/**
 * messageformat.js
 *
 * ICU PluralFormat + SelectFormat for JavaScript
 *
 * @author Alex Sexton - @SlexAxton
 * @version 0.1.7
 * @license WTFPL
 * @contributor_license Dojo CLA
*/
(function ( root ) {

  // Create the contructor function
  function MessageFormat ( locale, pluralFunc ) {
    var fallbackLocale;

    if ( locale && pluralFunc ) {
      MessageFormat.locale[ locale ] = pluralFunc;
    }

    // Defaults
    fallbackLocale = locale = locale || "en";
    pluralFunc = pluralFunc || MessageFormat.locale[ fallbackLocale = MessageFormat.Utils.getFallbackLocale( locale ) ];

    if ( ! pluralFunc ) {
      throw new Error( "Plural Function not found for locale: " + locale );
    }

    // Own Properties
    this.pluralFunc = pluralFunc;
    this.locale = locale;
    this.fallbackLocale = fallbackLocale;
  }

  // methods in common with the generated MessageFormat
  // check d
  c=function(d){
    if(!d){throw new Error("MessageFormat: No data passed to function.")}
  }
  // require number
  n=function(d,k,o){
    if(isNaN(d[k])){throw new Error("MessageFormat: `"+k+"` isnt a number.")}
    return d[k] - (o || 0);
  }
  // value
  v=function(d,k){
    c(d);
    return d[k];
  }
  // plural
  p=function(d,k,o,l,p){
    c(d);
    return d[k] in p ? p[d[k]] : (k = MessageFormat.locale[l](d[k]-o), k in p ? p[k] : p.other);
  }
  // select
  s=function(d,k,p){
    c(d);
    return d[k] in p ? p[d[k]] : p.other;
  }

  // Set up the locales object. Add in english by default
  MessageFormat.locale = {
    "en" : function ( n ) {
      if ( n === 1 ) {
        return "one";
      }
      return "other";
    }
  };

  // Build out our basic SafeString type
  // more or less stolen from Handlebars by @wycats
  MessageFormat.SafeString = function( string ) {
    this.string = string;
  };

  MessageFormat.SafeString.prototype.toString = function () {
    return this.string.toString();
  };

  MessageFormat.Utils = {
    numSub : function ( string, d, key, offset ) {
      // make sure that it's not an escaped octothorpe
      var s = string.replace( /(^|[^\\])#/g, '$1"+n(' + d + ',' + key + (offset ? ',' + offset : '') + ')+"' );
      return s.replace( /^""\+/, '' ).replace( /\+""$/, '' );
    },
    escapeExpression : function (string) {
      var escape = {
            "\n": "\\n",
            "\"": '\\"'
          },
          badChars = /[\n"]/g,
          possible = /[\n"]/,
          escapeChar = function(chr) {
            return escape[chr] || "&";
          };

      // Don't escape SafeStrings, since they're already safe
      if ( string instanceof MessageFormat.SafeString ) {
        return string.toString();
      }
      else if ( string === null || string === false ) {
        return "";
      }

      if ( ! possible.test( string ) ) {
        return string;
      }
      return string.replace( badChars, escapeChar );
    },
    getFallbackLocale: function( locale ) {
      var tagSeparator = locale.indexOf("-") >= 0 ? "-" : "_";

      // Lets just be friends, fallback through the language tags
      while ( ! MessageFormat.locale.hasOwnProperty( locale ) ) {
        locale = locale.substring(0, locale.lastIndexOf( tagSeparator ));
        if (locale.length === 0) {
          return null;
        }
      }

      return locale;
    }
  };

  var mparser = require( './message_parser' );

  MessageFormat.prototype.parse = function () {
    // Bind to itself so error handling works
    return mparser.parse.apply( mparser, arguments );
  };

