/*
 *  Unit-API - Units of Measurement API for Java
 *  Copyright (c) 2005-2016, Jean-Marie Dautelle, Werner Keil, V2COM.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions
 *    and the following disclaimer in the documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of JSR-363 nor the names of its contributors may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package systems.uom.ucum.format;

import static tec.uom.se.AbstractUnit.ONE;
import systems.uom.ucum.internal.SI;
import systems.uom.ucum.internal.format.UCUMFormatParser;
import tec.uom.se.AbstractConverter;
import tec.uom.se.AbstractUnit;
import tec.uom.se.format.AbstractUnitFormat;
import tec.uom.se.format.SymbolMap;
import tec.uom.se.function.MultiplyConverter;
import tec.uom.se.function.RationalConverter;
import tec.uom.se.internal.format.TokenException;
import tec.uom.se.internal.format.TokenMgrError;
import tec.uom.se.unit.AnnotatedUnit;
import tec.uom.se.unit.MetricPrefix;

import javax.measure.Quantity;
import javax.measure.Unit;
import javax.measure.UnitConverter;
import javax.measure.format.ParserException;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.text.ParsePosition;
import java.util.*;

/**
 * <p>
 * This class provides the interface for formatting and parsing
 * {@link AbstractUnit units} according to the <a
 * href="http://unitsofmeasure.org/">Uniform Code for CommonUnits of Measure</a>
 * (UCUM).
 * </p>
 *
 * <p>
 * For a technical/historical overview of this format please read <a
 * href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=61354">
 * CommonUnits of Measure in Clinical Information Systems</a>.
 * </p>
 *
 * <p>
 * As of revision 1.16, the BNF in the UCUM standard contains an <a
 * href="http://unitsofmeasure.org/ticket/4">error</a>. I've attempted to work
 * around the problem by modifying the BNF productions for &lt;Term&gt;. Once
 * the error in the standard is corrected, it may be necessary to modify the
 * productions in the UCUMFormatParser.jj file to conform to the standard.
 * </p>
 *
 * @author <a href="mailto:eric-r@northwestern.edu">Eric Russell</a>
 * @author <a href="mailto:units@catmedia.us">Werner Keil</a>
 * @version 0.7, 6 April 2016
 */
public abstract class UCUMFormat extends AbstractUnitFormat {
    /**
         * 
         */
    // private static final long serialVersionUID = 8586656823290135155L;

    // A helper to declare bundle names for all instances
    private static final String BUNDLE_BASE = UCUMFormat.class.getName();

    // /////////////////
    // Class methods //
    // /////////////////

    /**
     * Returns the instance for formatting/parsing using the given variant
     * 
     * @param variant
     *            the <strong>UCUM</strong> variant to use
     */
    public static UCUMFormat getInstance(Variant variant) {
        switch (variant) {
        case CASE_INSENSITIVE:
            return Parsing.DEFAULT_CI;
        case CASE_SENSITIVE:
            return Parsing.DEFAULT_CS;
        case PRINT:
            return Print.DEFAULT;
        default:
            throw new IllegalArgumentException("Unknown variant: " + variant);
        }
    }

    /**
     * Returns an instance for formatting and parsing using user defined symbols
     * 
     * @param variant
     *            the <strong>UCUM</strong> variant to use
     * @param symbolMap
     *            the map of user defined symbols to use
     */
    public static UCUMFormat getInstance(Variant variant, SymbolMap symbolMap) {
        switch (variant) {
        case CASE_INSENSITIVE:
            return new Parsing(symbolMap, false);
        case CASE_SENSITIVE:
            return new Parsing(symbolMap, true);
        case PRINT:
            return new Print(symbolMap);
        default:
            throw new IllegalArgumentException("Unknown variant: " + variant);
        }
    }

    /**
     * The symbol map used by this instance to map between {@link AbstractUnit
     * Unit}s and <code>String</code>s.
     */
    final SymbolMap symbolMap;

    /**
     * Get the symbol map used by this instance to map between
     * {@link AbstractUnit Unit}s and <code>String</code>s, etc...
     * 
     * @return SymbolMap the current symbol map
     */
    @Override
    protected SymbolMap getSymbols() {
        return symbolMap;
    }

