'use strict';

var traverse = module.exports = function (schema, opts, cb) {
  // Legacy support for v0.3.1 and earlier.
  if (typeof opts == 'function') {
    cb = opts;
    opts = {};
  }

  cb = opts.cb || cb;
  var pre = (typeof cb == 'function') ? cb : cb.pre || function() {};
  var post = cb.post || function() {};

  _traverse(opts, pre, post, schema, '', schema);
};


traverse.keywords = {
  additionalItems: true,
  items: true,
  contains: true,
  additionalProperties: true,
  propertyNames: true,
  not: true,
  if: true,
  then: true,
  else: true
};

traverse.arrayKeywords = {
  items: true,
  allOf: true,
  anyOf: true,
  oneOf: true
};

traverse.propsKeywords = {
  $defs: true,
  definitions: true,
  properties: true,
  patternProperties: true,
  dependencies: true
};

traverse.skipKeywords = {
  default: true,
  enum: true,
  const: true,
  required: true,
  maximum: true,
  minimum: true,
  exclusiveMaximum: true,
  exclusiveMinimum: true,
  multipleOf: true,
  maxLength: true,
  minLength: true,
  pattern: true,
  format: true,
  maxItems: true,
  minItems: true,
  uniqueItems: true,
  maxProperties: true,
  minProperties: true
};


function _traverse(opts, pre, post, schema, jsonPtr, rootSchema, parentJsonPtr, parentKeyword, parentSchema, keyIndex) {
  if (schema && typeof schema == 'object' && !Array.isArray(schema)) {
    pre(schema, jsonPtr, rootSchema, parentJsonPtr, parentKeyword, parentSchema, keyIndex);
    for (var key in schema) {
      var sch = schema[key];
      if (Array.isArray(sch)) {
        if (key in traverse.arrayKeywords) {
          for (var i=0; i<sch.length; i++)
            _traverse(opts, pre, post, sch[i], jsonPtr + '/' + key + '/' + i, rootSchema, jsonPtr, key, schema, i);
        }
      } else if (key in traverse.propsKeywords) {
        if (sch && typeof sch == 'object') {
          for (var prop in sch)
            _traverse(opts, pre, post, sch[prop], jsonPtr + '/' + key + '/' + escapeJsonPtr(prop), rootSchema, jsonPtr, key, schema, prop);
        }
      } else if (key in traverse.keywords || (opts.allKeys && !(key in traverse.skipKeywords))) {
        _traverse(opts, pre, post, sch, jsonPtr + '/' + key, rootSchema, jsonPtr, key, schema);
      }
    }
    post(schema, jsonPtr, rootSchema, parentJsonPtr, parentKeyword, parentSchema, keyIndex);
  }
}


function escapeJsonPtr(str) {
  return str.replace(/~/g, '~0').replace(/\//g, '~1');
}