import { DataMapper } from '@aws/dynamodb-data-mapper'
import { FactoryProvider } from '@nestjs/common/interfaces'
import { DynamoDB } from 'aws-sdk'

import { getModelForClass, getModelToken } from '../util'
import { DYNAMO_DB_CLIENT, DYNAMO_DB_DATA_MAPPER } from './dynamodb.constants'
import { DynamoDBClass, DynamoDBClassWithOptions } from './dynamodb.interfaces'

type ModelFactory = (dynamoDBClient: DynamoDB, mapper: DataMapper) => any

export function createDynamoDBProvider(
  models: DynamoDBClassWithOptions[],
): FactoryProvider[] {
  const buildProvider = (
    { name }: DynamoDBClass,
    modelFactory: ModelFactory,
  ) => ({
    provide: getModelToken(name),
    useFactory: modelFactory,
    inject: [DYNAMO_DB_CLIENT, DYNAMO_DB_DATA_MAPPER],
  })

  return models.reduce((providers, dynamoDBClassWithOptions) => {
    const modelFactory = (dynamoDBClient: DynamoDB, mapper: DataMapper) =>
      getModelForClass<InstanceType<DynamoDBClass>>(
        dynamoDBClassWithOptions.dynamoDBClass,
        dynamoDBClassWithOptions.tableOptions,
        dynamoDBClient,
        mapper,
      )

    const modelProvider = buildProvider(
      dynamoDBClassWithOptions.dynamoDBClass,
      modelFactory,
    )

    return [...providers, modelProvider]
  }, [])
}