#!/usr/bin/env bash

TARGET=aarch64-linux-android
export PREFIX=/tmp/"$TARGET"-emerald

export CFLAGS="-O3"
export CPPFLAGS="$CFLAGS"
export CXXFLAGS="$CFLAGS -static-libgcc -static-libstdc++"
export LDFLAGS="-s -w"

export CFLAGS_FOR_TARGET="$CFLAGS"
export CPPFLAGS_FOR_TARGET="$CFLAGS"
export CXXFLAGS_FOR_TARGET="$CFLAGS"
export LDFLAGS_FOR_TARGET="$LDFLAGS"

download() {
	if [ $# != 3 ]; then
		echo "download(): Invalid arguments - expected \$URL \$DESTINATION \$CHECKSUM"
		return 1
	fi
	local URL="$1"
	local DESTINATION="$2"
	local CHECKSUM="$3"

	if [ -f "$DESTINATION" ] && [ "$CHECKSUM" != "SKIP_CHECKSUM" ]; then
		# Keep existing file if checksum matches.
		local EXISTING_CHECKSUM
		EXISTING_CHECKSUM=$(sha256sum "$DESTINATION" | cut -f 1 -d ' ')
		if [ "$EXISTING_CHECKSUM" = "$CHECKSUM" ]; then return; fi
	fi

	local TMPFILE
	TMPFILE=$(mktemp "${TMPDIR:-/tmp}/download.emerald-dl.XXXXXXXXX")
	echo "Downloading ${URL}"
	if curl --fail --retry 20 --retry-connrefused --retry-delay 30 --location --output "$TMPFILE" "$URL"; then
		local ACTUAL_CHECKSUM
		ACTUAL_CHECKSUM=$(sha256sum "$TMPFILE" | cut -f 1 -d ' ')
		if [ "$CHECKSUM" != "SKIP_CHECKSUM" ]; then
			if [ "$CHECKSUM" != "$ACTUAL_CHECKSUM" ]; then
				printf >&2 "Wrong checksum for %s:\nExpected: %s\nFound: %s\n" \
					"$URL" "$ACTUAL_CHECKSUM" "$CHECKSUM"
				return 1
			fi
		elif [ -z "$CHECKSUM" ]; then
			printf "WARNING: No checksum check for %s:\nExpected: %s\n" \
				"$URL" "$ACTUAL_CHECKSUM"
		fi
		mv "$TMPFILE" "$DESTINATION"
		return 0
	fi

	echo "Failed to download $URL" >&2
	return 1
}