// schemas.js

var express = require('express'),
    Parse = require('parse/node').Parse,
    PromiseRouter = require('./PromiseRouter'),
    Schema = require('./Schema');

var router = new PromiseRouter();

function mongoFieldTypeToSchemaAPIType(type) {
  if (type[0] === '*') {
    return {
      type: 'Pointer',
      targetClass: type.slice(1),
    };
  }
  if (type.startsWith('relation<')) {
    return {
      type: 'Relation',
      targetClass: type.slice('relation<'.length, type.length - 1),
    };
  }
  switch (type) {
    case 'number':   return {type: 'Number'};
    case 'string':   return {type: 'String'};
    case 'boolean':  return {type: 'Boolean'};
    case 'date':     return {type: 'Date'};
    case 'object':   return {type: 'Object'};
    case 'array':    return {type: 'Array'};
    case 'geopoint': return {type: 'GeoPoint'};
    case 'file':     return {type: 'File'};
  }
}

function mongoSchemaAPIResponseFields(schema) {
  fieldNames = Object.keys(schema).filter(key => key !== '_id');
  response = fieldNames.reduce((obj, fieldName) => {
    obj[fieldName] = mongoFieldTypeToSchemaAPIType(schema[fieldName])
    return obj;
  }, {});
  response.ACL = {type: 'ACL'};
  response.createdAt = {type: 'Date'};
  response.updatedAt = {type: 'Date'};
  response.objectId = {type: 'String'};
  return response;
}

function mongoSchemaToSchemaAPIResponse(schema) {
  return {
    className: schema._id,
    fields: mongoSchemaAPIResponseFields(schema),
  };
}

function getAllSchemas(req) {
  if (!req.auth.isMaster) {
    return Promise.resolve({
      status: 401,
      response: {error: 'master key not specified'},
    });
  }
  return req.config.database.collection('_SCHEMA')
  .then(coll => coll.find({}).toArray())
  .then(schemas => ({response: {
    results: schemas.map(mongoSchemaToSchemaAPIResponse)
  }}));
}

function getOneSchema(req) {
  if (!req.auth.isMaster) {
    return Promise.resolve({
      status: 401,
      response: {error: 'unauthorized'},
    });
  }
  return req.config.database.collection('_SCHEMA')
  .then(coll => coll.findOne({'_id': req.params.className}))
  .then(schema => ({response: mongoSchemaToSchemaAPIResponse(schema)}))
  .catch(() => ({
    status: 400,
    response: {
      code: 103,
      error: 'class ' + req.params.className + ' does not exist',
    }
  }));
}

function createSchema(req) {
  if (!req.auth.isMaster) {
    return Promise.resolve({
      status: 401,
      response: {error: 'master key not specified'},
    });
  }
  if (req.params.className && req.body.className) {
    if (req.params.className != req.body.className) {
      return Promise.resolve({
        status: 400,
        response: {
          code: Parse.Error.INVALID_CLASS_NAME,
          error: 'class name mismatch between ' + req.body.className + ' and ' + req.params.className,
        },
      });
    }
  }
  var className = req.params.className || req.body.className;
  if (!className) {
    return Promise.resolve({
      status: 400,
      response: {
        code: 135,
        error: 'POST ' + req.path + ' needs class name',
      },
    });
  }
  return req.config.database.collection('_SCHEMA')
  .then(coll => Schema.load(coll))
  .then(schema => schema.validateClassName(req.body.className))
  .catch(error => {
    console.log(arguments);
    return {response: error};
  })
  .then(newSchema => {
    for (key in newSchema.data) {
    }
    return {response: {}};
  });
}

router.route('GET', '/schemas', getAllSchemas);
router.route('GET', '/schemas/:className', getOneSchema);
router.route('POST', '/schemas', createSchema);
router.route('POST', '/schemas/:className', createSchema);

module.exports = router;