#!/bin/bash

set -e
if [ ${EUID} -ne 0 ]; then
  echo "error: this script must be run as root" 1>&2
  exit 1
fi

GITHUB="https://github.com/golang/go/archive/"

V14="go1.4.3"
TGZ14="${V14}.tar.gz"

Vnew="go1.6"
TGZnew="${Vnew}.tar.gz"

INSTALL="/usr/local"

cd ${INSTALL}

rm -rf go*

wget -q ${GITHUB}${TGZ14}
tar xfz ${TGZ14}
mv go-${V14} ${V14}

wget -q ${GITHUB}${TGZnew}
tar xfz ${TGZnew}
mv go-${Vnew} ${Vnew}

export CGO_ENABLED=0

cd ${INSTALL}/${V14}/src
./make.bash &> /dev/null

export GOROOT_BOOTSTRAP=${INSTALL}/${V14}

if [ "$(uname -m)" == "x86_64" ]; then
  export GOARCH=amd64
else
  export GOARCH=386
fi

cd ${INSTALL}/${Vnew}/src
./make.bash &> /dev/null

cd ${INSTALL}
rm -rf go
mv ${Vnew} go
ln -s /usr/local/go /usr/local/go${Vnew}

export GOROOT="${INSTALL}/go"
export PATH="${PATH}:${GOROOT}/bin"

echo "add this to your .bashrc/.profile:"
echo ""
echo "export CGO_ENABLED=0"
echo "export GOPATH=~/go"
echo "export GOROOT=/usr/local/go"
echo "export PATH=\${PATH}:${GOROOT}/bin:~/go/bin"
echo ""

go version