provider "aws" {
  region = local.region
}

provider "kubernetes" {
  host                   = module.eks.cluster_endpoint
  cluster_ca_certificate = base64decode(module.eks.cluster_certificate_authority_data)

  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command     = "aws"
    # This requires the awscli to be installed locally where Terraform is executed
    args = ["eks", "get-token", "--cluster-name", module.eks.cluster_name]
  }
}

provider "helm" {
  kubernetes {
    host                   = module.eks.cluster_endpoint
    cluster_ca_certificate = base64decode(module.eks.cluster_certificate_authority_data)

    exec {
      api_version = "client.authentication.k8s.io/v1beta1"
      command     = "aws"
      # This requires the awscli to be installed locally where Terraform is executed
      args = ["eks", "get-token", "--cluster-name", module.eks.cluster_name]
    }
  }
}

provider "kubectl" {
  apply_retry_count      = 5
  host                   = module.eks.cluster_endpoint
  cluster_ca_certificate = base64decode(module.eks.cluster_certificate_authority_data)
  load_config_file       = false

  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command     = "aws"
    # This requires the awscli to be installed locally where Terraform is executed
    args = ["eks", "get-token", "--cluster-name", module.eks.cluster_name]
  }
}

data "aws_availability_zones" "available" {}

locals {
  name   = basename(path.cwd)
  region = "us-west-2"

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


  tags = {
    Blueprint  = local.name
    GithubRepo = "github.com/aws-ia/terraform-aws-eks-blueprints"
  }
}

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

#tfsec:ignore:aws-eks-enable-control-plane-logging
module "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = "~> 19.13"

  cluster_name                   = local.name
  cluster_version                = "1.27"
  cluster_endpoint_public_access = true

  vpc_id     = module.vpc.vpc_id
  subnet_ids = module.vpc.private_subnets

  eks_managed_node_groups = {
    initial = {
      instance_types = ["m5.large"]

      min_size     = 1
      max_size     = 5
      desired_size = 2
    }
  }

  tags = local.tags
}

################################################################################
# EKS Blueprints Addons
################################################################################

module "eks_blueprints_addons" {
  source  = "aws-ia/eks-blueprints-addons/aws"
  version = "~> 1.0"

  cluster_name      = module.eks.cluster_name
  cluster_endpoint  = module.eks.cluster_endpoint
  cluster_version   = module.eks.cluster_version
  oidc_provider_arn = module.eks.oidc_provider_arn

  # EKS Add-on
  eks_addons = {
    coredns    = {}
    vpc-cni    = {}
    kube-proxy = {}
  }

  # Add-ons
  enable_cert_manager         = true
  enable_aws_privateca_issuer = true
  aws_privateca_issuer = {
    acmca_arn        = aws_acmpca_certificate_authority.this.arn
    namespace        = "aws-privateca-issuer"
    create_namespace = true
  }

  helm_releases = {
    cert-manager-csi-driver = {
      description   = "Cert Manager CSI Driver Add-on"
      chart         = "cert-manager-csi-driver"
      namespace     = "cert-manager"
      chart_version = "v0.5.0"
      repository    = "https://charts.jetstack.io"
    }
  }

  tags = local.tags
}

#-------------------------------
# Associates a certificate with an AWS Certificate Manager Private Certificate Authority (ACM PCA Certificate Authority).
# An ACM PCA Certificate Authority is unable to issue certificates until it has a certificate associated with it.
# A root level ACM PCA Certificate Authority is able to self-sign its own root certificate.
#-------------------------------

resource "aws_acmpca_certificate_authority" "this" {
  type = "ROOT"

  certificate_authority_configuration {
    key_algorithm     = "RSA_4096"
    signing_algorithm = "SHA512WITHRSA"

    subject {
      common_name = var.certificate_dns
    }
  }

  tags = local.tags
}

resource "aws_acmpca_certificate" "this" {
  certificate_authority_arn   = aws_acmpca_certificate_authority.this.arn
  certificate_signing_request = aws_acmpca_certificate_authority.this.certificate_signing_request
  signing_algorithm           = "SHA512WITHRSA"

  template_arn = "arn:aws:acm-pca:::template/RootCACertificate/V1"

  validity {
    type  = "YEARS"
    value = 10
  }
}

resource "aws_acmpca_certificate_authority_certificate" "this" {
  certificate_authority_arn = aws_acmpca_certificate_authority.this.arn

  certificate       = aws_acmpca_certificate.this.certificate
  certificate_chain = aws_acmpca_certificate.this.certificate_chain
}

#-------------------------------
#  This resource creates a CRD of AWSPCAClusterIssuer Kind, which then represents the ACM PCA in K8
#-------------------------------

# Using kubectl to workaround kubernetes provider issue https://github.com/hashicorp/terraform-provider-kubernetes/issues/1453
resource "kubectl_manifest" "cluster_pca_issuer" {
  yaml_body = yamlencode({
    apiVersion = "awspca.cert-manager.io/v1beta1"
    kind       = "AWSPCAClusterIssuer"

    metadata = {
      name = module.eks.cluster_name
    }

    spec = {
      arn = aws_acmpca_certificate_authority.this.arn
      region : local.region
    }
  })

  depends_on = [
    module.eks_blueprints_addons
  ]
}

#-------------------------------
# This resource creates a CRD of Certificate Kind, which then represents certificate issued from ACM PCA,
# mounted as K8 secret
#-------------------------------

# Using kubectl to workaround kubernetes provider issue https://github.com/hashicorp/terraform-provider-kubernetes/issues/1453
resource "kubectl_manifest" "pca_certificate" {
  yaml_body = yamlencode({
    apiVersion = "cert-manager.io/v1"
    kind       = "Certificate"

    metadata = {
      name      = var.certificate_name
      namespace = "default"
    }

    spec = {
      commonName = var.certificate_dns
      duration   = "2160h0m0s"
      issuerRef = {
        group = "awspca.cert-manager.io"
        kind  = "AWSPCAClusterIssuer"
        name : module.eks.cluster_name
      }
      renewBefore = "360h0m0s"
      secretName  = join("-", [var.certificate_name, "clusterissuer"]) # This is the name with which the K8 Secret will be available
      usages = [
        "server auth",
        "client auth"
      ]
      privateKey = {
        algorithm : "RSA"
        size : 2048
      }
    }
  })

  depends_on = [
    kubectl_manifest.cluster_pca_issuer,
  ]
}

################################################################################
# Supporting Resources
################################################################################

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)]

  enable_nat_gateway = true
  single_nat_gateway = true

  public_subnet_tags = {
    "kubernetes.io/role/elb" = 1
  }

  private_subnet_tags = {
    "kubernetes.io/role/internal-elb" = 1
  }

  tags = local.tags
}