var isMac = /Mac/.test(navigator.platform);

var shortcuts = {
  'Cmd-B': toggleBold,
  'Cmd-I': toggleItalic,
  'Cmd-K': drawLink,
  'Cmd-Alt-I': drawImage,
  "Cmd-'": toggleBlockquote,
  'Cmd-Alt-L': toggleOrderedList,
  'Cmd-L': toggleUnOrderedList
};


/**
 * Fix shortcut. Mac use Command, others use Ctrl.
 */
function fixShortcut(name) {
  if (isMac) {
	name = name.replace('Ctrl', 'Cmd');
  } else {
	name = name.replace('Cmd', 'Ctrl');
  }
  return name;
}


/**
 * Create icon element for toolbar.
 */
function createIcon(name, options) {
  options = options || {};
  var el = document.createElement('a');

  var shortcut = options.shortcut || shortcuts[name];
  if (shortcut) {
	shortcut = fixShortcut(shortcut);
	el.title = shortcut;
	el.title = el.title.replace('Cmd', '⌘');
	if (isMac) {
	  el.title = el.title.replace('Alt', '⌥');
	}
  }

  el.className = options.className || 'icon-' + name;
  return el;
}

function createSep() {
  el = document.createElement('i');
  el.className = 'separator';
  el.innerHTML = '|';
  return el;
}


/**
 * The state of CodeMirror at the given position.
 */
function getState(cm, pos) {
  pos = pos || cm.getCursor('start');
  var stat = cm.getTokenAt(pos);
  if (!stat.type) return {};

  var types = stat.type.split(' ');

  var ret = {}, data, text;
  for (var i = 0; i < types.length; i++) {
	data = types[i];
	if (data === 'strong') {
	  ret.bold = true;
	} else if (data === 'variable-2') {
	  text = cm.getLine(pos.line);
	  if (/^\s*\d+\.\s/.test(text)) {
		ret['ordered-list'] = true;
	  } else {
		ret['unordered-list'] = true;
	  }
	} else if (data === 'atom') {
	  ret.quote = true;
	} else if (data === 'em') {
	  ret.italic = true;
	} else if (data === 'quote') {
	  ret.quote = true;
	}
  }
  return ret;
}


/**
 * Toggle full screen of the editor.
 */
function toggleFullScreen(editor) {
  var el = editor.codemirror.getWrapperElement();

  // https://developer.mozilla.org/en-US/docs/DOM/Using_fullscreen_mode
  var doc = document;
  var isFull = doc.fullScreen || doc.mozFullScreen || doc.webkitFullScreen;
  var request = function() {
	if (el.requestFullScreen) {
	  el.requestFullScreen();
	} else if (el.mozRequestFullScreen) {
	  el.mozRequestFullScreen();
	} else if (el.webkitRequestFullScreen) {
	  el.webkitRequestFullScreen(Element.ALLOW_KEYBOARD_INPUT);
	}
  };
  var cancel = function() {
	if (doc.cancelFullScreen) {
	  doc.cancelFullScreen();
	} else if (doc.mozCancelFullScreen) {
	  doc.mozCancelFullScreen();
	} else if (doc.webkitCancelFullScreen) {
	  doc.webkitCancelFullScreen();
	}
  };
  if (!isFull) {
	request();
  } else if (cancel) {
	cancel();
  }
}


/**
 * Action for toggling bold.
 */
function toggleBold(editor) {
  _toggleBlock(editor, 'bold', '**');
}


/**
 * Action for toggling italic.
 */
function toggleItalic(editor) {
  _toggleBlock(editor, 'italic', '*');
}

/**
 * Action for toggling code block.
 */
function toggleCodeBlock(editor) {
  _toggleBlock(editor, 'code', '```\r\n', '\r\n```');
}

/**
 * Action for toggling blockquote.
 */
function toggleBlockquote(editor) {
  var cm = editor.codemirror;
  _toggleLine(cm, 'quote');
}



/**
 * Action for toggling ul.
 */
function toggleUnOrderedList(editor) {
  var cm = editor.codemirror;
  _toggleLine(cm, 'unordered-list');
}


/**
 * Action for toggling ol.
 */
function toggleOrderedList(editor) {
  var cm = editor.codemirror;
  _toggleLine(cm, 'ordered-list');
}


/**
 * Action for drawing a link.
 */
function drawLink(editor) {
  var cm = editor.codemirror;
  var stat = getState(cm);
  _replaceSelection(cm, stat.link, '[', '](http://)');
}


/**
 * Action for drawing an img.
 */
function drawImage(editor) {
  var cm = editor.codemirror;
  var stat = getState(cm);
  _replaceSelection(cm, stat.image, '![Short description of image](http://', ')');
}


/**
 * Undo action.
 */
function undo(editor) {
  var cm = editor.codemirror;
  cm.undo();
  cm.focus();
}


