package org.unicode.cldr.draft;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.regex.MatchResult;

import com.ibm.icu.text.UCharacterIterator;

/**
 * Compresses list of Unicode character ranges given as starting and ending char
 * into a Base88 string.
 * 
 * Compression usage:
 * String encodedStr = base88EncodeList(List<Interval>);
 * 
 * Decompression usage:
 * List<Interval> decodedStrList = base88DecodeList(encodedStr);
 * 
 * Interval has two integers - first, last - to represent the range.
 */

public class CharacterListCompressor {

    static class Interval {
        int first;
        int last;

        public Interval(int first, int last) {
            this.first = first;
            this.last = last;
        }

        public String toString() {
            return "«" + first + "-" + last + "»";
        }

        public int first() {
            return first;
        }

        public int last() {
            return last;
        }
    }

    //
    // Pairs to Base88 methods
    //

    public static List<Integer> unicode2Base88(int code) {

        List<Integer> list = new ArrayList<Integer>();
        int rem = code % 88;
        list.add(rem);
        code = code / 88;

        if (code != 0) {
            rem = code % 88;
            list.add(rem);
            code = code / 88;
        }
        if (code != 0) {
            rem = code % 88;
            list.add(rem);
            code = code / 88;

            rem = code % 88;
            list.add(rem);
            code = code / 88;
        }
        return list;
    }

    public static int byteCount4Base88(int code) {
        int count = 0;
        code = code / 88;

        if (code != 0) {
            count = 1;
            code = code / 88;
        }
        if (code != 0) {
            count = 2;
        }
        return count;
    }

    public static List<Integer> compressPair2Base88(List<Integer> pair) {
        int value = pair.get(0);
        int type = pair.get(1);
        int code = value * 8 + type * 3;
        code += byteCount4Base88(code);

        return unicode2Base88(code);
    }

    public static List<List<Integer>> decodeBase88ToValueTypePairs(String str) {
        List<Integer> list = str2list(str);

        int metawindowsize = 8;
        List<List<Integer>> result = new ArrayList<List<Integer>>();
        int i = 0;

        while (i < list.size()) {
            int c = list.get(i);
            int meta = c % metawindowsize;
            int type = meta / 3;
            int leng = (meta % 3) + 1;

            if (leng == 3) {
                leng++;
            }

            int value = getCodeFromListAt(list, i, leng) / metawindowsize;
            addPair(result, value, type);
            i += leng;
        }
        return result;
    }

    public static int getCodeFromListAt(List<Integer> list, int start, int leng) {
        int result = 0;
        for (int i = 0; i < leng; i++) {
            int c = list.get(start + i);
            result += c * Math.pow(88, i);
        }
        return result;
    }

    public static void addPair(List<List<Integer>> pairs, int value, int type) {
        List<Integer> pair = new ArrayList<Integer>();
        pair.add(value);
        pair.add(type);
        pairs.add(pair);
    }

    public static String encodeValueTypePairs2Base88(List<List<Integer>> pairs) {
        List<Integer> result = new ArrayList<Integer>();
        for (int i = 0; i < pairs.size(); i++) {
            List<Integer> pair = pairs.get(i);
            result.addAll(compressPair2Base88(pair));
        }
        return list2str(result);
    }

    public final static String ascii = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%()*+,-.:;<=>?@[]^_`{|}~";

    public static String list2str(List<Integer> list) {
        StringBuilder str = new StringBuilder();
        for (int i = 0; i < list.size(); i++) {
            int code = list.get(i);

            str.append(ascii.charAt(code));
        }
        return str.toString();
    }

    public static List<Integer> str2list(String str) {
        List<Integer> list = new ArrayList<Integer>();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            int code = ascii.indexOf(ch);

            list.add(code);
        }
        return list;
    }

    public static String base88EncodeList(List<Interval> intervalList) {
        List<List<Integer>> pairs = getValueTypePairsFromStrRangeList(intervalList);
        String encoded = encodeValueTypePairs2Base88(pairs);

        return encoded;
    }

    public static List<Interval> base88DecodeList(String base88String) {
        List<List<Integer>> pairs = decodeBase88ToValueTypePairs(base88String);
        List<Interval> decoded = getStrRangeListFromValueTypePairs(pairs);

        return decoded;
    }

    // end of compression methods

    // Value Type pairs -- Str Range List
    public static List<List<Integer>> getValueTypePairsFromStrRangeList(List<Interval> ilist) {
        List<List<Integer>> result = new ArrayList<List<Integer>>();
        int lastCode = 0;

        for (int i = 0; i < ilist.size(); i++) {
            int value = 0;
            int first = ilist.get(i).first;
            int last = ilist.get(i).last;

            if (lastCode < first) {
                addPair(result, first - lastCode - 1, 0);
            }
            else if (lastCode > first) {
                addPair(result, lastCode - first - 1, 1);
            }
            else if (lastCode == first) {
                System.out.println("I am not expecting two contiguous chars to be the same");
            }
            lastCode = first;

            if (first < last) {
                value = last - first - 1;

