'use strict';
//parse Empty Node as self closing node
const buildOptions = require('./util').buildOptions;

const defaultOptions = {
  attributeNamePrefix: '@_',
  attrNodeName: false,
  textNodeName: '#text',
  ignoreAttributes: true,
  cdataTagName: false,
  cdataPositionChar: '\\c',
  format: false,
  indentBy: '  ',
  supressEmptyNode: false,
  tagValueProcessor: function(a) {
    return a;
  },
  attrValueProcessor: function(a) {
    return a;
  },
};

const props = [
  'attributeNamePrefix',
  'attrNodeName',
  'textNodeName',
  'ignoreAttributes',
  'cdataTagName',
  'cdataPositionChar',
  'format',
  'indentBy',
  'supressEmptyNode',
  'tagValueProcessor',
  'attrValueProcessor',
  'rootNodeName', //when array as root
];

function Parser(options) {
  this.options = buildOptions(options, defaultOptions, props);
  if (this.options.ignoreAttributes || this.options.attrNodeName) {
    this.isAttribute = function(/*a*/) {
      return false;
    };
  } else {
    this.attrPrefixLen = this.options.attributeNamePrefix.length;
    this.isAttribute = isAttribute;
  }
  if (this.options.cdataTagName) {
    this.isCDATA = isCDATA;
  } else {
    this.isCDATA = function(/*a*/) {
      return false;
    };
  }
  this.replaceCDATAstr = replaceCDATAstr;
  this.replaceCDATAarr = replaceCDATAarr;

  this.processTextOrObjNode = processTextOrObjNode

  if (this.options.format) {
    this.indentate = indentate;
    this.tagEndChar = '>\n';
    this.newLine = '\n';
  } else {
    this.indentate = function() {
      return '';
    };
    this.tagEndChar = '>';
    this.newLine = '';
  }

  if (this.options.supressEmptyNode) {
    this.buildTextNode = buildEmptyTextNode;
    this.buildObjNode = buildEmptyObjNode;
  } else {
    this.buildTextNode = buildTextValNode;
    this.buildObjNode = buildObjectNode;
  }

  this.buildTextValNode = buildTextValNode;
  this.buildObjectNode = buildObjectNode;
}

Parser.prototype.parse = function(jObj) {
  if(Array.isArray(jObj) && this.options.rootNodeName && this.options.rootNodeName.length > 1){
    jObj = {
      [this.options.rootNodeName] : jObj
    }
  }
  return this.j2x(jObj, 0).val;
};

Parser.prototype.j2x = function(jObj, level) {
  let attrStr = '';
  let val = '';
  for (let key in jObj) {
    if (typeof jObj[key] === 'undefined') {
      // supress undefined node
    } else if (jObj[key] === null) {
      val += this.indentate(level) + '<' + key + '/' + this.tagEndChar;
    } else if (jObj[key] instanceof Date) {
      val += this.buildTextNode(jObj[key], key, '', level);
    } else if (typeof jObj[key] !== 'object') {
      //premitive type
      const attr = this.isAttribute(key);
      if (attr) {
        attrStr += ' ' + attr + '="' + this.options.attrValueProcessor('' + jObj[key]) + '"';
      } else if (this.isCDATA(key)) {
        if (jObj[this.options.textNodeName]) {
          val += this.replaceCDATAstr(jObj[this.options.textNodeName], jObj[key]);
        } else {
          val += this.replaceCDATAstr('', jObj[key]);
        }
      } else {
        //tag value
        if (key === this.options.textNodeName) {
          if (jObj[this.options.cdataTagName]) {
            //value will added while processing cdata
          } else {
            val += this.options.tagValueProcessor('' + jObj[key]);
          }
        } else {
          val += this.buildTextNode(jObj[key], key, '', level);
        }
      }
    } else if (Array.isArray(jObj[key])) {
      //repeated nodes
      if (this.isCDATA(key)) {
        val += this.indentate(level);
        if (jObj[this.options.textNodeName]) {
          val += this.replaceCDATAarr(jObj[this.options.textNodeName], jObj[key]);
        } else {
          val += this.replaceCDATAarr('', jObj[key]);
        }
      } else {
        //nested nodes
        const arrLen = jObj[key].length;
        for (let j = 0; j < arrLen; j++) {
          const item = jObj[key][j];
          if (typeof item === 'undefined') {
            // supress undefined node
          } else if (item === null) {
            val += this.indentate(level) + '<' + key + '/' + this.tagEndChar;
          } else if (typeof item === 'object') {
            val += this.processTextOrObjNode(item, key, level)
          } else {
            val += this.buildTextNode(item, key, '', level);
          }
        }
      }
    } else {
      //nested node
      if (this.options.attrNodeName && key === this.options.attrNodeName) {
        const Ks = Object.keys(jObj[key]);
        const L = Ks.length;
        for (let j = 0; j < L; j++) {
          attrStr += ' ' + Ks[j] + '="' + this.options.attrValueProcessor('' + jObj[key][Ks[j]]) + '"';
        }
      } else {
        val += this.processTextOrObjNode(jObj[key], key, level)
      }
    }
  }
  return {attrStr: attrStr, val: val};
};

