// Copyright 2011 Mark Cavage, Inc.  All rights reserved.

var assert = require('assert');

var asn1 = require('asn1');

var parents = require('ldap-filter');

var Protocol = require('../protocol');

var Filter = require('./filter');
var AndFilter = require('./and_filter');
var ApproximateFilter = require('./approx_filter');
var EqualityFilter = require('./equality_filter');
var ExtensibleFilter = require('./ext_filter');
var GreaterThanEqualsFilter = require('./ge_filter');
var LessThanEqualsFilter = require('./le_filter');
var NotFilter = require('./not_filter');
var OrFilter = require('./or_filter');
var PresenceFilter = require('./presence_filter');
var SubstringFilter = require('./substr_filter');



///--- Globals

var BerReader = asn1.BerReader;


///--- Internal Parsers

/*
 * A filter looks like this coming in:
 *      Filter ::= CHOICE {
 *              and             [0]     SET OF Filter,
 *              or              [1]     SET OF Filter,
 *              not             [2]     Filter,
 *              equalityMatch   [3]     AttributeValueAssertion,
 *              substrings      [4]     SubstringFilter,
 *              greaterOrEqual  [5]     AttributeValueAssertion,
 *              lessOrEqual     [6]     AttributeValueAssertion,
 *              present         [7]     AttributeType,
 *              approxMatch     [8]     AttributeValueAssertion,
 *              extensibleMatch [9]     MatchingRuleAssertion --v3 only
 *      }
 *
 *      SubstringFilter ::= SEQUENCE {
 *              type               AttributeType,
 *              SEQUENCE OF CHOICE {
 *                      initial          [0] IA5String,
 *                      any              [1] IA5String,
 *                      final            [2] IA5String
 *              }
 *      }
 *
 * The extensibleMatch was added in LDAPv3:
 *
 *      MatchingRuleAssertion ::= SEQUENCE {
 *              matchingRule    [1] MatchingRuleID OPTIONAL,
 *              type            [2] AttributeDescription OPTIONAL,
 *              matchValue      [3] AssertionValue,
 *              dnAttributes    [4] BOOLEAN DEFAULT FALSE
 *      }
 */
function _parse(ber) {
  assert.ok(ber);

  function parseSet(f) {
    var end = ber.offset + ber.length;
    while (ber.offset < end)
      f.addFilter(_parse(ber));
  }

  var f;

  var type = ber.readSequence();
  switch (type) {

  case Protocol.FILTER_AND:
    f = new AndFilter();
    parseSet(f);
    break;

  case Protocol.FILTER_APPROX:
    f = new ApproximateFilter();
    f.parse(ber);
    break;

  case Protocol.FILTER_EQUALITY:
    f = new EqualityFilter();
    f.parse(ber);
    return f;

  case Protocol.FILTER_EXT:
    f = new ExtensibleFilter();
    f.parse(ber);
    return f;

  case Protocol.FILTER_GE:
    f = new GreaterThanEqualsFilter();
    f.parse(ber);
    return f;

  case Protocol.FILTER_LE:
    f = new LessThanEqualsFilter();
    f.parse(ber);
    return f;

  case Protocol.FILTER_NOT:
    var _f = _parse(ber);
    f = new NotFilter({
      filter: _f
    });
    break;

  case Protocol.FILTER_OR:
    f = new OrFilter();
    parseSet(f);
    break;

  case Protocol.FILTER_PRESENT:
    f = new PresenceFilter();
    f.parse(ber);
    break;

  case Protocol.FILTER_SUBSTRINGS:
    f = new SubstringFilter();
    f.parse(ber);
    break;

  default:
    throw new Error('Invalid search filter type: 0x' + type.toString(16));
  }


  assert.ok(f);
  return f;
}


function cloneFilter(input) {
  var child;
  if (input.type === 'and' || input.type === 'or') {
    child = input.filters.map(cloneFilter);
  } else if (input.type === 'not') {
    child = cloneFilter(input.filter);
  }
  switch (input.type) {
  case 'and':
    return new AndFilter({filters: child});
  case 'or':
    return new OrFilter({filters: child});
  case 'not':
    return new NotFilter({filter: child});
  case 'equal':
    return new EqualityFilter(input);
  case 'substring':
    return new SubstringFilter(input);
  case 'ge':
    return new GreaterThanEqualsFilter(input);
  case 'le':
    return new LessThanEqualsFilter(input);
  case 'present':
    return new PresenceFilter(input);
  case 'approx':
    return new ApproximateFilter(input);
  case 'ext':
    return new ExtensibleFilter(input);
  default:
    throw new Error('invalid filter type:' + input.type);
  }
}


function parseString(str) {
  var generic = parents.parse(str);
  // The filter object(s) return from ldap-filter.parse lack the toBer/parse
  // decoration that native ldapjs filter possess.  cloneFilter adds that back.
  return cloneFilter(generic);
}


///--- API

module.exports = {
  parse: function (ber) {
    if (!ber || !(ber instanceof BerReader))
      throw new TypeError('ber (BerReader) required');

    return _parse(ber);
  },

  parseString: parseString,

  isFilter: Filter.isFilter,

  AndFilter: AndFilter,
  ApproximateFilter: ApproximateFilter,
  EqualityFilter: EqualityFilter,
  ExtensibleFilter: ExtensibleFilter,
  GreaterThanEqualsFilter: GreaterThanEqualsFilter,
  LessThanEqualsFilter: LessThanEqualsFilter,
  NotFilter: NotFilter,
  OrFilter: OrFilter,
  PresenceFilter: PresenceFilter,
  SubstringFilter: SubstringFilter
};