/*

 *  Copyright 2009-present, Stephen Colebourne

 *

 *  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.joda.money.format;

import java.io.IOException;

import java.io.Serializable;

import java.math.BigDecimal;

import org.joda.money.BigMoney;

/**

 * Prints and parses the amount part of the money.

 * <p>

 * This class is immutable and thread-safe.

 */

final class AmountPrinterParser implements MoneyPrinter, MoneyParser, Serializable {

    /** Serialization version. */

    private static final long serialVersionUID = 1L;

    /** The style to use. */

    private final MoneyAmountStyle style;

    /**

     * Constructor.

     * @param style  the style, not null

     */

    AmountPrinterParser(MoneyAmountStyle style) {

        this.style = style;

    }

    //-----------------------------------------------------------------------

    public void print(MoneyPrintContext context, Appendable appendable, BigMoney money) throws IOException {

        var activeStyle = style.localize(context.getLocale());

        String str;

        if (money.isNegative()) {

            if (!activeStyle.isAbsValue()) {

                appendable.append(activeStyle.getNegativeSignCharacter());

            }

            str = money.negated().getAmount().toPlainString();

        } else {

            str = money.getAmount().toPlainString();

        }

        var zeroChar = activeStyle.getZeroCharacter();

        if (zeroChar != '0') {

            var diff = zeroChar - '0';

            var zeroConvert = new StringBuilder(str);

            for (var i = 0; i < str.length(); i++) {

                var ch = str.charAt(i);

                if (ch >= '0' && ch <= '9') {

                    zeroConvert.setCharAt(i, (char) (ch + diff));

                }

            }

            str = zeroConvert.toString();

        }

        var decPoint = str.indexOf('.');

        var afterDecPoint = decPoint + 1;

        if (activeStyle.getGroupingStyle() == GroupingStyle.NONE) {

            if (decPoint < 0) {

                appendable.append(str);

                if (activeStyle.isForcedDecimalPoint()) {

                    appendable.append(activeStyle.getDecimalPointCharacter());

                }

            } else {

                appendable.append(str.subSequence(0, decPoint))

                    .append(activeStyle.getDecimalPointCharacter()).append(str.substring(afterDecPoint));

            }

        } else {

            var groupingSize = activeStyle.getGroupingSize();

            var extendedGroupingSize = activeStyle.getExtendedGroupingSize();

            extendedGroupingSize = extendedGroupingSize == 0 ? groupingSize : extendedGroupingSize;

            var groupingChar = activeStyle.getGroupingCharacter();

            var pre = (decPoint < 0 ? str.length() : decPoint);

            var post = (decPoint < 0 ? 0 : str.length() - decPoint - 1);

            appendable.append(str.charAt(0));

            for (var i = 1; i < pre; i++) {

                if (isPreGroupingPoint(pre - i, groupingSize, extendedGroupingSize)) {

                    appendable.append(groupingChar);

                }

                appendable.append(str.charAt(i));

            }

            if (decPoint >= 0 || activeStyle.isForcedDecimalPoint()) {

                appendable.append(activeStyle.getDecimalPointCharacter());

            }

            if (activeStyle.getGroupingStyle() == GroupingStyle.BEFORE_DECIMAL_POINT) {

                if (decPoint >= 0) {

                    appendable.append(str.substring(afterDecPoint));

                }

            } else {

                for (var i = 0; i < post; i++) {

                    appendable.append(str.charAt(i + afterDecPoint));

                    if (isPostGroupingPoint(i, post, groupingSize, extendedGroupingSize)) {

                        appendable.append(groupingChar);

                    }

                }

            }

        }

    }

    private boolean isPreGroupingPoint(int remaining, int groupingSize, int extendedGroupingSize) {

        if (remaining >= groupingSize + extendedGroupingSize) {

            return (remaining - groupingSize) % extendedGroupingSize == 0;

        }

        return remaining % groupingSize == 0;

    }

    private boolean isPostGroupingPoint(int i, int post, int groupingSize, int extendedGroupingSize) {

        var atEnd = (i + 1) >= post;

        if (i > groupingSize) {

            return (i - groupingSize) % extendedGroupingSize == (extendedGroupingSize - 1) && !atEnd;

        }

        return i % groupingSize == (groupingSize - 1) && !atEnd;

    }

    @Override

    public void parse(MoneyParseContext context) {

        var len = context.getTextLength();

        var activeStyle = style.localize(context.getLocale());

        var buf = new char[len - context.getIndex()];

        var bufPos = 0;

        var dpSeen = false;

        var pos = context.getIndex();

        if (pos < len) {

            var ch = context.getText().charAt(pos++);

            if (ch == activeStyle.getNegativeSignCharacter()) {

                buf[bufPos++] = '-';

            } else if (ch == activeStyle.getPositiveSignCharacter()) {

                buf[bufPos++] = '+';

            } else if (ch >= activeStyle.getZeroCharacter() && ch < activeStyle.getZeroCharacter() + 10) {

                buf[bufPos++] = (char) ('0' + ch - activeStyle.getZeroCharacter());

            } else if (ch == activeStyle.getDecimalPointCharacter()) {

                buf[bufPos++] = '.';

                dpSeen = true;

            } else {

                context.setError();

                return;

            }

        }

        var lastWasGroup = false;

        for (; pos < len; pos++) {

            var ch = context.getText().charAt(pos);

            if (ch >= activeStyle.getZeroCharacter() && ch < activeStyle.getZeroCharacter() + 10) {

                buf[bufPos++] = (char) ('0' + ch - activeStyle.getZeroCharacter());

                lastWasGroup = false;

            } else if (ch == activeStyle.getDecimalPointCharacter() && !dpSeen) {

                buf[bufPos++] = '.';

                dpSeen = true;

                lastWasGroup = false;

            } else if (ch == activeStyle.getGroupingCharacter() && !lastWasGroup) {

                lastWasGroup = true;

            } else {

                break;

            }

        }

        if (lastWasGroup) {

            pos--;

        }

        try {

            context.setAmount(new BigDecimal(buf, 0, bufPos));

            context.setIndex(pos);

        } catch (NumberFormatException ex) {

            context.setError();

        }

    }

    @Override

    public String toString() {

        return "${amount}";

    }

}