resource "aws_iam_role" "sqs_to_elk" {
  path                 = "/service-role/"
  name                 = "sqs-to-elk"
  assume_role_policy   = data.aws_iam_policy_document.lambda_assume_role_policy.json
  max_session_duration = 3600
}

data "aws_iam_policy_document" "sqs_to_elk" {
  statement {
    resources = ["arn:aws:logs:us-east-1:${data.aws_caller_identity.current.account_id}:*"]
    actions   = ["logs:CreateLogGroup"]
  }

  statement {
    resources = ["arn:aws:logs:us-east-1:${data.aws_caller_identity.current.account_id}:log-group:/aws/lambda/*"]

    actions = [
      "logs:CreateLogStream",
      "logs:PutLogEvents",
    ]
  }

  statement {
    resources = ["*"]
    actions   = ["es:*"]
  }

  statement {
    resources = ["*"]
    actions   = ["sqs:*"]
  }

  statement {
    resources = [
      aws_secretsmanager_secret.mqtt.arn,
      aws_secretsmanager_secret.radiosondy.arn,
    ]

    actions = ["secretsmanager:GetSecretValue"]
  }
}

resource "aws_iam_role_policy" "sqs_to_elk" {
  name   = "sqs_to_elk"
  role   = aws_iam_role.sqs_to_elk.name
  policy = data.aws_iam_policy_document.sqs_to_elk.json
}

resource "aws_lambda_function" "sqs_to_elk" {
  function_name                  = "sqs-to-elk"
  handler                        = "sqs_to_elk.lambda_handler"
  s3_bucket                      = aws_s3_bucket_object.lambda.bucket
  s3_key                         = aws_s3_bucket_object.lambda.key
  source_code_hash               = data.archive_file.lambda.output_base64sha256
  publish                        = true
  memory_size                    = 128
  role                           = aws_iam_role.sqs_to_elk.arn
  runtime                        = "python3.9"
  timeout                        = 5
  reserved_concurrent_executions = 100
  environment {
    variables = {
      "ES" = aws_route53_record.es.fqdn
    }
  }
  tags = {
    Name = "sqs_to_elk"
  }
}

resource "aws_lambda_event_source_mapping" "sqs_to_elk" {
  event_source_arn                   = aws_sqs_queue.sqs_to_elk.arn
  function_name                      = aws_lambda_function.sqs_to_elk.arn
  batch_size                         = 20
  maximum_batching_window_in_seconds = 15
}

resource "aws_sns_topic_subscription" "sqs_to_elk" {
  topic_arn = aws_sns_topic.sonde_telem.arn
  protocol  = "sqs"
  endpoint  = aws_sqs_queue.sqs_to_elk.arn
}

resource "aws_sqs_queue" "sqs_to_elk" {
  name                      = "to-elk"
  receive_wait_time_seconds = 1
  message_retention_seconds = 1209600 # 14 days

  redrive_policy = jsonencode(
    {
      deadLetterTargetArn = "arn:aws:sqs:us-east-1:${data.aws_caller_identity.current.account_id}:to-elk-dlq"
      maxReceiveCount     = 100
    }
  )
  visibility_timeout_seconds = 10
}

data "aws_iam_policy_document" "sqs_to_elk_queue_policy" {
  statement {
    sid       = "__owner_statement"
    resources = ["${aws_sqs_queue.sqs_to_elk.arn}"]
    actions   = ["SQS:*"]

    principals {
      type        = "AWS"
      identifiers = ["arn:aws:iam::${data.aws_caller_identity.current.account_id}:root"]
    }
  }

  statement {
    sid       = "to-elk"
    resources = ["${aws_sqs_queue.sqs_to_elk.arn}"]
    actions   = ["SQS:SendMessage"]

    condition {
      test     = "ArnLike"
      variable = "aws:SourceArn"
      values   = ["${aws_sns_topic.sonde_telem.arn}"]
    }

    principals {
      type        = "AWS"
      identifiers = ["*"]
    }
  }
}

resource "aws_sqs_queue_policy" "sqs_to_elk" {
  queue_url = aws_sqs_queue.sqs_to_elk.id
  policy    = data.aws_iam_policy_document.sqs_to_elk_queue_policy.json
}