termux-packages/scripts/build/setup/termux_setup_ghc.sh

# Utility function to setup a GHC toolchain.
termux_setup_ghc() {
	if [ "$TERMUX_ON_DEVICE_BUILD" = "false" ]; then
		local TERMUX_GHC_VERSION=8.10.7
		local TERMUX_GHC_TEMP_FOLDER="${TERMUX_COMMON_CACHEDIR}/ghc-${TERMUX_GHC_VERSION}"
		local TERMUX_GHC_TAR="${TERMUX_GHC_TEMP_FOLDER}.tar.xz"
		local TERMUX_GHC_RUNTIME_FOLDER

		if [ "${TERMUX_PACKAGES_OFFLINE-false}" = "true" ]; then
			TERMUX_GHC_RUNTIME_FOLDER="${TERMUX_SCRIPTDIR}/build-tools/ghc-${TERMUX_GHC_VERSION}-runtime"
		else
			TERMUX_GHC_RUNTIME_FOLDER="${TERMUX_COMMON_CACHEDIR}/ghc-${TERMUX_GHC_VERSION}-runtime"
		fi

		export PATH="$TERMUX_GHC_RUNTIME_FOLDER/bin:$PATH"

		[ -d "$TERMUX_GHC_RUNTIME_FOLDER" ] && return

		termux_download "https://downloads.haskell.org/~ghc/${TERMUX_GHC_VERSION}/ghc-${TERMUX_GHC_VERSION}-x86_64-deb10-linux.tar.xz" \
			"$TERMUX_GHC_TAR" \
			a13719bca87a0d3ac0c7d4157a4e60887009a7f1a8dbe95c4759ec413e086d30

		rm -Rf "$TERMUX_GHC_TEMP_FOLDER"
		tar xf "$TERMUX_GHC_TAR" -C "$TERMUX_COMMON_CACHEDIR"

		(
			set -e
			unset CC CXX CFLAGS CXXFLAGS CPPFLAGS LDFLAGS AR AS CPP LD RANLIB READELF STRIP
			cd "$TERMUX_GHC_TEMP_FOLDER"
			./configure --prefix="$TERMUX_GHC_RUNTIME_FOLDER"
			make install
		)

		# Cabal passes a host string to the libraries' configure scripts that isn't valid.
		# After this patch we need to always pass --configure-option=--host=${TERMUX_HOST_PLATFORM}
		# to Setup.hs configure.
		(
			CABAL_TEMP_FOLDER="$(mktemp -d cabal.XXXXXX)"
			cd "${CABAL_TEMP_FOLDER}"

			mkdir -p Cabal-3.6.2.0
			curl -Ls \
				https://hackage.haskell.org/package/Cabal-3.6.2.0/Cabal-3.6.2.0.tar.gz |
				tar xzf - -C Cabal-3.6.2.0 --strip-components=1

			cd Cabal-3.6.2.0
			sed -i 's/maybeHostFlag = i/maybeHostFlag = [] -- i/' src/Distribution/Simple.hs

			runhaskell Setup configure --prefix="${TERMUX_GHC_RUNTIME_FOLDER}"
			runhaskell Setup build
			runhaskell Setup install
			ghc-pkg recache
		)
		rm -Rf "$TERMUX_GHC_TEMP_FOLDER" "$TERMUX_GHC_TAR"
	else
		if [[ "$TERMUX_MAIN_PACKAGE_FORMAT" = "debian" && "$(dpkg-query -W -f '${db:Status-Status}\n' ghc 2>/dev/null)" != "installed" ]] ||
			[[ "$TERMUX_MAIN_PACKAGE_FORMAT" = "pacman" && ! "$(pacman -Q ghc 2>/dev/null)" ]]; then
			echo "Package 'ghc' is not installed."
			exit 1
		fi
	fi
}