'use strict';

var modifiedPaths = require('./common').modifiedPaths;

/**
 * Applies defaults to update and findOneAndUpdate operations.
 *
 * @param {Object} filter
 * @param {Schema} schema
 * @param {Object} castedDoc
 * @param {Object} options
 * @method setDefaultsOnInsert
 * @api private
 */

module.exports = function(filter, schema, castedDoc, options) {
  var keys = Object.keys(castedDoc || {});
  var updatedKeys = {};
  var updatedValues = {};
  var numKeys = keys.length;
  var hasDollarUpdate = false;
  var modified = {};

  if (options && options.upsert) {
    for (var i = 0; i < numKeys; ++i) {
      if (keys[i].charAt(0) === '$') {
        modifiedPaths(castedDoc[keys[i]], '', modified);
        hasDollarUpdate = true;
      }
    }

    if (!hasDollarUpdate) {
      modifiedPaths(castedDoc, '', modified);
    }

    var paths = Object.keys(filter);
    var numPaths = paths.length;
    for (i = 0; i < numPaths; ++i) {
      var path = paths[i];
      var condition = filter[path];
      if (condition && typeof condition === 'object') {
        var conditionKeys = Object.keys(condition);
        var numConditionKeys = conditionKeys.length;
        var hasDollarKey = false;
        for (var j = 0; j < numConditionKeys; ++j) {
          if (conditionKeys[j].charAt(0) === '$') {
            hasDollarKey = true;
            break;
          }
        }
        if (hasDollarKey) {
          continue;
        }
      }
      updatedKeys[path] = true;
      modified[path] = true;
    }

    if (options && options.overwrite && !hasDollarUpdate) {
      // Defaults will be set later, since we're overwriting we'll cast
      // the whole update to a document
      return castedDoc;
    }

    if (options.setDefaultsOnInsert) {
      schema.eachPath(function(path, schemaType) {
        if (path === '_id') {
          // Ignore _id for now because it causes bugs in 2.4
          return;
        }
        if (schemaType.$isSingleNested) {
          // Only handle nested schemas 1-level deep to avoid infinite
          // recursion re: https://github.com/mongodb-js/mongoose-autopopulate/issues/11
          schemaType.schema.eachPath(function(_path, _schemaType) {
            if (path === '_id') {
              // Ignore _id for now because it causes bugs in 2.4
              return;
            }

            var def = _schemaType.getDefault(null, true);
            if (!isModified(modified, path + '.' + _path) &&
                typeof def !== 'undefined') {
              castedDoc = castedDoc || {};
              castedDoc.$setOnInsert = castedDoc.$setOnInsert || {};
              castedDoc.$setOnInsert[path + '.' + _path] = def;
              updatedValues[path + '.' + _path] = def;
            }
          });
        } else {
          var def = schemaType.getDefault(null, true);
          if (!isModified(modified, path) && typeof def !== 'undefined') {
            castedDoc = castedDoc || {};
            castedDoc.$setOnInsert = castedDoc.$setOnInsert || {};
            castedDoc.$setOnInsert[path] = def;
            updatedValues[path] = def;
          }
        }
      });
    }
  }

  return castedDoc;
};

function isModified(modified, path) {
  if (modified[path]) {
    return true;
  }
  var sp = path.split('.');
  var cur = sp[0];
  for (var i = 0; i < sp.length; ++i) {
    if (modified[cur]) {
      return true;
    }
    cur += '.' + sp[i];
  }
  return false;
}