package Function;

use strict;
use warnings;
use Util;
use FunctionBase;

# These flags indicate whether parameters are optional or output parameters.
use constant FLAG_PARAM_OPTIONAL => 1;
use constant FLAG_PARAM_OUTPUT => 2;
# These flags indicate how an empty string shall be translated to a C string:
# to a nullptr or to a pointer to an empty string.
use constant FLAG_PARAM_NULLPTR => 4;
use constant FLAG_PARAM_EMPTY_STRING => 8;

BEGIN {
     use Exporter   ();
     our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);

     # set the version for version checking
     $VERSION     = 1.00;
     @ISA         = qw(FunctionBase);
     @EXPORT      = qw(&func1 &func2 &func4);
     %EXPORT_TAGS = ( );
     # your exported package globals go here,
     # as well as any optionally exported functions
     @EXPORT_OK   = qw($Var1 %Hashit &func3 FLAG_PARAM_OPTIONAL FLAG_PARAM_OUTPUT
                       FLAG_PARAM_NULLPTR FLAG_PARAM_EMPTY_STRING);
     }
our @EXPORT_OK;

##################################################
### Function
# Commonly used algorithm for parsing a function declaration into
# its component pieces
#
#  class Function : FunctionBase
#    {
#       string rettype;
#       bool const;
#       bool static;
#       string name; e.g. gtk_accelerator_valid
#       string c_name;
#       string array param_type;
#       string array param_name;
#       string array param_default_value;
#       int array param_flags; (stores flags form params: 1 => optional, 2 => output)
#       hash param_mappings; (maps C param names (if specified) to the C++ index)
#       string array possible_args_list; (a list of space separated indexes)
#       string in_module; e.g. Gtk
#       string signal_when. e.g. first, last, or both.
#       string class e.g. GtkButton ( == of-object. Useful for signal because their names are not unique.
#       string entity_type. e.g. method or signal
#    }

# Subroutine to get an array of string of indices representing the possible
# combination of arguments based on whether some parameters are optional.
sub possible_args_list($$);

sub new_empty()
{
  my $self = {};
  bless $self;

  return $self;
}

# $objFunction new($function_declaration, $objWrapParser)
sub new($$)
{
  #Parse a function/method declaration.
  #e.g. guint gtk_something_set_thing(guint a, const gchar* something)

  my ($line, $objWrapParser) = @_;

  my $self = {};
  bless $self;

  #Initialize member data:
  $$self{rettype} = "";
  $$self{rettype_needs_ref} = 0; #Often the gtk function doesn't do an extra ref for the receiver.
  $$self{const} = 0;
  $$self{name} = "";
  $$self{param_types} = [];
  $$self{param_names} = [];
  $$self{param_default_values} = [];
  $$self{param_flags} = [];
  $$self{param_mappings} = {};
  $$self{possible_args_list} = [];
  $$self{in_module} = "";
  $$self{class} = "";
  $$self{entity_type} = "method";

  $line =~ s/^\s+//;  # Remove leading whitespace.
  $line =~ s/\s+/ /g; # Compress white space.

  if ($line =~ /^static\s+([^()]+)\s+(\S+)\s*\((.*)\)\s*$/)
  {
    $$self{rettype} = $1;
    $$self{name} = $2;
    $$self{c_name} = $2;
    $self->parse_param($3);
    $$self{static} = 1;
  }
  elsif ($line =~ /^([^()]+)\s+(\S+)\s*\((.*)\)\s*(const)*$/)
  {
    $$self{rettype} = $1;
    $$self{name} = $2;
    $$self{c_name} = $2;
    $self->parse_param($3);
    $$self{const} = defined($4);
  }
  else
  {
    $objWrapParser->error("fail to parse $line\n");
  }

  # Store the list of possible argument combinations based on if arguments
  # are optional.
  my $possible_args_list = $$self{possible_args_list};
  push(@$possible_args_list, $self->possible_args_list());

  return $self;
}


# $objFunction new_ctor($function_declaration, $objWrapParser)
# Like new(), but the function_declaration doesn't need a return type.
sub new_ctor($$)
{
  #Parse a function/method declaration.
  #e.g. guint gtk_something_set_thing(guint a, const gchar* something)

  my ($line, $objWrapParser) = @_;

  my $self = {};
  bless $self;

  #Initialize member data:
  $$self{rettype} = "";
  $$self{rettype_needs_ref} = 0;
  $$self{const} = 0;
  $$self{name} = "";
  $$self{param_types} = [];
  $$self{param_names} = [];
  $$self{param_default_values} = [];
  $$self{param_flags} = [];
  $$self{param_mappings} = {};
  $$self{possible_args_list} = [];
  $$self{in_module} = "";
  $$self{class} = "";
  $$self{entity_type} = "method";

