#! /usr/bin/awk -f

function do_empty() {
  if (diff!="" && deleted!="" && indx!="") {
    printf("Make patch give the file 1 line\n");
    printf("--- %s\n",diff);
    printf("+++ %s\n",diff);
    printf("@@ -0,0 +1 @@\n+\n");
    printf("Make patch delete the 1 line file\n");
    printf("--- %s\t\n",diff);
    printf("+++ /dev/null\t1970-01-01 01:00:00.000000000\n");
    printf("@@ -1 +0,0 @@\n-\n");
  }
  if (diff!="" && created!="" && indx!="") {
    printf("Make patch create the file with 1 line\n");
    printf("--- %s\n",diff);
    printf("+++ %s\n",diff);
    printf("@@ -0,0 +1 @@\n+\n");
    printf("Make patch create delete the line but keep the file\n");
    printf("--- %s\n",diff);
    printf("+++ %s\n",diff);
    printf("@@ -1 +0,0 @@\n-\n");
  }
  no_empty();
}

function no_empty() {
  diff="";
  deleted="";
  created="";
  indx="";
}

{
  if (in_hunk > 0) in_hunk--;
}

/^diff --git / {
  do_empty();
  if (! in_hunk) diff=$3;
}

/^deleted file mode / {
  if (! in_hunk && diff!="") deleted=$0;
}

/^new file mode / {
  if (! in_hunk && diff!="") created=$0;
}

/^index / {
  if (! in_hunk && diff!="") indx=$0;
}

/^--- / {
  no_empty();
}

/^@@ / {
  # read the hunk size
  p=index($2,",");
  if (p==0) c1=1;
  else c1=strtonum(substr($2, p+1));

  p=index($3,",");
  if (p==0) in_hunk=1;
  else in_hunk=strtonum(substr($2, p+1));

  if (c1 > in_hunk) in_hunk=c1;
}

{
  print;
}

END {
  do_empty();
}