#!/bin/awk -f
#!/opt/busybox/awk -f

function sh_escape(arg){
  return "'" gensub(/'/, "'\"'\"'", "g", arg) "'";
}

function argsplit(line, args, LOCAL, c, n, ctx) {
  ctx="space"; n=0;

  while ( length(line) > 0 ) {
    c = substr(line, 1, 1);
    line = substr(line, 2);
    if (ctx == "space" )
           if (c ~ /[ \t]/) ctx = "space";
      else if (c ~ /\\/) { n++; ctx = "escbare"; }
      else if (c ~ /"/)  { n++; ctx = "dquot"; }
      else if (c ~ /'/)  { n++; ctx = "squot"; }
      else   { n++; args[n] = c; ctx = "bare"; }
    else if (ctx == "bare")
           if (c ~ /[ \t]/) ctx = "space";
      else if (c ~ /\\/)  ctx = "escbare";
      else if (c ~ /"/)   ctx = "dquot";
      else if (c ~ /'/)   ctx = "squot";
      else args[n] = args[n] c;
    else if (ctx == "dquot")
           if (c ~ /"/)  ctx = "bare";
      else if (c ~ /\\/) ctx = "escdquot";
      else args[n] = args[n] c;
    else if (ctx == "squot")
      if (c ~ /'/)  ctx = "bare";
      else args[n] = args[n] c;
    else if (ctx == "escbare") {
      args[n] = args[n] c;
      ctx = "bare";
    }
    else if (ctx == "escdquot") {
      args[n] = args[n] c;
      ctx = "dquot";
    }
  }
} 

function macro(call, LOCAL, line, args) {
  argsplit(call, args);
  call="";

  for (n = 1; n in args; n++) call = call sh_escape(args[n]) " ";

  if (args[1] in MACROS) {
    oldRS=RS; oldORS=ORS;
    RS=""; ORS=""; line="";
    "printf '%s' " sh_escape(file) " | " sh_escape(ENVIRON["MD_MACROS"]) "/" call | getline line;
    RS=oldRS; ORS=oldORS;
    return line;
  } else {
    return HTML("<<" call ">>");
  }
}

BEGIN {
  if (ENVIRON["MD_MACROS"]) {
    AllowMacros = "true";
    "cd " sh_escape(ENVIRON["MD_MACROS"]) "; printf '%s/' *" |getline macro_list;
    split(macro_list, MACROS, "/");
    for (n in MACROS) { MACROS[MACROS[n]] = ""; delete MACROS[n]; }
    delete MACROS[""];
  }
}