#!/bin/bash
# Copyright (C) 2019 Ian Kelling
# SPDX-License-Identifier: AGPL-3.0-or-later

# usage: no args, run to install latest go.

if [ -z "$BASH_VERSION" ]; then echo "error: shell is not bash" >&2; exit 1; fi

shopt -s inherit_errexit 2>/dev/null ||: # ignore fail in bash < 4.4
source /a/bin/errhandle/err


m() { printf "$pre %s\n"  "$*"; "$@"; }
e() { printf "$pre %s\n"  "$*"; }
err() { echo "[$(date +'%Y-%m-%d %H:%M:%S%z')]: $0: $*" >&2; }

m cd /a/opt/go.git
# don't check for updates on go more than once a day
yesterday=$(( $(date +%s) - 60*60*24 ))
if (( $(stat -c %Y FETCH_HEAD) < yesterday )); then
  m git fetch
  touch ~/.local/gofetch

  vers=($(git tag | sort -Vr | grep -E '^go[0-9.]+$' | head))

  ver=${vers[0]}
  dl() {
    arch=$(dpkg --print-architecture)
    f=${ver}.linux-${arch}.tar.gz

    if [[ -e $f ]]; then
      timestamp=$(stat -c %Y $f)
    else
      timestamp=0
    fi
    m wget -nv -N https://dl.google.com/go/$f || ret=$?
  }
  dl
  # 8 is return code for 404. for a new release, they might not have a binary out yet
  if [[ $ret == 8 ]]; then
    ver=${vers[1]}
    dl
  fi

  new_timestamp=$(stat -c %Y $f)
  if [[ $timestamp != $new_timestamp || ! -e /usr/local/go/bin/go ]]; then
    m sudo rm -rf /usr/local/go
    m sudo tar -C /usr/local -xzf $f
  fi

  shopt -s nullglob
  for x in go*.tar.gz; do
    if [[ $x == $f ]]; then continue; fi
    rm -fv $x
  done

fi