#!/bin/sh

# safety subshell to avoid executing anything in case this script is not downloaded properly
(

: "${GHCUP_INSTALL_BASE_PREFIX:=$HOME}"
: "${BOOTSTRAP_HASKELL_GHC_VERSION:=recommended}"
: "${BOOTSTRAP_HASKELL_CABAL_VERSION:=recommended}"

die() {
    (>&2 printf "\\033[0;31m%s\\033[0m\\n" "$1")
    exit 2
}

edo()
{
    "$@" || die "\"$*\" failed!"
}

eghcup() {
    if [ -z "${BOOTSTRAP_HASKELL_VERBOSE}" ] ; then
        edo ghcup "$@"
    else
        edo ghcup --verbose "$@"
    fi
}

download_ghcup() {
	_plat="$(uname -s)"
	_arch=$(uname -m)
	_ghver="0.1.6"
	_base_url="https://downloads.haskell.org/~ghcup"

    case "${_plat}" in
        "linux"|"Linux")
			case "${_arch}" in
				x86_64|amd64)
					_url=${_base_url}/${_ghver}/x86_64-linux-ghcup-${_ghver}
					;;
				i*86)
					_url=${_base_url}/${_ghver}/i386-linux-ghcup-${_ghver}
					;;
				*) die "Unknown architecture: ${_arch}"
					;;
			esac
			;;
        "FreeBSD"|"freebsd")
			case "${_arch}" in
				x86_64|amd64)
					;;
				i*86)
					die "i386 currently not supported!"
					;;
				*) die "Unknown architecture: ${_arch}"
					;;
			esac
			_url=${_base_url}/${_ghver}/x86_64-portbld-freebsd-ghcup-${_ghver}
            ;;
        "Darwin"|"darwin")
			case "${_arch}" in
				x86_64|amd64)
					;;
				i*86)
					die "i386 currently not supported!"
					;;
				*) die "Unknown architecture: ${_arch}"
					;;
			esac
			_url=${_base_url}/${_ghver}/x86_64-apple-darwin-ghcup-${_ghver} ;;
        *) die "Unknown platform: ${_plat}"
			;;
    esac

	edo curl -Lf "${_url}" > "${GHCUP_INSTALL_BASE_PREFIX}"/.ghcup/bin/ghcup

	unset _plat _arch _url _ghver _base_url
}


echo
echo "Welcome to Haskell!"
echo
echo "This script will download and install the following binaries:"
echo "  * ghcup - The Haskell toolchain installer (for managing GHC/cabal versions)"
echo "  * ghc   - The Glasgow Haskell Compiler"
echo "  * cabal - The Cabal build tool"
echo
echo "ghcup installs only into the following directory, which can be removed anytime:"
echo "  $GHCUP_INSTALL_BASE_PREFIX/.ghcup"
echo

if [ -z "${BOOTSTRAP_HASKELL_NONINTERACTIVE}" ] ; then
    printf "\\033[0;35m%s\\033[0m\\n" "Press ENTER to proceed or ctrl-c to abort."
    printf "\\033[0;35m%s\\033[0m\\n" "Note that this script can be re-run at any given time."
    echo
    # Wait for user input to continue.
    # shellcheck disable=SC2034
    read -r answer </dev/tty
fi

edo mkdir -p "${GHCUP_INSTALL_BASE_PREFIX}"/.ghcup/bin

if command -V "ghcup" >/dev/null 2>&1 ; then
    if [ -z "${BOOTSTRAP_HASKELL_NO_UPGRADE}" ] ; then
        eghcup upgrade
    fi
else
	download_ghcup
    edo chmod +x "${GHCUP_INSTALL_BASE_PREFIX}"/.ghcup/bin/ghcup

