#!/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.

# Build script to run continuous integration on [Circle CI][1].
#
# [1]: https://circleci.com

# shellcheck disable=SC2181,SC2034,SC1091


# DEPENDENCIES #

# Source nvm to ensure that the `nvm` command is available:
. /opt/circleci/.nvm/nvm.sh


# VARIABLES #

# Define a username:
username="${CIRCLE_USERNAME}"

# Get the total number of VMs (parallelism):
total_nodes="${CIRCLE_NODE_TOTAL}"

# Get the VM index:
index="${CIRCLE_NODE_INDEX}"

# Define an output directory to store unit test results:
tests_log_dir="${CIRCLE_TEST_REPORTS}/junit"

# Define an output file to store log output:
log_file='/var/log/circle-ci.log'

# Determine the root project directory:
root_dir=$(dirname "$0")/../../..
root_dir=$(cd "${root_dir}" && echo "$PWD")

# Define the project source code directory:
base_dir="${root_dir}/lib/node_modules"

# Define the pattern for test filenames:
tests_pattern='test*.js'

# Define the pattern for filtering tests based on their file path:
tests_filter='.*/.*'

# Define the folder name for tests:
tests_folder='test'

# Define the folder name for test fixtures:
tests_fixtures_folder="${tests_folder}/fixtures"

# Define the directory path of top-level node module dependencies:
node_modules="${root_dir}/node_modules"

# Define the directory path for build artifacts:
build_dir="${root_dir}/build"

# Define the directory path for distributable files:
dist_dir="${root_dir}/dist"

# Define the directory path for external library dependencies:
deps_dir="${root_dir}/deps"

# Define the directory path for documentation:
docs_dir="${root_dir}/docs"

# Define the directory path for reports:
reports_dir="${root_dir}/reports"

# Define the directory for top-level tools:
tools_dir="${root_dir}/tools"

# Define the directory for project tools which are Node.js packages:
tools_pkgs_dir="${base_dir}/@stdlib/_tools"

# Define a heartbeat interval to periodically print messages in order to prevent Circle CI from prematurely ending a build due to long running commands:
heartbeat_interval='30s'

# Declare a variable for storing the heartbeat process id:
heartbeat_pid=""


# 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() {
	stop_heartbeat
}

# Starts a heartbeat.
#
# $1 - heartbeat interval
start_heartbeat() {
	echo 'Starting heartbeat...' >&2

	# Create a heartbeat and send to background:
	heartbeat "$1" &

	# Capture the heartbeat pid:
	heartbeat_pid=$!
	echo "Heartbeat pid: ${heartbeat_pid}" >&2
}

# Runs an infinite print loop.
#
# $1 - heartbeat interval
heartbeat() {
	while true; do
		echo "$(date) - heartbeat..." >&2;
		sleep "$1";
	done
}

# Stops the heartbeat print loop.
stop_heartbeat() {
	echo 'Stopping heartbeat...' >&2
	kill "${heartbeat_pid}"
}

# Creates a directory.
#
# $1 - directory path
create_dir() {
	mkdir -p "$1"
}

# Creates an output log file.
#
# $1 - log file path
create_log_file() {
	local owner
	owner=$(whoami)
	echo "Creating an output log file: $1." >&2
	sudo touch "$1"
	sudo chown "${owner}:${owner}" "$1"
}

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

# Sets the Node.js version.
#
# $1 - version
node_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
}

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

# Retries a command a maximum number of times.
#
# $1 - number of retries
# $2 - command to retry
retry() {
	local code
	for i in $(seq 1 "$1"); do
		# By way of operator precedence, the clause after `||` only gets executed if one of the prior commands fails...
		"$2" && code=0 && break || code="$?" && sleep 15;
	done
	return "${code}"
}

