// DatasetRepository.h

#ifndef DatasetRepository_H
#define DatasetRepository_H

// David Adamsmurthy
// July 2004
//
// Interface for database holding Dataset objects
// User is provided means to insert and extract dataset objects.
// This class provides a transient repository and has 
// the read and write methods to provide persistence.
//
// This class hold a CatalogError status that is reset when any method
// is called.
//
// The normal usage is as a singleton:
//   DatasetRepository* pdr = default_instance();
// An object of this type is created as the default.
// 
// This class also manages the GenericRepository that it uses 
// if the manage flag is set.
   
#include "dataset_catalog/CatalogError.h"
#include "dataset_catalog/GenericRepository.h"
#include "dataset_id/DatasetId.h"
#include "dataset_base/Dataset.h"

namespace dset {

class DatasetRepository {

public:  // typedefs
  
  typedef GenericRepository::size_type size_type;
  typedef CatalogError::Status Status;
  typedef std::map<DatasetId, const Dataset*> RepMap;
  typedef std::map<DatasetId, bool> ManageMap;

private: // data
  
  // Transient database.
  RepMap m_dss;
  ManageMap m_mgs;
  GenericRepository* m_prep;
  mutable Status m_error;
  bool m_manage;

private:  // Hidden function.
  
  // No copying allowed.
  DatasetRepository(const DatasetRepository&);
  
  // No assignment allowed.
  DatasetRepository& operator=(const DatasetRepository&);

public:  // static functions
                                              
  // Return the default concrete instance of this class.
  // First pass, use set_default_instance or 
  // define an invalid catalog if this fails.
  static DatasetRepository& default_instance();
  
  // Set the the default instance of this class with a connection
  // string. Fails with no change if the connection cannot be resolved.
  // Returns 0 for success.
  static int set_default_instance(std::string name = "");

  // Assign an empty dataset repository as the default by
  // 1. creating an empty SQLRESULT dataset repository dr.dat,
  // 2. appending a clause to resolver.dat and
  // 3. setting the latter as the connection configuration file.
  // This should only be used for testing.
  // The connection resolver is shared by all catalogs.
  // Returns 0 for success.
  static int create_default_instance();

public: // member functions
  
  // Default Constructor.
  DatasetRepository();
 
  // Constructor from a generic repository.
  explicit DatasetRepository(GenericRepository* rep);
    
  // Constructor from connection string.
  explicit DatasetRepository(std::string name);
  
  // Destructor.
  ~DatasetRepository();
  
  // Is this a valid repository?
  bool is_valid() const;

  // Error code.
  int error() const; 

  // Error message.
  std::string error_message() const; 

  // Return the number of entries.
  size_type size() const;

  // Return if the repository has a given ID either in transient 
  // or persistent store.
  bool has(DatasetId id) const;
  
  // Return the dataset associated with an ID.
  // If readnull is set, then an attempt is made to fetch the
  // dataset from persistent store if the transient value is null.
  const Dataset* extract(DatasetId id, bool readnull =false);
  
  // Return the datasets associated with a list of ID's.
  // A null entry is returned for any dataset that cannot be found.
  // Returns 0 if all entries are found not null.
  // Returns nonzero if any entries are not found or are null or for
  // any other error.
  int extract(const DatasetIdList& dids, DatasetList& dsts,
              bool readnull =false);

  // Put a dataset in the repository.
  // The ID is returned.
  // ID is invalid if the write fails.
  // The repository manages (deletes) the dataset if manage is true.
  DatasetId insert(const Dataset* pds, bool manage =false);

  // Remove a dataset from repository.
  // Returns 0 on success.
  int remove(DatasetId id);

  // Verify all entries
  bool verify() const; 
  
  // Output stream.
  std::ostream& ostr(std::ostream& str) const;

  // Web page.
  // entry:
  //   blank to show entire repository
  //   did=123-456 to show dataset with ID 123-456
  Text web_page(std::string baseurl, std::string entry);

};

}  // end namespace dset

// Output stream.
std::ostream&
operator<<(std::ostream& lhs, const dset::DatasetRepository& rhs);

#endif