/*

Copyright (C) 1993-2016 John W. Eaton

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.

Octave 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#if ! defined (octave_call_stack_h)
#define octave_call_stack_h 1

#include "octave-config.h"

#include <deque>
#include <string>

class octave_function;
class octave_user_code;
class octave_user_script;

#include "input.h"
#include "oct-map.h"
#include "symtab.h"

namespace octave
{
  class
  OCTINTERP_API
  call_stack
  {
  protected:

    call_stack (void) : cs (), curr_frame (0) { }

  public:

    class stack_frame
    {
    public:

      friend class call_stack;

      stack_frame (octave_function *fcn = 0, symbol_table::scope_id scope = 0,
                   symbol_table::context_id context = 0, size_t prev = 0)
        : m_fcn (fcn), m_line (-1), m_column (-1), m_scope (scope),
          m_context (context), m_prev (prev)
      { }

      stack_frame (const stack_frame& elt)
        : m_fcn (elt.m_fcn), m_line (elt.m_line), m_column (elt.m_column),
          m_scope (elt.m_scope), m_context (elt.m_context), m_prev (elt.m_prev)
      { }

      int line (void) const { return m_line; }

      int column (void) const { return m_column; }

      std::string fcn_file_name (void) const;

      std::string fcn_name (bool print_subfn = true) const;

      bool operator == (const stack_frame &rhs) const;

    private:

      octave_function *m_fcn;
      int m_line;
      int m_column;
      symbol_table::scope_id m_scope;
      symbol_table::context_id m_context;
      size_t m_prev;
    };

    typedef std::deque<stack_frame>::iterator iterator;
    typedef std::deque<stack_frame>::const_iterator const_iterator;

    typedef std::deque<stack_frame>::reverse_iterator reverse_iterator;
    typedef std::deque<stack_frame>::const_reverse_iterator const_reverse_iterator;

    static void create_instance (void);

    static bool instance_ok (void)
    {
      bool retval = true;

      if (! instance)
        create_instance ();

      if (! instance)
        error ("unable to create call stack object!");

      return retval;
    }

    // Current function (top of stack).
    static octave_function *current (void)
    {
      return instance_ok () ? instance->do_current () : 0;
    }

    // Current line in current function.
    static int current_line (void)
    {
      return instance_ok () ? instance->do_current_line () : -1;
    }

    // Current column in current function.
    static int current_column (void)
    {
      return instance_ok () ? instance->do_current_column () : -1;
    }

    // Caller function, may be built-in.
    static octave_function *caller (void)
    {
      return instance_ok () ? instance->do_caller () : 0;
    }

    static size_t current_frame (void)
    {
      return instance_ok () ? instance->do_current_frame () : 0;
    }

    static size_t size (void)
    {
      return instance_ok () ? instance->do_size () : 0;
    }

    static size_t num_user_code_frames (octave_idx_type& curr_user_frame)
    {
      return instance_ok ()
        ? instance->do_num_user_code_frames (curr_user_frame) : 0;
    }

    static symbol_table::scope_id current_scope (void)
    {
      return instance_ok () ? instance->do_current_scope () : 0;
    }

    static symbol_table::context_id current_context (void)
    {
      return instance_ok () ? instance->do_current_context () : 0;
    }

#if 0
    static stack_frame frame (size_t idx)
    {
      return instance_ok () ? instance->do_frame (idx) : stack_frame ();
    }
#endif

    // Function at location N on the call stack (N == 0 is current), may
    // be built-in.
    static octave_function *element (size_t n)
    {
      return instance_ok () ? instance->do_element (n) : 0;
    }

    // User code caller.
    static octave_user_code *caller_user_code (size_t nskip = 0)
    {
      return instance_ok () ? instance->do_caller_user_code (nskip) : 0;
    }

    // Line in user code caller.
    static int caller_user_code_line (void)
    {
      return instance_ok () ? instance->do_caller_user_code_line () : -1;
    }

    // Column in user code caller.
    static int caller_user_code_column (void)
    {
      return instance_ok () ? instance->do_caller_user_code_column () : -1;
    }

    // Current function that we are debugging.
    static octave_user_code *debug_user_code (void)
    {
      return instance_ok () ? instance->do_debug_user_code () : 0;
    }

    // Line number in current function that we are debugging.
    static int debug_user_code_line (void)
    {
      return instance_ok () ? instance->do_debug_user_code_line () : 0;
    }

    // Column number in current function that we are debugging.
    static int debug_user_code_column (void)
    {
      return instance_ok () ? instance->do_debug_user_code_column () : 0;
    }

    // Return TRUE if all elements on the call stack are scripts.
    static bool all_scripts (void)
    {
      return instance_ok () ? instance->do_all_scripts () : false;
    }

    static void
    push (octave_function *f,
          symbol_table::scope_id scope = symbol_table::current_scope (),
          symbol_table::context_id context = symbol_table::current_context ())
    {
      if (instance_ok ())
        instance->do_push (f, scope, context);
    }

    static void
    push (symbol_table::scope_id scope = symbol_table::current_scope (),
          symbol_table::context_id context = symbol_table::current_context ())
    {
      if (instance_ok ())
        instance->do_push (0, scope, context);
    }

    static void set_location (int l, int c)
    {
      if (instance_ok ())
        instance->do_set_location (l, c);
    }

    static void set_line (int l)
    {
      if (instance_ok ())
        instance->do_set_line (l);
    }

    static void set_column (int c)
    {
      if (instance_ok ())
        instance->do_set_column (c);
    }

    static bool goto_frame (size_t n = 0, bool verbose = false)
    {
      return instance_ok () ? instance->do_goto_frame (n, verbose) : false;
    }

