/*
 * Jalview - A Sequence Alignment Editor and Viewer ($$Version-Rel$$)
 * Copyright (C) $$Year-Rel$$ The Jalview Authors
 * 
 * This file is part of Jalview.
 * 
 * Jalview is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License 
 * as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *  
 * Jalview is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty 
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
 * PURPOSE.  See the GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with Jalview.  If not, see <http://www.gnu.org/licenses/>.
 * The Jalview Authors are detailed in the 'AUTHORS' file.
 */
package jalview.analysis;

import jalview.api.AlignViewportI;
import jalview.api.FinderI;
import jalview.datamodel.AlignmentI;
import jalview.datamodel.Range;
import jalview.datamodel.SearchResultMatchI;
import jalview.datamodel.SearchResults;
import jalview.datamodel.SearchResultsI;
import jalview.datamodel.SequenceGroup;
import jalview.datamodel.SequenceI;
import jalview.datamodel.VisibleContigsIterator;
import jalview.util.Comparison;

import java.util.List;
import java.util.Vector;

import com.stevesoft.pat.Regex;

/**
 * Implements the search algorithm for the Find dialog
 */
public class Finder implements FinderI
{
  /*
   * matched residue locations
   */
  private SearchResultsI searchResults;

  /*
   * sequences matched by id or description
   */
  private Vector<SequenceI> idMatches;

  /*
   * the viewport to search over
   */
  private AlignViewportI viewport;

  /*
   * sequence index in alignment to search from
   */
  private int sequenceIndex;

  /*
   * column position in sequence to search from, base 0
   * - absolute column number including any hidden columns
   * (position after start of last match for a repeat search)
   */
  private int columnIndex;

  /**
   * Constructor for searching a viewport
   * 
   * @param av
   */
  public Finder(AlignViewportI av)
  {
    this.viewport = av;
    this.sequenceIndex = 0;
    this.columnIndex = -1;
  }

  @Override
  public void findAll(String theSearchString, boolean matchCase,
          boolean searchDescription)
  {
    /*
     * search from the start
     */
    sequenceIndex = 0;
    columnIndex = -1;

    doFind(theSearchString, matchCase, searchDescription, true);

    /*
     * reset to start for next search
     */
    sequenceIndex = 0;
    columnIndex = -1;
  }

  @Override
  public void findNext(String theSearchString, boolean matchCase,
          boolean searchDescription)
  {
    doFind(theSearchString, matchCase, searchDescription, false);
    
    if (searchResults.isEmpty() && idMatches.isEmpty())
    {
      /*
       * search failed - reset to start for next search
       */
      sequenceIndex = 0;
      columnIndex = -1;
    }
  }

  /**
   * Performs a 'find next' or 'find all'
   * 
   * @param theSearchString
   * @param matchCase
   * @param searchDescription
   * @param findAll
   */
  protected void doFind(String theSearchString, boolean matchCase,
          boolean searchDescription, boolean findAll)
  {
    String searchString = matchCase ? theSearchString
            : theSearchString.toUpperCase();
    Regex searchPattern = new Regex(searchString);
    searchPattern.setIgnoreCase(!matchCase);

    searchResults = new SearchResults();
    idMatches = new Vector<>();

    SequenceGroup selection = viewport.getSelectionGroup();
    if (selection != null && selection.getSize() < 1)
    {
      selection = null; // ? ignore column-only selection
    }

    AlignmentI alignment = viewport.getAlignment();
    int end = alignment.getHeight();

    while (sequenceIndex < end)
    {
      SequenceI seq = alignment.getSequenceAt(sequenceIndex);
      boolean found = findNextMatch(seq, searchString, searchPattern,
              searchDescription);
      if (found && !findAll)
      {
        return;
      }
      if (!found)
      {
        sequenceIndex++;
        columnIndex = -1;
      }
    }
  }

