#!/usr/bin/bash

# declare known fields
base_fields=(pkgver pkgrel epoch)
section_scalar_fields=(pkgdesc url install changelog)
section_arch_fields=(source depends checkdepends makedepends optdepends provides conflicts replaces md5sums sha1sums sha224sums sha256sums sha384sums sha512sums)
section_array_fields=(arch groups license noextract options backup validpgpkeys "${section_arch_fields[@]}")
section_fields=("${section_scalar_fields[@]}" "${section_array_fields[@]}")

# load PKGBUILD
source "${1:-./PKGBUILD}"

# check if a variable is an array
is_array() {
	[[ "$(declare -p $1)" =~ "declare -a" ]]
}

# unset all field variables
clear_fields() {
	for field in "${section_fields[@]}"; do
		eval "unset $field"
	done
}

# print a field with indentation
print_field() {
	printf "\t$1 = %s\n" "$2"	
}

# print a scalar field
print_scalar_field() {
	eval "[[ -v "$1" ]] && print_field '$1' \"\${$1}\""
}

# print all values of an array field
print_array_field() {
	if ! [[ -v "$1" ]]; then return; fi
	if ! is_array "$1"; then
		print_scalar_field "$1"
	fi
	local f
	eval "for f in \"\${$1[@]}\"; do print_field "$1" \"\$f\"; done" 
}

# load section content from its package function
load_section_content() {
	if [[ -n $1 ]]; then
		suffix="_$1"
	else
		suffix=""
	fi
	if [[ ! "$(type -t "package$suffix")" = function ]]; then return; fi
	# eval only variable assignments in package function
	while read -r line; do
		eval "$line"
	done < <(declare -f "package$suffix" | grep -E '^[[:space:]]*(declare +)?[[:alnum:]_]*=')
}

# print fields for a section
print_section_content() {
	for field in "${section_scalar_fields[@]}"; do
		print_scalar_field "$field"
	done

	for field in "${section_array_fields[@]}"; do
		print_array_field "$field"
	done

	for a in "${arch[@]}"; do
		for field in "${section_arch_fields[@]}"; do
			print_array_field "${field}_$a"
		done
	done
}

# main

# determine pkgbase
if ! is_array pkgname; then
	pkgname=($pkgname)
fi
printf "pkgbase = %s\n" "${pkgbase:-${pkgname[0]}}"

# run pkgver function if needed
if [[ ! -v pkgver ]] && [[ "$(type -t pkgver)" = function ]]; then
	pkgver="$(pkgver)"
fi

# load base section content and print it
load_section_content
for field in "${base_fields[@]}"; do
	print_scalar_field "$field"
done
print_section_content

# load section content for each split package and print it
for splitname in "${pkgname[@]}"; do
	printf "\npkgname = %s\n" "$splitname"
	clear_fields
	load_section_content "$splitname"
	print_section_content
done