# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0

# --- root/locals.tf ---

locals {
  # ---------- TRANSIT GATEWAY LOCAL VARIABLES ----------
  # Boolean to indicate if a new Transit Gateway needs to be created or not
  create_tgw         = try(var.transit_gateway_attributes.name, null) != null ? true : false
  transit_gateway_id = local.create_tgw ? aws_ec2_transit_gateway.tgw[0].id : var.transit_gateway_id

  # ---------- TRANSIT GATEWAY ROUTES LOCAL VARIABLE ----------
  # Transit Gateway routes configuration
  transit_gateway_routes = {
    # Inspection VPC - with our without Internet access
    inspection = {
      endpoints = local.inspection_configuration == "with_internet" ? var.network_definition.value : "0.0.0.0/0"
    }

    # Egress VPC
    egress = {
      public = var.network_definition.value
    }

    # Shared Services VPC - with or without "dns" subnets
    shared_services = local.shared_services_tgw_route[local.shared_services_configuration]

    # Ingress VPC
    ingress = {
      public = var.network_definition.value
    }

    # Hybrid DNS VPC
    hybrid_dns = {
      endpoints = "0.0.0.0/0"
    }
  }

  # Shared Services TGW routing configuration - with our without "dns" subnets
  shared_services_tgw_route = {
    with_dns = {
      endpoints = "0.0.0.0/0"
      dns       = "0.0.0.0/0"
    }
    without_dns = {
      endpoints = "0.0.0.0/0"
    }
  }

  # ---------- DEFAULT DEFINITION OF VPC FLOW LOGS (NO DESTINATION) ----------
  vpc_flow_logs_default = {
    log_destination_type = "none"
  }

  # ---------- AWS NETWORK FIREWALL LOCAL VARIABLES ----------
  # Boolean to indicate if a new AWS Network Firewall needs to be created or not
  create_anfw = try(var.central_vpcs.inspection.aws_network_firewall.name, "empty") != "empty" ? true : false
  # List of network CIDR blocks to apply in Network Firewall's routing configuration
  network_cidr_list = local.network_pl ? [for entry in data.aws_ec2_managed_prefix_list.data_network_prefix_list[0].entries : entry.cidr] : [var.network_definition.value]
  # Routing configuration (depending the Inspection VPC configuration)
  anfw_routing_configuration = {
    with_internet = {
      centralized_inspection_with_egress = {
        tgw_subnet_route_tables    = try({ for k, v in module.central_vpcs["inspection"].rt_attributes_by_type_by_az.transit_gateway : k => v.id }, {})
        public_subnet_route_tables = try({ for k, v in module.central_vpcs["inspection"].rt_attributes_by_type_by_az.public : k => v.id }, {})
        network_cidr_blocks        = local.network_cidr_list
      }
    }
    without_internet = {
      centralized_inspection_without_egress = {
        tgw_subnet_route_tables = try({ for k, v in module.central_vpcs["inspection"].rt_attributes_by_type_by_az.transit_gateway : k => v.id }, {})
      }
    }
  }

  # ---------- SPOKE VPC LOCAL VARIABLES ----------
  # Default values for var.spoke_vpcs
  number_vpcs     = try(var.spoke_vpcs.number_vpcs, 0)
  routing_domains = local.number_vpcs > 0 ? try(var.spoke_vpcs.routing_domains, ["spokes"]) : []
  # List of the VPC Information (from map)
  vpc_information = values(try(var.spoke_vpcs.vpc_information, []))

  # Boolean to indicate if the network's route definition is done with a managed prefix list (for the Transit Gateway Route Tables)
  network_pl = var.network_definition.type == "PREFIX_LIST" ? true : false

  # ---------- TRANSIT GATEWAY ROUTING LOCAL VARIABLES ----------
  # Inspection Flow - "all", "east-west", "north-south". By default: "all"
  inspection_flow = try(var.central_vpcs.inspection.inspection_flow, "all")

  # Spoke VPC TGW RT: 0.0.0.0/0 to Inspection VPC
  spoke_to_inspection_default = (contains(keys(var.central_vpcs), "inspection") && !contains(keys(var.central_vpcs), "egress")) || ((length(setintersection(keys(var.central_vpcs), ["inspection", "egress"])) == 2) && local.inspection_flow != "east-west")
  # Spoke VPC TGW RT: 0.0.0.0/0 to Egress VPC
  spoke_to_egress_default = (contains(keys(var.central_vpcs), "egress") && !contains(keys(var.central_vpcs), "inspection")) || ((length(setintersection(keys(var.central_vpcs), ["inspection", "egress"])) == 2) && local.inspection_flow == "east-west")
  # Spoke VPC TGW RT: Network's CIDR(s) to Inspection VPC
  spoke_to_inspection_network = ((length(setintersection(keys(var.central_vpcs), ["inspection", "egress"])) == 2) && local.inspection_flow == "east-west")
  # Inspection VPC TGW RT: 0.0.0.0/0 to Egress VPC && Egress VPC TGW RT: Network's CIDR(s) to Inspection VPC
  inspection_and_egress_routes = ((length(setintersection(keys(var.central_vpcs), ["inspection", "egress"])) == 2) && local.inspection_flow != "east-west")
  # Ingress VPC TGW RT: Network's CIDR(s) to Inspection VPC
  ingress_to_inspection_network = ((length(setintersection(keys(var.central_vpcs), ["inspection", "ingress"])) == 2) && local.inspection_flow != "east-west")

