#!/bin/sh

# Main settings:
#   * BOOTSTRAP_HASKELL_NONINTERACTIVE - any nonzero value for noninteractive installation
#   * BOOTSTRAP_HASKELL_NO_UPGRADE - any nonzero value to not trigger the upgrade
#   * GHCUP_USE_XDG_DIRS - any nonzero value to respect The XDG Base Directory Specification
#   * BOOTSTRAP_HASKELL_VERBOSE - any nonzero value for more verbose installation
#   * BOOTSTRAP_HASKELL_GHC_VERSION
#   * BOOTSTRAP_HASKELL_CABAL_VERSION

# License: LGPL-3.0


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

plat="$(uname -s)"
arch=$(uname -m)
ghver="0.1.14.1"
base_url="https://downloads.haskell.org/~ghcup"

case "${plat}" in
        MSYS*|MINGW*)
			: "${GHCUP_INSTALL_BASE_PREFIX:=/c}"
			GHCUP_DIR=${GHCUP_INSTALL_BASE_PREFIX}/ghcup
			GHCUP_BIN=${GHCUP_INSTALL_BASE_PREFIX}/ghcup/bin
			;;
		*)
			: "${GHCUP_INSTALL_BASE_PREFIX:=$HOME}"
			export GHCUP_USE_XDG_DIRS

			if [ -n "${GHCUP_USE_XDG_DIRS}" ] ; then
				GHCUP_DIR=${XDG_DATA_HOME:=$HOME/.local/share}/ghcup
				GHCUP_BIN=${XDG_BIN_HOME:=$HOME/.local/bin}
			else
				GHCUP_DIR=${GHCUP_INSTALL_BASE_PREFIX}/.ghcup
				GHCUP_BIN=${GHCUP_INSTALL_BASE_PREFIX}/.ghcup/bin
			fi
			;;
esac

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


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

warn() {
	case "${plat}" in
			MSYS*|MINGW*)
				echo -e "\\033[0;35m$1\\033[0m"
				;;
			*)
				printf "\\033[0;35m%s\\033[0m\\n" "$1"
				;;
	esac
}

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

eghcup() {
	edo _eghcup "$@"
}

_eghcup() {
	if [ -n "${BOOTSTRAP_HASKELL_YAML}" ] ; then
		args="-s ${BOOTSTRAP_HASKELL_YAML}"
	fi 
    if [ -z "${BOOTSTRAP_HASKELL_VERBOSE}" ] ; then
        ghcup ${args} "$@"
    else
        ghcup ${args} --verbose "$@"
    fi
}

_done() {
	case "${plat}" in
			MSYS*|MINGW*)
				echo
				echo "All done!"
				echo
				echo "In a new powershell or cmd.exe session, now you can..."
				echo
				echo "Start a simple repl via:"
				echo "  ghci"
				echo
				echo "Start a new haskell project in the current directory via:"
				echo "  cabal init --interactive"
				echo
				echo "Install other GHC versions and tools via:"
				echo "  ghcup list"
				echo "  ghcup install <tool> <version>"
				echo
				echo "To install system libraries and update msys2/mingw64,"
				echo "open the \"Mingw haskell shell\""
				echo "and the \"Mingw package management docs\""
				echo "desktop shortcuts."
				;;
			*)
				echo
				echo "All done!"
				echo
				echo "To start a simple repl, run:"
				echo "  ghci"
				echo
				echo "To start a new haskell project in the current directory, run:"
				echo "  cabal init --interactive"
				echo
				echo "To install other GHC versions and tools, run:"
				echo "  ghcup tui"
				;;

	esac


	exit 0
}

download_ghcup() {

    case "${plat}" in
        "linux"|"Linux")
			case "${arch}" in
				x86_64|amd64)
					# we could be in a 32bit docker container, in which
					# case uname doesn't give us what we want
					if [ "$(getconf LONG_BIT)" = "32" ] ; then
						_url=${base_url}/${ghver}/i386-linux-ghcup-${ghver}
					elif [ "$(getconf LONG_BIT)" = "64" ] ; then
						_url=${base_url}/${ghver}/x86_64-linux-ghcup-${ghver}
					else
						die "Unknown long bit size: $(getconf LONG_BIT)"
					fi
					;;
				i*86)
					_url=${base_url}/${ghver}/i386-linux-ghcup-${ghver}
					;;
				armv7*)
					_url=${base_url}/${ghver}/armv7-linux-ghcup-${ghver}
					;;
				aarch64|arm64|armv8l)
					_url=${base_url}/${ghver}/aarch64-linux-ghcup-${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} ;;
        MSYS*|MINGW*)
			case "${arch}" in
				x86_64|amd64)
					_url=https://downloads.haskell.org/~ghcup/tmp/x86_64-mingw64-ghcup-7.exe
					;;
				*) die "Unknown architecture: ${arch}"
					;;
			esac
			;;
        *) die "Unknown platform: ${plat}"
			;;
    esac
    case "${plat}" in
        MSYS*|MINGW*)
			edo curl -Lf "${_url}" > "${GHCUP_BIN}"/ghcup.exe
			edo chmod +x "${GHCUP_BIN}"/ghcup.exe
			;;
		*)
			edo curl -Lf "${_url}" > "${GHCUP_BIN}"/ghcup
			edo chmod +x "${GHCUP_BIN}"/ghcup
			;;
	esac

