/*
 **********************************************************************
 * Copyright (c) 2002-2010, International Business Machines
 * Corporation and others.  All Rights Reserved.
 **********************************************************************
 * Author: John Emmons
 **********************************************************************
 */

package org.unicode.cldr.posix;

import java.io.PrintWriter;
import java.util.BitSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import org.unicode.cldr.util.CLDRFile;
import org.unicode.cldr.util.SortedBag;

import com.ibm.icu.impl.Utility;
import com.ibm.icu.lang.UCharacter;
import com.ibm.icu.text.CollationElementIterator;
import com.ibm.icu.text.Normalizer;
import com.ibm.icu.text.RuleBasedCollator;
import com.ibm.icu.text.UTF16;
import com.ibm.icu.text.UnicodeSet;
import com.ibm.icu.text.UnicodeSetIterator;

public class POSIX_LCCollate {

    public RuleBasedCollator col;
    UnicodeSet chars;
    SortedBag allItems;
    SortedBag contractions;
    CLDRFile collrules;
    int longest_char;

    public POSIX_LCCollate(CLDRFile doc, UnicodeSet repertoire, CLDRFile collrules, UnicodeSet CollateSet,
        String codeset, POSIXVariant variant) throws Exception {
        String rules = "";
        String collationType = "standard";
        boolean UsingDefaultCollateSet = false;

        if (CollateSet.isEmpty()) // Generate default collation set from exemplar characters;
        {
            CollateSet.addAll(repertoire);
            UsingDefaultCollateSet = true;
        }

        chars = new UnicodeSet(repertoire).retainAll(CollateSet);

        this.collrules = collrules;
        if (collrules != null) {
            if (variant.collation_type == "default") {
                String path = "//ldml/collations/defaultCollation";
                collationType = collrules.getWinningValue(path);
            } else {
                collationType = variant.collation_type;
            }

            String path = "//ldml/collations/collation[@type=\"" + collationType + "\"]/cr";
            rules = collrules.getStringValue(path);

        }

        // Useful for debugging collation settings
        // System.out.println("Setting string is :"+settings);
        // System.out.println("Rules   string is :"+rules);

        if (rules != null && rules.length() > 0)
            col = new RuleBasedCollator(rules);
        else
            col = (RuleBasedCollator) RuleBasedCollator.getInstance();

        // Add all the tailored characters if we are using the default collation set
        if (codeset.equals("UTF-8") && UsingDefaultCollateSet) {
            UnicodeSet tailored = col.getTailoredSet();
            UnicodeSetIterator it = new UnicodeSetIterator(tailored);
            while (it.next()) {
                if (it.codepoint != UnicodeSetIterator.IS_STRING && UCharacter.isBMP(it.codepoint) &&
                    (!UCharacter.isLowSurrogate((char) it.codepoint) &&
                        !UCharacter.isHighSurrogate((char) it.codepoint)))
                    chars.add(it.codepoint);
            }
        }

        col.setStrength(RuleBasedCollator.IDENTICAL);
        allItems = new SortedBag(col);
        contractions = new SortedBag(col);

        // add all the chars
        longest_char = 0;
        for (UnicodeSetIterator it = new UnicodeSetIterator(chars); it.next();) {
            allItems.add(it.getString());
            int CharNameLength = POSIXUtilities.POSIXCharName(it.getString()).length();
            if (CharNameLength > longest_char)
                longest_char = CharNameLength;
        }

        // get the tailored contractions
        // we need to filter only the ones in chars
        UnicodeSet tailored = col.getTailoredSet();
        getFilteredSet(chars, tailored);