function processTextOrObjNode (object, key, level) {
  const result = this.j2x(object, level + 1);
  if (object[this.options.textNodeName] !== undefined && Object.keys(object).length === 1) {
    return this.buildTextNode(result.val, key, result.attrStr, level);
  } else {
    return this.buildObjNode(result.val, key, result.attrStr, level);
  }
}

function replaceCDATAstr(str, cdata) {
  str = this.options.tagValueProcessor('' + str);
  if (this.options.cdataPositionChar === '' || str === '') {
    return str + '<![CDATA[' + cdata + ']]' + this.tagEndChar;
  } else {
    return str.replace(this.options.cdataPositionChar, '<![CDATA[' + cdata + ']]' + this.tagEndChar);
  }
}

function replaceCDATAarr(str, cdata) {
  str = this.options.tagValueProcessor('' + str);
  if (this.options.cdataPositionChar === '' || str === '') {
    return str + '<![CDATA[' + cdata.join(']]><![CDATA[') + ']]' + this.tagEndChar;
  } else {
    for (let v in cdata) {
      str = str.replace(this.options.cdataPositionChar, '<![CDATA[' + cdata[v] + ']]>');
    }
    return str + this.newLine;
  }
}

function buildObjectNode(val, key, attrStr, level) {
  if (attrStr && val.indexOf('<') === -1) {
    return (
      this.indentate(level) +
      '<' +
      key +
      attrStr +
      '>' +
      val +
      //+ this.newLine
      // + this.indentate(level)
      '</' +
      key +
      this.tagEndChar
    );
  } else {
    return (
      this.indentate(level) +
      '<' +
      key +
      attrStr +
      this.tagEndChar +
      val +
      //+ this.newLine
      this.indentate(level) +
      '</' +
      key +
      this.tagEndChar
    );
  }
}

function buildEmptyObjNode(val, key, attrStr, level) {
  if (val !== '') {
    return this.buildObjectNode(val, key, attrStr, level);
  } else {
    return this.indentate(level) + '<' + key + attrStr + '/' + this.tagEndChar;
    //+ this.newLine
  }
}

function buildTextValNode(val, key, attrStr, level) {
  return (
    this.indentate(level) +
    '<' +
    key +
    attrStr +
    '>' +
    this.options.tagValueProcessor(val) +
    '</' +
    key +
    this.tagEndChar
  );
}

function buildEmptyTextNode(val, key, attrStr, level) {
  if (val !== '') {
    return this.buildTextValNode(val, key, attrStr, level);
  } else {
    return this.indentate(level) + '<' + key + attrStr + '/' + this.tagEndChar;
  }
}

function indentate(level) {
  return this.options.indentBy.repeat(level);
}

function isAttribute(name /*, options*/) {
  if (name.startsWith(this.options.attributeNamePrefix)) {
    return name.substr(this.attrPrefixLen);
  } else {
    return false;
  }
}

function isCDATA(name) {
  return name === this.options.cdataTagName;
}

//formatting
//indentation
//\n after each closing or self closing tag

module.exports = Parser;