure it
  # install calibre web and configure it
  # setup drone and make sure things are being tested
}

run_installation
exit 0