/*
    * 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.
   */
  
  /*
   * This is not the original file distributed by the Apache Software Foundation
   * It has been modified by the Hipparchus project
   */
  
  package org.hipparchus.linear;
  
  import java.text.FieldPosition;
  import java.text.NumberFormat;
  import java.text.ParsePosition;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  
  import org.hipparchus.exception.LocalizedCoreFormats;
  import org.hipparchus.exception.MathIllegalStateException;
  import org.hipparchus.util.CompositeFormat;
  
  /**
   * Formats a {@code nxm} matrix in components list format
   * "{{a<sub>0</sub><sub>0</sub>,a<sub>0</sub><sub>1</sub>, ...,
   * a<sub>0</sub><sub>m-1</sub>},{a<sub>1</sub><sub>0</sub>,
   * a<sub>1</sub><sub>1</sub>, ..., a<sub>1</sub><sub>m-1</sub>},{...},{
   * a<sub>n-1</sub><sub>0</sub>, a<sub>n-1</sub><sub>1</sub>, ...,
   * a<sub>n-1</sub><sub>m-1</sub>}}".
   * <p>The prefix and suffix "{" and "}", the row prefix and suffix "{" and "}",
   * the row separator "," and the column separator "," can be replaced by any
   * user-defined strings. The number format for components can be configured.</p>
   *
   * <p>White space is ignored at parse time, even if it is in the prefix, suffix
   * or separator specifications. So even if the default separator does include a space
   * character that is used at format time, both input string "{{1,1,1}}" and
   * " { { 1 , 1 , 1 } } " will be parsed without error and the same matrix will be
   * returned. In the second case, however, the parse position after parsing will be
   * just after the closing curly brace, i.e. just before the trailing space.</p>
   *
   * <p><b>Note:</b> the grouping functionality of the used {@link NumberFormat} is
   * disabled to prevent problems when parsing (e.g. 1,345.34 would be a valid number
   * but conflicts with the default column separator).</p>
   *
   */
  public class RealMatrixFormat {
  
      /** The default prefix: "{". */
      private static final String DEFAULT_PREFIX = "{";
      /** The default suffix: "}". */
      private static final String DEFAULT_SUFFIX = "}";
      /** The default row prefix: "{". */
      private static final String DEFAULT_ROW_PREFIX = "{";
      /** The default row suffix: "}". */
      private static final String DEFAULT_ROW_SUFFIX = "}";
      /** The default row separator: ",". */
      private static final String DEFAULT_ROW_SEPARATOR = ",";
      /** The default column separator: ",". */
      private static final String DEFAULT_COLUMN_SEPARATOR = ",";
      /** Prefix. */
      private final String prefix;
      /** Suffix. */
      private final String suffix;
      /** Row prefix. */
      private final String rowPrefix;
      /** Row suffix. */
      private final String rowSuffix;
      /** Row separator. */
      private final String rowSeparator;
      /** Column separator. */
      private final String columnSeparator;
      /** The format used for components. */
      private final NumberFormat format;
  
      /**
       * Create an instance with default settings.
       * <p>The instance uses the default prefix, suffix and row/column separator:
       * "[", "]", ";" and ", " and the default number format for components.</p>
       */
      public RealMatrixFormat() {
          this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ROW_PREFIX, DEFAULT_ROW_SUFFIX,
                  DEFAULT_ROW_SEPARATOR, DEFAULT_COLUMN_SEPARATOR, CompositeFormat.getDefaultNumberFormat());
      }
  
      /**
       * Create an instance with a custom number format for components.
      * @param format the custom format for components.
      */
     public RealMatrixFormat(final NumberFormat format) {
         this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ROW_PREFIX, DEFAULT_ROW_SUFFIX,
                 DEFAULT_ROW_SEPARATOR, DEFAULT_COLUMN_SEPARATOR, format);
     }
 
     /**
      * Create an instance with custom prefix, suffix and separator.
      * @param prefix prefix to use instead of the default "{"
      * @param suffix suffix to use instead of the default "}"
      * @param rowPrefix row prefix to use instead of the default "{"
      * @param rowSuffix row suffix to use instead of the default "}"
      * @param rowSeparator tow separator to use instead of the default ";"
      * @param columnSeparator column separator to use instead of the default ", "
      */
     public RealMatrixFormat(final String prefix, final String suffix,
                             final String rowPrefix, final String rowSuffix,
                             final String rowSeparator, final String columnSeparator) {
         this(prefix, suffix, rowPrefix, rowSuffix, rowSeparator, columnSeparator,
                 CompositeFormat.getDefaultNumberFormat());
     }
 
