local Array = require("lockbox.util.array");
local Stream = require("lockbox.util.stream");
local Queue = require("lockbox.util.queue");

local String = require("string");
local Bit = require("lockbox.util.bit");

local PCBC = {};

PCBC.Cipher = function()

	local public = {};

	local key;
	local blockCipher;
	local padding;
	local inputQueue;
	local outputQueue;
	local iv;

	public.setKey = function(keyBytes)
		key = keyBytes;
		return public;
	end

	public.setBlockCipher = function(cipher)
		blockCipher = cipher;
		return public;
	end

	public.setPadding = function(paddingMode)
		padding = paddingMode;
		return public;
	end

	public.init = function()
		inputQueue = Queue();
		outputQueue = Queue();
		iv = nil;
		return public;
	end

	public.update = function(messageStream)
		local byte = messageStream();
		while (byte ~= nil) do
			inputQueue.push(byte);
			if(inputQueue.size() >= blockCipher.blockSize) then
				local block = Array.readFromQueue(inputQueue,blockCipher.blockSize);

				if(iv == nil) then
					iv = block;
				else
					local out = block;
					out = Array.XOR(iv,out);
					out = blockCipher.encrypt(key,out);
					iv = Array.XOR(out,block);
					Array.writeToQueue(outputQueue,out);
				end
			end
			byte = messageStream();
		end
		return public;
	end

	public.finish = function()
		paddingStream = padding(blockCipher.blockSize,inputQueue.getHead());
		public.update(paddingStream);

		return public;
	end

	public.getOutputQueue = function()
		return outputQueue;
	end

	public.asHex = function()
		return Stream.toHex(outputQueue.pop);
	end

	public.asBytes = function()
		return Stream.toArray(outputQueue.pop);
	end

	return public;

end

PCBC.Decipher = function()

	local public = {};

	local key;
	local blockCipher;
	local padding;
	local inputQueue;
	local outputQueue;
	local iv;

	public.setKey = function(keyBytes)
		key = keyBytes;
		return public;
	end

	public.setBlockCipher = function(cipher)
		blockCipher = cipher;
		return public;
	end

	public.setPadding = function(paddingMode)
		padding = paddingMode;
		return public;
	end

	public.init = function()
		inputQueue = Queue();
		outputQueue = Queue();
		iv = nil;
		return public;
	end

	public.update = function(messageStream)
		local byte = messageStream();
		while (byte ~= nil) do
			inputQueue.push(byte);
			if(inputQueue.size() >= blockCipher.blockSize) then
				local block = Array.readFromQueue(inputQueue,blockCipher.blockSize);

				if(iv == nil) then
					iv = block;
				else
					local out = block;
					out = blockCipher.decrypt(key,out);
					out = Array.XOR(iv,out);
					Array.writeToQueue(outputQueue,out);
					iv = Array.XOR(out,block);
				end
			end
			byte = messageStream();
		end
		return public;
	end

	public.finish = function()
		paddingStream = padding(blockCipher.blockSize,inputQueue.getHead());
		public.update(paddingStream);

		return public;
	end

	public.getOutputQueue = function()
		return outputQueue;
	end

	public.asHex = function()
		return Stream.toHex(outputQueue.pop);
	end

	public.asBytes = function()
		return Stream.toArray(outputQueue.pop);
	end

	return public;

end


return PCBC;