  /**
   * Answers the start-end column range of the visible region of
   * <code>sequence</code> starting at or after the given <code>column</code>.
   * If there are no hidden columns, this just returns the remaining width of
   * the sequence. The range is restricted to the current <code>selection</code>
   * if there is one. Answers null if there are no visible columns at or after
   * <code>column</code>.
   */
  protected Range getNextVisibleSequenceRegion(SequenceI sequence,
          int column)
  {
    int seqColStart = column;
    int seqColEnd = sequence.getLength() - 1;

    /*
     * restrict search to (next) visible column region, 
     * in case there are hidden columns
     */
    AlignmentI alignment = viewport.getAlignment();
    VisibleContigsIterator visibleRegions = alignment.getHiddenColumns()
            .getVisContigsIterator(column, alignment.getWidth(),
                    false);
    int[] visible = visibleRegions.hasNext() ? visibleRegions.next() : null;
    if (visible == null)
    {
      columnIndex = seqColEnd + 1;
      return null;
    }
    seqColStart = Math.max(seqColStart, visible[0]);
    seqColEnd = Math.min(seqColEnd, visible[1]);

    /*
     * restrict search to selected region if there is one
     */
    SequenceGroup selection = viewport.getSelectionGroup();
    if (selection != null)
    {
      int selectionStart = selection.getStartRes();
      int selectionEnd = selection.getEndRes();
      if (selectionStart > seqColEnd || selectionEnd < seqColStart)
      {
        /*
         * sequence region doesn't overlap selection region 
         */
        columnIndex = seqColEnd + 1;
        return null;
      }
      seqColStart = Math.max(seqColStart, selectionStart);
      seqColEnd = Math.min(seqColEnd, selectionEnd);
    }

    return new Range(seqColStart, seqColEnd);
  }

  /**
   * Finds the next match in the given sequence, starting at column at
   * <code>columnIndex</code>. Answers true if a match is found, else false. If
   * a match is found, <code>columnIndex</code> is advanced to the column after
   * the start of the matched region, ready for a search from the next position.
   * 
   * @param seq
   * @param searchString
   * @param searchPattern
   * @param matchDescription
   * @return
   */
  protected boolean findNextMatch(SequenceI seq, String searchString,
          Regex searchPattern, boolean matchDescription)
  {
    SequenceGroup selection = viewport.getSelectionGroup();
    if (selection != null && !selection.contains(seq))
    {
      /*
       * this sequence is not in the selection - advance to next sequence
       */
      return false;
    }

    if (columnIndex < 0)
    {
      /*
       * at start of sequence; try find by residue number, in sequence id,
       * or (optionally) in sequence description
       */
      if (doNonMotifSearches(seq, searchString, searchPattern,
              matchDescription))
      {
        return true;
      }
    }

    /*
     * search for next match in sequence string
     */
    int end = seq.getLength();
    while (columnIndex < end)
    {
      if (searchNextVisibleRegion(seq, searchPattern))
      {
        return true;
      }
    }
    return false;
  }

  /**
   * Searches the sequence, starting from <code>columnIndex</code>, and adds the
   * next match (if any) to <code>searchResults</code>. The search is restricted
   * to the next visible column region, and to the <code>selection</code> region
   * if there is one. Answers true if a match is added, else false.
   * 
   * @param seq
   * @param searchPattern
   * @return
   */
  protected boolean searchNextVisibleRegion(SequenceI seq, Regex searchPattern)
  {
    Range visible = getNextVisibleSequenceRegion(seq, columnIndex);
    if (visible == null)
    {
      return false;
    }
    String seqString = seq.getSequenceAsString(visible.start, visible.end + 1);
    String noGaps = AlignSeq.extractGaps(Comparison.GapChars, seqString);

    if (searchPattern.search(noGaps))
    {
      int sequenceStartPosition = seq.findPosition(visible.start);
      recordMatch(seq, searchPattern, sequenceStartPosition);
      return true;
    }
    else
    {
      /*
       * no match - advance columnIndex past this visible region
       * so the next visible region (if any) is searched next
       */
      columnIndex = visible.end + 1;
    }

    return false;
  }

  /**
   * Adds the match held in the <code>searchPattern</code> Regex to the
   * <code>searchResults</code>, unless it is a subregion of the last match
   * recorded. <code>columnIndex</code> is advanced to the position after the
   * start of the matched region, ready for the next search. Answers true if a
   * match was added, else false.
   * 
   * @param seq
   * @param searchPattern
   * @param firstResiduePosition
   * @return
   */
  protected boolean recordMatch(SequenceI seq, Regex searchPattern,
          int firstResiduePosition)
  {
    /*
     * get start/end of the match in sequence coordinates
     */
    int offset = searchPattern.matchedFrom();
    int matchStartPosition = firstResiduePosition + offset;
    int matchEndPosition = matchStartPosition
            + searchPattern.charsMatched() - 1;

