/*
 * Copyright (c) 2003-2009, John Wiegley.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of New Artisans LLC nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <system.hh>

#include "pyinterp.h"

namespace ledger {

using namespace python;

shared_ptr<python_interpreter_t> python_session;

char * argv0;

void export_amount();
void export_balance();
void export_chain();
void export_commodity();
void export_expr();
void export_flags();
void export_format();
void export_global();
void export_item();
void export_journal();
void export_post();
void export_report();
void export_scope();
void export_session();
void export_timelog();
void export_times();
void export_utils();
void export_value();
void export_xact();

void initialize_for_python()
{
  export_amount();
  export_balance();
  export_chain();
  export_commodity();
  export_expr();
  export_flags();
  export_format();
  export_global();
  export_item();
  export_journal();
  export_post();
  export_report();
  export_scope();
  export_session();
  export_timelog();
  export_times();
  export_utils();
  export_value();
  export_xact();

  scope().attr("session") = python_session;
}

struct python_run
{
  object result;

  python_run(python_interpreter_t * intepreter,
	     const string& str, int input_mode)
    : result(handle<>(borrowed(PyRun_String(str.c_str(), input_mode,
					    intepreter->main_nspace.ptr(),
					    intepreter->main_nspace.ptr())))) {}
  operator object() {
    return result;
  }
};

void python_interpreter_t::initialize()
{
  TRACE_START(python_init, 1, "Initialized Python");

  try {
    DEBUG("python.interp", "Initializing Python");

    Py_Initialize();
    assert(Py_IsInitialized());

    object main_module = python::import("__main__");
    if (! main_module)
      throw_(std::logic_error,
	     _("Python failed to initialize (couldn't find __main__)"));

    main_nspace = extract<dict>(main_module.attr("__dict__"));
    if (! main_nspace)
      throw_(std::logic_error,
	     _("Python failed to initialize (couldn't find __dict__)"));

    python::detail::init_module("ledger", &initialize_for_python);

    is_initialized = true;

    // Hack ledger.__path__ so it points to a real location
    python::object module_sys = import("sys"); 
    python::object sys_dict   = module_sys.attr("__dict__");

    python::list paths(sys_dict["path"]);

    bool path_initialized = false;
    int n = python::extract<int>(paths.attr("__len__")());
    for (int i = 0; i < n; i++) {
      python::extract<std::string> str(paths[i]);
      path pathname(str);
      DEBUG("python.interp", "sys.path = " << pathname);

      if (exists(pathname / "ledger" / "__init__.py")) {
	if (python::object module_ledger = import("ledger")) {
	  DEBUG("python.interp",
		"Setting ledger.__path__ = " << (pathname / "ledger"));

	  python::object ledger_dict = module_ledger.attr("__dict__");
	  python::list temp_list;
	  temp_list.append((pathname / "ledger").string());

	  ledger_dict["__path__"] = temp_list;
	} else {
	  throw_(std::logic_error,
		 _("Python failed to initialize (couldn't find ledger)"));
	}
	path_initialized = true;
	break;
      }
    }
#if defined(DEBUG_ON)
    if (! path_initialized)
      DEBUG("python.init",
	    "Ledger failed to find 'ledger/__init__.py' on the PYTHONPATH");
#endif
  }
  catch (const error_already_set&) {
    PyErr_Print();
    throw_(std::logic_error, _("Python failed to initialize"));
  }

  TRACE_FINISH(python_init, 1);
}

object python_interpreter_t::import(const string& str)
{
  if (! is_initialized)
    initialize();

  try {
    object mod = python::import(str.c_str());
    if (! mod)
      throw_(std::logic_error, _("Failed to import Python module %1") << str);
 
    // Import all top-level entries directly into the main namespace
    main_nspace.update(mod.attr("__dict__"));

    return mod;
  }
  catch (const error_already_set&) {
    PyErr_Print();
  }
  return object();
}

object python_interpreter_t::eval(std::istream& in, py_eval_mode_t mode)
{
  bool	 first = true;
  string buffer;
  buffer.reserve(4096);

  while (! in.eof()) {
    char buf[256];
    in.getline(buf, 255);
    if (buf[0] == '!')
      break;
    if (first)
      first = false;
    else
      buffer += "\n";
    buffer += buf;
  }

  if (! is_initialized)
    initialize();

  try {
    int input_mode = -1;
    switch (mode) {
    case PY_EVAL_EXPR:  input_mode = Py_eval_input;   break;
    case PY_EVAL_STMT:  input_mode = Py_single_input; break;
    case PY_EVAL_MULTI: input_mode = Py_file_input;   break;
    }

    return python_run(this, buffer, input_mode);
  }
  catch (const error_already_set&) {
    PyErr_Print();
    throw_(std::logic_error, _("Failed to evaluate Python code"));
  }
  return object();
}

