/*   Copyright 2004 The Apache Software Foundation
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.xmlbeans.impl.values;

import org.apache.xmlbeans.SchemaType;
import org.apache.xmlbeans.XmlErrorCodes;
import org.apache.xmlbeans.XmlObject;
import org.apache.xmlbeans.XmlOptions;
import org.apache.xmlbeans.impl.common.ValidationContext;
import org.apache.xmlbeans.impl.schema.BuiltinSchemaTypeSystem;
import org.apache.xmlbeans.impl.util.MathUtil;
import org.apache.xmlbeans.impl.util.XsTypeConverter;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;

public class JavaDecimalHolder extends XmlObjectBase {
    public SchemaType schemaType() {
        return BuiltinSchemaTypeSystem.ST_DECIMAL;
    }

    private BigDecimal _value;

    // SIMPLE VALUE ACCESSORS BELOW -------------------------------------------

    // sets/gets raw text value
    protected String compute_text(NamespaceManager nsm) {
        return XsTypeConverter.printDecimal(_value);
    }

    protected void set_text(String s) {
        boolean allowExponent = has_store() && get_store().get_locale().isLoadAllowDecimalExponent();
        if (_validateOnSet()) {
            validateLexical(s, _voorVc, allowExponent);
        }

        try {
            set_BigDecimal(MathUtil.parseAsBigDecimal(s));
        } catch (Exception e) {
            _voorVc.invalid(XmlErrorCodes.DECIMAL, new Object[]{s});
        }
    }

    protected void set_nil() {
        _value = null;
    }

    /**
     * Performs lexical validation only.
     */

    public static void validateLexical(String v, ValidationContext context) {
        validateLexical(v, context, false);
    }

    public static void validateLexical(String v, ValidationContext context, boolean allowExponent) {
        validateLexical(v, context, allowExponent, XmlOptions.DEFAULT_MAX_NUMBER_CHARS);
    }

    public static void validateLexical(String v, ValidationContext context, boolean allowExponent,
                                       int maxNumberOfChars) {
        if (allowExponent) {
            // long-standing lenient behaviour: accept whatever BigDecimal accepts,
            // which includes scientific/exponent notation such as "1E5".
            try {
                MathUtil.parseAsBigDecimal(v, maxNumberOfChars);
            } catch (Exception e) {
                context.invalid(XmlErrorCodes.DECIMAL, new Object[]{v});
            }
            return;
        }

        // TODO - will want to validate Chars with built in white space handling
        //        However, this fcn sometimes takes a value with wsr applied
        //        already
        int l = v.length();
        int i = 0;

        if (i < l) {
            int ch = v.charAt(i);

            if (ch == '+' || ch == '-') {
                i++;
            }
        }

        boolean sawDot = false;
        boolean sawDigit = false;

        for (; i < l; i++) {
            int ch = v.charAt(i);

            if (ch == '.') {
                if (sawDot) {
                    context.invalid(XmlErrorCodes.DECIMAL,
                        new Object[]{"saw '.' more than once: " + v});
                    return;
                }

                sawDot = true;
            } else if (ch >= '0' && ch <= '9') {
                sawDigit = true;
            } else {
                // TODO - may need to escape error char
                context.invalid(XmlErrorCodes.DECIMAL,
                    new Object[]{"unexpected char '" + ch + "'"});
                return;
            }
        }

        if (!sawDigit) {
            context.invalid(XmlErrorCodes.DECIMAL,
                new Object[]{"expected at least one digit"});
        }
    }

    // numerics: fractional
    public BigDecimal getBigDecimalValue() {
        check_dated();
        return _value;
    }

    // setters
    protected void set_BigDecimal(BigDecimal v) {
        _value = v;
    }

    // comparators
    protected int compare_to(XmlObject decimal) {
        return _value.compareTo(((XmlObjectBase) decimal).getBigDecimalValue());
    }

    protected boolean equal_to(XmlObject decimal) {
        return (_value.compareTo(((XmlObjectBase) decimal).getBigDecimalValue())) == 0;
    }

    private static final BigInteger _maxlong = BigInteger.valueOf(Long.MAX_VALUE);
    private static final BigInteger _minlong = BigInteger.valueOf(Long.MIN_VALUE);

    /**
     * Note, this is carefully aligned with hash codes for all xsd:decimal
     * primitives.
     */
    protected int value_hash_code() {
        if (_value.scale() > 0) {
            if (_value.setScale(0, RoundingMode.DOWN).compareTo(_value) != 0) {
                return decimalHashCode();
            }
        }

        BigInteger intval = MathUtil.toBigInteger(_value);

        if (intval.compareTo(_maxlong) > 0 ||
            intval.compareTo(_minlong) < 0) {
            return intval.hashCode();
        }

        long longval = intval.longValue();

        return (int) ((longval >> 32) * 19 + longval);
    }

    /**
     * This method will has BigDecimals with the same arithmetic value to
     * the same hash code (eg, 2.3 &amp; 2.30 will have the same hash.)
     * This differs from BigDecimal.hashCode()
     */
    protected int decimalHashCode() {
        assert _value.scale() > 0;

        // Get decimal value as string, and strip off zeroes on the right
        String strValue = _value.toString();
        int i;
        for (i = strValue.length() - 1; i >= 0; i--) {
            if (strValue.charAt(i) != '0') {
                break;
            }
        }

        assert strValue.indexOf('.') < i;

        // Return the canonicalized string hashcode
        return strValue.substring(0, i + 1).hashCode();
    }
}