     /**
      * Create an instance with custom prefix, suffix, separator and format
      * for components.
      * @param prefix prefix to use instead of the default "{"
      * @param suffix suffix to use instead of the default "}"
      * @param rowPrefix row prefix to use instead of the default "{"
      * @param rowSuffix row suffix to use instead of the default "}"
      * @param rowSeparator tow separator to use instead of the default ";"
      * @param columnSeparator column separator to use instead of the default ", "
      * @param format the custom format for components.
      */
     public RealMatrixFormat(final String prefix, final String suffix,
                             final String rowPrefix, final String rowSuffix,
                             final String rowSeparator, final String columnSeparator,
                             final NumberFormat format) {
         this.prefix            = prefix;
         this.suffix            = suffix;
         this.rowPrefix         = rowPrefix;
         this.rowSuffix         = rowSuffix;
         this.rowSeparator      = rowSeparator;
         this.columnSeparator   = columnSeparator;
         this.format            = format;
         // disable grouping to prevent parsing problems
         this.format.setGroupingUsed(false);
     }
 
     /**
      * Get the set of locales for which real vectors formats are available.
      * <p>This is the same set as the {@link NumberFormat} set.</p>
      * @return available real vector format locales.
      */
     public static Locale[] getAvailableLocales() {
         return NumberFormat.getAvailableLocales();
     }
 
     /**
      * Get the format prefix.
      * @return format prefix.
      */
     public String getPrefix() {
         return prefix;
     }
 
     /**
      * Get the format suffix.
      * @return format suffix.
      */
     public String getSuffix() {
         return suffix;
     }
 
     /**
      * Get the format prefix.
      * @return format prefix.
      */
     public String getRowPrefix() {
         return rowPrefix;
     }
 
     /**
      * Get the format suffix.
      * @return format suffix.
      */
     public String getRowSuffix() {
         return rowSuffix;
     }
 
     /**
      * Get the format separator between rows of the matrix.
      * @return format separator for rows.
      */
     public String getRowSeparator() {
         return rowSeparator;
     }
 
     /**
      * Get the format separator between components.
      * @return format separator between components.
      */
     public String getColumnSeparator() {
         return columnSeparator;
     }
 
     /**
      * Get the components format.
      * @return components format.
      */
     public NumberFormat getFormat() {
         return format;
     }
 
     /**
      * Returns the default real vector format for the current locale.
      * @return the default real vector format.
      * @since 1.4
      */
     public static RealMatrixFormat getRealMatrixFormat() {
         return getRealMatrixFormat(Locale.getDefault());
     }
 
     /**
      * Returns the default real vector format for the given locale.
      * @param locale the specific locale used by the format.
      * @return the real vector format specific to the given locale.
      * @since 1.4
      */
     public static RealMatrixFormat getRealMatrixFormat(final Locale locale) {
         return new RealMatrixFormat(CompositeFormat.getDefaultNumberFormat(locale));
     }
 
     /**
      * This method calls {@link #format(RealMatrix,StringBuffer,FieldPosition)}.
      *
      * @param m RealMatrix object to format.
      * @return a formatted matrix.
      */
     public String format(RealMatrix m) {
         return format(m, new StringBuffer(), new FieldPosition(0)).toString();
     }
 
     /**
      * Formats a {@link RealMatrix} object to produce a string.
      * @param matrix the object to format.
      * @param toAppendTo where the text is to be appended
      * @param pos On input: an alignment field, if desired. On output: the
      *            offsets of the alignment field
      * @return the value passed in as toAppendTo.
      */
     public StringBuffer format(RealMatrix matrix, StringBuffer toAppendTo,
                                FieldPosition pos) {
 
         pos.setBeginIndex(0);
         pos.setEndIndex(0);
 
         // format prefix
         toAppendTo.append(prefix);
 