    /*
     * update columnIndex to next column after the start of the match
     * (findIndex returns a value base 1, columnIndex is held base 0)
     */
    columnIndex = seq.findIndex(matchStartPosition);

    /*
     * check that this match is not a subset of the previous one (JAL-2302)
     */
    List<SearchResultMatchI> matches = searchResults.getResults();
    SearchResultMatchI lastMatch = matches.isEmpty() ? null
            : matches.get(matches.size() - 1);

    if (lastMatch == null || !lastMatch.contains(seq, matchStartPosition,
            matchEndPosition))
    {
      searchResults.addResult(seq, matchStartPosition, matchEndPosition);
      return true;
    }

    return false;
  }

  /**
   * Does searches other than for residue patterns. Currently this includes
   * <ul>
   * <li>find residue by position (if search string is a number)</li>
   * <li>match search string to sequence id</li>
   * <li>match search string to sequence description (optional)</li>
   * </ul>
   * Answers true if a match is found, else false.
   * 
   * @param seq
   * @param searchString
   * @param searchPattern
   * @param includeDescription
   * @return
   */
  protected boolean doNonMotifSearches(SequenceI seq, String searchString,
          Regex searchPattern, boolean includeDescription)
  {
    /*
     * position sequence search to start of sequence
     */
    columnIndex = 0;

    if (searchForResidueNumber(seq, searchString))
    {
      return true;
    }
    if (searchSequenceName(seq, searchPattern))
    {
      return true;
    }
    if (includeDescription && searchSequenceDescription(seq, searchPattern))
    {
      return true;
    }
    return false;
  }

  /**
   * Searches for a match with the sequence description, and if found, adds the
   * sequence to the list of match ids (but not as a duplicate). Answers true if
   * a match was added, else false.
   * 
   * @param seq
   * @param searchPattern
   * @return
   */
  protected boolean searchSequenceDescription(SequenceI seq, Regex searchPattern)
  {
    String desc = seq.getDescription();
    if (desc != null && searchPattern.search(desc) && !idMatches.contains(seq))
    {
      idMatches.addElement(seq);
      return true;
    }
    return false;
  }

  /**
   * Searches for a match with the sequence name, and if found, adds the
   * sequence to the list of match ids (but not as a duplicate). Answers true if
   * a match was added, else false.
   * 
   * @param seq
   * @param searchPattern
   * @return
   */
  protected boolean searchSequenceName(SequenceI seq, Regex searchPattern)
  {
    if (searchPattern.search(seq.getName()) && !idMatches.contains(seq))
    {
      idMatches.addElement(seq);
      return true;
    }
    return false;
  }

  /**
   * Tries to interpret the search string as a residue position, and if valid,
   * adds the position to the search results and returns true, else answers
   * false
   */
  protected boolean searchForResidueNumber(SequenceI seq, String searchString)
  {
    try
    {
      int res = Integer.parseInt(searchString);
      if (seq.getStart() <= res && seq.getEnd() >= res)
      {
        searchResults.addResult(seq, res, res);
        return true;
      }
    } catch (NumberFormatException ex)
    {
    }
    return false;
  }

  /* (non-Javadoc)
   * @see jalview.analysis.FinderI#getIdMatch()
   */
  @Override
  public Vector<SequenceI> getIdMatches()
  {
    return idMatches;
  }

  /* (non-Javadoc)
   * @see jalview.analysis.FinderI#getSearchResults()
   */
  @Override
  public SearchResultsI getSearchResults()
  {
    return searchResults;
  }
}