#ifndef ICL_FILE_LIST_H
#define ICL_FILE_LIST_H

#include <iclShallowCopyable.h>
#include <string>

namespace icl{
  
  /** \cond */
  class FileListImpl;
  struct FileListImplDelOp { static void delete_func(FileListImpl *i); };
  /** \endcond */

  /// Utility class implementing a list of files \ingroup UTILS_G
  class FileList : public ShallowCopyable<FileListImpl,FileListImplDelOp>{
    public:

    /// Create a null file-list
    FileList();
    
    /// Create a file-list of given type
    /** pattern migtht be a file pattern like "images/ *.ppm"
        a single file like "./theimage.jpg" or a file seqenece file
        with postfix ".seq" which is a textfile where each line is
        single filename.\n
        
        \section Sequence File (postfix ".seq")
        Sequence files which are determined by their postfix ".seq" are
        are treated in a special way. A sequence file must contain a new-line
        separated list of filename (in particular other sequence files).
        Each entry of the seqence file is then added using a recursive "add"-
        function. If a sequence file contains other sequence files, this files
        are parsed recursively in the same way. Sequence files may not contain
        file patterns like "*.ppm".\n
        To avoid infinite recursion, the FileLists implementation internally
        holds a list of all already contained sequence files, so adding the 
        same sequence more than once (even indirect by other sequence files)
        will have no effect.
        
        \section Omiting Doubled Files
        Another feature of the FileList class is provided using an additional
        constructor flag "omitDoubledFiles". If this flag is set to true 
        (it is false by default), the FileLists implementation will internally
        skip files, which have already been added.


        @param pattern the file pattern Either something like
                       images/ *.p[gnp]m or a seqence file name
    **/
    FileList(const std::string &pattern, bool omitDoubledFiles=false);

    /// create a file list by given set of filenames
    /** double filenames are allowed in this mode. Sequence files are not
        handled in a special way.*/
    FileList(const std::vector<std::string> &filenames);

    /// does nothing
    ~FileList();

    /// returns the number of files in this list
    int size() const;
    
    /// returns the i-th filename in this list
    const std::string &operator[](int i) const;

    /// adds all files from another FileList to this
    void join(const FileList &other);

    /// shows the filelist to std::out
    void show() const;
    
    /// generates a ".seq" from this FileList
    void toSequenceFile(const std::string &seqFileName) const;
    
    /// translates a hashpattern to a regular expression
    static std::string translateHashPattern(const std::string &hashPattern);
  };
} 

#endif