/**
 * Copyright (c) 2011 10gen Inc.
 *
 * This program is free software: you can redistribute it and/or  modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * As a special exception, the copyright holders give permission to link the
 * code of portions of this program with the OpenSSL library under certain
 * conditions as described in each individual source file and distribute
 * linked combinations including the program with the OpenSSL library. You
 * must comply with the GNU Affero General Public License in all respects for
 * all of the code used other than as permitted herein. If you modify file(s)
 * with this exception, you may extend this exception to your version of the
 * file(s), but you are not obligated to do so. If you do not wish to do so,
 * delete this exception statement from your version. If you delete this
 * exception statement from all source files in the program, then also delete
 * it in the license file.
 */

#pragma once

#include <iosfwd>
#include <string>
#include <vector>

#include "mongo/util/assert_util.h"

namespace mongo {

class FieldPath {
public:
    /**
     * Constructor.
     *
     * @param fieldPath the dotted field path std::string or non empty pre-split vector.
     * The constructed object will have getPathLength() > 0.
     * Uassert if any component field names do not pass validation.
     */
    FieldPath(const std::string& fieldPath);
    FieldPath(const std::vector<std::string>& fieldPath);

    /**
      Get the number of path elements in the field path.

      @returns the number of path elements
     */
    size_t getPathLength() const;

    /**
      Get a particular path element from the path.

      @param i the zero based index of the path element.
      @returns the path element
     */
    const std::string& getFieldName(size_t i) const;

    /**
      Get the full path.

      @param fieldPrefix whether or not to include the field prefix
      @returns the complete field path
     */
    std::string getPath(bool fieldPrefix) const;

    /**
      Write the full path.

      @param outStream where to write the path to
      @param fieldPrefix whether or not to include the field prefix
    */
    void writePath(std::ostream& outStream, bool fieldPrefix) const;

    /**
       Get the prefix string.

       @returns the prefix string
     */
    static const char* getPrefix();

    static const char prefix[];

    /**
     * A FieldPath like this but missing the first element (useful for recursion).
     * Precondition getPathLength() > 1.
     */
    FieldPath tail() const;

private:
    /** Uassert if a field name does not pass validation. */
    static void uassertValidFieldName(const std::string& fieldName);

    /**
     * Push a new field name to the back of the vector of names comprising the field path.
     * Uassert if 'fieldName' does not pass validation.
     */
    void pushFieldName(const std::string& fieldName);

    std::vector<std::string> vFieldName;
};
}


/* ======================= INLINED IMPLEMENTATIONS ========================== */

namespace mongo {

inline size_t FieldPath::getPathLength() const {
    return vFieldName.size();
}

inline const std::string& FieldPath::getFieldName(size_t i) const {
    dassert(i < getPathLength());
    return vFieldName[i];
}

inline const char* FieldPath::getPrefix() {
    return prefix;
}
}