provider "aws" {
  region = local.region
}

data "aws_availability_zones" "available" {}

locals {
  region = "us-east-1"
  name   = "ex-${basename(path.cwd)}"

  vpc_cidr = "10.0.0.0/16"
  azs      = slice(data.aws_availability_zones.available.names, 0, 3)

  container_name = "ecs-sample"
  container_port = 80

  tags = {
    Name       = local.name
    Example    = local.name
    Repository = "https://github.com/terraform-aws-modules/terraform-aws-ecs"
  }

  network_acls = {
    public_inbound = [
      {
        rule_number = 100
        rule_action = "allow"
        from_port   = 80
        to_port     = 80
        protocol    = "tcp"
        cidr_block  = "10.0.0.0/16"
      },
      {
        rule_number = 110
        rule_action = "allow"
        from_port   = 443
        to_port     = 443
        protocol    = "tcp"
        cidr_block  = "10.0.0.0/16"
      },
      {
        rule_number = 120
        rule_action = "allow"
        from_port   = 22
        to_port     = 22
        protocol    = "tcp"
        cidr_block  = "10.0.0.0/16"
      }
    ]
    public_outbound = [
      {
        rule_number = 100
        rule_action = "allow"
        from_port   = 80
        to_port     = 80
        protocol    = "tcp"
        cidr_block  = "10.0.0.0/16"
      },
      {
        rule_number = 110
        rule_action = "allow"
        from_port   = 443
        to_port     = 443
        protocol    = "tcp"
        cidr_block  = "10.0.0.0/16"
      }
    ]
  }
}

################################################################################
# Cluster
################################################################################

module "ecs_cluster" {
  source  = "terraform-aws-modules/ecs/aws"
  version = "5.2.2"

  cluster_name = local.name

  # Capacity provider - autoscaling groups
  default_capacity_provider_use_fargate = false
  create_task_exec_iam_role             = true
  task_exec_iam_role_name               = "ecs_monitor_task_exec_role"
  task_exec_iam_role_policies           = { "module.ecs_cluster.module.cluster.aws_iam_policy.task_exec[0]" : "arn:aws:iam::aws:policy/AmazonPrometheusRemoteWriteAccess" }
  autoscaling_capacity_providers = {
    # On-demand instances
    ex-1 = {
      auto_scaling_group_arn         = module.autoscaling["ex-1"].autoscaling_group_arn
      managed_termination_protection = "ENABLED"

      managed_scaling = {
        maximum_scaling_step_size = 5
        minimum_scaling_step_size = 1
        status                    = "ENABLED"
        target_capacity           = 60
      }

      default_capacity_provider_strategy = {
        weight = 60
        base   = 20
      }
    }
  }

  tags = local.tags
}


module "autoscaling" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 6.5"

  for_each = {
    # On-demand instances
    ex-1 = {
      instance_type              = "t3.large"
      use_mixed_instances_policy = false
      mixed_instances_policy     = {}
      user_data                  = <<-EOT
        #!/bin/bash
        cat <<'EOF' >> /etc/ecs/ecs.config
        ECS_CLUSTER=${local.name}
        ECS_LOGLEVEL=debug
        ECS_CONTAINER_INSTANCE_TAGS=${jsonencode(local.tags)}
        ECS_ENABLE_TASK_IAM_ROLE=true
        EOF
      EOT
    }
  }

  name = "${local.name}-${each.key}"

  image_id      = jsondecode(data.aws_ssm_parameter.ecs_optimized_ami.value)["image_id"]
  instance_type = each.value.instance_type

  security_groups                 = [module.autoscaling_sg.security_group_id]
  user_data                       = base64encode(each.value.user_data)
  ignore_desired_capacity_changes = true

  create_iam_instance_profile = true
  iam_role_name               = local.name
  iam_role_description        = "ECS role for ${local.name}"
  iam_role_policies = {
    AmazonEC2ContainerServiceforEC2Role = "arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceforEC2Role"
    AmazonSSMManagedInstanceCore        = "arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"
  }

  vpc_zone_identifier = module.vpc.private_subnets
  health_check_type   = "EC2"
  min_size            = 1
  max_size            = 5
  desired_capacity    = 2

  # https://github.com/hashicorp/terraform-provider-aws/issues/12582
  autoscaling_group_tags = {
    AmazonECSManaged = true
  }

  # Required for  managed_termination_protection = "ENABLED"
  protect_from_scale_in = true

  # Spot instances
  use_mixed_instances_policy = each.value.use_mixed_instances_policy
  mixed_instances_policy     = each.value.mixed_instances_policy

  metadata_options = {
    http_tokens = "required"
  }

  tags = local.tags
}

module "autoscaling_sg" {
  source  = "terraform-aws-modules/security-group/aws"
  version = "~> 5.0"

  name        = local.name
  description = "Autoscaling group security group"
  vpc_id      = module.vpc.vpc_id

  computed_ingress_with_source_security_group_id = [
    {
      rule                     = "http-80-tcp"
      source_security_group_id = module.alb_sg.security_group_id
    }
  ]
  number_of_computed_ingress_with_source_security_group_id = 1

  tags = local.tags
}

module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "~> 5.0"

  name = local.name
  cidr = local.vpc_cidr

  azs             = local.azs
  private_subnets = [for k, v in local.azs : cidrsubnet(local.vpc_cidr, 4, k)]
  public_subnets  = [for k, v in local.azs : cidrsubnet(local.vpc_cidr, 8, k + 48)]

  public_dedicated_network_acl  = true
  public_inbound_acl_rules      = local.network_acls["public_inbound"]
  public_outbound_acl_rules     = local.network_acls["public_outbound"]
  private_dedicated_network_acl = true
  private_inbound_acl_rules     = local.network_acls["public_inbound"]
  private_outbound_acl_rules    = local.network_acls["public_outbound"]

  manage_default_network_acl = true
  enable_nat_gateway         = true
  single_nat_gateway         = true

  tags = local.tags
}

data "aws_ssm_parameter" "ecs_optimized_ami" {
  name = "/aws/service/ecs/optimized-ami/amazon-linux-2/recommended"
}

module "alb_sg" {
  source  = "terraform-aws-modules/security-group/aws"
  version = "~> 5.0"

  name        = "${local.name}-service"
  description = "Service security group"
  vpc_id      = module.vpc.vpc_id

  ingress_rules       = ["http-80-tcp"]
  ingress_cidr_blocks = ["10.0.0.0/16"]
  egress_cidr_blocks  = module.vpc.private_subnets_cidr_blocks

  tags = local.tags
}

module "ecs_monitoring" {
  source               = "../../modules/ecs-monitoring"
  aws_ecs_cluster_name = module.ecs_cluster.cluster_name
  task_role_arn        = module.ecs_cluster.task_exec_iam_role_arn
  execution_role_arn   = module.ecs_cluster.task_exec_iam_role_arn

  depends_on = [
    module.ecs_cluster
  ]
}