  $line =~ s/^\s+//;  # Remove leading whitespace.
  $line =~ s/\s+/ /g; # Compress white space.

  if ($line =~ /^(\S+)\s*\((.*)\)\s*/)
  {
    $$self{name} = $1;
    $$self{c_name} = $1;
    $self->parse_param($2);
  }
  else
  {
    $objWrapParser->error("fail to parse $line\n");
  }

  # Store the list of possible argument combinations based on if arguments
  # are optional.
  my $possible_args_list = $$self{possible_args_list};
  push(@$possible_args_list, $self->possible_args_list());

  return $self;
}

# $num num_args()
sub num_args #($)
{
  my ($self) = @_;
  my $param_types = $$self{param_types};
  return $#$param_types+1;
}

# parses C++ parameter lists.
# forms a list of types, names, and default values
sub parse_param($$)
{
  my ($self, $line) = @_;

  my $type = "";
  my $name = "";
  my $name_pos = -1;
  my $value = "";
  my $id = 0;
  my $has_value = 0;
  my $flags = 0;
  my $curr_param = 0;

  my $param_types = $$self{param_types};
  my $param_names = $$self{param_names};
  my $param_default_values = $$self{param_default_values};
  my $param_flags = $$self{param_flags};
  my $param_mappings = $$self{param_mappings};

  # Mappings from a C name to this C++ param defaults to empty (no mapping).
  my $mapping = "";

  # clean up space and handle empty case
  $line = string_trim($line);
  $line =~ s/\s+/ /g; # Compress whitespace.
  return if ($line =~ /^$/);

  # Add a ',' at the end. No special treatment of the last parameter is necessary,
  # if it's followed by a comma, like the other parameters.
  $line .= ',' if (substr($line, -1) ne ',');

  # Parse through the argument list.
  #
  # We must find commas (,) that separate parameters, and equal signs (=) that
  # separate parameter names from optional default values.
  # '&', '*' and '>' are delimiters in split() because they must be separated
  # from the parameter name even if there is no space char between.
  # Commas within "<.,.>" or "{.,.}" or "(.,.)" do not end a parameter.
  # This parsing is not guaranteed to work well if there are several levels
  # of (()) or {{}}. X<Y<Z>> works in the normal case where there is nothing
  # but possibly spaces between the multiple ">>".
  # Quoted strings are not detected. If a quoted string exists in a function
  # prototype, it's probably as part of a default value, inside ("x") or {"y"}.
  #
  my @str = ();
  foreach (split(/(\bconst\b|[,=&*>]|<.*?>|{.*?}|\(.*?\)|\s+)/, $line))
  {
    next if ( !defined($_) or $_ eq "" );

    if ($_ =~ /^(?:const|[*&>]|<.*>|\(.*\)|\s+)$/)
    {
      # Any separator, except ',' or '=' or {.*}.
      push(@str, $_);
      next;
    }
    elsif ($_ =~ /^{(.*)}$/)
    {
      if (!$has_value)
      {
        # gmmproc options have been specified for the current parameter so
        # process them.

        # Get the options.
        my $options = $1;

        # Check if param should be optional or an output param.
        $flags = FLAG_PARAM_OPTIONAL if($options =~ /\?/);
        $flags |= FLAG_PARAM_OUTPUT if($options =~ />>/);

        # Delete "NULL" from $options, so it won't be interpreted as a parameter name.
        if ($options =~ s/(!?\bNULL\b)//)
        {
          $flags |= ($1 eq "!NULL") ? FLAG_PARAM_EMPTY_STRING : FLAG_PARAM_NULLPTR;
        }

        # Check if it should be mapped to a C param.
        if ($options =~ /(\w+|\.)/)
        {
          $mapping = $1;
          $mapping = $name if($mapping eq ".");
        }
      }
      else
      {
        # {...} in a default value.
        push(@str, $_);
      }
      next;
    }
    elsif ( $_ eq "=" ) #Default value
    {
      $str[$name_pos] = "" if ($name_pos >= 0);
      # The type is everything before the = character, except the parameter name.
      $type = join("", @str);
      @str = (); #Wipe it so that it will only contain the default value, which comes next.
      $has_value = 1;
      next;
    }
    elsif ( $_ eq "," ) #The end of one parameter:
    {
      if ($has_value)
      {
        $value = join("", @str); # If there's a default value, then it's the part before the next ",".
      }
      else
      {
        $str[$name_pos] = "" if ($name_pos >= 0);
        $type = join("", @str);
      }

      if ($name eq "")
      {
        $name = sprintf("p%s", $#$param_types + 2)
      }

      $type = string_trim($type);

      push(@$param_types, $type);
      push(@$param_names, $name);
      push(@$param_default_values, $value);
      push(@$param_flags, $flags);

