/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *      https://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.commons.codec.language.bm;

import org.apache.commons.codec.EncoderException;
import org.apache.commons.codec.StringEncoder;

/**
 * Encodes strings into their Beider-Morse phonetic encoding.
 * <p>
 * Beider-Morse phonetic encodings are optimized for family names. However, they may be useful for a wide range of words.
 * </p>
 * <p>
 * This encoder is intentionally mutable to allow dynamic configuration through bean properties. As such, it is mutable, and may not be thread-safe. If you
 * require a guaranteed thread-safe encoding then use {@link PhoneticEngine} directly.
 * </p>
 * <h2>Encoding overview</h2>
 * <p>
 * Beider-Morse phonetic encodings is a multi-step process. Firstly, a table of rules is consulted to guess what language the word comes from. For example, if
 * it ends in "{@code ault}" then it infers that the word is French. Next, the word is translated into a phonetic representation using a language-specific
 * phonetics table. Some runs of letters can be pronounced in multiple ways, and a single run of letters may be potentially broken up into phonemes at different
 * places, so this stage results in a set of possible language-specific phonetic representations. Lastly, this language-specific phonetic representation is
 * processed by a table of rules that re-writes it phonetically taking into account systematic pronunciation differences between languages, to move it towards a
 * pan-indo-european phonetic representation. Again, sometimes there are multiple ways this could be done and sometimes things that can be pronounced in several
 * ways in the source language have only one way to represent them in this average phonetic language, so the result is again a set of phonetic spellings.
 * </p>
 * <p>
 * Some names are treated as having multiple parts. This can be due to two things. Firstly, they may be hyphenated. In this case, each individual hyphenated
 * word is encoded, and then these are combined end-to-end for the final encoding. Secondly, some names have standard prefixes, for example, "{@code Mac/Mc}" in
 * Scottish (English) names. As sometimes it is ambiguous whether the prefix is intended or is an accident of the spelling, the word is encoded once with the
 * prefix and once without it. The resulting encoding contains one and then the other result.
 * </p>
 * <h2>Encoding format</h2>
 * <p>
 * Individual phonetic spellings of an input word are represented in upper- and lower-case roman characters. Where there are multiple possible phonetic
 * representations, these are joined with a pipe ({@code |}) character. If multiple hyphenated words where found, or if the word may contain a name prefix, each
 * encoded word is placed in ellipses and these blocks are then joined with hyphens. For example, "{@code d'ortley}" has a possible prefix. The form without
 * prefix encodes to "{@code ortlaj|ortlej}", while the form with prefix encodes to " {@code dortlaj|dortlej}". Thus, the full, combined encoding is
 * "{@code (ortlaj|ortlej)-(dortlaj|dortlej)}".
 * </p>
 * <p>
 * The encoded forms are often quite a bit longer than the input strings. This is because a single input may have many potential phonetic interpretations. For
 * example, "{@code Renault}" encodes to " {@code rYnDlt|rYnalt|rYnult|rinDlt|rinalt|rinult}". The {@code APPROX} rules will tend to produce larger encodings as
 * they consider a wider range of possible, approximate phonetic interpretations of the original word. Down-stream applications may wish to further process the
 * encoding for indexing or lookup purposes, for example, by splitting on pipe ({@code |}) and indexing under each of these alternatives.
 * </p>
 * <p>
 * <strong>Note</strong>: this version of the Beider-Morse encoding is equivalent with v3.4 of the reference implementation.
 * </p>
 * <p>
 * This class is Not ThreadSafe.
 * </p>
 *
 * @see <a href="https://stevemorse.org/phonetics/bmpm.htm">Beider-Morse Phonetic Matching</a>
 * @see <a href="https://stevemorse.org/phoneticinfo.htm">Reference implementation</a>
 * @since 1.6
 */
public class BeiderMorseEncoder implements StringEncoder {