    // ////////////////
    // Constructors //
    // ////////////////
    /**
     * Base constructor.
     */
    UCUMFormat(SymbolMap symbolMap) {
        this.symbolMap = symbolMap;
    }

    // ///////////
    // Parsing //
    // ///////////
    public abstract Unit<? extends Quantity<?>> parse(CharSequence csq,
            ParsePosition cursor) throws ParserException;

    protected Unit<?> parse(CharSequence csq, int index) throws ParserException {
        return parse(csq, new ParsePosition(index));
    }

    @Override
    public abstract Unit<? extends Quantity<?>> parse(CharSequence csq)
            throws ParserException;

    // //////////////
    // Formatting //
    // //////////////
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public Appendable format(Unit<?> unknownUnit, Appendable appendable)
            throws IOException {
        if (!(unknownUnit instanceof AbstractUnit)) {
            throw new UnsupportedOperationException(
                    "The UCUM format supports only known units (AbstractUnit instances)");
        }
        AbstractUnit unit = (AbstractUnit) unknownUnit;
        CharSequence symbol;
        CharSequence annotation = null;
        if (unit instanceof AnnotatedUnit) {
            AnnotatedUnit annotatedUnit = (AnnotatedUnit) unit;
            unit = annotatedUnit.getActualUnit();
            annotation = annotatedUnit.getAnnotation();
        }
        String mapSymbol = symbolMap.getSymbol(unit);
        if (mapSymbol != null) {
            symbol = mapSymbol;
        } else if (unit.getBaseUnits() != null) {
            Map<? extends AbstractUnit<?>, Integer> productUnits = unit
                    .getBaseUnits();
            StringBuffer app = new StringBuffer();
            for (AbstractUnit<?> u : productUnits.keySet()) {
                StringBuffer temp = new StringBuffer();
                temp = (StringBuffer) format(u, temp);
                if ((temp.indexOf(".") >= 0) || (temp.indexOf("/") >= 0)) {
                    temp.insert(0, '(');
                    temp.append(')');
                }
                int pow = productUnits.get(u);
                if (app.length() > 0) { // Not the first unit.
                    if (pow >= 0) {
                        app.append('.');
                    } else {
                        app.append('/');
                        pow = -pow;
                    }
                } else { // First unit.
                    if (pow < 0) {
                        app.append("1/");
                        pow = -pow;
                    }
                }
                app.append(temp);
                if (pow != 1) {
                    app.append(Integer.toString(pow));
                }
            }
            symbol = app;
        } else if (!unit.isSystemUnit() || unit.equals(SI.KILOGRAM)) {
            final StringBuilder temp = new StringBuilder();
            UnitConverter converter;
            boolean printSeparator;
            if (unit.equals(SI.KILOGRAM)) {
                // A special case because KILOGRAM is a BaseUnit instead of
                // a transformed unit, for compatability with existing SI
                // unit system.
                format(SI.GRAM, temp);
                converter = MetricPrefix.KILO.getConverter();
                printSeparator = true;
            } else {
                Unit<?> parentUnit = unit.getSystemUnit();
                converter = unit.getConverterTo(parentUnit);
                if (parentUnit.equals(SI.KILOGRAM)) {
                    // More special-case hackery to work around gram/kilogram
                    // incosistency
                    parentUnit = SI.GRAM;
                    converter = converter.concatenate(MetricPrefix.KILO
                            .getConverter());
                }
                format(parentUnit, temp);
                printSeparator = !parentUnit.equals(ONE);
            }
            formatConverter(converter, printSeparator, temp);
            symbol = temp;
        } else if (unit.getSymbol() != null) {
            symbol = unit.getSymbol();
        } else {
            throw new IllegalArgumentException(
                    "Cannot format the given Object as UCUM units (unsupported unit "
                            + unit.getClass().getName()
                            + "). "
                            + "Custom units types should override the toString() method as the default implementation uses the UCUM format.");
        }

        appendable.append(symbol);
        if (annotation != null && annotation.length() > 0) {
            appendAnnotation(symbol, annotation, appendable);
        }

        return appendable;
    }

    public void label(Unit<?> unit, String label) {
    }

    public boolean isLocaleSensitive() {
        return false;
    }

    void appendAnnotation(CharSequence symbol, CharSequence annotation,
            Appendable appendable) throws IOException {
        appendable.append('{');
        appendable.append(annotation);
        appendable.append('}');
    }

