#!/bin/env awk -f

function debug(t) { printf "%s\n", t >>"/dev/stderr"; }

function PATH( str,    seg, out ) {
  while ( str ) {
    seg = str;
    sub( /\/.*$/, "", seg);
    sub( /^[^\/]*\//, "", str);
 
    if      ( seg == ".." )  sub(/\/[^\/]*\/?$/, "", out);
    else if ( seg ~ /^\.?$/) sub(/\/?$/, "/", out);
    else sub(/\/?$/, "/" seg, out);

    if (seg == str) break;
  }
  if (!(str && out)) sub(/\/?$/,"/" out);
  return out;
}

function HEX_DECODE( pfx, inp,    out, n, k ) {
  k = length(pfx);
  gsub(/[].*+?^${}()|\\[]/,"\\\\&",pfx);
  while ( inp ) if ( n = match(inp, pfx "[0-9a-fA-F][0-9a-fA-F]") ) {
    out = out substr(inp, 1, n - 1);
    inp = substr(inp, n + k);
    if      (inp ~  /^[0-9]/) n = 16 * substr(inp, 1, 1);
    else if (inp ~  /^[aA]/)  n = 160;
    else if (inp ~  /^[bB]/)  n = 176;
    else if (inp ~  /^[cC]/)  n = 192;
    else if (inp ~  /^[dD]/)  n = 208;
    else if (inp ~  /^[eE]/)  n = 224;
    else if (inp ~  /^[fF]/)  n = 240;
    if      (inp ~ /^.[0-9]/) n += substr(inp, 2, 1);
    else if (inp ~ /^.[aA]/)  n += 10;
    else if (inp ~ /^.[bB]/)  n += 11;
    else if (inp ~ /^.[cC]/)  n += 12;
    else if (inp ~ /^.[dD]/)  n += 13;
    else if (inp ~ /^.[eE]/)  n += 14;
    else if (inp ~ /^.[fF]/)  n += 15;
    out = out sprintf("%c", n);
    inp = substr(inp, 3);
  } else {
    out = out inp;
    break;
  }
  return out;
}

function HTML( text ) {
  gsub( /&/,  "\\&",  text );
  gsub( /</,  "\\&lt;",   text );
  gsub( />/,  "\\&gt;",   text );
  gsub( /"/,  "\\&quot;", text );
  gsub( /'/,  "\\&#x27;", text );
  gsub( /\[/, "\\&#x5B;", text );
  gsub( /\]/, "\\&#x5D;", text );
  gsub( /\r/, "\\&#x0D;", text );
  gsub( /\n/, "\\&#x0A;", text );
  gsub( /\\/, "\\&#x5C;", text );
  return text;
}

function URL( text ) {
  gsub( /&/,  "%26", text );
  gsub( /"/,  "%22", text );
  gsub( /'/,  "%27", text );
  gsub( /`/,  "%60", text );
  gsub( /\?/, "%3F", text );
  gsub( /#/,  "%23", text );
  gsub( /\[/, "%5B", text );
  gsub( /\]/, "%5D", text );
  gsub( / /,  "%20", text );
  gsub( /\t/, "%09", text );
  gsub( /\r/, "%0D", text );
  gsub( /\n/, "%0A", text );
  gsub( /%/,  "%25", text );
  gsub( /\\/, "%5C", text );
  return text;
}

function _cgilite_urldecode( str, arr, spl,   form, k, n, key) {
  if (! spl) spl="&"
  split(str, form, spl);
  for ( k in form ) {
    key = form[k]; sub(/=.*$/, "", key);
    sub(/^[^=]*=/, "", form[k]);
    if ( key in arr ) {
      n = 1; while ( (key, n) in arr ) n++;
      arr[key,n] = HEX_DECODE( "%", form[k]);
    } else {
      arr[key] = HEX_DECODE( "%", form[k]);
    }
  }
}

function _cgilite_request(    key, val) {
  # Read request from client connection

  # Read Headers
  getline; REQUEST_METHOD = $1; REQUEST_URI = $2; SERVER_PROTOCOL = $3;
  while ( getline ) {
    if ($0 ~ /^\r?$/) break;
    else if ($0 ~ /^[a-zA-Z][0-9a-zA-Z_-]+: .*/) {
      key = toupper($0);
      sub(/:.*$/, "", key);
      gsub(/-/, "_", key);
      _HEADER[key] = $0;
      sub(/^[^:]:[\t ]*/, "", _HEADER[key]);
      sub(/[\t ]*\r?$/, "", _HEADER[key]);
    }
  }
  CONTENT_LENGTH = _HEADER["CONTENT_LENGTH"];
  CONTENT_TYPE   = _HEADER["CONTENT_TYPE"];

  PATH_INFO = REQUEST_URI; gsub(/\?.*$/, "", PATH_INFO)
  PATH_INFO = PATH( HEX_DECODE( "%", PATH_INFO ) );
  QUERY_STRING = REQUEST_URI;
  if ( !gsub(/^[^?]+\?/, "", QUERY_STRING) ) QUERY_STRING = "";

  # Set up _GET[]-Array
  _cgilite_urldecode(QUERY_STRING, _GET);

  if ( _HEADER["CONTENT_TYPE"] == "application/x-www-form-urlencoded" \
       && _HEADER["CONTENT_LENGTH"] ) {
    # Set up _POST[]-Array

    val = ""; key = "head -c " _HEADER["CONTENT_LENGTH"];
    while (key |getline) val = val $0; close(key);
    _cgilite_urldecode(val, _POST);
  }

  if ( _HEADER["COOKIE"] ) {
    # Set up _COOKIE[]-Array
    _cgilite_urldecode(_HEADER["COOKIE"], _COOKIE, "; ?");
  }

  if ( _HEADER["REFERER"] ) {
    key = HEADER["REFERER"];
    if (! sub(/^[^\?]+?/, "", key)) key = ""
    _cgilite_urldecode(key, _REF);
  }

}

function _cgilite_headers() {
  # Import request data from webserver environment variables
}

BEGIN {
  REQUEST_METHOD=""; REQUEST_URI=""; SERVER_PROTOCOL="";
  PATH_INFO=""; QUERY_STRING=""; CONTENT_LENGTH=""; CONTENT_TYPE="";
  split("", _GET); split("", _POST); split("", _REF);
  split("", _HEADER); split("", _COOKIE);

  if ( ENVIRON["REQUEST_METHOD"] ) {
    _cgilite_headers();
  } else {
    _cgilite_request();
  }
}