    /**
     * Creates a new builder for a Beider-Morse encoder.
     *
     * @since 1.23.0
     */
    public static final class Builder {

        private PhoneticEngine engine = PhoneticEngine.builder().get();

        private Builder() {
            // empty.
        }

        /**
         * Gets a new Beider-Morse encoder with the current configuration.
         *
         * @return a new Beider-Morse encoder with the current configuration.
         */
        public BeiderMorseEncoder get() {
            return new BeiderMorseEncoder(this);
        }

        /**
         * Sets the phonetic engine to use.
         *
         * @param engine the phonetic engine to use.
         * @return this builder, for chaining.
         */
        public Builder setPhoneticEngine(final PhoneticEngine engine) {
            this.engine = engine != null ? engine : PhoneticEngine.builder().get();
            return this;
        }
    }

    /**
     * Creates a new builder for a BeiderMorseEncoder.
     *
     * @return a new builder for a BeiderMorseEncoder.
     * @since 1.23.0
     */
    public static Builder builder() {
        return new Builder();
    }

    /** A cached object. */
    private PhoneticEngine engine = PhoneticEngine.builder().get();

    /**
     * Constructs a new instance.
     *
     * @deprecated Use {@link #builder()} to create a new instance.
     */
    @Deprecated
    public BeiderMorseEncoder() {
        // empty
    }

    private BeiderMorseEncoder(final Builder builder) {
        engine = builder.engine;
    }

    @Override
    public Object encode(final Object source) throws EncoderException {
        if (!(source instanceof String)) {
            throw new EncoderException("BeiderMorseEncoder encode parameter is not of type String");
        }
        return encode((String) source);
    }

    @Override
    public String encode(final String source) throws EncoderException {
        return source != null ? engine.encode(source) : null;
    }

    /**
     * Gets the name type currently in operation.
     *
     * @return The NameType currently being used.
     */
    public NameType getNameType() {
        return engine.getNameType();
    }

    /**
     * Gets the rule type currently in operation.
     *
     * @return The RuleType currently being used.
     */
    public RuleType getRuleType() {
        return engine.getRuleType();
    }

    /**
     * Tests whether multiple phonetic encodings are concatenated or just the first one is kept.
     *
     * @return true if multiple encodings are concatenated, false if just the first one is returned.
     */
    public boolean isConcat() {
        return engine.isConcat();
    }

    /**
     * Sets how multiple possible phonetic encodings are combined.
     *
     * @param concat true if multiple encodings are to be combined with a '|', false if just the first one is to be considered.
     */
    public void setConcat(final boolean concat) {
        engine = PhoneticEngine.builder().setAll(engine).setConcat(concat).get();
    }

    /**
     * Sets the number of maximum of phonemes that shall be considered by the engine.
     * <p>
     * A value less than 0 will reset the maximum number of phonemes to the default {@value PhoneticEngine.Builder#MAX_PHONEMES}.
     * </p>
     *
     * @param maxPhonemes the maximum number of phonemes returned by the engine.
     * @since 1.7
     */
    public void setMaxPhonemes(final int maxPhonemes) {
        engine = PhoneticEngine.builder().setAll(engine).setMaxPhonemes(maxPhonemes).get();
    }

    /**
     * Sets the type of name. Use {@link NameType#GENERIC} unless you specifically want phonetic encodings optimized for Ashkenazi or Sephardic Jewish family
     * names.
     * <p>
     * A null value will reset the name type to the default of {@link NameType#GENERIC}.
     * </p>
     *
     * @param nameType the NameType in use.
     */
    public void setNameType(final NameType nameType) {
        engine = PhoneticEngine.builder().setAll(engine).setNameType(nameType).get();
    }

    /**
     * Sets the rule type to apply. This will widen or narrow the range of phonetic encodings considered.
     * <p>
     * A null value will reset the rule type to the default of {@link RuleType#APPROX}.
     * </p>
     *
     * @param ruleType {@link RuleType#APPROX} or {@link RuleType#EXACT} for approximate or exact phonetic matches.
     */
    public void setRuleType(final RuleType ruleType) {
        engine = PhoneticEngine.builder().setAll(engine).setRuleType(ruleType).get();
    }
}