    /**
     * Formats the given converter to the given StringBuffer. This is similar to
     * what {@link ConverterFormat} does, but there's no need to worry about
     * operator precedence here, since UCUM only supports multiplication,
     * division, and exponentiation and expressions are always evaluated left-
     * to-right.
     * 
     * @param converter
     *            the converter to be formatted
     * @param continued
     *            <code>true</code> if the converter expression should begin
     *            with an operator, otherwise <code>false</code>. This will
     *            always be true unless the unit being modified is equal to
     *            Unit.ONE.
     * @param buffer
     *            the <code>StringBuffer</code> to append to. Contains the
     *            already-formatted unit being modified by the given converter.
     */
    void formatConverter(UnitConverter converter, boolean continued,
            StringBuilder buffer) {
        boolean unitIsExpression = ((buffer.indexOf(".") >= 0) || (buffer
                .indexOf("/") >= 0));
        MetricPrefix prefix = symbolMap.getPrefix(converter);
        if ((prefix != null) && (!unitIsExpression)) {
            buffer.insert(0, symbolMap.getSymbol(prefix));
        } else if (converter == AbstractConverter.IDENTITY) {
            // do nothing
        } else if (converter instanceof MultiplyConverter) {
            if (unitIsExpression) {
                buffer.insert(0, '(');
                buffer.append(')');
            }
            MultiplyConverter multiplyConverter = (MultiplyConverter) converter;
            double factor = multiplyConverter.getFactor();
            long lFactor = (long) factor;
            if ((lFactor != factor) || (lFactor < -9007199254740992L)
                    || (lFactor > 9007199254740992L)) {
                throw new IllegalArgumentException(
                        "Only integer factors are supported in UCUM");
            }
            if (continued) {
                buffer.append('.');
            }
            buffer.append(lFactor);
        } else if (converter instanceof RationalConverter) {
            if (unitIsExpression) {
                buffer.insert(0, '(');
                buffer.append(')');
            }
            RationalConverter rationalConverter = (RationalConverter) converter;
            if (!rationalConverter.getDividend().equals(BigInteger.ONE)) {
                if (continued) {
                    buffer.append('.');
                }
                buffer.append(rationalConverter.getDividend());
            }
            if (!rationalConverter.getDivisor().equals(BigInteger.ONE)) {
                buffer.append('/');
                buffer.append(rationalConverter.getDivisor());
            }
        } else { // All other converter type (e.g. exponential) we use the
                 // string representation.
            buffer.insert(0, converter.toString() + "(");
            buffer.append(")");
        }
    }

    // static final ResourceBundle.Control getControl(final String key) {
    // return new ResourceBundle.Control() {
    // @Override
    // public List<Locale> getCandidateLocales(String baseName, Locale locale) {
    // if (baseName == null)
    // throw new NullPointerException();
    // if (locale.equals(new Locale(key))) {
    // return Arrays.asList(
    // locale,
    // Locale.GERMANY,
    // // no Locale.GERMAN here
    // Locale.ROOT);
    // } else if (locale.equals(Locale.GERMANY)) {
    // return Arrays.asList(
    // locale,
    // // no Locale.GERMAN here
    // Locale.ROOT);
    // }
    // return super.getCandidateLocales(baseName, locale);
    // }
    // };
    // }

    // /////////////////
    // Inner classes //
    // /////////////////

    /**
     * Variant of unit representation in the UCUM standard
     * 
     * @see <a
     *      href="http://unitsofmeasure.org/ucum.html#section-Character-Set-and-Lexical-Rules">
     *      UCUM - Character Set and Lexical Rules</a>
     */
    public static enum Variant {
        CASE_SENSITIVE, CASE_INSENSITIVE, PRINT
    }

    /**
     * The Print format is used to output units according to the "print" column
     * in the UCUM standard. Because "print" symbols in UCUM are not unique,
     * this class of UCUMFormat may not be used for parsing, only for
     * formatting.
     */
    private static final class Print extends UCUMFormat {

        /**
         *
         */
        // private static final long serialVersionUID = 2990875526976721414L;
        private static final SymbolMap PRINT_SYMBOLS = SymbolMap
                .of(ResourceBundle.getBundle(BUNDLE_BASE + "_Print"));
        private static final Print DEFAULT = new Print(PRINT_SYMBOLS);

        public Print(SymbolMap symbols) {
            super(symbols);
        }

        @Override
        public Unit<? extends Quantity<?>> parse(CharSequence csq,
                ParsePosition pos) throws IllegalArgumentException {
            throw new UnsupportedOperationException(
                    "The print format is for pretty-printing of units only. Parsing is not supported.");
        }