# Performs install tasks.
#
# $1 - log file
install() {
	echo 'Installing...' >&2
	make FC=gfortran FORTRAN_COMPILER=gfortran install >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'Error occurred during install.' >&2
		echo 'Retry 1 of 2...' >&2
		sleep 15s
		echo 'Installing...' >&2
		make FC=gfortran FORTRAN_COMPILER=gfortran install >> "$1" 2>&1
		if [[ "$?" -ne 0 ]]; then
			echo 'Error occurred during install.' >&2
			echo 'Retry 2 of 2...' >&2
			sleep 30s
			echo 'Installing...' >&2
			make FC=gfortran FORTRAN_COMPILER=gfortran install >> "$1" 2>&1
			if [[ "$?" -ne 0 ]]; then
				echo 'Error occurred during install.' >&2
				echo 'Failed to install 3 times. Aborting install.' >&2
				return 1
			fi
		fi
	fi
	echo 'Install successful.' >&2
	return 0
}

# Performs development environment initialization tasks.
#
# $1 - log file
dev_init() {
	echo 'Initializing development environment...' >&2
	make init >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'Error occurred during initialization.' >&2
		return 1
	fi
	echo 'Initialization successful.' >&2
	return 0
}

# Initializes the environment.
#
# $1 - Node.js version
# $2 - log file
init() {
	node_version "$1"
	if [[ "$?" -ne 0 ]]; then
		return 1
	fi
	clean_node "$2"
	if [[ "$?" -ne 0 ]]; then
		return 1
	fi
	install "$2"
	if [[ "$?" -ne 0 ]]; then
		return 1
	fi
	dev_init "$2"
	if [[ "$?" -ne 0 ]]; then
		return 1
	fi
	return 0
}

# Checks dependencies.
#
# $1 - log file
check_deps() {
	echo 'Checking dependencies...' >&2
	make check-deps >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'Dependencies are out-of-date.' >&2
		return 1
	fi
	echo 'Dependencies are up-to-date.' >&2
	return 0
}

# Checks licenses.
#
# $1 - log file
check_licenses() {
	echo 'Checking licenses...' >&2
	make check-licenses-production >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'Detected dependency licensing issues.' >&2
		return 1
	fi
	echo 'No dependency licensing issues detected.' >&2
	return 0
}

# Performs lint tasks.
#
# $1 - log file
lint() {
	echo 'Linting filenames...' >&2
	make lint-filenames >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'Linting filenames failed.' >&2
		return 1
	fi
	make lint-header-filenames >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'Linting filenames failed.' >&2
		return 1
	fi
	echo 'Linting package.json files...' >&2
	make lint-pkg-json >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'Linting package.json failed.' >&2
		return 1
	fi
	# FIXME: linting of Markdown files takes too long; need to speed-up via distributed tasks or only linting files which changed
	# echo 'Linting Markdown files...' >&2
	# make lint-markdown >> "$1" 2>&1
	# if [[ "$?" -ne 0 ]]; then
	# 	echo 'Linting Markdown failed.' >&2
	# 	return 1
	# fi
	echo 'Linting passed.' >&2
	return 0
}

# Tests the ability to install the project via npm.
#
# $1 - log file
test_npm_install() {
	echo 'Testing npm install...' >&2
	make test-npm-install >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'npm install failed.' >&2
		return 1
	fi
	echo 'Successfully performed npm install.' >&2

	echo 'Testing npm install (via GitHub)...' >&2
	make test-npm-install-github >> "$1" 2>&1
	if [[ "$?" -ne 0 ]]; then
		echo 'npm install (via GitHub) failed.' >&2
		return 1
	fi
	echo 'Successfully performed npm install (via GitHub).' >&2

	return 0
}

# Finds test files.
find_tests() {
	local kernel
	local tests

	kernel=$(uname -s)

	# On Mac OSX, in order to use `|` and other regular expression operators, we need to use enhanced regular expression syntax (-E); see https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man7/re_format.7.html#//apple_ref/doc/man/7/re_format.
	if [[ "${kernel}" = "Darwin" ]]; then
		tests=$(find -E "${root_dir}" -name "${tests_pattern}" -regex "${tests_filter}" '!' -path "${root_dir}/.*" '!' -path "${node_modules}/*" '!' -path "${tools_dir}/*" '!' -path "${tools_pkgs_dir}/*" '!' -path "${deps_dir}/*" '!' -path "${docs_dir}/*" '!' -path "${build_dir}/*" '!' -path "${dist_dir}/*" '!' -path "${reports_dir}/*" '!' -path "${root_dir}/**/{tests_fixtures_folder}/*")
	else
		tests=$(find "${root_dir}" -regextype posix-extended -name "${tests_pattern}" -regex "${tests_filter}" '!' -path "${root_dir}/.*" '!' -path "${node_modules}/*" '!' -path "${tools_dir}/*" '!' -path "${tools_pkgs_dir}/*" '!' -path "${deps_dir}/*" '!' -path "${docs_dir}/*" '!' -path "${build_dir}/*" '!' -path "${dist_dir}/*" '!' -path "${reports_dir}/*" '!' -path "${root_dir}/**/{tests_fixtures_folder}/*")
	fi
	echo "${tests}"
}

