/**
 * Module Dependencies.
 */
var loopback = require('../loopback');
var ModelBuilder = require('loopback-datasource-juggler').ModelBuilder;
var modeler = new ModelBuilder();
var assert = require('assert');

/**
 * Define the built in loopback.Model.
 */

var Model = module.exports = modeler.define('Model');

Model.shared = true;

/*!
 * Called when a model is extended.
 */

Model.setup = function () {
  var ModelCtor = this;
  
  ModelCtor.sharedCtor = function (data, id, fn) {
    if(typeof data === 'function') {
      fn = data;
      data = null;
      id = null;
    } else if (typeof id === 'function') {
      fn = id;
    
      if(typeof data !== 'object') {
        id = data;
        data = null;
      } else {
        id = null;
      }
    }
  
    if(id && data) {
      var model = new ModelCtor(data);
      model.id = id;
      fn(null, model);
    } else if(data) {
      fn(null, new ModelCtor(data));
    } else if(id) {
      ModelCtor.findById(id, function (err, model) {
        if(err) {
          fn(err);
        } else if(model) {
          fn(null, model);
        } else {
          err = new Error('could not find a model with id ' + id);
          err.statusCode = 404;
        
          fn(err);
        }
      });
    } else {
      fn(new Error('must specify an id or data'));
    }
  }

  // before remote hook
  ModelCtor.beforeRemote = function (name, fn) {
    var self = this;
    if(this.app) {
      var remotes = this.app.remotes();
      remotes.before(self.pluralModelName + '.' + name, function (ctx, next) {
        fn(ctx, ctx.result, next);
      });
    } else {
      var args = arguments;
      this.once('attached', function () {
        self.beforeRemote.apply(self, args);
      });
    }
  };
  
  // after remote hook
  ModelCtor.afterRemote = function (name, fn) {
    var self = this;
    if(this.app) {
      var remotes = this.app.remotes();
      remotes.after(self.pluralModelName + '.' + name, function (ctx, next) {
        fn(ctx, ctx.result, next);
      });
    } else {
      var args = arguments;
      this.once('attached', function () {
        self.afterRemote.apply(self, args);
      });
    }
  };

  // Map the prototype method to /:id with data in the body
  ModelCtor.sharedCtor.accepts = [
    {arg: 'id', type: 'any', http: {source: 'path'}}
    // {arg: 'instance', type: 'object', http: {source: 'body'}}
  ];

  ModelCtor.sharedCtor.http = [
    {path: '/:id'}
  ];
  
  ModelCtor.sharedCtor.returns = {root: true};
  
  return ModelCtor;
};

/*!
 * Get the reference to ACL in a lazy fashion to avoid race condition in require
 */
var ACL = null;
function getACL() {
  return ACL || (ACL = require('./acl').ACL);
}

/**
 * Check if the given access token can invoke the method
 *
 * @param {AccessToken} token The access token
 * @param {*} modelId The model id
 * @param {String} method The method name
 * @param callback The callback function
 *
 * @callback callback
 * @param {String|Error} err The error object
 * @param {Boolean} allowed is the request allowed
 */
Model.checkAccess = function(token, modelId, method, callback) {
  var ANONYMOUS = require('./access-token').ANONYMOUS;
  token = token || ANONYMOUS;
  var ACL = getACL();
  var methodName = 'string' === typeof method? method: method && method.name;
  ACL.checkAccessForToken(token, this.modelName, modelId, methodName, callback);
};

/**
 * Determine the access type for the given `RemoteMethod`.
 *
 * @api private
 * @param {RemoteMethod} method
 */

Model._getAccessTypeForMethod = function(method) {
  if(typeof method === 'string') {
    method = {name: method};
  }
  assert(
    typeof method === 'object', 
    'method is a required argument and must be a RemoteMethod object'
  );

  var ACL = getACL();

  switch(method.name) {
    case'create':
      return ACL.WRITE;
    case 'updateOrCreate':
      return ACL.WRITE;
    case 'upsert':
      return ACL.WRITE;
    case 'exists':
      return ACL.READ;
    case 'findById':
      return ACL.READ;
    case 'find':
      return ACL.READ;
    case 'findOne':
      return ACL.READ;
    case 'destroyById':
      return ACL.WRITE;
    case 'deleteById':
      return ACL.WRITE;
    case 'removeById':
      return ACL.WRITE;
    case 'count':
      return ACL.READ;
    break;
    default:
      return ACL.EXECUTE;
    break;
  }
}

// setup the initial model
Model.setup();