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


echo
echo "Welcome to Haskell!"
echo
echo "This script will download and install the following binaries:"
echo "  * ghcup - The Haskell toolchain installer"
echo "  * ghc   - The Glasgow Haskell Compiler"
echo "  * cabal - The Cabal build tool for managing Haskell software"
echo "  * stack - (optional) A cross-platform program for developing Haskell projects"
echo "  * hls   - (optional) A language server for developers to integrate with their editor/IDE"
echo
if [ -z "${GHCUP_USE_XDG_DIRS}" ] ; then
	echo "ghcup installs only into the following directory,"
    echo "which can be removed anytime:"
	case "${plat}" in
			MSYS*|MINGW*)
				echo "  $(cygpath -w "$GHCUP_DIR")"
				;;
			*)
				echo "  $GHCUP_DIR"
				;;
	esac
else
	echo "ghcup installs into XDG directories as long as"
    echo "'GHCUP_USE_XDG_DIRS' is set."
fi
echo

if [ -z "${BOOTSTRAP_HASKELL_NONINTERACTIVE}" ] ; then
    warn "Press ENTER to proceed or ctrl-c to abort."
    warn "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_BIN}"

if command -V "ghcup" >/dev/null 2>&1 ; then
    if [ -z "${BOOTSTRAP_HASKELL_NO_UPGRADE}" ] ; then
        _eghcup upgrade || download_ghcup
    fi
else
	download_ghcup
fi

echo
echo "$(if [ -n "${BOOTSTRAP_HASKELL_YAML}" ] ; then ghcup -s "${BOOTSTRAP_HASKELL_YAML}" tool-requirements ; else ghcup tool-requirements ; fi)"
echo

if [ -z "${BOOTSTRAP_HASKELL_NONINTERACTIVE}" ] ; then
    warn "Press ENTER to proceed or ctrl-c to abort."
    warn "Installation may take a while."
    echo

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

eghcup --cache install ghc "${BOOTSTRAP_HASKELL_GHC_VERSION}"

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

adjust_cabal_config() {
	edo cabal user-config -a "extra-prog-path: $(cygpath -w $GHCUP_BIN), $(cygpath -w "$HOME"/AppData/Roaming/cabal/bin), $(cygpath -w "$GHCUP_DIR"/msys64/usr/bin), $(cygpath -w "$GHCUP_DIR"/msys64/mingw64/bin)" -a "extra-include-dirs: $(cygpath -w "$GHCUP_DIR"/msys64/mingw64/include)" -a "extra-lib-dirs: $(cygpath -w "$GHCUP_DIR"/msys64/mingw64/lib)" -f init
}

case "${plat}" in
        MSYS*|MINGW*)
			if [ -z "${BOOTSTRAP_HASKELL_NONINTERACTIVE}" ] ; then
				warn "Create an initial cabal.config including relevant msys2 paths (recommended)?"
				warn "[Y] Yes  [N] No  [?] Help (default is \"Y\")."
				echo
				while true; do
					read -r mingw_answer </dev/tty

					case $mingw_answer in
						[Yy]* | "")
							adjust_cabal_config
							break ;;
						[Nn]*)
							echo "Make sure that your global cabal.config references the correct mingw64 paths (extra-prog-path, extra-include-dirs and extra-lib-dirs)."
							sleep 5
							break ;;
						*)
							echo "Possible choices are:"
							echo
							echo "Y - Yes, create a cabal.config with pre-set paths to msys2/mingw64 (default)"
							echo "N - No, leave the current/default cabal config untouched"
							echo
							echo "Please make your choice and press ENTER."
							;;
					esac
				done
			else
				adjust_cabal_config
			fi
			;;
esac


edo cabal new-update

if [ -z "${BOOTSTRAP_HASKELL_NONINTERACTIVE}" ] ; then
	warn "Do you want to install haskell-language-server (HLS) now?"
	warn "HLS is a language-server that provides IDE-like functionality"
	warn "and can integrate with different editors, such as Vim, Emacs, VS Code, Atom, ..."
	warn "Also see https://github.com/haskell/haskell-language-server/blob/master/README.md"
	warn ""
	warn "[Y] Yes  [N] No  [?] Help (default is \"N\")."
	warn ""

