/*
Wenn im IE6+7
ein Meta Tag (meta name="description" content="") steht
klappt das komplette insertAtCaret nicht, da dann
createTextRange nicht als Eigenschaft erkennt und in den dritten else Zweig geht.
sonst geht er in den Zweig
else if (textField.createTextRange) {
und alles klappt.
*/
function show_preview(textarea_obj) {

}

// Constants
var CONST_NL = "\n";
// Add a handler to an event
function addEventHandler(obj, eventType, handler) {
  if (window.opera && obj.addEventListener) {
    obj.addEventListener(eventType, handler, false);
    return true;
  } else if (obj.addEventListener) {
    obj.addEventListener(eventType, handler, true);
    return true;
  } else if (obj.attachEvent) {
    var r = obj.attachEvent("on"+eventType, handler);
    return r;
  } else {
    return false;
  }
}

function controlsSetBold(textField)
{
  insertAtCaret(textField, '[b]', '[/b]');
}

function controlsSetItalic(textField)
{
  insertAtCaret(textField, '[i]', '[/i]');
}

function controlsSetUnderline(textField)
{
  insertAtCaret(textField, '[u]', '[/u]');
}

// A dummy string replacer function
/*
function controlsReplace(textField)
{
  insertAtCaret(textField, 'replaced', null, true);
}
*/

function controlsSetLink(textField)
{
  var LinkToInsert = false;
  LinkToInsert = prompt("Bitte geben Sie den Link ein", "www.");
        insertAtCaret(textField,LinkToInsert, null, true);
  if (LinkToInsert != null) {
    var Ergebnis = LinkToInsert.match(/^(www\.)?[\w-]+\.[a-zA-Z]{2,6}(\/{1}[\w_-]*)*(\.[a-zA-Z]{2,5})?(\?{1}[a-zA-Z0-9_=&]*)?$/i);
    if (Ergebnis) {
      TextforLink = prompt("Bitte geben Sie den Text für den Link ein","Linktext");
      if (TextforLink == null) {
        TextforLink = LinkToInsert;
      }
      var linkstr='[a('+LinkToInsert+')('+TextforLink+')] ';
      insertAtCaret(textField,linkstr, null, true);
    } else alert("Der Link scheint nicht korrekt. Bitte überprüfen Sie die Schreibweise!\nBeispiele:\nwww.a-s-b.eu\nwww.a-s-b.eu/kurse.php")
  }
}

/**
 * Insert string at the current caret position.
 *
 * @param {object} textField  The subject of the function.
 * @param {string} beforeStr  This string will be inserted before the caret.
 * @param {string} afterStr  This string will be inserted after the caret. Its default is ''.
 * @param {boolean} replace  If this flag is set to true, the inserted string
 *                           replace the formerly selected text by the caret.
 *                           Its default is false.
 * @param {boolean} select  If this flag is set to true, the inserted string (and the
 *                          formerly selected text if replace was false) is selected.
 *                           Its default is true.
 */
function insertAtCaret(textField, before, after, replace, select) {
  if (arguments.length < 3 || !after) after = '';
  if (arguments.length < 4 || !replace) replace = false;
  if (arguments.length < 5 || select) select = true;

  if (typeof textField.selectionStart != 'undefined') {
    var startPos = textField.selectionStart;
    var endPos = textField.selectionEnd;
    textField.value = textField.value.substr(0, startPos) + before
            + (replace ? "" : textField.value.substring(startPos, endPos))
            + after + textField.value.substr(endPos);
    if (select) {
      textField.setSelectionRange(startPos,
        endPos + before.length + after.length - (replace ? endPos-startPos : 0));
    } else {
      startPos = startPos + before.length + after.length;
      textField.setSelectionRange(startPos , startPos);
    }
  } else if (textField.createTextRange) {
    textField.focus();
    var pos = getCaret(textField);

    var range = document.selection.createRange();
    // Adding the before/after text to the textRange
    range.text = before+(replace ? "" : range.text)+after;

