'use strict';

var Ajv = require('ajv');
var mutent = require('mutent');

function getAjvInstance (options) {
  if (options.ajv) {
    return options.ajv
  }
  return new Ajv({
    allErrors: process.env.NODE_ENV !== 'production',
    coerceTypes: true,
    removeAdditional: true,
    useDefaults: true,
    ...options.ajvOptions
  })
}

function mutentJsonSchema (options) {
  const ajv = getAjvInstance(options);

  const validate = ajv.compile(options.schema.valueOf());

  function hook (entity, ctx) {
    if (!validate(entity.valueOf())) {
      return Promise.reject(
        new mutent.MutentError(
          'EMUT_INVALID_ENTITY',
          'Current entity does not match the configured schema.',
          {
            adapter: mutent.getAdapterName(ctx.adapter),
            intent: ctx.intent,
            argument: ctx.argument,
            data: entity.valueOf(),
            errors: validate.errors
          }
        )
      )
    }
  }

  return {
    hooks: {
      onEntity: hook,
      beforeCreate: hook,
      beforeUpdate: hook
    }
  }
}

module.exports = mutentJsonSchema;