#!/usr/bin/env bash

# SPDX-FileCopyrightText: 2023 Patrick Spek <p.spek@tyil.nl>
#
# SPDX-License-Identifier: AGPL-3.0-or-later

# Read a particular value from a key/value configuration file. Using this
# function introduces a dependency on awk.
config() {
	config_for "${BASHTARD_PLATFORM[fqdn]}" "$@"
}

config_subkeys() {
	config_subkeys_for "${BASHTARD_PLATFORM[fqdn]}" "$@"
}

config_for() {
	local host=$1 ; shift
	local key=$1 ; shift

	# Use a variable definition test to define default, in order to ensure
	# it is _not_ defined if no argument for it was passed, but _is_
	# defined even if an empty string was passed.
	test -v 1 && { local default=$1 ; shift ; }

	local default
	local file
	local files

	files=(
		"$BASHTARD_ETCDIR/secrets"
		"$BASHTARD_ETCDIR/hosts.d/$host"
		"$BASHTARD_ETCDIR/os.d/${BASHTARD_PLATFORM[key]}"
		"$BASHTARD_ETCDIR/defaults"
	)

	if [[ -n "$BASHTARD_PLAYBOOK" ]]
	then
		debug "bashtard/config_for" "BASHTARD_PLAYBOOK=$BASHTARD_PLAYBOOK, adding etc entries"
		files+=(
			"$(playbook_path "base")/etc/os.d/${BASHTARD_PLATFORM[key]}"
			"$(playbook_path "base")/etc/defaults"
		)
	fi

	files+=(
		"$BASHTARD_SHAREDIR/os.d/${BASHTARD_PLATFORM[key]}"
		"$BASHTARD_SHAREDIR/defaults"
	)

	# Check configuration files
	for file in "${files[@]}"
	do
		debug "bashtard/config_for" "Checking for '$key' in '$file'"

		[[ ! -f $file ]] && continue

		# Check if the lookup is a reference variable, defined by using
		# &= instead of just a single = as seperator. If this exists,
		# do a new config_for lookup, this time using the value as the
		# key for the new lookup.
		value="$(awk -F= '$1 == "'"$key"'&" { print $0 }' "$file" | cut -d'=' -f 2-)"

		if [[ -n $value ]]
		then
			debug "bashtard/config_for" "Found reference for $key to $value in $file"

			printf "%s" "$(config_for "$host" "$value")"
			return
		fi

		# Use awk to find the right line, then use cut to get the
		# actual value. Cutting it out with awk _is_ possible, but
		# comes with whitespace issues or having to deal with values
		# containing the seperator (=), so using cut is much simpler
		# and easier to understand.
		value="$(awk -F= '$1 == "'"$key"'" { print $0 }' "$file" | cut -d'=' -f 2-)"

		if [[ -n $value ]]
		then
			debug "bashtard/config_for" "Found $key=$value in $file"

			printf "%s" "$value"
			return
		fi
	done

	# Return default value, if one has been defined
	if test -v default
	then
		printf "%s" "$default"
		return
	fi

	# Error
	alert "bashtard/config_for" "No configuration value for $key"
}

config_subkeys_for() {
	local host=$1 ; shift
	local key=$1 ; shift

	local file
	local files
	local results

	files=(
		"$BASHTARD_ETCDIR/secrets"
		"$BASHTARD_ETCDIR/hosts.d/$host"
		"$BASHTARD_ETCDIR/os.d/${BASHTARD_PLATFORM[key]}"
		"$BASHTARD_ETCDIR/defaults"
	)

	if [[ -n "$BASHTARD_PLAYBOOK" ]]
	then
		debug "bashtard/config_for" "BASHTARD_PLAYBOOK=$BASHTARD_PLAYBOOK, adding etc entries"
		files+=(
			"$BASHTARD_ETCDIR/playbooks.d/$BASHTARD_PLAYBOOK/etc/os.d/${BASHTARD_PLATFORM[key]}"
			"$BASHTARD_ETCDIR/playbooks.d/$BASHTARD_PLAYBOOK/etc/defaults"
		)
	fi

	files+=(
		"$BASHTARD_SHAREDIR/os.d/${BASHTARD_PLATFORM[key]}"
		"$BASHTARD_SHAREDIR/defaults"
	)

	# Check configuration files
	for file in "${files[@]}"
	do
		debug "bashtard/config_subkeys" "Checking for subkeys of '$key' in '$file'"

		[[ ! -f $file ]] && continue

		while read -r result
		do
			local subkey

			subkey="$(awk -F. '{ print $1 }' <<< "${result#"$key."}")"

			debug "bashtard/config_subkeys" "Found '$subkey' as subkey of '$key' through '$result'"
			results+=("$subkey")
		done < <(grep "^$key\." "$file" | awk -F= '{ print $1 }')
	done

	# Return unique results
	for result in "${results[@]}"
	do
		printf "%s\n" "$result"
	done | sort -u
}