    // Selecting the needed text
    if (select) {
      pos.selectionLength = replace ? before.length + after.length :
        pos.selectionLength + before.length + after.length;
    } else {
      pos.position += before.length + after.length;
      pos.selectionLength = 0;
    }
    setCaret(textField, pos);
  } else {
    var position = textField.value.length+before.length;
    textField.value += (before + after);
    setCursorPosition(textField, position);
  }
}

/**
 * Get the caret position info of the given textfield
 *
 * @param {object} textField  The subject of the function.
 * @param {boolean} MSIEReturnNotLogicalPosition  This parameter is used for inner purpose.
 *
 * @return {object}  Returns a simple JavaScript object with position and selectionLength properties
 */
function getCaret(textField, MSIEReturnNotLogicalPosition)
{
  if (arguments.length < 2) MSIEReturnNotLogicalPosition = false;

  if (typeof textField.selectionStart != "undefined") {
    textField.focus();
    return {
      position: textField.selectionStart,
      selectionLength: textField.selectionEnd-textField.selectionStart
    };
  // Handling this issue in case of Internet Explorer need a little hack.
  // The problem is, that IE handle the concept of new line different
  // from text field value and textRange "character" unit point of view.
  // In the value the \r,\n charcters exist separately, but when use
  // the textRange.move("charcter", 1) new line is only one step.
  // That's why we need a little correction.
  } else if (textField.createTextRange) {
    var newLineNumAfterCursor = 0;
    match = textField.value.match(/\n/g);
    if (match) {
      newLineNumAfterCursor = match.length;
    }

    textField.focus();
    var position = textField.value.length;
    var selectionLength = document.selection.createRange().text.length;
    var cursor = document.selection.createRange().duplicate();

    while (cursor.parentElement() == textField && cursor.move('character', 1)) {
      if (textField.value.charAt(position - 1) == CONST_NL) {
        position -= 1;
        newLineNumAfterCursor--;
      }
      position--;
    }

    if (MSIEReturnNotLogicalPosition) {
      return {
        position: position + 1,
        selectionLength: selectionLength
      };
    } else {
      return {
        position: position + 1 - (newLineNumAfterCursor),
        selectionLength: selectionLength
      };
    }
  }
}

/**
 * Set the caret in the given textfield
 *
 * @param {object} textField  The subject of the function.
 * @param {object} pos  This parameter could be a number or a simple JavaScript
 *                      object with position and selectionLength properties.
 *                      If number was given the function creates a position
 *                      object, where the position property is the given number
 *                      and the selectionLength is 0. If the parameter is an
 *                      object and has no position property, then the function
 *                      set it to the current caret position. The selectionLength
 *                      property could be negative.
 * @param {number} scrollTop  If this parameter is peresent, the function
 *                            try to set the textField's scrollTop property.
 */
function setCaret(textField, pos, scrollTop)
{
  // If the function was called with a number only
  if (typeof pos == "number") {
    pos = {position: pos, selectionLength: 0}
  }
  // If the function was called with an object only with a selectionLength property
  if (typeof pos.position == "undefined") {
    pos.position = getCaret(textField).position;
  }
  // If negative selectionLength was given
  if (pos.selectionLength < 0) {
    pos.position += pos.selectionLength;
    pos.selectionLength = -pos.selectionLength;
  }

  if (typeof textField.selectionStart != 'undefined') {
    textField.focus();
    textField.setSelectionRange(pos.position, pos.position+pos.selectionLength);
  } else if (textField.createTextRange) {
    var textRange = textField.createTextRange();
    textRange.moveStart("character", pos.position);
    textRange.collapse();
    textRange.moveEnd("character", pos.selectionLength);
    textRange.select();
  }
  if (typeof scrollTop != "undefined" && typeof textField.scrollTop != "undefined") {
    textField.scrollTop = scrollTop;
  }
}