////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2012-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// 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
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include "defun.h"
#include "interpreter.h"
#include "oct-time.h"
#include "ov-struct.h"
#include "pager.h"
#include "profiler.h"

namespace octave
{
  profiler::stats::stats (void)
    : m_time (0.0), m_calls (0), m_recursive (false),
      m_parents (), m_children ()
  { }

  octave_value
  profiler::stats::function_set_value (const function_set& list)
  {
    const octave_idx_type n = list.size ();

    RowVector retval (n);
    octave_idx_type i = 0;
    for (const auto& nm : list)
      retval(i++) = nm;

    assert (i == n);

    return retval;
  }

  profiler::tree_node::tree_node (tree_node *p, octave_idx_type f)
    : m_parent (p), m_fcn_id (f), m_children (), m_time (0.0), m_calls (0)
  { }

  profiler::tree_node::~tree_node ()
  {
    for (auto& idx_tnode : m_children)
      delete idx_tnode.second;
  }

  profiler::tree_node*
  profiler::tree_node::enter (octave_idx_type fcn)
  {
    tree_node *retval;

    child_map::iterator pos = m_children.find (fcn);
    if (pos == m_children.end ())
      {
        retval = new tree_node (this, fcn);
        m_children[fcn] = retval;
      }
    else
      retval = pos->second;

    ++retval->m_calls;
    return retval;
  }

  profiler::tree_node*
  profiler::tree_node::exit (octave_idx_type /* fcn */)
  {
    // FIXME: These assert statements don't make sense if profile() is called
    //        from within a function hierarchy to begin with.  See bug #39587.
    //  assert (m_parent);
    //  assert (m_fcn_id == fcn);

    return m_parent;
  }

  void
  profiler::tree_node::build_flat (flat_profile& data) const
  {
    // If this is not the top-level node, update profile entry for this function.
    if (m_fcn_id != 0)
      {
        stats& entry = data[m_fcn_id - 1];

        entry.m_time += m_time;
        entry.m_calls += m_calls;

        assert (m_parent);
        if (m_parent->m_fcn_id != 0)
          {
            entry.m_parents.insert (m_parent->m_fcn_id);
            data[m_parent->m_fcn_id - 1].m_children.insert (m_fcn_id);
          }

        if (! entry.m_recursive)
          for (const tree_node *i = m_parent; i; i = i->m_parent)
            if (i->m_fcn_id == m_fcn_id)
              {
                entry.m_recursive = true;
                break;
              }
      }

    // Recurse on children.
    for (const auto& idx_tnode : m_children)
      idx_tnode.second->build_flat (data);
  }

  octave_value
  profiler::tree_node::get_hierarchical (double *total) const
  {
    // Note that we don't generate the entry just for this node, but
    // rather a struct-array with entries for all children.  This way, the
    // top-node (for which we don't want a real entry) generates already
    // the final hierarchical profile data.

    const octave_idx_type n = m_children.size ();

    Cell rv_indices (n, 1);
    Cell rv_times (n, 1);
    Cell rv_totals (n, 1);
    Cell rv_calls (n, 1);
    Cell rv_children (n, 1);

    octave_idx_type i = 0;
    for (const auto& idx_tnode : m_children)
      {
        const tree_node& entry = *idx_tnode.second;
        double child_total = entry.m_time;

        rv_indices(i) = octave_value (idx_tnode.first);
        rv_times(i) = octave_value (entry.m_time);
        rv_calls(i) = octave_value (entry.m_calls);
        rv_children(i) = entry.get_hierarchical (&child_total);
        rv_totals(i) = octave_value (child_total);

        if (total)
          *total += child_total;

        ++i;
      }
    assert (i == n);

    octave_map retval;

    retval.assign ("Index", rv_indices);
    retval.assign ("SelfTime", rv_times);
    retval.assign ("TotalTime", rv_totals);
    retval.assign ("NumCalls", rv_calls);
    retval.assign ("Children", rv_children);

    return retval;
  }

  profiler::profiler (void)
    : m_known_functions (), m_fcn_index (),
      m_enabled (false), m_call_tree (new tree_node (nullptr, 0)),
      m_active_fcn (nullptr), m_last_time (-1.0)
  { }

  profiler::~profiler (void)
  {
    delete m_call_tree;
  }

  void
  profiler::set_active (bool value)
  {
    m_enabled = value;
  }

  void
  profiler::enter_function (const std::string& fcn)
  {
    // The enter class will check and only call us if the profiler is active.
    assert (enabled ());
    assert (m_call_tree);

    // If there is already an active function, add to its time before
    // pushing the new one.
    if (m_active_fcn && m_active_fcn != m_call_tree)
      add_current_time ();

    // Map the function's name to its index.
    octave_idx_type fcn_idx;
    fcn_index_map::iterator pos = m_fcn_index.find (fcn);
    if (pos == m_fcn_index.end ())
      {
        m_known_functions.push_back (fcn);
        fcn_idx = m_known_functions.size ();
        m_fcn_index[fcn] = fcn_idx;
      }
    else
      fcn_idx = pos->second;

    if (! m_active_fcn)
      m_active_fcn = m_call_tree;

    m_active_fcn = m_active_fcn->enter (fcn_idx);

    m_last_time = query_time ();

