/**
 * syringe.js
 * @version 0.4.0
 * https://github.com/noeldelgado/Syringe.js
 * Licensed under the MIT lincese
 */
/* globals CSSRule */
(function () {
  'use strict';

  var Syringe = {
    config: {
      prefixedProperties: null
    },

    style: null,
    sheet: null,
    rules: null,
    buffer: {},
    _level: 0,

    inject: function inject(options) {
      if (this.style === null) {
        Syringe._createStyleSheet();
      }

      // Reset variables for iteration
      this._level = 0;
      this.buffer.selectors = [];
      this.buffer.blocks = [];

      // Handle rules to be injected
      this._iterate(options);

      // Inject rules
      return this._insertRules();
    },

    removeAll: function removeAll() {
      while(this.rules.length) {
        if (this.sheet.deleteRule) {
          this.sheet.deleteRule(this.rules.length - 1);
        } else {
          this.sheet.removeRule(this.rules.length - 1);
        }
      }

      /* IE8 at-rule */
      if (this.sheet.imports) {
        while(this.sheet.imports.length) {
          this.sheet.removeImport(this.sheet.imports.length - 1);
        }
      }

      this._removeStyleSheet();
    },

    remove: function remove(selector) {
      var rules, rulesLength, selectorsLength, j;

      if (!selector) {return false;}

      rules = this.rules;
      rulesLength = rules.length;
      selectorsLength = selector.length;

      if (typeof selector === "string") {
        while(rulesLength--) {
          this._deleteRule(rules[rulesLength], rulesLength, selector);
        }
      }

      if (selector instanceof Array) {
        while(rulesLength--) {
          for (j = 0; j < selectorsLength; j++) {
            this._deleteRule(rules[rulesLength], rulesLength, selector[j]);
          }
        }
      }

      if (this.rules.length === 0) {
        this._removeStyleSheet();
      }
    },

    _deleteRule: function _deleteRule(rule, index, selector) {
      var isKeyframe, isAtRule, isMedia, isFontFace, selectorNoSpaces;

      if (!rule) {return;}

      if (this.sheet.deleteRule) {
        isKeyframe = this._re.keyframe.exec(selector);
        isAtRule = this._re.atRule.exec(selector);
        isMedia = this._re.media.exec(selector);
        isFontFace = this._re.fontFace.exec(selector);

        if (rule.type === 1 && (rule.selectorText === selector)) { // CSSRule.STYLE_RULE
          this.sheet.deleteRule(index);
        } else if (rule.type === 3 && isAtRule) { // CSSRule.IMPORT_RULE
          if (rule.href === isAtRule[1]) {
            this.sheet.deleteRule(index);
          }
        } else if (rule.type === 4 && isMedia) { // CSSRule.MEDIA_RULE
          selectorNoSpaces = selector.replace(/\s/g, '');
          if (rule.cssText.replace(/\s/g, '').substring(0, selectorNoSpaces.length) === selectorNoSpaces) {
            this.sheet.deleteRule(index);
          }
        } else if (rule.type === 5 && isFontFace) { // CSSFontFaceRule
          this.sheet.deleteRule(index);
        } else if (rule.type === 7 && isKeyframe) { // CSSRule.KEYFRAMES_RULE
          if (rule.name === isKeyframe[2]) {
            this.sheet.deleteRule(index);
          }
        }

        return;
      }

      // IE-8
      if (rule.selectorText.toLowerCase() === selector) {
        this.sheet.removeRule(index);
      } else {
        isAtRule = this._re.atRule.exec(selector);
        if (isAtRule && this.sheet.imports) {
          for (var i = 0; i< this.sheet.imports.length; i++) {
            if (this.sheet.imports[i].href.indexOf(isAtRule[1]) > 0) {
              this.sheet.removeImport(i);
            }
          }
        }
      }
    },

    _iterate: function iterate(obj) {
      var selector, lastSelector, property;

      for (selector in obj) {
        if (obj.hasOwnProperty(selector)) {
          lastSelector = (this.buffer.selectors.length - 1);

          if (typeof obj[selector] === "object") {
            // Handle rule blocks
            this._level++;

            if (this._level === 1) {
              this.buffer.selectors.push(selector);
              lastSelector = this.buffer.selectors.length - 1;
            } else {
              this._addToBlock(lastSelector, selector + "{");
            }

            if (this._isEmptyObject(obj[selector])) {
              this._level--;
              this.buffer.blocks[lastSelector] = "";
            } else {
              this._iterate(obj[selector]);

              if (this._level > 1) {
                this.buffer.blocks[lastSelector] += "}";
              }

              this._level--;
            }
          } else {
            // handle declarations
            property = selector;

            if (this._re.camelCase.test(selector) === true) {
              property = this._toDash(selector);
            }

            if (this.config.prefixedProperties) {
              if (lastSelector < 0) { // empty ruleset, special case for @import rule
                lastSelector = 0;
                this.buffer.selectors.push("");
              }
              this._addToBlock(lastSelector, this._getPrefixedDeclarations(property, obj[selector]));
            } else {
              this._addToBlock(lastSelector, this._getDeclaration(property, obj[selector]));
            }
          }
        }
      }
    },