        UnicodeSet uca_contractions = new UnicodeSet(
            "[{\u0406\u0308}{\u0410\u0306}{\u0410\u0308}{\u0413\u0301}{\u0413\u0341}{\u0415\u0306}{\u0416\u0308}{\u0417\u0308}{\u0418\u0306}{\u0418\u0308}{\u041A\u0301}{\u041A\u0341}{\u041E\u0308}{\u0423\u0306}{\u0423\u0308}{\u0423\u030B}{\u0427\u0308}{\u042B\u0308}{\u042D\u0308}{\u0430\u0306}{\u0430\u0308}{\u0433\u0301}{\u0433\u0341}{\u0435\u0306}{\u0436\u0308}{\u0437\u0308}{\u0438\u0306}{\u0438\u0308}{\u043A\u0301}{\u043A\u0341}{\u043E\u0308}{\u0443\u0306}{\u0443\u0308}{\u0443\u030B}{\u0447\u0308}{\u044B\u0308}{\u044D\u0308}{\u0456\u0308}{\u0474\u030F}{\u0475\u030F}{\u04D8\u0308}{\u04D9\u0308}{\u04E8\u0308}{\u04E9\u0308}{\u0627\u0653}{\u0627\u0654}{\u0627\u0655}{\u0648\u0654}{\u064A\u0654}{\u09C7\u09BE}{\u09C7\u09D7}{\u0B47\u0B3E}{\u0B47\u0B56}{\u0B47\u0B57}{\u0B92\u0BD7}{\u0BC6\u0BBE}{\u0BC6\u0BD7}{\u0BC7\u0BBE}{\u0C46\u0C56}{\u0CBF\u0CD5}{\u0CC6\u0CC2}{\u0CC6\u0CC2\u0CD5}{\u0CC6\u0CD5}{\u0CC6\u0CD6}{\u0CCA\u0CD5}{\u0D46\u0D3E}{\u0D46\u0D57}{\u0D47\u0D3E}{\u0DD9\u0DCA}{\u0DD9\u0DCF}{\u0DD9\u0DCF\u0DCA}{\u0DD9\u0DDF}{\u0DDC\u0DCA}{\u0E4D\u0E32}{\u0ECD\u0EB2}{\u0F71\u0F72}{\u0F71\u0F74}{\u0F71\u0F80}{\u0FB2\u0F71}{\u0FB2\u0F71\u0F80}{\u0FB2\u0F80}{\u0FB2\u0F81}{\u0FB3\u0F71}{\u0FB3\u0F71\u0F80}{\u0FB3\u0F80}{\u0FB3\u0F81}{\u1025\u102E}]");

        getFilteredSet(uca_contractions, tailored);
    }

    private void getFilteredSet(UnicodeSet chars, UnicodeSet tailored) {
        for (UnicodeSetIterator it = new UnicodeSetIterator(tailored); it.next();) {
            if (it.codepoint != UnicodeSetIterator.IS_STRING) continue;
            String s = it.getString();
            s = Normalizer.compose(s, false); // normalize to make sure
            if (!UTF16.hasMoreCodePointsThan(s, 1)) continue;
            if (!chars.containsAll(s)) continue;
            contractions.add(s);
            allItems.add(s);
        }
    }

    public void write(PrintWriter out) {

        out.println("*************");
        out.println("LC_COLLATE");
        out.println("*************");
        out.println();

        writeDefinitions(out);
        out.println();
        writeList(out);
        out.println();
        out.println("* assignment of characters to weights");
        out.println();
        for (Object o : allItems) {
            String currentChar = (String) o;
            out.println(showLine(col, currentChar));
        }
        out.print("UNDEFINED");
        for (int i = longest_char - 9; i > 0; i--)
            out.print(" ");
        out.print(" ");
        out.println("IGNORE;IGNORE;IGNORE;...");
        out.println();
        out.println("order_end");
        out.println();
        out.println("END LC_COLLATE");
    }

    private void writeDefinitions(PrintWriter out) {
        // collating-element <A-A> from "<U0041><U0041>"
        StringBuffer buffer = new StringBuffer();
        Iterator<Object> it = contractions.iterator();
        while (it.hasNext()) {
            Object o;
            try {
                o = it.next();
            } catch (NullPointerException ex) {
                continue;
            }
            buffer.setLength(0);
            String s = (String) o;
            buffer.append("collating-element ")
                .append(POSIXUtilities.POSIXContraction(s))
                .append(" from \"")
                .append(POSIXUtilities.POSIXCharName(s))
                .append("\"");
            out.println(buffer.toString());
        }
    }