                // range is big and spit it
                int rangesize = 0x3c8; // 968 = 88 * 88 / 8
                while (value >= rangesize) {

                    addPair(result, rangesize - 1, 2); // rangesize chars - 0..(rangesize - 1)
                    value -= rangesize; // rangesize chars are already added above
                    lastCode += rangesize;
                }
                addPair(result, value, 2);
                lastCode = last;
            }
        }
        return result;
    }

    public static List<Interval> getStrRangeListFromValueTypePairs(List<List<Integer>> pairs) {
        ArrayList<Interval> result = new ArrayList<Interval>();

        int lastCode = 0;
        for (int i = 0; i < pairs.size(); i++) {
            List<Integer> pair = pairs.get(i);

            int value = pair.get(0);
            int type = pair.get(1);

            if (type == 0) {
                lastCode += value + 1;
                addInterval(result, lastCode, lastCode);
            }
            else if (type == 1) {
                lastCode -= value + 1;
                addInterval(result, lastCode, lastCode);
            }
            else if (type == 2) {
                int first = lastCode + 1;
                int last = first + value;
                addInterval(result, first, last);
                lastCode += value + 1;
            }
        }
        return result;
    }

    public static void addInterval(List<Interval> list, int first, int last) {
        Interval i = new Interval(first, last);
        list.add(i);
    }

    // Str Range List -- Range Str

    public static List<Interval> getStrRangeListFromRangeStr(String str) {
        ArrayList<Interval> result = new ArrayList<Interval>();
        final UCharacterIterator it = UCharacterIterator.getInstance(str);

        int first;
        while ((first = it.nextCodePoint()) != UCharacterIterator.DONE) {
            int last = it.nextCodePoint();
            addInterval(result, first, last);
        }
        return result;
    }

    //
    // To String methods
    //
    public static String strRangeList2string(List<Interval> ilist) {

        StringBuilder sbuild = new StringBuilder();
        for (int i = 0; i < ilist.size(); i++) {
            int first = ilist.get(i).first;
            int last = ilist.get(i).last;

            for (int j = first; j <= last; j++) {
                sbuild.appendCodePoint(j);
            }
        }
        return sbuild.toString();
    }

    public static String rangeString2string(String rstr) {

        StringBuilder sbuild = new StringBuilder();
        final UCharacterIterator it = UCharacterIterator.getInstance(rstr);

        int first;
        while ((first = it.nextCodePoint()) != UCharacterIterator.DONE) {
            int last = it.nextCodePoint();

            for (int j = first; j <= last; j++) {
                sbuild.appendCodePoint(j);
            }
        }
        return sbuild.toString();
    }

    //
    // String comparison methods
    //

    public static boolean isStringsEqual(String s1, String s2) {

        final UCharacterIterator it1 = UCharacterIterator.getInstance(s1);
        final UCharacterIterator it2 = UCharacterIterator.getInstance(s2);
        int c1 = 0;
        int c2 = 0;
        int count = 0;
        while (c1 == c2 && c1 != UCharacterIterator.DONE) {
            count++;
            c1 = it1.nextCodePoint();
            c2 = it2.nextCodePoint();

            System.out.print("Comparing c1 = c2 = ");
            System.out.print(c1);
            System.out.print((char) c1);
            System.out.print(" ; count = ");
            System.out.println(count);
        }
        System.out.print(count);
        System.out.println(" characters compared");

        if (c1 != c2) {
            System.out.print("Mismatch at c1 = ");
            System.out.print(c1);
            System.out.print(" c2 = ");
            System.out.println(c2);
            return false;
        }
        return true;
    }

    // Main

    public static void main(String[] args) {

        StringBuilder strBuild = new StringBuilder();
        try {
            Scanner sc = new Scanner(new File("/home/cibu/CharData.java"), "UTF-8");
            while (sc.hasNext()) {
                if (sc.findInLine("\\/\\*.*,\"(.*)\"},\\s*") != null) {
                    MatchResult match = sc.match();
                    String str = match.group(1);
                    str = str.replaceAll("\\\\(.)", "$1");
                    System.out.println(str);
                    strBuild.append(str);
                }
                else {
                    sc.next();
                }
            }
            sc.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        String str = strBuild.toString();

        if (str.length() == 0) {
            str = "\uDBFF\uDC00\uDBFF\uDFFD\u0001\u0001";
        }

        List<Interval> ilist = getStrRangeListFromRangeStr(str);

        String encodedStr = base88EncodeList(ilist);
        List<Interval> decodedStrRangeList = base88DecodeList(encodedStr);

        String str1 = rangeString2string(str);
        String str2 = strRangeList2string(decodedStrRangeList);
        isStringsEqual(str1, str2);

        try {
            BufferedWriter out = new BufferedWriter(new FileWriter("/tmp/compressed.txt"));
            out.write(encodedStr);
            out.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}