  # Spoke VPCs Propagate to Inspection TGW RT
  spoke_to_inspection_propagation = contains(keys(var.central_vpcs), "inspection")
  # Spoke VPCs Propagate to Egress TGW RT
  spoke_to_egress_propagation = (contains(keys(var.central_vpcs), "egress") && !contains(keys(var.central_vpcs), "inspection")) || ((length(setintersection(keys(var.central_vpcs), ["inspection", "egress"])) == 2) && local.inspection_flow == "east-west")
  # Spoke VPCs Propagate to Ingress TGW RT
  spoke_to_ingress_propagation = (contains(keys(var.central_vpcs), "ingress") && !contains(keys(var.central_vpcs), "inspection")) || ((length(setintersection(keys(var.central_vpcs), ["inspection", "ingress"])) == 2) && local.inspection_flow == "east-west")
  # Spoke VPCs Propagate to Spoke TGW RT
  spoke_to_spoke_propagation = !contains(keys(var.central_vpcs), "inspection") || (contains(keys(var.central_vpcs), "inspection") && local.inspection_flow == "north-south")

  # ---------- CENTRAL VPC LOCAL VARIABLES ----------
  # Inspection / Shared Services VPC configuration
  inspection_configuration      = contains(keys(try(var.central_vpcs.inspection.subnets, {})), "public") ? "with_internet" : "without_internet"
  shared_services_configuration = contains(keys(try(var.central_vpcs.shared_services.subnets, {})), "dns") ? "with_dns" : "without_dns"

  # Subnet configuration (all Central VPCs)
  subnet_config = {
    inspection      = local.inspection_subnet[local.inspection_configuration]
    egress          = local.egress_subnet
    shared_services = local.shared_services_subnet[local.shared_services_configuration]
    ingress         = local.ingress_subnet
    hybrid_dns      = local.hybrid_dns_subnet
  }

  # Inspection VPC Subnet configuration. Two options: with public subnets, and without public subnets
  inspection_subnet = {
    with_internet = {
      public = merge(
        {
          name_prefix               = try(var.central_vpcs.inspection.subnets.public.name_prefix, "inspection-vpc-public")
          nat_gateway_configuration = try(var.central_vpcs.inspection.subnets.public.nat_gateway_configuration, "all_azs")
          tags                      = try(var.central_vpcs.inspection.subnets.public.tags, {})
        },
        try(var.central_vpcs.inspection.subnets.public, {})
      )
      endpoints = merge(
        {
          name_prefix             = try(var.central_vpcs.inspection.subnets.endpoints.name_prefix, "inspection-vpc-endpoints")
          connect_to_public_natgw = try(var.central_vpcs.inspection.subnets.public.nat_gateway_configuration, "all_azs") != "none" ? true : false
          tags                    = try(var.central_vpcs.inspection.subnets.endpoints.tags, {})
        },
        try(var.central_vpcs.inspection.subnets.endpoints, {})
      )
      transit_gateway = merge(
        {
          name_prefix                                     = try(var.central_vpcs.inspection.subnets.transit_gateway.name_prefix, "inspection-vpc-tgw")
          transit_gateway_default_route_table_association = false
          transit_gateway_default_route_table_propagation = false
          transit_gateway_appliance_mode_support          = "enable"
          tags                                            = try(var.central_vpcs.inspection.subnets.transit_gateway.tags, {})
        },
        try(var.central_vpcs.inspection.subnets.transit_gateway, {})
      )
    }
    without_internet = {
      endpoints = merge(
        {
          name_prefix = try(var.central_vpcs.inspection.subnets.endoints.name_prefix, "inspection-vpc-endpoints")
          tags        = try(var.central_vpcs.inspection.subnets.endpoints.tags, {})
        },
        try(var.central_vpcs.inspection.subnets.endpoints, {})
      )
      transit_gateway = merge(
        {
          name_prefix                                     = try(var.central_vpcs.inspection.subnets.transit_gateway.name_prefix, "inspection-vpc-tgw")
          transit_gateway_default_route_table_association = false
          transit_gateway_default_route_table_propagation = false
          transit_gateway_appliance_mode_support          = "enable"
          tags                                            = try(var.central_vpcs.inspection.subnets.transit_gateway.tags, {})
        },
        try(var.central_vpcs.inspection.subnets.transit_gateway, {})
      )
    }
  }