    Set<Weights> nonUniqueWeights = new HashSet<Weights>();
    Set<Weights> allWeights = new HashSet<Weights>();
    Map<String, Weights> stringToWeights = new HashMap<String, Weights>();

    private void writeList(PrintWriter out) {
        // BitSet alreadySeen = new BitSet();
        BitSet needToWrite = new BitSet();
        needToWrite.set(1); // special weight for uniqueness
        // int maxSeen = 0;
        for (Object o : allItems) {
            String string = (String) o;
            Weights w = new Weights(col.getCollationElementIterator(string));
            w.primaries.setBits(needToWrite);
            w.secondaries.setBits(needToWrite);
            w.tertiaries.setBits(needToWrite);
            if (allWeights.contains(w)) nonUniqueWeights.add(w);
            allWeights.add(w);
            stringToWeights.put(string, w);
        }
        out.println("");
        out.println("* Define collation weights as symbols");
        out.println("");

        for (int i = 0; i < needToWrite.size(); ++i) {
            if (needToWrite.get(i)) {
                out.print("collating-symbol ");
                out.println(getID('X', i));
            }
        }

        out.println("");
        out.println("order_start forward;" +
            (col.isFrenchCollation() ? "backward" : "forward")
            + ";forward;forward");
        out.println("");

        out.println("");
        out.println("* collation weights in order");
        out.println("");
        for (int i = 0; i < needToWrite.size(); ++i) {
            if (needToWrite.get(i))
                out.println(getID('X', i));
        }
    }

    /**
     * @param col
     * @param string
     */
    private String showLine(RuleBasedCollator col, String string) {
        String prefix = "";
        StringBuffer result = new StringBuffer();
        String ThisChar = POSIXUtilities.POSIXContraction(string);
        result.append(ThisChar);
        // pad for nice formatting
        for (int i = longest_char - ThisChar.length(); i > 0; i--)
            result.append(" ");
        result.append(" ");
        // gather data
        Weights w = stringToWeights.get(string);
        result.append(w.primaries)
            .append(";")
            .append(w.secondaries)
            .append(";")
            .append(w.tertiaries)
            .append(";");

        if (nonUniqueWeights.contains(w)) {
            String decomposed = Normalizer.decompose(string, false);
            if (decomposed.length() > 1) {
                result.append("\"");
                result.append(POSIXUtilities.POSIXCharName(decomposed));
                result.append("\"");
            } else {
                result.append(ThisChar);
            }
        } else
            result.append(ThisChar);

        if (prefix.length() != 0) result.insert(0, prefix);
        return result.toString();
    }

    /**
     * @param leadChar
     * @param i
     * @return
     */
    private static String getID(char leadChar, int i) {
        int length;
        if (i < 256) {
            length = 2;
        } else {
            length = 4;
        }
        return "<" + leadChar + Utility.hex(i, length) + ">";
    }

    private class Weights {
        WeightList primaries = new WeightList();
        WeightList secondaries = new WeightList();
        WeightList tertiaries = new WeightList();

        public Weights(CollationElementIterator it) {
            while (true) {
                int ce = it.next();
                if (ce == CollationElementIterator.NULLORDER) break;
                int p = CollationElementIterator.primaryOrder(ce);
                primaries.append(p);
                secondaries.append(CollationElementIterator.secondaryOrder(ce));
                tertiaries.append(CollationElementIterator.tertiaryOrder(ce));
            }
        }

        public boolean equals(Object other) {
            Weights that = (Weights) other;
            return primaries.equals(that.primaries)
                && secondaries.equals(that.secondaries)
                && tertiaries.equals(that.tertiaries);
        }

        public int hashCode() {
            return (primaries.hashCode() * 37
                + secondaries.hashCode()) * 37
                + tertiaries.hashCode();
        }
    }

    private class WeightList {
        char[] weights = new char[100];
        // TODO lengthen on demand
        int count = 0;

        public void append(int i) {
            // add each 16-bit quantity
            for (int j = 16; j >= 0; j -= 16) {
                char b = (char) (i >>> j);
                if (b == 0) continue;
                weights[count++] = b;
            }
        }

        public void setBits(BitSet s) {
            for (int j = 0; j < count; ++j)
                s.set(weights[j]);
        }

        public String toString() {
            if (count == 0) return "IGNORE";
            if (count == 1) return getID('X', weights[0]);
            String result = "\"";
            for (int i = 0; i < count; ++i) {
                result += getID('X', weights[i]);
            }
            return result + "\"";
        }

        public boolean equals(Object other) {
            WeightList that = (WeightList) other;
            for (int j = 0; j < count; ++j) {
                if (weights[j] != that.weights[j]) return false;
            }
            return true;
        }

        public int hashCode() {
            int result = count;
            for (int j = 0; j < count; ++j)
                result = result * 37 + weights[j];
            return result;
        }
    }
}
