package dc9.server.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

import dc9.server.io.world.WorldLoader;
import dc9.server.util.ISAACCipher;

public class RS2LoginProtocol {
    private InputStream in = null;
    private OutputStream out = null;
    private Stream inStream, outStream;
    private ISAACCipher inStreamDecryption, outStreamDecryption;

    public RS2LoginProtocol(Socket s) throws IOException {
        this.in = s.getInputStream();
        this.out = s.getOutputStream();
        this.inStream = new Stream(new byte[2042]);
        this.outStream = new Stream(new byte[2042]);
        login();
    }

    private void login() throws IOException {
        try {
            fillStream(2);

            /**
             * Initial login request (Login opcode)
             */
            int loginOpcode = inStream.readUnsignedByte();
            System.out.println("Login opcode: " + loginOpcode);
            loginOpcode = 0;

            /**
             * Name hash
             */
            @SuppressWarnings("unused")
            int nameHash = inStream.readUnsignedByte();

            /**
             * Write 8 bytes (1 long) to client.
             */
            outStream.writeQWord(1);

            /**
             * Write login opcode back to client
             */
            outStream.writeByte(loginOpcode);

            /**
             * Create and write ISAAC seed half (severSessionKey)
             */
            long serverSessionKey = ((long) (java.lang.Math.random() * 99999999D) << 32)
                    + (long) (java.lang.Math.random() * 99999999D);
            outStream.writeQWord(serverSessionKey);

            /**
             * Flush Stream
             */
            out.write(outStream.buffer, 0, outStream.currentOffset);
            outStream.currentOffset = 0;
            fillStream(2);

            /**
             * Connection opcode
             */
            int opcode = inStream.readUnsignedByte();
            if (opcode != 16 && opcode != 18) {
                System.out.println("Unexpected opcode: " + opcode);
                return;
            }

            /**
             * RSA encrypted block size
             */
            int RSABlockSize = inStream.readUnsignedByte();
            int RSAEncryptedBlockSize = RSABlockSize - (36 + 1 + 1 + 2);
            fillStream(RSABlockSize);

            /**
             * Magic ID (use is unknown)
             */
            int magicID = inStream.readUnsignedByte();
            if (magicID != 255) {
                System.out.println("Expected magid ID of 255; read " + magicID);
                return;
            }

            /**
             * Client version
             */
            int clientVersion = inStream.readUnsignedWord();
            if (clientVersion != 317) {
                System.out.println("Invalid client version: " + clientVersion);
                return;
            }

            /**
             * Memory version
             */
            int memoryVersion = inStream.readUnsignedByte();
            System.out.println("Client memory version: "
                    + (memoryVersion == 0 ? "high" : "low"));

            /**
             * Read CRC keys
             */
            int[] CRC_KEYS = new int[10];
            for (int i = 0; i < 9; i++) {
                CRC_KEYS[i] = inStream.readDWord();
            }

            /**
             * Read RSA encoded block
             */
            RSAEncryptedBlockSize--;
            int RSAEncodedBlock = inStream.readUnsignedByte();
            if (RSAEncryptedBlockSize != RSAEncodedBlock) {
                System.out.println("Encrypted data lenth ("
                        + RSAEncryptedBlockSize
                        + ") did not equal RSA encoded block ("
                        + RSAEncodedBlock + ")");
                return;
            }

            /**
             * RSA opcode
             */
            int RSAOpcode = inStream.readUnsignedByte();
            if (RSAOpcode != 10) {
                System.out.println("RSA opcode was expected to be 10; read "
                        + RSAOpcode);
                return;
            }
            System.out.println("RSA opcode: " + RSAOpcode);

            /**
             * Read server & client session key
             */
            long clientSessionKey = inStream.readQWord();
            serverSessionKey = inStream.readQWord();

            System.out.println("Client session key: " + serverSessionKey);
            System.out.println("Server session key: " + serverSessionKey);

            /**
             * Player username and password
             */
            String username = inStream.readString();
            username.toLowerCase();
            username.trim();
            String properName = Character.toUpperCase(username.charAt(0)) + username.substring(1, username.length());
            username = properName;

            String password = inStream.readString();

            System.out.println("Player username: " + username + ", password: "
                    + password);

            /**
             * ISAAC Seeds
             */
            int seed[] = new int[4];

            seed[0] = (int) (clientSessionKey >> 32);
            seed[1] = (int) clientSessionKey;
            seed[2] = (int) (serverSessionKey >> 32);
            seed[3] = (int) serverSessionKey;

            /**
             * Initialize ISAAC decryptor
             */
            for (int i = 0; i < 4; i++) {
                System.out.println("InStream seed[" + i + "]: 0x"
                        + Integer.toHexString(seed[i]));
            }
            inStreamDecryption = new ISAACCipher(seed);
            for (int i = 0; i < 4; i++) {
                seed[i] += 50;
            }
            for (int i = 0; i < 4; i++) {
                System.out.println("OutStream seed[" + i + "]: 0x"
                        + Integer.toHexString(seed[i]));
            }
            outStreamDecryption = new ISAACCipher(seed);
            outStream.packetEncryption = outStreamDecryption;

            /**
             * Finalize login
             */
            out.write(2);
            out.write(0);
            out.write(0);
        } catch (IOException e) {
            System.err.println("An error occured during log in.");
            e.printStackTrace();
        }

        /**
         * Initialize world loading
         */
        new WorldLoader(outStream, out);
    }

    private void fillStream(int i) throws java.io.IOException {
        inStream.currentOffset = 0;
        in.read(inStream.buffer, 0, i);
    }
}