  }

  void
  profiler::exit_function (const std::string& fcn)
  {
    if (m_active_fcn)
      {
        assert (m_call_tree);
        // FIXME: This assert statements doesn't make sense if profile() is called
        //        from within a function hierarchy to begin with.  See bug #39587.
        //assert (m_active_fcn != m_call_tree);

        // Usually, if we are disabled this function is not even called.  But the
        // call disabling the profiler is an exception.  So also check here
        // and only record the time if enabled.
        if (enabled ())
          add_current_time ();

        fcn_index_map::iterator pos = m_fcn_index.find (fcn);
        // FIXME: This assert statements doesn't make sense if profile() is called
        //        from within a function hierarchy to begin with.  See bug #39587.
        //assert (pos != m_fcn_index.end ());
        m_active_fcn = m_active_fcn->exit (pos->second);

        // If this was an "inner call", we resume executing the parent function
        // up the stack.  So note the start-time for this!
        m_last_time = query_time ();
      }
  }

  void
  profiler::reset (void)
  {
    if (enabled ())
      error ("Can't reset active profiler.");

    m_known_functions.clear ();
    m_fcn_index.clear ();

    if (m_call_tree)
      {
        delete m_call_tree;
        m_call_tree = new tree_node (nullptr, 0);
        m_active_fcn = nullptr;
      }

    m_last_time = -1.0;
  }

  octave_value
  profiler::get_flat (void) const
  {
    octave_value retval;

    const octave_idx_type n = m_known_functions.size ();

    flat_profile flat (n);

    if (m_call_tree)
      {
        m_call_tree->build_flat (flat);

        Cell rv_names (n, 1);
        Cell rv_times (n, 1);
        Cell rv_calls (n, 1);
        Cell rv_recursive (n, 1);
        Cell rv_parents (n, 1);
        Cell rv_children (n, 1);

        for (octave_idx_type i = 0; i != n; ++i)
          {
            rv_names(i) = octave_value (m_known_functions[i]);
            rv_times(i) = octave_value (flat[i].m_time);
            rv_calls(i) = octave_value (flat[i].m_calls);
            rv_recursive(i) = octave_value (flat[i].m_recursive);
            rv_parents(i) = stats::function_set_value (flat[i].m_parents);
            rv_children(i) = stats::function_set_value (flat[i].m_children);
          }

        octave_map m;

        m.assign ("FunctionName", rv_names);
        m.assign ("TotalTime", rv_times);
        m.assign ("NumCalls", rv_calls);
        m.assign ("IsRecursive", rv_recursive);
        m.assign ("Parents", rv_parents);
        m.assign ("Children", rv_children);

        retval = m;
      }
    else
      {
        static const char *fn[] =
          {
            "FunctionName",
            "TotalTime",
            "NumCalls",
            "IsRecursive",
            "Parents",
            "Children",
            nullptr
          };

        static octave_map m (dim_vector (0, 1), string_vector (fn));

        retval = m;
      }

    return retval;
  }

  octave_value
  profiler::get_hierarchical (void) const
  {
    octave_value retval;

    if (m_call_tree)
      retval = m_call_tree->get_hierarchical ();
    else
      {
        static const char *fn[] =
          {
            "Index",
            "SelfTime",
            "NumCalls",
            "Children",
            nullptr
          };

        static octave_map m (dim_vector (0, 1), string_vector (fn));

        retval = m;
      }

    return retval;
  }

  double
  profiler::query_time (void) const
  {
    sys::time now;

    // FIXME: is this volatile declaration really needed?
    // See bug #34210 for additional details.
    volatile double dnow = now.double_value ();

    return dnow;
  }

  void
  profiler::add_current_time (void)
  {
    if (m_active_fcn)
      {
        const double t = query_time ();

        m_active_fcn->add_time (t - m_last_time);
      }
  }
}

// Enable or disable the profiler data collection.
DEFMETHOD (__profiler_enable__, interp, args, ,
           doc: /* -*- texinfo -*-
@deftypefn {} {} __profiler_enable__ ()
Undocumented internal function.
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin > 1)
    print_usage ();

  octave::profiler& profiler = interp.get_profiler ();

  if (nargin == 1)
    profiler.set_active (args(0).bool_value ());

  return ovl (profiler.enabled ());
}

// Clear all collected profiling data.
DEFMETHOD (__profiler_reset__, interp, args, ,
           doc: /* -*- texinfo -*-
@deftypefn {} {} __profiler_reset__ ()
Undocumented internal function.
@end deftypefn */)
{
  if (args.length () != 0)
    print_usage ();

  octave::profiler& profiler = interp.get_profiler ();

  profiler.reset ();

  return ovl ();
}

// Query the timings collected by the profiler.
DEFMETHOD (__profiler_data__, interp, args, nargout,
           doc: /* -*- texinfo -*-
@deftypefn {} {} __profiler_data__ ()
Undocumented internal function.
@end deftypefn */)
{
  if (args.length () != 0)
    print_usage ();

  octave::profiler& profiler = interp.get_profiler ();

  if (nargout > 1)
    return ovl (profiler.get_flat (), profiler.get_hierarchical ());
  else
    return ovl (profiler.get_flat ());
}