    _insertRules: function _insertRules() {
      var i, blocksLength, rulesLength, result, selector, block, isMedia, isKeyframe, keyframeName;

      blocksLength = this.buffer.blocks.length;
      rulesLength = this.rules.length;
      result = "";

      for (i = 0; i < blocksLength; i++) {
        selector = this.buffer.selectors[i];
        block = this.buffer.blocks[i];
        isMedia = this._re.media.exec(selector);
        isKeyframe = this._re.keyframe.exec(selector);
        keyframeName= "";

        // @import at-rule
        if (selector === "") {
          result += block;

          if (this.sheet.insertRule) {
            this.sheet.insertRule(block, rulesLength);
          } else if (this.sheet.addImport) { // IE8-
            this.sheet.addImport(this._re.atRule.exec(block)[1]);
          }

          continue;
        }

        // @keyframes
        if (isKeyframe) {
          keyframeName = " " + isKeyframe[2];
          if (!!window.CSSRule) {
            if (CSSRule.KEYFRAMES_RULE) {
              selector = "@keyframes" + keyframeName;
            } else if (CSSRule.WEBKIT_KEYFRAMES_RULE) {
              selector = "@-webkit-keyframes" + keyframeName;
            } else if (CSSRule.MOZ_KEYFRAMES_RULE) {
              selector = "@-moz-keyframes" + keyframeName;
            } else {
              selector = "";
            }
          } else {
            selector = "";
          }
        }

        // media querie, IE8 validation
        if (isMedia) {
          if ((window.matchMedia === undefined && window.msMatchMedia === undefined) &&
              (window.styleMedia === undefined && window.media === undefined)) {
            selector = "";
          }
        }

        if (selector && block) {
          if (this.sheet.insertRule) {
            this.sheet.insertRule(selector + "{" + block + "}", rulesLength);
          } else {
            this.sheet.addRule(selector, block, 0);
          }
        }

        result += selector + "{" + block + "}";
        selector = block = isKeyframe = keyframeName = null;
      }

      return result;
    },

    _addToBlock: function _addToBlock(index, value) {
      if (this.buffer.blocks[index] === undefined) {
        this.buffer.blocks[index] = "";
      }
      this.buffer.blocks[index] += value;
    },

    _getDeclaration: function _getDeclaration(property, value) {
      var declaration;
      if (property === "@import") {
        declaration = (property + " " + value);
      } else {
        declaration = (property + ":" + value);
      }
      return declaration + ";";
    },

    _getPrefixedDeclarations: function _getPrefixedDeclarations(property, value) {
      var result, index, prefixedProps, prefixedPropsLength;

      if (this.config.prefixedProperties[property]) {
        result = "";
        prefixedProps = this._getPrefixedSelector(property);
        prefixedPropsLength = prefixedProps.length;

        for (index = 0; index < prefixedPropsLength; index++) {
          result += this._getDeclaration(prefixedProps[index], value);
        }

        return result;
      }

      return this._getDeclaration(property, value);
    },

    _getPrefixedSelector: function _getPrefixedSelector(selector) {
      var result = []
        , prefixes = this.config.prefixedProperties[selector]
        , index = 0
        , prefixesLength = prefixes.length;

      for (; index < prefixesLength; index++) {
        result.push('-' + prefixes[index] + '-' + selector);
      }

      result.push(selector);
      return result;
    },

    _re: {
      camelCase: new RegExp("[A-Z]\\w+"),
      keyframe: new RegExp("@(.*)?keyframes (.*)"),
      atRule: new RegExp("@import url\\((.*)\\)"),
      media: new RegExp("@media"),
      fontFace: new RegExp("@font-face")
    },

    _toDash: function _toDash(string) {
      return string.replace(/([A-Z])/g, function (letter) {
        return '-' + letter.toLowerCase();
      });
    },

    _isEmptyObject: function _isEmptyObject(obj) {
      for (var prop in obj) {
        if (obj.hasOwnProperty(prop)) {
          return false;
        }
      }
      return true;
    },

    _removeStyleSheet: function _removeStyleSheet() {
      // The complete style element must be deleted to
      // update the style settings in Firefox and Opera
      this.style.parentNode.removeChild(this.style);
      this.style = null;
    },

    _createStyleSheet: function _createStyleSheet() {
      this.style = document.createElement('style');
      this.style.setAttribute("type", "text/css");
      document.getElementsByTagName("head")[0].appendChild(this.style);
      if (this.style.sheet === undefined) {
        this.sheet = this.style.styleSheet;
      } else {
        this.sheet = this.style.sheet;
      }
      if (this.sheet.cssRules) {
        this.rules = this.sheet.cssRules;
      } else {
        this.rules = this.sheet.rules;
      }
    }
  };

  if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
    module.exports = Syringe;
  } else { window.Syringe = Syringe; }
})();