package org.madore.android.unicodeMap;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.sql.SQLException;
import android.content.Context;
import android.content.res.AssetManager;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteStatement;
import android.database.sqlite.SQLiteOpenHelper;

public class UnicodeDatabase {

    protected static final String DATABASE_NAME = "unicode.db";
    protected static final int DATABASE_VERSION = 1;
    protected static final String UNICODE_TABLE_NAME = "unicode";

    protected static class DatabaseInit extends SQLiteOpenHelper {

	final Context context;

	DatabaseInit(Context context) {
	    super(context, DATABASE_NAME, null, DATABASE_VERSION);
	    this.context = context;
	}

	protected void parseUnicodeData(SQLiteDatabase db) {
	    AssetManager amgr = context.getAssets();
	    try {
		BufferedReader rd
		    = new BufferedReader(new InputStreamReader(amgr.open("UnicodeData.txt"),
							       "US-ASCII"));
		SQLiteStatement cmd
		    = db.compileStatement("INSERT INTO "+UNICODE_TABLE_NAME
					  +" VALUES ( ? , ? , ? )");
		String line;
		while ( ( line = rd.readLine() ) != null ) {
		    String[] fields = line.split(";");
		    int codePoint = Integer.parseInt(fields[0], 16);
		    String name = fields[1];
		    String category = fields[2];
		    if ( name.charAt(0) == '<' )
			continue;
		    cmd.bindLong(1, codePoint);
		    cmd.bindString(2, name);
		    cmd.bindString(3, category);
		    cmd.execute();
		}
	    } catch (UnsupportedEncodingException e) {
		throw new AssertionError("US-ASCII encoding unsupported");
	    } catch (IOException e) {
		throw new RuntimeException(e);
	    }
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
	    db.execSQL("CREATE TABLE "+UNICODE_TABLE_NAME+" ( "
		       +"id INTEGER PRIMARY KEY , "
		       +"name TEXT , "
		       +"category TEXT )");
	    parseUnicodeData(db);
	}

	@Override
        public void onUpgrade(SQLiteDatabase db,
			      int oldVersion, int newVersion) {
            db.execSQL("DROP TABLE IF EXISTS "+UNICODE_TABLE_NAME);
            onCreate(db);
        }

    }

    SQLiteDatabase db;

    public UnicodeDatabase(Context context) {
	DatabaseInit dbinit = new DatabaseInit(context);
	if ( true )
	    db = dbinit.getReadableDatabase();
	else {
	    db = dbinit.getWritableDatabase();
	    db.execSQL("DELETE FROM "+UNICODE_TABLE_NAME);
	    dbinit.parseUnicodeData(db);
	}
    }

    protected final static String[] queryColumns = { "id", "name", "category" };

    public UnicodeCharacter getSingle(int codePoint) {
	final Cursor c
	    = db.query(UNICODE_TABLE_NAME, queryColumns,
		       "id=?",
		       new String[] { Integer.toString(codePoint) },
		       null, null, null, null);
	UnicodeCharacter ch;
	if ( c.getCount() > 0 ) {
	    c.moveToFirst();
	    ch = new UnicodeCharacter(c.getInt(0),
				      c.getString(1),
				      UnicodeCharacter.Category.fromCode(c.getString(2)));
	} else
	    ch = null;
	c.close();
	return ch;
    }

    protected final static String[] countColumns = { "count(*)" };

    public int countRange(int from, int to) {
	final Cursor c
	    = db.query(UNICODE_TABLE_NAME, countColumns,
		       "id >= ? AND id < ?",
		       new String[] { Integer.toString(from),
				      Integer.toString(to) },
		       null, null, null, null);
	if ( c.getCount() != 1 )
	    throw new AssertionError("\"SELECT count(*)\" returned no result");
	c.moveToFirst();
	int cnt = c.getInt(0);
	c.close();
	return cnt;
    }

    private static class CursorIterable
	implements Iterable<UnicodeCharacter> {
	protected final Cursor c;
	public CursorIterable(Cursor c) {
	    this.c = c;
	}
	public Iterator<UnicodeCharacter> iterator() {
	    final boolean hasData = c.getCount() > 0;
	    if ( hasData )
		c.moveToFirst();
	    else
		c.close();
	    return (new Iterator<UnicodeCharacter>() {
		boolean hasNext = hasData;
		public boolean hasNext() { return hasNext; }
		public UnicodeCharacter next() {
		    if ( hasNext ) {
			UnicodeCharacter ch
			    = new UnicodeCharacter(c.getInt(0), c.getString(1),
						   UnicodeCharacter.Category.fromCode(c.getString(2)));
			if ( c.isLast() ) {
			    hasNext = false;
			    c.close();
			} else
			    c.moveToNext();
			return ch;
		    } else
			throw new NoSuchElementException();
		}
		public void remove() {
		    throw new UnsupportedOperationException();
		}
	    });
	}
    }

    public Iterable<UnicodeCharacter> getRange(int from, int to) {
	final Cursor c
	    = db.query(UNICODE_TABLE_NAME, queryColumns,
		       "id >= ? AND id < ?",
		       new String[] { Integer.toString(from),
				      Integer.toString(to) },
		       null, null, null, null);
	return new CursorIterable(c);
    }

}