terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 3.27"
    }
    random = {
      source  = "hashicorp/random"
      version = "3.1.0"
    }
  }

  required_version = ">= 0.14.9"
}

provider "aws" {
  profile = "default"
  region  = "us-east-1"
}

resource "random_string" "random" {
  length  = 8
  special = false
  lower   = true
  number  = true
  upper   = false
}

resource "aws_lambda_function" "lambda_s3_handler" {
  function_name    = "process-s3-new-objects"
  filename         = data.archive_file.lambda_zip_file.output_path
  source_code_hash = data.archive_file.lambda_zip_file.output_base64sha256
  handler          = "index.handler"
  role             = aws_iam_role.iam_for_lambda.arn
  runtime          = "nodejs14.x"
}

data "archive_file" "lambda_zip_file" {
  type        = "zip"
  source_file = "${path.module}/src/index.js"
  output_path = "${path.module}/lambda.zip"
}

resource "aws_iam_role" "iam_for_lambda" {
  name = "iam_for_lambda"

  assume_role_policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": "sts:AssumeRole",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Effect": "Allow",
      "Sid": ""
    }
  ]
}
EOF
  inline_policy {
    name   = "lambda_logs_policy"
    policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [
    {
        "Sid": "AllowLambdaFunctionToCreateLogs",
        "Action": [ 
            "logs:*" 
        ],
        "Effect": "Allow",
        "Resource": [ 
            "arn:aws:logs:*:*:*" 
        ]
    }
  ]
}
EOF
  }
}

resource "aws_lambda_permission" "allow_bucket_invoke_lambda" {
  statement_id  = "AllowExecutionFromS3Bucket"
  action        = "lambda:InvokeFunction"
  function_name = aws_lambda_function.lambda_s3_handler.arn
  principal     = "s3.amazonaws.com"
  source_arn    = aws_s3_bucket.my_bucket.arn
}

resource "aws_s3_bucket" "my_bucket" {
  bucket = "my-bucket-${random_string.random.result}"
}

resource "aws_s3_bucket_notification" "bucket_notification" {
  bucket = aws_s3_bucket.my_bucket.id

  lambda_function {
    lambda_function_arn = aws_lambda_function.lambda_s3_handler.arn
    events              = ["s3:ObjectCreated:*"]
  }

  depends_on = [aws_lambda_permission.allow_bucket_invoke_lambda]
}

output "name_of_bucket" {
  value       = aws_s3_bucket.my_bucket.bucket
  description = "The name of the bucket"
}