# Allocates tests based on the node (VM) index.
#
# $1 - total number of nodes
# $2 - node index
allocate_tests() {
	local tests

	# Keep those tests (rows) where the VM index equals the modulo:
	tests=$(find_tests | sort | awk -v "n=$1" -v "i=$2" '{if (NR % n == i) printf "%s ", $0} END {print ""}')
	echo "${tests}"
}

# Runs unit tests.
#
# $1 - tests
# $2 - log directory
run_tests() {
	local log_file
	local path
	local slug

	echo 'Running tests...' >&2

	# shellcheck disable=SC2116
	for test in $(echo "$1"); do
		echo "Running test: ${test}" >&2

		# Remove the base source code directory path from the test path (using POSIX shell variable expansion):
		path="${test#${base_dir}/}"

		# Slugify the path (basic algorithm):
		slug=$(echo "${path}" | sed -e 's/[^[:alnum:]]/_/g' | tr -s '-' | tr '[:upper:]' '[:lower:]')

		# Define the output log file path:
		log_file="$2/test-results.${slug}.xml"

		# Create the log file:
		create_log_file "${log_file}"
		if [[ "$?" -ne 0 ]]; then
			echo "Unable to create log file: ${log_file}." >&2
			return 1
		fi
		# Run the tests, writing the results to the created log file:
		make FILES="${test}" test-files-xunit >> "${log_file}" 2>&1
		if [[ "$?" -ne 0 ]]; then
			echo 'Tests failed.' >&2
			return 1
		fi
		echo 'Tests passed.' >&2
	done
	echo 'All tests passed.' >&2
	return 0
}

# Main execution sequence.
main() {
	local TASKS
	local tests
	local task
	local len
	local i

	TASKS=(check_deps check_licenses lint test_npm_install)
	len="${#TASKS[@]}"

	create_log_file "${log_file}"
	if [[ "$?" -ne 0 ]]; then
		on_error 1
	fi
	create_dir "${tests_log_dir}"
	if [[ "$?" -ne 0 ]]; then
		on_error 1
	fi

	# Start the heartbeat:
	start_heartbeat "${heartbeat_interval}"

	# Initialize the environment:
	init stable "${log_file}"
	if [[ "$?" -ne 0 ]]; then
		on_error 1
	fi

	echo 'Assigning initial tasks...' >&2
	i="${index}"
	while [[ "${i}" -lt "${len}" ]]; do
		task="${TASKS[${i}]}"
		echo "Task: ${task}." >&2
		if [[ "${task}" = "check_deps" ]]; then
			check_deps "${log_file}"
			if [[ "$?" -ne 0 ]]; then
				on_error 1
			fi
		elif [[ "${task}" = "check_licenses" ]]; then
			check_licenses "${log_file}"
			if [[ "$?" -ne 0 ]]; then
				on_error 1
			fi
		elif [[ "${task}" = "lint" ]]; then
			lint "${log_file}"
			if [[ "$?" -ne 0 ]]; then
				on_error 1
			fi
		elif [[ "${task}" = "test_npm_install" ]]; then
			test_npm_install "${log_file}"
			if [[ "$?" -ne 0 ]]; then
				on_error 1
			fi
		fi
		# shellcheck disable=SC2003
		i=$(expr "${i}" + "${len}")
	done

	echo 'Allocating tests...' >&2
	tests=$(allocate_tests "${total_nodes}" "${index}")
	echo "${tests}" >&2

	run_tests "${tests}" "${tests_log_dir}"
	if [[ "$?" -ne 0 ]]; then
		on_error 1
	fi

	print_success
	cleanup
	exit 0
}

# Run main:
main