# Report functions which have a depth greater than X.
use base ("Understand::Codecheck");
use strict;
use constant ERR1 => 'Complexity(%1) greater than allowed(%2)';

sub register_tr_text {
  my $check = shift;
  $check->add_tr_text(ERR1);
}

sub name {
  return "Program Unit Cyclomatic Complexity";
}

sub description {
  return "Program Units which have a Cyclomatic Complexity greater than X";
}

sub detailed_description {
  return  <<"END_DESC"
<p><b>Rationale</b><br>
Overly complex programs are difficult to comprehend and have many possible paths making them difficult to test and validate. There are several variants for Cyclomatic Complexity:</p>
<p><b>Cyclomatic Complexity</b><br> 
Also known as McCabe Cyclomatic complexity or as Conditional Complexity and is defined as per the original NIST paper on the subject:<br>
Edges - Nodes + Connected Components.</p>
<p><b>Modified Cyclomatic Complexity</b><br> 
The Cyclomatic Complexity except that each decision in a multi-decision structure (switch in C/Java, Case in Ada, computed 
Goto and arithmetic if in FORTRAN) statement is not counted and instead the entire multi-way decision structure counts as 1</p>
<p><b>Strict Cyclomatic Complexity</b><br> 
The Cyclomatic Complexity with logical conjunction and logical and in conditional expressions also adding 1 to the complexity for each 
of their occurrences.</p>
END_DESC
}

sub test_language {
  my $language = shift;
  return 1;
}

sub test_entity {
  return 1;
}

sub test_global {
  return 0;
}

sub define_options{
  my $check = shift;
  $check->option->integer("maxComplexity","Maximum Complexity","5");
  $check->option->radio_vert("metric","Variant",["Cyclomatic Complexity","Modified Cyclomatic Complexity","Strict Cyclomatic Complexity"],"Cyclomatic Complexity");
}

sub check {
  my $check = shift;
  my $file = shift;
  return unless $file->kind->check("file");
  my $maxComplexity = $check->option->lookup("maxComplexity");
  my $metric = "Cyclomatic";
  $metric = "CyclomaticModified" if $check->option->lookup("metric") =~ /Modified/;
  $metric = "CyclomaticStrict" if $check->option->lookup("metric") =~ /Strict/;
  #Get all the function references
  my @entrefs = $file->filerefs("define, declare body, vhdl declare","ada entry, ada function, ada package, ada procedure, ada protected, ada task,"
     ."c function,"
   ."csharp method,"
   ."fortran block data, fortran function, fortran interface, fortran program, fortran subroutine,"
   ."java method,"
   ."jovial subroutine,"
   ."pascal compunit, pascal function, pascal procedure,"
   ."vhdl procedure, vhdl function, vhdl process, vhdl architecture",1);
   

  foreach my $funcDef (@entrefs){
    my $complexity = $funcDef->ent->metric($metric);
    if ($complexity > $maxComplexity) {
      $check->violation($funcDef->ent,$funcDef->file,$funcDef->line,$funcDef->column,ERR1,$complexity,$maxComplexity);
    }
  }
   
}