        @Override
        void appendAnnotation(CharSequence symbol, CharSequence annotation,
                Appendable appendable) throws IOException {
            if (symbol != null && symbol.length() > 0) {
                appendable.append('(');
                appendable.append(annotation);
                appendable.append(')');
            } else {
                appendable.append(annotation);
            }
        }

        @Override
        public Unit<? extends Quantity<?>> parse(CharSequence csq)
                throws IllegalArgumentException {
            return parse(csq, new ParsePosition(0));

        }
    }

    /**
     * The Parsing format outputs formats and parses units according to the
     * "c/s" or "c/i" column in the UCUM standard, depending on which SymbolMap
     * is passed to its constructor.
     */
    private static final class Parsing extends UCUMFormat {
        // private static final long serialVersionUID = -922531801940132715L;
        private static final SymbolMap CASE_SENSITIVE_SYMBOLS = SymbolMap
                .of(ResourceBundle.getBundle(BUNDLE_BASE + "_CS",
                        new ResourceBundle.Control() {
                            @Override
                            public List<Locale> getCandidateLocales(
                                    String baseName, Locale locale) {
                                if (baseName == null)
                                    throw new NullPointerException();
                                if (locale.equals(new Locale("", "CS"))) {
                                    return Arrays.asList(locale, Locale.ROOT);
                                }
                                return super.getCandidateLocales(baseName,
                                        locale);
                            }
                        }));
        private static final SymbolMap CASE_INSENSITIVE_SYMBOLS = SymbolMap
                .of(ResourceBundle.getBundle(BUNDLE_BASE + "_CI",
                        new ResourceBundle.Control() {
                            @Override
                            public List<Locale> getCandidateLocales(
                                    String baseName, Locale locale) {
                                if (baseName == null)
                                    throw new NullPointerException();
                                if (locale.equals(new Locale("", "CI"))) {
                                    return Arrays.asList(locale, Locale.ROOT);
                                } else if (locale.equals(Locale.GERMANY)) { // TODO
                                                                            // why
                                                                            // GERMANY?
                                    return Arrays.asList(locale,
                                    // no Locale.GERMAN here
                                            Locale.ROOT);
                                }
                                return super.getCandidateLocales(baseName,
                                        locale);
                            }
                        }));
        private static final Parsing DEFAULT_CS = new Parsing(
                CASE_SENSITIVE_SYMBOLS, true);
        private static final Parsing DEFAULT_CI = new Parsing(
                CASE_INSENSITIVE_SYMBOLS, false);
        private final boolean caseSensitive;

        public Parsing(SymbolMap symbols, boolean caseSensitive) {
            super(symbols);
            this.caseSensitive = caseSensitive;
        }

        @Override
        public Unit<? extends Quantity<?>> parse(CharSequence csq,
                ParsePosition cursor) throws ParserException {
            // Parsing reads the whole character sequence from the parse
            // position.
            int start = cursor.getIndex();
            int end = csq.length();
            if (end <= start) {
                return ONE;
            }
            String source = csq.subSequence(start, end).toString().trim();
            if (source.length() == 0) {
                return ONE;
            }
            if (!caseSensitive) {
                source = source.toUpperCase();
            }
            UCUMFormatParser parser = new UCUMFormatParser(symbolMap,
                    new ByteArrayInputStream(source.getBytes()));
            try {
                Unit<?> result = parser.parseUnit();
                cursor.setIndex(end);
                return result;
            } catch (TokenException e) {
                if (e.currentToken != null) {
                    cursor.setErrorIndex(start + e.currentToken.endColumn);
                } else {
                    cursor.setErrorIndex(start);
                }
                throw new ParserException(e);
            } catch (TokenMgrError e) {
                cursor.setErrorIndex(start);
                throw new IllegalArgumentException(e.getMessage());
            }
        }

        @Override
        public Unit<? extends Quantity<?>> parse(CharSequence csq)
                throws ParserException {
            return parse(csq, new ParsePosition(0));
        }
    }
}