#!/bin/bash


set -o errexit
#set -o xtrace


VERSION="1.11"


print_help() {
    echo "Usage: ./golang_install.sh [OPTIONS]"
    echo -e "\nOptions::"
    echo -e "  -i|--install\tInstall Go matches current arch"
    echo -e "  -r|--remove\tTo remove currently installed version"
    echo -e "  -v|--version\tInstall specified version,default version 1.11"
    echo -e "  -h|--help\tDisplay this message"
    echo -e "\nExample::"
    echo -e "  ./golang_install.sh\t\t#Install version 1.11"
    echo -e "  ./golang_install.sh -v XXX\t#Install specified version"
    echo -e "  ./golang_install.sh -r\t#Uninstall Go"
}


remove_golang() {
    rm -rf "$HOME/.go/"
    sed -i '/# GoLang/d' "$HOME/.${shell_profile}"
    sed -i '/export GOROOT/d' "$HOME/.${shell_profile}"
    sed -i '/:$GOROOT/d' "$HOME/.${shell_profile}"
    sed -i '/export GOPATH/d' "$HOME/.${shell_profile}"
    sed -i '/:$GOPATH/d' "$HOME/.${shell_profile}"
    if [ -d "/usr/local/go" ]; then
        echo "Please remove /usr/local/go !"
    fi
}


if [ -n "`$SHELL -c 'echo $ZSH_VERSION'`" ]; then
    # assume Zsh
    shell_profile="zshrc"
elif [ -n "`$SHELL -c 'echo $BASH_VERSION'`" ]; then
    # assume Bash
    shell_profile="bashrc"
fi


if [ -n "$1" ]; then
    case $1 in
        -r|--remove )
    remove_golang
    echo "Go removed..."
    exit 0
            ;;
        -i|--install )
            echo "Install Golang..."
            ;;
-v|--version )
    shift
    if [ -n "$1" ]; then
VERSION=$1
        echo "Go version:$VERSION"
    else
echo "Version is NULL!"
print_help
exit 0
    fi
    ;;
-h|--help )
    print_help
    exit 0
    ;;
        * )
            echo "Invalid parameter: "$1
    print_help
            exit 1
    esac
fi


if test "$(uname -m)" = "aarch64" ; then
    ARCH="arm64";
    DFILE="go$VERSION.linux-arm64.tar.gz"
else
    ARCH="amd64";
    DFILE="go$VERSION.linux-amd64.tar.gz"
fi


if [ -d "$HOME/.go" ] || [ -d "$HOME/go" ]; then
    echo "The 'go' or '.go' directories already exist. Exiting."
    exit 1
fi


echo "Downloading $DFILE ..."
wget -O /tmp/go.tar.gz https://go.dev/dl/$DFILE


if [ $? -ne 0 ]; then
    echo "Download failed! Exiting."
    exit 1
fi


echo "Extracting File..."
tar -C "$HOME" -xzf /tmp/go.tar.gz
mv "$HOME/go" "$HOME/.go"
touch "$HOME/.${shell_profile}"
{
    echo '# GoLang'
    echo 'export GOROOT=$HOME/.go'
    echo 'export PATH=$PATH:$GOROOT/bin'
    echo 'export GOPATH=$HOME/go'
    echo 'export PATH=$PATH:$GOPATH/bin'
} >> "$HOME/.${shell_profile}"


mkdir -p $HOME/go/{src,pkg,bin}
echo -e "\nGo $VERSION was installed.\nMake sure to relogin into your shell or run:"
echo -e "\n\tsource $HOME/.${shell_profile}\n\nto update your environment variables."
echo "Tip: Opening a new terminal window usually just works. :)"
rm -f /tmp/go.tar.gz