  MessageFormat.prototype.precompile = function ( ast ) {
    var self = this,
        needOther = false;

    function _next ( data ) {
      var res = JSON.parse( JSON.stringify( data ) );
      res.pf_count++;
      return res;
    }
    function interpMFP ( ast, data ) {
      // Set some default data
      data = data || { keys: {}, offset: {} };
      var r = [], i, tmp;

      switch ( ast.type ) {
        case 'program':
          return interpMFP( ast.program );
        case 'messageFormatPattern':
          for ( i = 0; i < ast.statements.length; ++i ) {
            r.push(interpMFP( ast.statements[i], data ));
          }
          tmp = r.join('+') || '""';
          return data.pf_count ? tmp : 'function(d){return ' + tmp + '}';
        case 'messageFormatPatternRight':
          for ( i = 0; i < ast.statements.length; ++i ) {
            r.push(interpMFP( ast.statements[i], data ));
          }
          return r.join('+');
        case 'messageFormatElement':
          data.pf_count = data.pf_count || 0;
          if ( ast.output ) {
            return 'v(d,"' + ast.argumentIndex + '")';
          }
          else {
            data.keys[data.pf_count] = '"' + ast.argumentIndex + '"';
            return interpMFP( ast.elementFormat, data );
          }
          return '';
        case 'elementFormat':
          if ( ast.key === 'select' ) {
            return 's(d,' + data.keys[data.pf_count] + ',' + interpMFP( ast.val, data ) + ')';
          }
          else if ( ast.key === 'plural' ) {
            data.offset[data.pf_count || 0] = ast.val.offset || 0;
            return 'p(d,' + data.keys[data.pf_count] + ',' + (data.offset[data.pf_count] || 0)
              + ',"' + self.fallbackLocale + '",' + interpMFP( ast.val, data ) + ')';
          }
          return '';
        /* // Unreachable cases.
        case 'pluralStyle':
        case 'selectStyle':*/
        case 'pluralFormatPattern':
          data.pf_count = data.pf_count || 0;
          needOther = true;
          // We're going to simultaneously check to make sure we hit the required 'other' option.

          for ( i = 0; i < ast.pluralForms.length; ++i ) {
            if ( ast.pluralForms[ i ].key === 'other' ) {
              needOther = false;
            }
            r.push('"' + ast.pluralForms[ i ].key + '":' + interpMFP( ast.pluralForms[ i ].val, _next(data) ));
          }
          if ( needOther ) {
            throw new Error("No 'other' form found in pluralFormatPattern " + data.pf_count);
          }
          return '{' + r.join(',') + '}';
        case 'selectFormatPattern':

          data.pf_count = data.pf_count || 0;
          data.offset[data.pf_count] = 0;
          needOther = true;

          for ( i = 0; i < ast.pluralForms.length; ++i ) {
            if ( ast.pluralForms[ i ].key === 'other' ) {
              needOther = false;
            }
            r.push('"' + ast.pluralForms[ i ].key + '":' + interpMFP( ast.pluralForms[ i ].val, _next(data) ));
          }
          if ( needOther ) {
            throw new Error("No 'other' form found in selectFormatPattern " + data.pf_count);
          }
          return '{' + r.join(',') + '}';
        /* // Unreachable
        case 'pluralForms':
        */
        case 'string':
          tmp = '"' + MessageFormat.Utils.escapeExpression( ast.val ) + '"';
          if ( data.pf_count ) {
            tmp = MessageFormat.Utils.numSub( tmp, 'd', data.keys[data.pf_count-1], data.offset[data.pf_count-1]);
          }
          return tmp;
        default:
          throw new Error( 'Bad AST type: ' + ast.type );
      }
    }
    return interpMFP( ast );
  };

  MessageFormat.prototype.compile = function ( message ) {
    return (new Function( 'MessageFormat',
      'return ' +
        this.precompile(
          this.parse( message )
        )
    ))(MessageFormat);
  };


  if (typeof exports !== 'undefined') {
    if (typeof module !== 'undefined' && module.exports) {
      exports = module.exports = MessageFormat;
    }
    exports.MessageFormat = MessageFormat;
  }
  else if (typeof define === 'function' && define.amd) {
    define(function() {
      return MessageFormat;
    });
  }
  else {
    root['MessageFormat'] = MessageFormat;
  }

})( this );