// Copyright (c) 2004-present, Facebook, Inc.
// All Rights Reserved.
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

// pythonutil.h - utilities to glue C++ code to python
// no-check-code

#ifndef FBHGEXT_CSTORE_PYTHONUTIL_H
#define FBHGEXT_CSTORE_PYTHONUTIL_H

// The PY_SSIZE_T_CLEAN define must be defined before the Python.h include,
// as per the documentation.
#define PY_SSIZE_T_CLEAN

#include <Python.h>
#include <exception>

// Py_BuildValue treats NULL as NONE, so we have to have a non-null pointer.
#define MAGIC_EMPTY_STRING ""

#include "hgext/extlib/cstore/key.h"
#include "hgext/extlib/cstore/match.h"
#include "hgext/extlib/cstore/store.h"
#include "hgext/extlib/ctreemanifest/treemanifest.h"

/**
 * C++ exception that represents an issue at the python C api level.
 * When this is thrown, it's assumed that the python error message has been set
 * and that the catcher of the exception should just return an error code value
 * to the python API.
 */
class pyexception : public std::exception {
  public:
    pyexception() {
    }
};

/**
 * Wrapper class for PyObject pointers.
 * It is responsible for managing the Py_INCREF and Py_DECREF calls.
 */
class PythonObj {
  private:
    PyObject *obj;

  public:
    PythonObj();

    PythonObj(PyObject *obj);

    PythonObj(const PythonObj& other);

    ~PythonObj();

    PythonObj& operator=(const PythonObj &other);

    operator PyObject* () const;

    operator bool() const;

    /**
     * Function used to obtain a return value that will persist beyond the life
     * of the PythonObj. This is useful for returning objects to Python C apis
     * and letting them manage the remaining lifetime of the object.
     */
    PyObject *returnval();

    /**
     * Invokes getattr to retrieve the attribute from the python object.
     */
    PythonObj getattr(const char *name);

    /**
     * Executes the current callable object if it's callable.
     */
    PythonObj call(const PythonObj &args);

    /**
     * Invokes the specified method on this instance.
     */
    PythonObj callmethod(const char *name, const PythonObj &args);
};

class PythonStore : public Store {
  private:
    PythonObj _get;
    PythonObj _storeObj;
  public:
    PythonStore(PythonObj store);

    PythonStore(const PythonStore &store);

    virtual ~PythonStore() {}

    ConstantStringRef get(const Key &key);
};

class PythonMatcher : public Matcher {
  private:
    PythonObj _matcherObj;
  public:
    PythonMatcher(PythonObj matcher) :
      _matcherObj(matcher) {}

    virtual ~PythonMatcher() {}

    bool matches(const std::string &path);
    bool matches(const char *path, const size_t pathlen);
    bool visitdir(const std::string &path);
};

class PythonDiffResult : public DiffResult {
  private:
    PythonObj _diff;
  public:
    PythonDiffResult(PythonObj diff) :
      _diff(diff) {
    }
    virtual void add(const std::string &path,
                     const char *beforeNode, const char *beforeFlag,
                     const char *afterNode, const char *afterFlag);
    virtual void addclean(const std::string &path);
    PythonObj getDiff() {
      return this->_diff;
    }
};
#endif // FBHGEXT_CSTORE_PYTHONUTIL_H