  # Egress VPC Subnet configuration.
  egress_subnet = {
    public = merge(
      {
        name_prefix               = try(var.central_vpcs.egress.subnets.public.name_prefix, "egress-vpc-public")
        nat_gateway_configuration = try(var.central_vpcs.egress.subnets.public.nat_gateway_configuration, "all_azs")
        tags                      = try(var.central_vpcs.egress.subnets.public.tags, {})
      },
      try(var.central_vpcs.egress.subnets.public, {})
    )
    transit_gateway = merge(
      {
        name_prefix                                     = try(var.central_vpcs.egress.subnets.transit_gateway.name_prefix, "egress-vpc-tgw")
        connect_to_public_natgw                         = try(var.central_vpcs.inspection.subnets.public.nat_gateway_configuration, "all_azs") != "none" ? true : false
        transit_gateway_default_route_table_association = false
        transit_gateway_default_route_table_propagation = false
        tags                                            = try(var.central_vpcs.egress.subnets.transit_gateway.tags, {})
      },
      try(var.central_vpcs.egress.subnets.transit_gateway, {})
    )
  }

  # Shared Services VPC Subnet configuration.
  shared_services_subnet = {
    with_dns = {
      endpoints = merge(
        {
          name_prefix = try(var.central_vpcs.shared_services.subnets.endpoints.name_prefix, "shared-services-vpc-endpoints")
          tags        = try(var.central_vpcs.shared_services.subnets.endpoints.tags, {})
        },
        try(var.central_vpcs.shared_services.subnets.endpoints, {})
      )
      dns = merge(
        {
          name_prefix = try(var.central_vpcs.shared_services.subnets.dns.name_prefix, "shared-services-vpc-dns")
          tags        = try(var.central_vpcs.shared_services.subnets.dns.tags, {})
        },
        try(var.central_vpcs.shared_services.subnets.dns, {})
      )
      transit_gateway = merge(
        {
          name_prefix                                     = try(var.central_vpcs.shared_services.subnets.transit_gateway.name_prefix, "shared-services-vpc-tgw")
          transit_gateway_default_route_table_association = false
          transit_gateway_default_route_table_propagation = false
          tags                                            = try(var.central_vpcs.shared_services.subnets.transit_gateway.tags, {})
        },
        try(var.central_vpcs.shared_services.subnets.transit_gateway, {})
      )
    }
    without_dns = {
      endpoints = merge(
        {
          name_prefix = try(var.central_vpcs.shared_services.subnets.endpoints.name_prefix, "shared-services-vpc-endpoints")
          tags        = try(var.central_vpcs.shared_services.subnets.endpoints.tags, {})
        },
        try(var.central_vpcs.shared_services.subnets.endpoints, {})
      )
      transit_gateway = merge(
        {
          name_prefix                                     = try(var.central_vpcs.shared_services.subnets.transit_gateway.name_prefix, "shared-services-vpc-tgw")
          transit_gateway_default_route_table_association = false
          transit_gateway_default_route_table_propagation = false
          tags                                            = try(var.central_vpcs.shared_services.subnets.transit_gateway.tags, {})
        },
        try(var.central_vpcs.shared_services.subnets.transit_gateway, {})
      )
    }
  }

  # Ingress VPC Subnet configuration.
  ingress_subnet = {
    public = merge(
      {
        name_prefix = try(var.central_vpcs.ingress.subnets.public.name_prefix, "ingress-vpc-public")
        tags        = try(var.central_vpcs.ingress.subnets.public.tags, {})
      },
      try(var.central_vpcs.ingress.subnets.public, {})
    )
    transit_gateway = merge(
      {
        name_prefix                                     = try(var.central_vpcs.ingress.subnets.transit_gateway.name_prefix, "ingress-vpc-tgw")
        transit_gateway_default_route_table_association = false
        transit_gateway_default_route_table_propagation = false
        tags                                            = try(var.central_vpcs.ingress.subnets.transit_gateway.tags, {})
      },
      try(var.central_vpcs.ingress.subnets.transit_gateway, {})
    )
  }

  # Hybrid DNS Subnet configuration.
  hybrid_dns_subnet = {
    endpoints = merge(
      {
        name_prefix = try(var.central_vpcs.hybrid_dns.subnets.endpoints.name_prefix, "hybrid-dns-endpoint")
        tags        = try(var.central_vpcs.hybrid_dns.subnets.endpoints.tags, {})
      },
      try(var.central_vpcs.hybrid_dns.subnets.endpoints, {})
    )
    transit_gateway = merge(
      {
        name_prefix                                     = try(var.central_vpcs.hybrid_dns.subnets.transit_gateway.name_prefix, "hybrid-dns-tgw")
        transit_gateway_default_route_table_association = false
        transit_gateway_default_route_table_propagation = false
        tags                                            = try(var.central_vpcs.hybrid_dns.subnets.transit_gateway.tags, {})
      },
      try(var.central_vpcs.hybrid_dns.subnets.transit_gateway, {})
    )
  }
}