	cat <<-EOF > "${GHCUP_INSTALL_BASE_PREFIX}"/.ghcup/env || die "Failed to create env file"
		export PATH="\$HOME/.cabal/bin:\${GHCUP_INSTALL_BASE_PREFIX:=\$HOME}/.ghcup/bin:\$PATH"
		EOF
	# shellcheck disable=SC1090
    edo . "${GHCUP_INSTALL_BASE_PREFIX}"/.ghcup/env
    eghcup upgrade
fi

echo
echo "$(ghcup tool-requirements)"
echo

if [ -z "${BOOTSTRAP_HASKELL_NONINTERACTIVE}" ] ; then
    printf "\\033[0;35m%s\\033[0m\\n" "Press ENTER to proceed or ctrl-c to abort."
    printf "\\033[0;35m%s\\033[0m\\n" "Installation may take a while."
    echo

    # Wait for user input to continue.
    # shellcheck disable=SC2034
    read -r answer </dev/tty
fi

eghcup --cache install "${BOOTSTRAP_HASKELL_GHC_VERSION}"

eghcup set "${BOOTSTRAP_HASKELL_GHC_VERSION}"
eghcup --cache install-cabal "${BOOTSTRAP_HASKELL_CABAL_VERSION}"

edo cabal new-update

printf "\\033[0;35m%s\\033[0m\\n" ""
printf "\\033[0;35m%s\\033[0m\\n" "Installation done!"
printf "\\033[0;35m%s\\033[0m\\n" ""

if [ -z "${BOOTSTRAP_HASKELL_NONINTERACTIVE}" ] ; then
    echo "In order to run ghc and cabal, you need to adjust your PATH variable."
    echo "You may want to source '$GHCUP_INSTALL_BASE_PREFIX/.ghcup/env' in your shell"
    echo "configuration to do so (e.g. ~/.bashrc)."

	case $SHELL in
		*/zsh) # login shell is zsh
			GHCUP_PROFILE_FILE="$HOME/.zshrc"
			MY_SHELL="zsh" ;;
		*/bash) # login shell is bash
			GHCUP_PROFILE_FILE="$HOME/.bashrc"
			MY_SHELL="bash" ;;
		*/sh) # login shell is sh, but might be a symlink to bash or zsh
			if [ -n "${BASH}" ] ; then
				GHCUP_PROFILE_FILE="$HOME/.bashrc"
				MY_SHELL="bash"
			elif [ -n "${ZSH_VERSION}" ] ; then
				GHCUP_PROFILE_FILE="$HOME/.zshrc"
				MY_SHELL="zsh"
			else
				exit 0
			fi
			;;
		*) exit 0 ;;
	esac


	printf "\\033[0;35m%s\\033[0m\\n" ""
	printf "\\033[0;35m%s\\033[0m\\n" "Detected ${MY_SHELL} shell on your system..."
	printf "\\033[0;35m%s\\033[0m\\n" "If you want ghcup to automatically add the required PATH variable to \"${GHCUP_PROFILE_FILE}\""
	printf "\\033[0;35m%s\\033[0m\\n" "answer with YES, otherwise with NO and press ENTER."
	printf "\\033[0;35m%s\\033[0m\\n" ""

    while true; do
        read -r next_answer </dev/tty

        case $next_answer in
            [Yy]*)
                echo "[ -f \"\${GHCUP_INSTALL_BASE_PREFIX:=\$HOME}/.ghcup/env\" ] && source \"\${GHCUP_INSTALL_BASE_PREFIX:=\$HOME}/.ghcup/env\"" >> "${GHCUP_PROFILE_FILE}"
                printf "\\033[0;35m%s\\033[0m\\n" "OK! ${GHCUP_PROFILE_FILE} has been modified. Restart your terminal for the changes to take effect,"
                printf "\\033[0;35m%s\\033[0m\\n" "or type \"source ${GHCUP_INSTALL_BASE_PREFIX}/.ghcup/env\" to apply them in your current terminal session."
                exit 0;;
            [Nn]*)
                exit 0;;
            *)
                echo "Please type YES or NO and press enter.";;
        esac
    done
fi
)

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