      # Map from the c_name to the C++ index (no map if no name given).
      $$param_mappings{$mapping} = $curr_param if($mapping);

      #Clear variables, ready for the next parameter.
      @str = ();
      $type= "";
      $value = "";
      $has_value = 0;
      $name = "";
      $name_pos = -1;
      $flags = 0;
      $curr_param++;

      # Mappings from a C name to this C++ param defaults to empty (no mapping).
      $mapping = "";

      $id = 0;
      next;
    }

    # Anything but a separator in split().
    push(@str, $_);

    if (!$has_value)
    {
      # The last identifier before ',', '=', or '{.*}' is the parameter name.
      # E.g. int name, unsigned long int name = 42, const unsigned int& name.
      # The name must be preceded by at least one other identifier (the type).
      # 'const' is treated specially, as it can't by itself denote the type.
      $id++;
      if ($id >= 2)
      {
        $name = $_;
        $name_pos = $#str;
      }
    }
  } # end foreach
}

# add_parameter_autoname($, $type, $name)
# Adds e.g "sometype somename"
sub add_parameter_autoname($$)
{
  my ($self, $type) = @_;

  add_parameter($self, $type, "");
}

# add_parameter($, $type, $name)
# Adds e.g GtkSomething* p1"
sub add_parameter($$$)
{
  my ($self, $type, $name) = @_;
  $type = string_unquote($type);
  $type =~ s/-/ /g;

  my $param_names = $$self{param_names};

  if ($name eq "")
  {
    $name = sprintf("p%s", $#$param_names + 2);
  }

  push(@$param_names, $name);

  my $param_types = $$self{param_types};
  push(@$param_types, $type);

  return $self;
}

# $string get_refdoc_comment($existing_signal_docs, $signal_flags)
# Generate a readable prototype for signals and merge the prototype into the
# existing Doxygen comment block.
sub get_refdoc_comment($$$)
{
  my ($self, $documentation, $signal_flags) = @_;

  my $str = "  /**\n";

  $str .= "   * \@par Slot Prototype:\n";
  $str .= "   * <tt>$$self{rettype} on_my_\%$$self{name}(";

  my $param_names = $$self{param_names};
  my $param_types = $$self{param_types};
  my $num_params  = scalar(@$param_types);

  # List the parameters:
  for(my $i = 0; $i < $num_params; ++$i)
  {
    $str .= $$param_types[$i] . ' ' . $$param_names[$i];
    $str .= ", " if($i < $num_params - 1);
  }

  $str .= ")</tt>\n";
  $str .= "   *\n";

  if ($signal_flags)
  {
    $str .= "   * Flags: $signal_flags\n   *\n";
  }

  if($documentation ne "")
  {
    # Remove the initial '/** ' from the existing docs and merge it.
    $documentation =~ s/\/\*\*\s+/ \* /;
    $str .= $documentation;
  }
  else
  {
    # Close the doc block if there's no existing docs.
    $str .= "   */\n";
  }

  # Return the merged documentation.
  return $str;
}

sub get_is_const($)
{
  my ($self) = @_;

  return $$self{const};
}

# string array possible_args_list()
# Returns an array of string of space separated indexes representing the
# possible argument combinations based on whether parameters are optional.
sub possible_args_list($$)
{
  my ($self, $start_index) = @_;

  my $param_names = $$self{param_names};
  my $param_types = $$self{param_types};
  my $param_flags = $$self{param_flags};

  my @result = ();

  # Default starting index is 0 (The first call will have an undefined start
  # index).
  my $i = $start_index || 0;

  if($i > $#$param_types)
  {
  	# If index is past last arg, return an empty array inserting an empty
  	# string if this function has no parameters.
  	push(@result, "") if ($i == 0);
  	return @result;
  }
  elsif($i == $#$param_types)
  {
    # If it's the last arg just add its index:
  	push(@result, "$i");
  	# And if it's optional also add an empty string to represent that it is
  	# not added.
  	push(@result, "") if ($$param_flags[$i] & FLAG_PARAM_OPTIONAL);
  	return @result;
  }

  # Get the possible indices for remaining params without this one.
  my @remaining = possible_args_list($self, $i + 1);

  # Prepend this param's index to the remaining ones.
  foreach my $possibility (@remaining)
  {
  	if($possibility)
  	{
  	  push(@result, "$i " . $possibility);
  	}
  	else
  	{
  	  push(@result, "$i");
  	}
  }

  # If this parameter is optional, append the remaining possibilities without
  # this param's type and name.
  if($$param_flags[$i] & FLAG_PARAM_OPTIONAL)
  {
    foreach my $possibility (@remaining)
    {
  	  push(@result, $possibility);
    }
  }

  return @result;
}

1; # indicate proper module load.