package com.enation.framework.util;


import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.CharArrayWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;

/**
 * Provides encoding of raw bytes to base64-encoded characters, and
 * decoding of base64 characters to raw bytes.
 * date: 06 August 1998
 * modified: 14 February 2000
 * modified: 22 September 2000
 *
 * @author Kevin Kelley (kelley@ruralnet.net)
 * @version 1.3
 */
public class Base64 {

    /**
     * returns an array of base64-encoded characters to represent the
     * passed data array.
     *
     * @param data the array of bytes to encode
     * @return base64-coded character array.
     */
    public static char[] encode(byte[] data) {
        char[] out = new char[((data.length + 2) / 3) * 4];

        //
        // 3 bytes encode to 4 chars.  Output is always an even
        // multiple of 4 characters.
        //
        for (int i = 0, index = 0; i < data.length; i += 3, index += 4) {
            boolean quad = false;
            boolean trip = false;

            int val = (0xFF & data[i]);
            val <<= 8;
            if ((i + 1) < data.length) {
                val |= (0xFF & data[i + 1]);
                trip = true;
            }
            val <<= 8;
            if ((i + 2) < data.length) {
                val |= (0xFF & data[i + 2]);
                quad = true;
            }
            out[index + 3] = alphabet[(quad ? (val & 0x3F) : 64)];
            val >>= 6;
            out[index + 2] = alphabet[(trip ? (val & 0x3F) : 64)];
            val >>= 6;
            out[index + 1] = alphabet[val & 0x3F];
            val >>= 6;
            out[index + 0] = alphabet[val & 0x3F];
        }
        return out;
    }

    /**
     * Decodes a BASE-64 encoded stream to recover the original
     * data. White space before and after will be trimmed away,
     * but no other manipulation of the input will be performed.
     *
     * As of version 1.2 this method will properly handle input
     * containing junk characters (newlines and the like) rather
     * than throwing an error. It does this by pre-parsing the
     * input and generating from that a count of VALID input
     * characters.
     **/
    public static byte[] decode(char[] data) {
        // as our input could contain non-BASE64 data (newlines,
        // whitespace of any sort, whatever) we must first adjust
        // our count of USABLE data so that...
        // (a) we don't misallocate the output array, and
        // (b) think that we miscalculated our data length
        //     just because of extraneous throw-away junk

        int tempLen = data.length;
        for (int ix = 0; ix < data.length; ix++) {
            if ((data[ix] > 255) || codes[data[ix]] < 0)
                --tempLen; // ignore non-valid chars and padding
        }
        // calculate required length:
        //  -- 3 bytes for every 4 valid base64 chars
        //  -- plus 2 bytes if there are 3 extra base64 chars,
        //     or plus 1 byte if there are 2 extra.

        int len = (tempLen / 4) * 3;
        if ((tempLen % 4) == 3)
            len += 2;
        if ((tempLen % 4) == 2)
            len += 1;

        byte[] out = new byte[len];


        int shift = 0; // # of excess bits stored in accum
        int accum = 0; // excess bits
        int index = 0;

        // we now go through the entire array (NOT using the 'tempLen' value)
        for (int ix = 0; ix < data.length; ix++) {
            int value = (data[ix] > 255) ? -1 : codes[data[ix]];

            if (value >= 0)// skip over non-code
            {
                accum <<= 6; // bits shift up by 6 each time thru
                shift += 6; // loop, with new bits being put in
                accum |= value; // at the bottom.
                if (shift >= 8)// whenever there are 8 or more shifted in,
                {
                    shift -= 8; // write them out (from the top, leaving any
                    out[index++] = // excess at the bottom for next iteration.
                        (byte) ((accum >> shift) & 0xff);
                }
            }
            // we will also have skipped processing a padding null byte ('=') here;
            // these are used ONLY for padding to an even length and do not legally
            // occur as encoded data. for this reason we can ignore the fact that
            // no index++ operation occurs in that special case: the out[] array is
            // initialized to all-zero bytes to start with and that works to our
            // advantage in this combination.
        }

        // if there is STILL something wrong we just have to throw up now!
        if (index != out.length) {
            throw new Error("Miscalculated data length (wrote " +
                index + " instead of " + out.length + ")");
        }

        return out;
    }


    //
    // code characters for values 0..63
    //
    private static char[] alphabet =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".toCharArray();

    //
    // lookup table for converting base64 characters to value in range 0..63
    //
    private static byte[] codes = new byte[256];

    static {
        for (int i = 0; i < 256; i++)
            codes[i] = -1;
        for (int i = 'A'; i <= 'Z'; i++)
            codes[i] = (byte) (i - 'A');
        for (int i = 'a'; i <= 'z'; i++)
            codes[i] = (byte) (26 + i - 'a');
        for (int i = '0'; i <= '9'; i++)
            codes[i] = (byte) (52 + i - '0');
        codes['+'] = 62;
        codes['/'] = 63;
    }




    ///////////////////////////////////////////////////
    // remainder (main method and helper functions) is
    // for testing purposes only, feel free to clip it.
    ///////////////////////////////////////////////////

    public static void main(String[] args) {
        boolean decode = false;

        if (args.length == 0) {
            //System.out.println("usage:  java Base64 [-d[ecode]] filename");
            System.exit(0);
        }
        for (int i = 0; i < args.length; i++) {
            if ("-decode".equalsIgnoreCase(args[i]))
                decode = true;
            else if ("-d".equalsIgnoreCase(args[i]))
                decode = true;
        }

        String filename = args[args.length - 1];
        File file = new File(filename);
        if (!file.exists()) {
            //System.out.println("Error:  file '" + filename + "' doesn't exist!");
            System.exit(0);
        }

        if (decode) {
            char[] encoded = readChars(file);
            byte[] decoded = decode(encoded);
            writeBytes(file, decoded);
        }
        else {
            byte[] decoded = readBytes(file);
            char[] encoded = encode(decoded);
            writeChars(file, encoded);
        }
    }

    private static byte[] readBytes(File file) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            InputStream fis = new FileInputStream(file);
            InputStream is = new BufferedInputStream(fis);
            int count = 0;
            byte[] buf = new byte[16384];
            while ((count = is.read(buf)) != -1) {
                if (count > 0)
                    baos.write(buf, 0, count);
            }
            is.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        return baos.toByteArray();
    }

    private static char[] readChars(File file) {
        CharArrayWriter caw = new CharArrayWriter();
        try {
            Reader fr = new FileReader(file);
            Reader in = new BufferedReader(fr);
            int count = 0;
            char[] buf = new char[16384];
            while ((count = in.read(buf)) != -1) {
                if (count > 0)
                    caw.write(buf, 0, count);
            }
            in.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        return caw.toCharArray();
    }

    private static void writeBytes(File file, byte[] data) {
        try {
            OutputStream fos = new FileOutputStream(file);
            OutputStream os = new BufferedOutputStream(fos);
            os.write(data);
            os.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void writeChars(File file, char[] data) {
        try {
            Writer fos = new FileWriter(file);
            Writer os = new BufferedWriter(fos);
            os.write(data);
            os.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
    ///////////////////////////////////////////////////
    // end of test code.
    ///////////////////////////////////////////////////

}