#!/bin/bash

# load config
source installer.cfg || { exit 1; }


function check_network() {
  echo "Sending ping to wikipedia.de ..."
  ping -c 1 wikipedia.de || {
    echo "Pleas set up network access."
    return 1
  }
}

function increase_cow_space() {
  # May be useful when running 'pacman -Syu' on the live medium.
  # Usually not necessary!

  # make sure that we are on a live medium:
  findmnt /run/archiso/cowspace || {
    echo "Not on live medium, did not increase cowspace!"
    return 1
  }

  echo "Increasing cowspace partition of live medium ..."
  mount -o remount,size=2G /run/archiso/cowspace || return $?
}

function get_block_devices(){
  # return: the following variables:
  #   BLOCK_DEVICES (array with each block device as one entry)

  local tmp
#  # get list of devices , one per line
#  #
#  # -> remove everything after first whitespace
#  #    -> with sed; alternative: awk '{print $1}'
#  # -> add "/dev/" at start of each line
#  tmp=$(lsblk --noheadings --nodeps | sed 's|\s.*$||; s|^|&/dev/|') || return $?
  tmp=$(lsblk -dplnx size -o name | grep -Ev "boot|rpmb|loop")

  readarray -t BLOCK_DEVICES <<<"$tmp"
}

function get_block_devices_with_size() {
  # return: the following variables:
  #   BLOCK_DEVICE_SIZES (space separated list of block devices and their sizes)

  # one could use sed to remove multiple white spaces
  # sed 's|\s\s*| |'
  BLOCK_DEVICE_SIZES="$(lsblk -dplnx size -o name,size | grep -Ev "boot|rpmb|loop" | tac)"
}

function get_text_input {
  # If variable with name $1 is zero, then ask user for input.
  # Only one line user input is allowed.
  # User input must not be empty.
  #
  # $1: name of variable to store user input
  # $2: text to display (e.g. "Enter hostname:")
  if [ "$#" -ne 2 ]; then
    echo "get_text_input requires two args!";
    return 1
  fi
  for i in "$@"; do
    if [ -z "$i" ]; then
      echo "get_menu_selections: all given args must not be empty";
      return 1;
    fi
  done

  local -n VAR=$1
  if [ -z "$VAR" ]; then
    # if VAR has no value yet, ask user for input!
    echo "$2"
    read -r VAR || return $?
  fi

  # check string length to be greater than zero!
  if [ "${#VAR}" -lt 1 ]; then
    echo "get_text_input must not be empty!";
    return 1;
  fi
}

function get_menu_selection {
  # If variable with name $1 is zero, then ask user to select one option.
  #
  # $1: name of variable to store user selection
  # $2: text to display
  # $3: name of variable with space-separated menu options to display (each menu option consists of an item and a description)
  if [ "$#" -ne 3 ]; then
    echo "get_menu_selection requires three args!";
    return 1
  fi
  for i in "$@"; do
    if [ -z "$i" ]; then
      echo "get_menu_selections: all given args must not be empty";
      return 1;
    fi
  done


  local -n VAR=$1
  if [ -z "$VAR" ]; then
    # if VAR has no value yet, ask user for input!

    local -n MENU_OPTIONS=$3
    VAR=$(dialog --stdout --menu "$2" 0 0 0 ${MENU_OPTIONS}) || {
      echo "Error during menu selection!"
      exit 1
    }
    clear
  fi
}

function get_user_input() {
  # return: the following variables:
  #   BIOS_TYPE (uefi or bios)
  #   KERNEL    (linux or linux-lts)
  #   FS        (BTRFS, EXT4, F2FS)
  #   HOSTNAME
  #   USERNAME, USER_PWD
  #   LUKS_PWD

  #  get_block_devices || return $?
  get_block_devices_with_size || return $?
  get_menu_selection  TARGET_BLOCK_DEVICE "Select target device for installation" BLOCK_DEVICE_SIZES || return $?

  TMP1="uefi Newer-mainboards bios Legacy-BIOS-on-older-mainboards"
  get_menu_selection  BIOS_TYPE "Select your bios type" TMP1 || return $?

  TMP1="linux-lts Long-Time-Stable-Linux-kernel linux Latest-Linux-kernel"
  get_menu_selection  KERNEL "Select kernel version" TMP1 || return $?

  TMP1="BTRFS allows-snapshots-and-dynamic-extension-of-the-fs EXT4 default-fs-of-many-distributions F2FS Flash-Friendly-fs-for-SSD-or-NVMe"
  get_menu_selection  FS "Select filesystem to use" TMP1 || return $?

  get_text_input HOSTNAME "Enter hostname:" || return $?
  get_text_input USERNAME "Enter username:" || return $?

  if [ -z "${USER_PWD}" ]; then
    get_text_input USER_PWD "Enter a user password:" || return $?
    get_text_input USER_PWD2 "Please enter the password again:" || return $?
    [[ "${USER_PWD}" == "${USER_PWD2}" ]] || {
      echo "Passwords did not match";
      exit 1;
    }
  fi
  if [ -z "${LUKS_PWD}" ]; then
    get_text_input LUKS_PWD "Enter a disk encryption password:" || return $?
    get_text_input LUKS_PWD2 "Please enter the password again:" || return $?
    [[ "${LUKS_PWD}" == "${LUKS_PWD2}" ]] || {
      echo "Passwords did not match";
      exit 1;
    }
  fi
}

function get_cpu_vendor() {
    # return: the following variables:
    #   CPU_VENDOR ("amd", "intel", "none")

  if [ -z "${CPU_VENDOR}" ]; then
    # if CPU_VENDOR has no value yet, ask user for input!

    local vendor_id
    vendor_id=$(cat /proc/cpuinfo | grep vendor_id | head -1 | sed 's|vendor_id\s*:\s*||')

    if [ "$vendor_id" = "AuthenticAMD" ]; then
      CPU_VENDOR="amd"
    elif [ "$vendor_id" = "GenuineIntel" ]; then
      CPU_VENDOR="intel"
    else
      echo "Unknown CPU vendor: $vendor_id"
      return 1
    fi
  fi
}

function main() {
  check_network  || return $?
  get_user_input || return $?
  get_cpu_vendor || return $?
}

main "$@"