         // format rows
         final int rows = matrix.getRowDimension();
         for (int i = 0; i < rows; ++i) {
             toAppendTo.append(rowPrefix);
             for (int j = 0; j < matrix.getColumnDimension(); ++j) {
                 if (j > 0) {
                     toAppendTo.append(columnSeparator);
                 }
                 CompositeFormat.formatDouble(matrix.getEntry(i, j), format, toAppendTo, pos);
             }
             toAppendTo.append(rowSuffix);
             if (i < rows - 1) {
                 toAppendTo.append(rowSeparator);
             }
         }
 
         // format suffix
         toAppendTo.append(suffix);
 
         return toAppendTo;
     }
 
     /**
      * Parse a string to produce a {@link RealMatrix} object.
      *
      * @param source String to parse.
      * @return the parsed {@link RealMatrix} object.
      * @throws MathIllegalStateException if the beginning of the specified string
      * cannot be parsed.
      */
     public RealMatrix parse(String source) {
         final ParsePosition parsePosition = new ParsePosition(0);
         final RealMatrix result = parse(source, parsePosition);
         if (parsePosition.getIndex() == 0) {
             throw new MathIllegalStateException(LocalizedCoreFormats.CANNOT_PARSE_AS_TYPE,
                                                 source, parsePosition.getErrorIndex(),
                                                 Array2DRowRealMatrix.class);
         }
         return result;
     }
 
     /**
      * Parse a string to produce a {@link RealMatrix} object.
      *
      * @param source String to parse.
      * @param pos input/ouput parsing parameter.
      * @return the parsed {@link RealMatrix} object.
      */
     public RealMatrix parse(String source, ParsePosition pos) {
         int initialIndex = pos.getIndex();
 
         final String trimmedPrefix = prefix.trim();
         final String trimmedSuffix = suffix.trim();
         final String trimmedRowPrefix = rowPrefix.trim();
         final String trimmedRowSuffix = rowSuffix.trim();
         final String trimmedColumnSeparator = columnSeparator.trim();
         final String trimmedRowSeparator = rowSeparator.trim();
 
         // parse prefix
         CompositeFormat.parseAndIgnoreWhitespace(source, pos);
         if (!CompositeFormat.parseFixedstring(source, trimmedPrefix, pos)) {
             return null;
         }
 
         // parse components
         List<List<Number>> matrix = new ArrayList<>();
         List<Number> rowComponents = new ArrayList<>();
         for (boolean loop = true; loop;){
 
             if (!rowComponents.isEmpty()) {
                 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                 if (!CompositeFormat.parseFixedstring(source, trimmedColumnSeparator, pos)) {
                     if (trimmedRowSuffix.length() != 0 &&
                         !CompositeFormat.parseFixedstring(source, trimmedRowSuffix, pos)) {
                         return null;
                     } else {
                         CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                         if (CompositeFormat.parseFixedstring(source, trimmedRowSeparator, pos)) {
                             matrix.add(rowComponents);
                             rowComponents = new ArrayList<>();
                             continue;
                         } else {
                             loop = false;
                         }
                     }
                 }
             } else {
                 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                 if (trimmedRowPrefix.length() != 0 &&
                     !CompositeFormat.parseFixedstring(source, trimmedRowPrefix, pos)) {
                     return null;
                 }
             }
 
             if (loop) {
                 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                 Number component = CompositeFormat.parseNumber(source, format, pos);
                 if (component != null) {
                     rowComponents.add(component);
                 } else {
                     if (rowComponents.isEmpty()) {
                         loop = false;
                     } else {
                         // invalid component
                         // set index back to initial, error index should already be set
                         pos.setIndex(initialIndex);
                         return null;
                     }
                 }
             }
 
         }
 
         if (!rowComponents.isEmpty()) {
             matrix.add(rowComponents);
         }
 
         // parse suffix
         CompositeFormat.parseAndIgnoreWhitespace(source, pos);
         if (!CompositeFormat.parseFixedstring(source, trimmedSuffix, pos)) {
             return null;
         }
 
         // do not allow an empty matrix
         if (matrix.isEmpty()) {
             pos.setIndex(initialIndex);
             return null;
         }
 
         // build vector
         double[][] data = new double[matrix.size()][];
         int row = 0;
         for (List<Number> rowList : matrix) {
             data[row] = new double[rowList.size()];
             for (int i = 0; i < rowList.size(); i++) {
                 data[row][i] = rowList.get(i).doubleValue();
             }
             row++;
         }
         return MatrixUtils.createRealMatrix(data);
     }
 }