    static void restore_frame (size_t n)
    {
      goto_frame (n);
    }

    static bool goto_frame_relative (int n, bool verbose = false)
    {
      return instance_ok ()
        ? instance->do_goto_frame_relative (n, verbose) : false;
    }

    static void goto_caller_frame (void)
    {
      if (instance_ok ())
        instance->do_goto_caller_frame ();
    }

    static void goto_base_frame (void)
    {
      if (instance_ok ())
        instance->do_goto_base_frame ();
    }

    static octave_map backtrace (size_t nskip = 0)
    {
      octave_idx_type curr_user_frame = -1;

      return instance_ok ()
        ? instance->do_backtrace (nskip, curr_user_frame, true)
        : octave_map ();
    }

    static octave_map backtrace (size_t nskip, octave_idx_type& curr_user_frame,
                                 bool print_subfn = true)
    {
      return instance_ok ()
        ? instance->do_backtrace (nskip, curr_user_frame, print_subfn)
        : octave_map ();
    }

    static std::list<call_stack::stack_frame>
    backtrace_frames (size_t nskip = 0)
    {
      octave_idx_type curr_user_frame = -1;

      return instance_ok ()
        ? instance->do_backtrace_frames (nskip, curr_user_frame)
        : std::list<call_stack::stack_frame> ();
    }

    static std::list<call_stack::stack_frame>
    backtrace_frames (size_t nskip, octave_idx_type& curr_user_frame)
    {
      return instance_ok ()
        ? instance->do_backtrace_frames (nskip, curr_user_frame)
        : std::list<call_stack::stack_frame> ();
    }

    static octave_map empty_backtrace (void);

    static void pop (void)
    {
      if (instance_ok ())
        instance->do_pop ();
    }

    static void clear (void)
    {
      if (instance_ok ())
        instance->do_clear ();
    }

  private:

    // The current call stack.
    std::deque<stack_frame> cs;

    size_t curr_frame;

    static call_stack *instance;

    static void cleanup_instance (void) { delete instance; instance = 0; }

    int do_current_line (void) const;

    int do_current_column (void) const;

    octave_function *do_caller (void) const
    {
      return curr_frame > 1 ? cs[curr_frame-1].m_fcn : cs[0].m_fcn;
    }

    size_t do_current_frame (void) { return curr_frame; }

    size_t do_size (void) { return cs.size (); }

    size_t do_num_user_code_frames (octave_idx_type& curr_user_frame) const;

    symbol_table::scope_id do_current_scope (void) const
    {
      return curr_frame > 0 && curr_frame < cs.size ()
                                            ? cs[curr_frame].m_scope : 0;
    }

    symbol_table::context_id do_current_context (void) const
    {
      return curr_frame > 0 && curr_frame < cs.size ()
                                            ? cs[curr_frame].m_context : 0;
    }

#if 0
    const stack_frame& do_frame (size_t idx)
    {
      static stack_frame foobar;

      return idx < cs.size () ? cs[idx] : foobar;
    }
#endif

    octave_function *do_element (size_t n)
    {
      octave_function *retval = 0;

      if (cs.size () > n)
        {
          stack_frame& elt = cs[n];
          retval = elt.m_fcn;
        }

      return retval;
    }

    octave_user_code *do_caller_user_code (size_t nskip) const;
    int do_caller_user_code_line (void) const;
    int do_caller_user_code_column (void) const;

    octave_user_code *do_debug_user_code (void) const;
    int do_debug_user_code_line (void) const;
    int do_debug_user_code_column (void) const;

    bool do_all_scripts (void) const;

    void do_push (octave_function *fcn, symbol_table::scope_id scope,
                  symbol_table::context_id context)
    {
      size_t prev_frame = curr_frame;
      curr_frame = cs.size ();
      cs.push_back (stack_frame (fcn, scope, context, prev_frame));
      symbol_table::set_scope_and_context (scope, context);
    }

    octave_function *do_current (void) const
    {
      octave_function *retval = 0;

      if (! cs.empty ())
        {
          const stack_frame& elt = cs[curr_frame];
          retval = elt.m_fcn;
        }

      return retval;
    }

    void do_set_location (int l, int c)
    {
      if (! cs.empty ())
        {
          stack_frame& elt = cs.back ();

          elt.m_line = l;
          elt.m_column = c;
        }
    }

    void do_set_line (int l)
    {
      if (! cs.empty ())
        {
          stack_frame& elt = cs.back ();

          elt.m_line = l;
        }
    }

    void do_set_column (int c)
    {
      if (! cs.empty ())
        {
          stack_frame& elt = cs.back ();

          elt.m_column = c;
        }
    }

    std::list<call_stack::stack_frame>
    do_backtrace_frames (size_t nskip, octave_idx_type& curr_user_frame) const;

    octave_map do_backtrace (size_t nskip,
                             octave_idx_type& curr_user_frame,
                             bool print_subfn) const;

    bool do_goto_frame (size_t n, bool verbose);

    bool do_goto_frame_relative (int n, bool verbose);

    void do_goto_caller_frame (void);

    void do_goto_base_frame (void);

    void do_pop (void)
    {
      if (cs.size () > 1)
        {
          const stack_frame& elt = cs.back ();
          curr_frame = elt.m_prev;
          cs.pop_back ();
          const stack_frame& new_elt = cs[curr_frame];
          symbol_table::set_scope_and_context (new_elt.m_scope,
                                               new_elt.m_context);
        }
    }

    void do_clear (void) { cs.clear (); }
  };
}

#if defined (OCTAVE_USE_DEPRECATED_FUNCTIONS)

OCTAVE_DEPRECATED ("use 'octave::call_stack' instead")
typedef octave::call_stack octave_call_stack;

#endif

#endif