object python_interpreter_t::eval(const string& str, py_eval_mode_t mode)
{
  if (! is_initialized)
    initialize();

  try {
    int input_mode = -1;
    switch (mode) {
    case PY_EVAL_EXPR:  input_mode = Py_eval_input;   break;
    case PY_EVAL_STMT:  input_mode = Py_single_input; break;
    case PY_EVAL_MULTI: input_mode = Py_file_input;   break;
    }

    return python_run(this, str, input_mode);
  }
  catch (const error_already_set&) {
    PyErr_Print();
    throw_(std::logic_error, _("Failed to evaluate Python code"));
  }
  return object();
}

value_t python_interpreter_t::python_command(call_scope_t& args)
{
  if (! is_initialized)
    initialize();

  char ** argv(new char *[args.size() + 1]);

  argv[0] = new char[std::strlen(argv0) + 1];
  std::strcpy(argv[0], argv0);

  for (std::size_t i = 0; i < args.size(); i++) {
    string arg = args[i].as_string();
    argv[i + 1] = new char[arg.length() + 1];
    std::strcpy(argv[i + 1], arg.c_str());
  }

  int status = Py_Main(static_cast<int>(args.size()) + 1, argv);

  for (std::size_t i = 0; i < args.size() + 1; i++)
    delete[] argv[i];
  delete[] argv;
  
  if (status != 0)
    throw status;

  return NULL_VALUE;
}

option_t<python_interpreter_t> *
python_interpreter_t::lookup_option(const char * p)
{
  switch (*p) {
  case 'i':
    OPT(import_);
    break;
  }
  return NULL;
}

expr_t::ptr_op_t python_interpreter_t::lookup(const string& name)
{
  // Give our superclass first dibs on symbol definitions
  if (expr_t::ptr_op_t op = session_t::lookup(name))
    return op;

  const char * p = name.c_str();
  switch (*p) {
  case 'o':
    if (WANT_OPT()) { const char * q = p + OPT_PREFIX_LEN;
      if (option_t<python_interpreter_t> * handler = lookup_option(q))
	return MAKE_OPT_HANDLER(python_interpreter_t, handler);
    }
    break;

  case 'p':
    if (WANT_PRECMD()) { const char * q = p + PRECMD_PREFIX_LEN;
      switch (*q) {
      case 'p':
	if (is_eq(q, "python"))
	  return MAKE_FUNCTOR(python_interpreter_t::python_command);
	break;
      }
    }
    break;
  }

  if (is_initialized && main_nspace.has_key(name.c_str())) {
    DEBUG("python.interp", "Python lookup: " << name);

    if (python::object obj = main_nspace.get(name.c_str()))
      return WRAP_FUNCTOR(functor_t(name, obj));
  }

  return NULL;
}
  
value_t python_interpreter_t::functor_t::operator()(call_scope_t& args)
{
  try {
    std::signal(SIGINT, SIG_DFL);
    if (! PyCallable_Check(func.ptr())) {
      extract<value_t> val(func);
      std::signal(SIGINT, sigint_handler);
      if (val.check())
	return val();
#if 1
      // jww (2009-02-24): Distinguish between "no return" and a value with an
      // unconvertable type
      return NULL_VALUE;
#else
      throw_(calc_error,
	     _("Could not evaluate Python variable '%1'") << name);
#endif
    } else {
      if (args.size() > 0) {
	list arglist;
	if (args.value().is_sequence())
	  foreach (const value_t& value, args.value().as_sequence())
	    arglist.append(value);
	else
	  arglist.append(args.value());

	if (PyObject * val =
	    PyObject_CallObject(func.ptr(), python::tuple(arglist).ptr())) {
	  extract<value_t> xval(val);
	  value_t result;
	  if (xval.check()) {
	    result = xval();
	    Py_DECREF(val);
	  } else {
	    Py_DECREF(val);
	    throw_(calc_error,
		   _("Could not evaluate Python variable '%1'") << name);
	  }
	  std::signal(SIGINT, sigint_handler);
	  return result;
	}
	else if (PyErr_Occurred()) {
	  PyErr_Print();
	  throw_(calc_error, _("Failed call to Python function '%1'") << name);
	} else {
	  assert(false);
	}
      } else {
	std::signal(SIGINT, sigint_handler);
	return call<value_t>(func.ptr());
      }
    }
  }
  catch (const error_already_set&) {
    std::signal(SIGINT, sigint_handler);
    PyErr_Print();
    throw_(calc_error, _("Failed call to Python function '%1'") << name);
  }
  catch (...) {
    std::signal(SIGINT, sigint_handler);
  }
  std::signal(SIGINT, sigint_handler);

  return NULL_VALUE;
}

} // namespace ledger