#!/usr/bin/ruby

#I'll put this in here as an example

#

#should maybe use environment variables for these
$CC="g++"
CFLAGS="-O2 -march=native -std=c++17"
$EFLAGS = "" #extra flags
SRCDIR="src"
BUILDDIR="build"
INCLUDE=""
LIB=""
EXT=".cpp" #extension of source file
#should maybe use environment variables for these

#standalone funcs
if __FILE__ == $0
	ANSI_RED = "\e[31m"
	ANSI_CLEAR = "\e[0m"
	RUB = "#{ANSI_RED}RUB#{ANSI_CLEAR}"

	def error(msg)
		puts "#{RUB}: error: #{msg}"
		exit 1
	end

	def message(msg)
		puts "#{RUB}: #{msg}"
	end
end

#handle argument parsing yourself
def parse(arg)
	case arg
	when "clean"
		`rm build/*`
		`rm #{APPNAME}`
		exit(0)

	when "debug"
		$EFLAGS = "-DDEBUG"
		main
	
	else
		#error "unknown argument: #{arg}"
	end

	case arg.split("=")[0]
	when "cc"
		$CC = arg.split("=")[1]
		main
	end
end

#same as above
def args
	case ARGV.count
	when 0
		main
	when 1
		parse(ARGV[0])
	else
		puts "too many arguments"
	end
end

#main build function
def main
	error("src directory empty") if Dir.children(SRCDIR).count == 0

	#create a thread for each compilation unit
	threads = []

	Dir.each_child(SRCDIR) {|x|
		threads << Thread.new {
			system("#{$CC} #{INCLUDE} #{CFLAGS} #{$EFLAGS} -c #{SRCDIR}/#{x} -o #{BUILDDIR}/#{File.basename(x, ".*") + ".o"}") if x.end_with?(EXT)
			message "compiled: #{x}\n" if x.end_with?(EXT)
		}
	}

	threads.each{ |t| t.join }

	#wait for each thread to finish 
	until threads.map { |t| t.alive? }.include?(false) 
	end

	#link
	build = Dir.each_child(BUILDDIR)
	o_files = []
	build.each { |s|
		o_files.append("#{BUILDDIR}/#{s}")
	}

	`#{$CC} #{CFLAGS} #{$EFLAGS} #{o_files.join(" ")} -o #{APPNAME} #{LIB}`
	exit(0)
end

#run some functions
args