#!/usr/bin/env bash

## CONSTANTS

BASE_ARCHIVE_URL='https://git.artcode.re/miaou/miaou-bash/archive'
BASE_TAG_URL='https://git.artcode.re/api/v1/repos/miaou/miaou-bash/tags'

## FUNCTIONS

function upgrade {
  echo 'upgrading...'
  execute_miaou_lib self-upgrade
}

function install {
  local release
  release=$(
    curl -s "$BASE_TAG_URL" |
      grep '"name":' |
      cut -d '"' -f4
  )
  echo "deploying release=$release in progress..."

  local tempfile='/tmp/miaou-bash-latest.tar.gz'
  if curl -so "$tempfile" "${BASE_ARCHIVE_URL}/${release}.tar.gz"; then
    if sudo tar -xzf "$tempfile" --directory "$(dirname "$MIAOU_BASH_DIR")"; then
      rm "$tempfile"
      if execute_miaou_lib initiate; then
        echo 'successfully deployed'
      else
        miaou_error 'unable to initiate further'
      fi
    else
      miaou_error 'unable to uncompress archive'
    fi
  else
    miaou_error 'unable to download release'
  fi
}

function assert_supported_distro {
  if ! grep -E '^ID=debian|^ID_LIKE=debian' /etc/os-release &&
    ! grep -E '^ID=arch|^ID_LIKE=arch' /etc/os-release; then
    local distro
    distro=$(grep -oP '^ID=\K(.*)' /etc/os-release)
    >&2 echo "unsupported GNU/Linux distribution: $distro"
    >&2 echo 'only debian-like OR arch-like currently supported'
    return 10
  fi
}

function once_installed {
  [[ -v MIAOU_BASH_DIR && -d "$MIAOU_BASH_DIR" &&
    -L /etc/inputrc &&
    "$(readlink /etc/inputrc)" == "$MIAOU_BASH_DIR"/etc/inputrc ]]
}

function miaou_error {
  >&2 echo --------------------------------------------------------------
  >&2 echo "MIAOU_ERROR: $1"
  >&2 echo "Either retry later when a newer version will come up"
  >&2 echo "Or report the errorstack printed out above to: contact@artcode.re"
  >&2 echo --------------------------------------------------------------
  >&2 echo "QUICK FIX:"
  >&2 echo "  MIAOU_BASH_DIR=/opt/miaou-bash"
  >&2 echo "  export MIAOU_BASH_DIR"
  >&2 echo "  sudo -E \"\$MIAOU_BASH_DIR\"/bin/miaou-bash \"\$MIAOU_BASH_DIR\"/lib/initiate.bash"
}

function execute_miaou_lib {
  sudo -E "$MIAOU_BASH_DIR"/bin/miaou-bash "$MIAOU_BASH_DIR"/lib/"$1".bash 3>&1
}

function assert_bash {
  if [[ $(basename "$SHELL") != 'bash' ]]; then
    >&2 echo "running on SHELL=$SHELL rather than 'bash'!"
    return 11
  fi
}

function sudo_root {
  if [[ "$UID" -ne 0 ]] && ! sudo -vp 'SUDO privilege required: '; then
    >&2 echo "unauthorized!"
    return 12
  fi
}
## MAIN

set -Eeuo pipefail
if assert_supported_distro && assert_bash && sudo_root; then
  if [[ ! -v MIAOU_BASH_DIR ]]; then
    MIAOU_BASH_DIR=/opt/miaou-bash
    export MIAOU_BASH_DIR
  fi

  deployment_type_adjective="${1:-installed}" # `miaou-bash --self-upgrade` provides the 'upgrade' term
  if once_installed; then upgrade; else install; fi
  if [[ $deployment_type_adjective == 'installed' ]]; then
    exec bash -l
  fi
else
  >&2 echo "MIAOU_ERROR: missing requirements"
fi