/**
 * Redo action.
 */
function redo(editor) {
  var cm = editor.codemirror;
  cm.redo();
  cm.focus();
}

/**
 * Preview action.
 */
function togglePreview(editor) {
  var toolbar = editor.toolbar.preview;
  var parse = editor.constructor.markdown;
  var cm = editor.codemirror;
  var wrapper = cm.getWrapperElement();
  var preview = wrapper.lastChild;
  if (!/editor-preview/.test(preview.className)) {
	preview = document.createElement('div');
	preview.className = 'editor-preview';
	wrapper.appendChild(preview);
  }
  if (/editor-preview-active/.test(preview.className)) {
	preview.className = preview.className.replace(
	  /\s*editor-preview-active\s*/g, ''
	);
	toolbar.className = toolbar.className.replace(/\s*active\s*/g, '');
  } else {
	/* When the preview button is clicked for the first time,
	 * give some time for the transition from editor.css to fire and the view to slide from right to left,
	 * instead of just appearing.
	 */
	setTimeout(function() {preview.className += ' editor-preview-active'}, 1);
	toolbar.className += ' active';
  }
  var text = cm.getValue();
  preview.innerHTML = parse(text);
}

function _replaceSelection(cm, active, start, end) {
  var text;
  var startPoint = cm.getCursor('start');
  var endPoint = cm.getCursor('end');
  if (active) {
	text = cm.getLine(startPoint.line);
	start = text.slice(0, startPoint.ch);
	end = text.slice(startPoint.ch);
	cm.replaceRange(start + end, {line: startPoint.line, ch: 0});
  } else {
	text = cm.getSelection();
	cm.replaceSelection(start + text + end);

	startPoint.ch += start.length;
	endPoint.ch += start.length;
  }
  cm.setSelection(startPoint, endPoint);
  cm.focus();
}


function _toggleLine(cm, name) {
  var stat = getState(cm);
  var startPoint = cm.getCursor('start');
  var endPoint = cm.getCursor('end');
  var repl = {
	'quote': /^(\s*)\>\s+/,
	'unordered-list': /^(\s*)(\*|\-|\+)\s+/,
	'ordered-list': /^(\s*)\d+\.\s+/
  };
  var map = {
	'quote': '> ',
	'unordered-list': '* ',
	'ordered-list': '1. '
  };
  for (var i = startPoint.line; i <= endPoint.line; i++) {
	(function(i) {
	  var text = cm.getLine(i);
	  if (stat[name]) {
		text = text.replace(repl[name], '$1');
	  } else {
		text = map[name] + text;
	  }
	  cm.replaceRange(text, {line: i, ch: 0}, {line: i, ch: 99999999999999});
	})(i);
  }
  cm.focus();
}

function _toggleBlock(editor, type, start_chars, end_chars){
  end_chars = (typeof end_chars === 'undefined') ? start_chars : end_chars;
  var cm = editor.codemirror;
  var stat = getState(cm);

  var text;
  var start = start_chars;
  var end = end_chars;

  var startPoint = cm.getCursor('start');
  var endPoint = cm.getCursor('end');
  
  if (stat[type]) {
	text = cm.getLine(startPoint.line);
	start = text.slice(0, startPoint.ch);
	end = text.slice(startPoint.ch);
	if(type == "bold"){
		start = start.replace(/(\*\*|__)(?![\s\S]*(\*\*|__))/, "");
		end = end.replace(/(\*\*|__)/, "");
	}
	else if(type == "italic"){
		start = start.replace(/(\*|_)(?![\s\S]*(\*|_))/, "");
		end = end.replace(/(\*|_)/, "");
	}
	cm.replaceRange(start + end, {line: startPoint.line, ch: 0}, {line: startPoint.line, ch: 99999999999999});
	
	startPoint.ch -= 2;
	endPoint.ch -= 2;
  } else {
	text = cm.getSelection();
	if(type == "bold"){
		text = text.split("**").join("");
		text = text.split("__").join("");
	}
	else if(type == "italic"){
		text = text.split("*").join("");
		text = text.split("_").join("");
	}
	cm.replaceSelection(start + text + end);

	startPoint.ch += start_chars.length;
	endPoint.ch = startPoint.ch + text.length;
  }
  
  cm.setSelection(startPoint, endPoint);
  cm.focus();
}


/* The right word count in respect for CJK. */
function wordCount(data) {
  var pattern = /[a-zA-Z0-9_\u0392-\u03c9]+|[\u4E00-\u9FFF\u3400-\u4dbf\uf900-\ufaff\u3040-\u309f\uac00-\ud7af]+/g;
  var m = data.match(pattern);
  var count = 0;
  if( m === null ) return count;
  for (var i = 0; i < m.length; i++) {
	if (m[i].charCodeAt(0) >= 0x4E00) {
	  count += m[i].length;
	} else {
	  count += 1;
	}
  }
  return count;
}