class Sus::Output::Backtrace

def self.first(identity = nil)
	# This implementation could be a little more efficient.
	self.new(caller_locations(1), identity&.path, 1)
end

def self.for(exception, identity = nil)
	# I've disabled the root filter here, because partial backtraces are not very useful.
	# We might want to do something to improve presentation of the backtrace based on the root instead.
	self.new(exception.backtrace_locations) # , identity&.path)
end

def filter(root = @root)
	if @root
		stack = @stack.select do |frame|
			frame.path.start_with?(@root)
		end
	else
		stack = @stack
	end
	
	if @limit
		stack = stack.take(@limit)
	end
	
	return stack
end

def initialize(stack, root = nil, limit = nil)
	@stack = stack
	@root = root
	@limit = limit
end

def print(output)
	if @limit == 1
		filter.each do |frame|
			output.write " ", :path, frame.path, :line, ":", frame.lineno
		end
	else
		output.indented do
			filter.each do |frame|
				output.puts :indent, :path, frame.path, :line, ":", frame.lineno, :reset, " ", frame.label
			end
		end
	end
end