resource "aws_kinesis_firehose_delivery_stream" "cwl-s3-firehose-stream" {
  name        = var.stream-name
  destination = "extended_s3"

  extended_s3_configuration {
    role_arn            = aws_iam_role.firehose-stream-iam-role.arn
    bucket_arn          = var.dest-bucket-arn
    prefix              = trimprefix(var.dest-bucket-prefix, "/")
    error_output_prefix = "FirehoseErrors/"
    kms_key_arn         = var.dest-bucket-kmskey-arn
    cloudwatch_logging_options {
      enabled         = var.enable-firehose-errorlog
      log_group_name  = try(aws_cloudwatch_log_group.firehose-log[0].name, null)
      log_stream_name = "DestinationDelivery"
    }
  }
  server_side_encryption {
    enabled  = true
    key_type = "CUSTOMER_MANAGED_CMK"
    key_arn  = var.firehose-kmskey-arn
  }
}

resource "aws_cloudwatch_log_group" "firehose-log" {
  count             = var.enable-firehose-errorlog ? 1 : 0
  name              = "/aws/kinesisfirehose/${var.stream-name}"
  retention_in_days = 365
}

resource "aws_cloudwatch_log_subscription_filter" "cwl-sub-filter" {
  log_group_name  = var.source-cwlgroup-name
  name            = "stream-to-s3"
  role_arn        = aws_iam_role.cwlog-stream-role.arn
  filter_pattern  = ""
  destination_arn = aws_kinesis_firehose_delivery_stream.cwl-s3-firehose-stream.arn
}

resource "random_id" "rid" {
  byte_length = 4
}

resource "aws_iam_role" "firehose-stream-iam-role" {
  name        = "firehose-stream-role-${var.stream-name}-${random_id.rid.dec}"
  description = "Kinesis Firehose IAM role for streaming logs from CloudwatchLog to S3"
  assume_role_policy = jsonencode(
    {
      "Version" : "2012-10-17",
      "Statement" : [
        {
          "Sid" : "FirehoseStreaming",
          "Effect" : "Allow",
          "Principal" : {
            "Service" : "firehose.amazonaws.com"
          },
          "Action" : "sts:AssumeRole"
        }
      ]
    }
  )
}

resource "aws_iam_role_policy_attachment" "firehose-role-policy-attachment" {
  role       = aws_iam_role.firehose-stream-iam-role.name
  policy_arn = aws_iam_policy.firehose-role-policy.arn
}

resource "aws_iam_policy" "firehose-role-policy" {
  name        = "kinesis-firehose-log-stream-${var.stream-name}-${random_id.rid.dec}"
  description = "Policy for Kinesis Firehose streaming logs to s3"
  policy = jsonencode(
    {
      "Version" : "2012-10-17",
      "Statement" : [
        {
          "Effect" : "Allow",
          "Action" : [
            "s3:AbortMultipartUpload",
            "s3:GetBucketLocation",
            "s3:GetObject",
            "s3:ListBucket",
            "s3:ListBucketMultipartUploads",
            "s3:PutObject"
          ],
          "Resource" : [
            var.dest-bucket-arn,
            "${var.dest-bucket-arn}/*"
          ]
        },
        {
          "Effect" : "Allow",
          "Action" : [
            "kms:Decrypt",
            "kms:GenerateDataKey"
          ],
          "Resource" : [
            var.dest-bucket-kmskey-arn
          ]
        },
        {
          "Effect" : "Allow",
          "Action" : [
            "logs:PutLogEvents",
            "logs:PutLogEventsBatch",
            "logs:CreateLogStream"
          ],
          "Resource" : [
            "arn:aws:logs:*:*:log-group:/aws/kinesisfirehose/${var.stream-name}/*"
          ]
        }
      ]
    }
  )
}


resource "aws_iam_role" "cwlog-stream-role" {
  name        = "cloudwatchlog-stream-role-${var.stream-name}-${random_id.rid.dec}"
  description = "CloudwatchLog role for streaming to firehose"
  assume_role_policy = jsonencode(
    {
      "Version" : "2012-10-17",
      "Statement" : [
        {
          "Sid" : "CloudwatchLogStreaming",
          "Effect" : "Allow",
          "Principal" : {
            "Service" : "logs.${var.cwl-region}.amazonaws.com"
          },
          "Action" : "sts:AssumeRole"
        }
      ]
    }
  )
}


resource "aws_iam_role_policy_attachment" "cwlog-role-policy-attachment" {
  role       = aws_iam_role.cwlog-stream-role.name
  policy_arn = aws_iam_policy.cwlog-role-policy.arn
}

resource "aws_iam_policy" "cwlog-role-policy" {
  name        = "cloudwatchlog-stream-${var.stream-name}-${random_id.rid.dec}"
  description = "Policy for CloudWatch Logs streaming to Kinesis Firehose"
  policy = jsonencode(
    {
      "Version" : "2012-10-17",
      "Statement" : [
        {
          "Effect" : "Allow",
          "Action" : ["firehose:PutRecord"],
          "Resource" : [
            "arn:aws:firehose:${var.cwl-region}:${data.aws_caller_identity.this.account_id}:deliverystream/${var.stream-name}"
          ]
        }
      ]
    }
  )
}

data "aws_caller_identity" "this" {}