package dev.peerat.framework;

import java.lang.reflect.Method;
import java.security.MessageDigest;
import java.util.List;
import java.util.regex.Matcher;

import dev.peerat.framework.utils.json.JsonMap;

public class RouteMapper<U extends User>{
	
	private Router<U> router;
	
	private RouteState[] states;
	private int[] calls;
	private int dif;
	
	public RouteMapper(Router<U> router){
		this.router = router;
		this.states = new RouteState[0];
	}

	public void register(Object instance, Method method, Route route){
		int length = states.length+1;
		method.setAccessible(true);
		this.states = addElement(states, new RouteState[length], new RouteState(instance, method, route));
		if(this.calls != null) this.calls = new int[length];
	}
	
	public void activeReOrdering(){
		this.calls = new int[states.length];
		this.dif = 2;
	}
	
	public boolean exec(Context context, HttpReader reader, HttpWriter writer, List<RouteInterceptor> interceptors) throws Exception{
		RouteState target = null;
		Matcher matcher = null;
		
		String path = context.getPath();
		
		synchronized(states){
			for(int i = 0; i < states.length; i++){
				RouteState state = states[i];
				matcher = state.match(path);
				if(matcher != null){
					if(state.isWebSocket()){
						switchToWebSocket(reader, writer);
						reader = new WebSocketReader(reader);
						writer = new WebSocketWriter(writer);
						if(state.needLogin()){
							String token = reader.<JsonMap>readJson().get("token");
							context.setUser(this.router.getUser(token));
						}
					}
					if((!context.isLogged()) && state.needLogin()){
						writer.response(401, router.getDefaultHeaders(context.getType()));
						return true;
					}
					target = state;
					order(i);
					break;
				}
			}
		}
		if(target != null){
			for(RouteInterceptor interceptor : interceptors){
				if(!interceptor.intercept(matcher, context, reader, writer, target.getMethod())) return true;
			}
			target.getMethod().invoke(target.getInstance(), target.bindMethod(matcher, context, reader, writer));
			return true;
		}
		return false;
	}
	
	private void order(int index){
		if(this.calls == null) return;
		int call = this.calls[index]++;
		if(call >= (Integer.MAX_VALUE-(dif+1))){
			for(int i = 0; i < this.calls.length; i++) this.calls[i]/=dif;
			dif++;
			call = this.calls[index];
		}
		if(index < 1) return;
		if(call > this.calls[index-1]){
			switchElement(states, index, index-1);
			
			this.calls[index] = this.calls[index-1];
			this.calls[index-1] = call;
		}
	}
	
	private <E> E[] addElement(E[] current, E[] growed, E element){
		System.arraycopy(current, 0, growed, 0, current.length);
		growed[current.length] = element;
		return growed;
	}
	
	private <E> void switchElement(E[] array, int before, int after){
		E tmp = array[before];
		array[before] = array[after];
		array[after] = tmp;
	}
	
	private void switchToWebSocket(HttpReader reader, HttpWriter writer) throws Exception{
		String key = reader.getHeader("Sec-WebSocket-Key");
		if (key == null) throw new IllegalArgumentException();

		writer.write("HTTP/1.1 101 Switching Protocols\n");
		writer.write("Connection: Upgrade\n");
		writer.write("Upgrade: websocket\n");
		writer.write("Sec-WebSocket-Accept: " + printBase64Binary(MessageDigest.getInstance("SHA-1")
					.digest((key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").getBytes("UTF-8"))) + "\n");
		writer.write("\n");
		writer.flush();
	}


	// From javax.xml.bind.DatatypeConverter
	private String printBase64Binary(byte[] array){
		char[] arrayOfChar = new char[(array.length + 2) / 3 * 4];
		int i = _printBase64Binary(array, 0, array.length, arrayOfChar, 0);
		assert i == arrayOfChar.length;
		return new String(arrayOfChar);
	}

	private int _printBase64Binary(byte[] paramArrayOfbyte, int paramInt1, int paramInt2,
			char[] paramArrayOfchar, int paramInt3){
		int i = paramInt2;
		int j;
		for (j = paramInt1; i >= 3; j += 3){
			paramArrayOfchar[paramInt3++] = encode(paramArrayOfbyte[j] >> 2);
			paramArrayOfchar[paramInt3++] = encode(
					(paramArrayOfbyte[j] & 0x3) << 4 | paramArrayOfbyte[j + 1] >> 4 & 0xF);
			paramArrayOfchar[paramInt3++] = encode(
					(paramArrayOfbyte[j + 1] & 0xF) << 2 | paramArrayOfbyte[j + 2] >> 6 & 0x3);
			paramArrayOfchar[paramInt3++] = encode(paramArrayOfbyte[j + 2] & 0x3F);
			i -= 3;
		}
		if (i == 1){
			paramArrayOfchar[paramInt3++] = encode(paramArrayOfbyte[j] >> 2);
			paramArrayOfchar[paramInt3++] = encode((paramArrayOfbyte[j] & 0x3) << 4);
			paramArrayOfchar[paramInt3++] = '=';
			paramArrayOfchar[paramInt3++] = '=';
		}
		if (i == 2){
			paramArrayOfchar[paramInt3++] = encode(paramArrayOfbyte[j] >> 2);
			paramArrayOfchar[paramInt3++] = encode(
					(paramArrayOfbyte[j] & 0x3) << 4 | paramArrayOfbyte[j + 1] >> 4 & 0xF);
			paramArrayOfchar[paramInt3++] = encode((paramArrayOfbyte[j + 1] & 0xF) << 2);
			paramArrayOfchar[paramInt3++] = '=';
		}
		return paramInt3;
	}

	private char encode(int paramInt){
		return encodeMap[paramInt & 0x3F];
	}

	private static final char[] encodeMap = initEncodeMap();

	private static char[] initEncodeMap(){
		char[] arrayOfChar = new char[64];
		byte b;
		for (b = 0; b < 26; b++)
			arrayOfChar[b] = (char) (65 + b);
		for (b = 26; b < 52; b++)
			arrayOfChar[b] = (char) (97 + b - 26);
		for (b = 52; b < 62; b++)
			arrayOfChar[b] = (char) (48 + b - 52);
		arrayOfChar[62] = '+';
		arrayOfChar[63] = '/';
		return arrayOfChar;
	}

}