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

		case $hls_answer in
			[Yy]*)
				eghcup --cache install hls
				break ;;
			[Nn]* | "")
				break ;;
			*)
				echo "Possible choices are:"
				echo
				echo "Y - Yes, install the haskell-langauge-server"
				echo "N - No, don't install anything more (default)"
				echo
				echo "Please make your choice and press ENTER."
				;;
		esac
	done

	warn "Do you want to install stack now?"
	warn "Stack is a haskell build tool similar to cabal that is used by some projects."
	warn "Also see https://docs.haskellstack.org/"
	warn ""
	warn "[Y] Yes  [N] No  [?] Help (default is \"N\")."
	warn ""

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

		case $stack_answer in
			[Yy]*)
				eghcup --cache install stack
				break ;;
			[Nn]* | "")
				break ;;
			*)
				echo "Possible choices are:"
				echo
				echo "Y - Yes, install stack"
				echo "N - No, don't install anything more (default)"
				echo
				echo "Please make your choice and press ENTER."
				;;
		esac
	done

    echo "In order to run ghc and cabal, you need to adjust your PATH variable."
    echo "You may want to source '$GHCUP_DIR/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="$HOME/.zshrc"
				MY_SHELL="zsh"
			else
			    _done
			fi
			;;
		*/fish) # login shell is fish
			GHCUP_PROFILE_FILE="$HOME/.config/fish/config.fish"
			MY_SHELL="fish" ;;
		*) _done ;;
	esac


	warn ""
	warn "Detected ${MY_SHELL} shell on your system..."
	warn "If you want ghcup to automatically add the required PATH variable to \"${GHCUP_PROFILE_FILE}\""
	warn ""
	warn "[Y] Yes  [N] No  [?] Help (default is \"Y\")."
	warn ""

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

        case $next_answer in
            [Nn]*)
                _done ;;
            [Yy]* | "")
				case $MY_SHELL in
					"") break ;;
					fish)
						if ! grep -q "ghcup-env" "${GHCUP_PROFILE_FILE}" ; then
							mkdir -p "${GHCUP_PROFILE_FILE%/*}"
							echo "# ghcup-env" >> "${GHCUP_PROFILE_FILE}"
							echo "set -q GHCUP_INSTALL_BASE_PREFIX[1]; or set GHCUP_INSTALL_BASE_PREFIX \$HOME" >> "${GHCUP_PROFILE_FILE}"
							echo "test -f $GHCUP_DIR/env ; and set -gx PATH \$HOME/.cabal/bin $GHCUP_BIN \$PATH" >> "${GHCUP_PROFILE_FILE}"
						fi
						break ;;
					bash)
						if ! grep -q "ghcup-env" "${GHCUP_PROFILE_FILE}" ; then
							echo "[ -f \"${GHCUP_DIR}/env\" ] && source \"${GHCUP_DIR}/env\" # ghcup-env" >> "${GHCUP_PROFILE_FILE}"
						fi
						case "${plat}" in
							"Darwin"|"darwin")
								if ! grep -q "ghcup-env" "${HOME}/.bash_profile" ; then
									echo "[[ -f ~/.bashrc ]] && source ~/.bashrc # ghcup-env" >> "${HOME}/.bash_profile"
								fi
								;;
						esac
						break ;;

					zsh)
						if ! grep -q "ghcup-env" "${GHCUP_PROFILE_FILE}" ; then
							echo "[ -f \"${GHCUP_DIR}/env\" ] && source \"${GHCUP_DIR}/env\" # ghcup-env" >> "${GHCUP_PROFILE_FILE}"
						fi
						break ;;
				esac
                warn "OK! ${GHCUP_PROFILE_FILE} has been modified. Restart your terminal for the changes to take effect,"
                warn "or type \"source ${GHCUP_DIR}/env\" to apply them in your current terminal session."
				_done
                ;;
			*)
				echo "Possible choices are:"
				echo
				echo "Y - Yes, update my \"${GHCUP_PROFILE_FILE}\" (default)"
				echo "N - No, don't mess with my configuration"
				echo
				echo "Please make your choice and press ENTER."
				;;
        esac
    done
fi

_done

)

# vim: tabstop=4 shiftwidth=4 expandtab