#!/usr/bin/env bash
#
# @license Apache-2.0
#
# Copyright (c) 2017 The Stdlib Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Script to run unit tests against multiple Node.js versions.
#
# Note that this script depends on [nvm][1]. To install `nvm`, see the nvm [documentation][1].
#
# [1]: https://github.com/creationix/nvm


# DEPENDENCIES #

# Source nvm to ensure that the `nvm` command is available:
. "${HOME}/.nvm/nvm.sh"


# VARIABLES #

# Initialize the test file list:
tests=''

# Define the Node.js versions to test:
versions=(0.10 0.12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 node)

# Cache the current Node.js version:
current_version=$(nvm current)


# FUNCTIONS #

# Defines an error handler.
#
# $1 - error status
on_error() {
	echo 'ERROR: An error was encountered during execution.' >&2
	cleanup
	exit "$1"
}

# Runs clean-up tasks.
cleanup() {
	init "${current_version}"
}

# Prints usage information.
usage() {
	echo '' >&2
	echo 'Usage: test_node_versions [options] file1 file2 ...' >&2
	echo '' >&2
	echo 'Options:' >&2
	echo '' >&2
	echo '  -h,    --help                Print this message.' >&2
	echo '         --versions versions   Versions to test; e.g., `4,5,6`.' >&2
	echo '' >&2
}

# Prints a success message.
print_success() {
	echo 'Success!' >&2
}

# Installs a Node.js version.
#
# $1 - version
install_version() {
	echo "Installing Node.js version: $1..." >&2
	nvm install "$1"
	if [[ "$?" -ne 0 ]]; then
		echo "Unable to install Node.js version: $1." >&2
		return 1
	fi
	# Update the npm client. Older clients cannot, e.g., handle scoped modules.
	npm update -g npm

	echo "Successfully installed Node.js version: $1." >&2
	return 0
}

# Sets the Node.js version.
#
# $1 - version
set_version() {
	echo "Switching to Node.js version: $1..." >&2
	nvm use "$1"
	if [[ "$?" -ne 0 ]]; then
		echo "Unable to set Node.js version to $1." >&2
		return 1
	fi
	echo "Node.js version set to $1." >&2
	return 0
}

# Removes a Node.js version.
#
# $1 - version
uninstall_version() {
	echo "Removing Node.js version: $1..." >&2
	nvm uninstall "$1"
	if [[ "$?" -ne 0 ]]; then
		echo "Unable to remove Node.js version: $1." >&2
		return 1
	fi
	echo "Successfully removed Node.js version: $1." >&2
	return 0
}

# Remove node modules.
clean_node() {
	echo 'Removing node module dependencies...' >&2
	make clean-node
	if [[ "$?" -ne 0 ]]; then
		echo 'Error when attempting to remove dependencies.' >&2
		return 1
	fi
	echo 'Dependencies successfully removed.' >&2
	return 0
}

# Installs dependencies.
install() {
	echo 'Installing...' >&2
	make install-node
	if [[ "$?" -ne 0 ]]; then
		echo 'Error occurred during install.' >&2
		return 1
	fi
	echo 'Install successful.' >&2
	return 0
}

# Initializes a Node.js environment.
#
# $1 - Node.js version
init() {
	set_version "$1"
	if [[ "$?" -ne 0 ]]; then
		return 1
	fi
	clean_node
	if [[ "$?" -ne 0 ]]; then
		return 1
	fi
	install
	if [[ "$?" -ne 0 ]]; then
		return 1
	fi
	return 0
}

# Runs unit tests.
#
# $1 - list of Node.js versions to test
run_tests() {
	local version
	local flg

	for v in $(echo "$1"); do
		# Reset the cleanup flag:
		flg='0'

		# Resolve a version to a locally installed version:
		version=$(nvm version "${v}")
		if [[ "${version}" = "N/A" ]]; then
			echo "Unable to resolve \`${v}\` to a locally installed version." >&2
			flg='1'
			install_version "${v}"
			if [[ "$?" -ne 0 ]]; then
				on_error 1
			fi
		else
			echo "Resolved \`${v}\` to locally installed version \`${version}\`." >&2
		fi
		init "${v}"
		if [[ "$?" -ne 0 ]]; then
			on_error 1
		fi
		make TESTS="'""${tests}""'" test
		# Note: we don't explicitly handle return values here in order to let tests complete across all versions.

		# If the version was not already installed, reset the current version and remove the recently installed version...
		if [[ "${flg}" = "1" ]]; then
			set_version "${current_version}"
			uninstall_version "${v}"
			if [[ "$?" -ne 0 ]]; then
				on_error 1
			fi
		fi
	done
}

# Main execution sequence.
main() {
	run_tests "${versions[*]}"
	print_success
	cleanup
	exit 0
}

# Parse command-line options...
while :; do
	case "$1" in
		'-h' | '--help')
			usage
			exit 0
			;;

		'--versions')
			if [[ -n "$2" ]]; then
				versions="$2"
				shift
			else
				printf 'ERROR: "--versions" option requires a non-empty option argument.\n' >&2
				on_error 1
			fi
			;;

		'--versions='?*)
			# Delete everything up to "=" and assign the remainder:
			versions="${1#*=}"
			;;

		'--versions=')
			# Handle empty `--versions=` option:
			printf 'ERROR: "--versions" option requires a non-empty option argument.\n' >&2
				on_error 1
			;;

		'--')
			# End of all options:
			shift
			break
			;;

		-?*)
			printf 'WARNING: unknown option (ignored): %s\n' "$1" >&2
			break
			;;

		*)
			# Default case (e.g., if no more options) break out of loop:
			break
	esac

	shift
done

# Test file paths are the rest of the positional parameters:
tests="$@"

# Run main:
main