# Some instance variables
locals {
  ami_selection = "minion" # master, minion, ...
}

# Rather than pass in the aws security group, we just look it up. This will
# probably be useful other places, as well.
data "aws_security_group" "typical-host" {
  name   = "typical-host"
  vpc_id = var.vpc_id
}

# Use the default EBS key
data "aws_kms_key" "ebs-key" {
  key_id = "alias/ebs_root_encrypt_decrypt"
}

resource "aws_network_interface" "instance" {
  for_each        = toset(var.instance_count)
  subnet_id       = var.subnets[each.value - 1]
  security_groups = [data.aws_security_group.typical-host.id, aws_security_group.instance_security_group.id]
  description     = "${var.instance_name}-${each.value}"
  tags            = merge(local.standard_tags, var.tags, { Name = "${var.instance_name}-${each.value}" })
}

# resource "aws_eip" "instance" {
#   for_each = toset(var.instance_count)
#   vpc = true
#   tags = merge(local.standard_tags, var.tags, { Name = "${var.instance_name}-${each.value}" })
# }

# resource "aws_eip_association" "instance" {
#   for_each = toset(var.instance_count)
#   network_interface_id = aws_network_interface.instance[each.key].id
#   allocation_id = aws_eip.instance[each.key].id
# }

resource "aws_instance" "instance" {
  # TODO: Make instance count numeric. While Instance count is currently a list of strings so
  # that the names are nicely 1, 2, and 3, but this could also have been solved with a '+1'. A count
  # seems like it would be cleaner.
  for_each = toset(var.instance_count)
  #availability_zone = var.azs[count.index % 2]
  tenancy                              = "default"
  ebs_optimized                        = true
  disable_api_termination              = var.instance_termination_protection
  instance_initiated_shutdown_behavior = "stop"
  instance_type                        = var.environment == "prod" ? "t3a.medium" : "t3a.small"
  key_name                             = "msoc-build"
  monitoring                           = false # checkov:skip=CKV_AWS_126:Detailed monitoring not needed at this time
  iam_instance_profile                 = module.instance_profile.profile_id

  metadata_options {
    http_endpoint = "enabled"
    # checkov:skip=CKV_AWS_79:see tfsec explanation
    # tfsec:ignore:aws-ec2-enforce-http-token-imds Saltstack doesn't use s3 sources appropriately; see https://github.com/saltstack/salt/issues/60668
    http_tokens   = "optional"
  }

  ami = local.ami_map[local.ami_selection]
  # We need to ignore ebs_block_device changes, because if the AMI changes, so does the snapshot_id.
  # If they add a feature to block more specific changes (eg `ebs_block_devices[*].snapshot_id`), then
  # that could be removed.
  lifecycle { ignore_changes = [ami, key_name, user_data, ebs_block_device] }

  # These device definitions are optional, but added for clarity.
  root_block_device {
    volume_type = "gp2"
    #volume_size = "60"
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
  }

  ebs_block_device {
    # swap
    device_name           = "/dev/xvdm"
    volume_size           = 48
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
    # Snapshot IDs need to be grabbed from the ami, or it will replace every time. It's ugly.
    # This may prompt replacement when the AMI is updated.
    # See:
    #   https://github.com/hashicorp/terraform/issues/19958
    #   https://github.com/terraform-providers/terraform-provider-aws/issues/13118
    snapshot_id = local.block_device_mappings[local.ami_selection]["/dev/xvdm"].ebs.snapshot_id
  }
  ebs_block_device {
    # /home
    device_name = "/dev/xvdn"
    # volume_size = xx
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
    snapshot_id           = local.block_device_mappings[local.ami_selection]["/dev/xvdn"].ebs.snapshot_id

  }
  ebs_block_device {
    # /var
    device_name = "/dev/xvdo"
    # volume_size = xx
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
    snapshot_id           = local.block_device_mappings[local.ami_selection]["/dev/xvdo"].ebs.snapshot_id
  }
  ebs_block_device {
    # /var/tmp
    device_name = "/dev/xvdp"
    # volume_size = xx
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
    snapshot_id           = local.block_device_mappings[local.ami_selection]["/dev/xvdp"].ebs.snapshot_id
  }
  ebs_block_device {
    # /var/log
    device_name = "/dev/xvdq"
    # volume_size = xx
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
    snapshot_id           = local.block_device_mappings[local.ami_selection]["/dev/xvdq"].ebs.snapshot_id
  }
  ebs_block_device {
    # /var/log/audit
    device_name = "/dev/xvdr"
    # volume_size = xx
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
    snapshot_id           = local.block_device_mappings[local.ami_selection]["/dev/xvdr"].ebs.snapshot_id
  }
  ebs_block_device {
    # /tmp
    device_name = "/dev/xvds"
    # volume_size = xx
    delete_on_termination = true
    encrypted             = true
    kms_key_id            = data.aws_kms_key.ebs-key.arn
    snapshot_id           = local.block_device_mappings[local.ami_selection]["/dev/xvds"].ebs.snapshot_id
  }

  network_interface {
    device_index         = 0
    network_interface_id = aws_network_interface.instance[each.key].id
  }

  #TODO switch to dynamic tag
  user_data   = data.template_cloudinit_config.cloud_init_config[each.key].rendered
  tags        = merge(local.standard_tags, var.tags, { "Name" : length(var.instance_count) > 1 ? "${var.instance_name}-${each.value}" : var.instance_name })
  volume_tags = merge(local.standard_tags, var.tags, var.instance_tags[tonumber(each.key) - 1], { "Name" : length(var.instance_count) > 1 ? "${var.instance_name}-${each.value}" : var.instance_name })
}

module "private_dns_record" {
  for_each = toset(var.instance_count)
  source   = "../../submodules/dns/private_A_record"

  name            = "${var.instance_name}-${each.value}"
  ip_addresses    = [aws_instance.instance[each.key].private_ip]
  dns_info        = var.dns_info
  reverse_enabled = var.reverse_enabled

  providers = {
    aws.c2 = aws.c2
  }
}

# Render a multi-part cloud-init config making use of the part
# above, and other source files
data "template_cloudinit_config" "cloud_init_config" {
  for_each      = toset(var.instance_count)
  gzip          = true
  base64_encode = true

  # Main cloud-config configuration file.
  part {
    filename     = "init.cfg"
    content_type = "text/cloud-config"
    content = templatefile("${path.module}/cloud-init/cloud-init.tpl",
      {
        hostname            = "${var.instance_name}-${each.value}"
        fqdn                = "${var.instance_name}-${each.value}.${var.dns_info["private"]["zone"]}"
        environment         = var.environment
        salt_master         = local.salt_master
        proxy               = local.proxy
        aws_partition       = var.aws_partition
        aws_partition_alias = var.aws_partition_alias
        aws_region          = var.aws_region
      }
    )
  }

}

#----------------------------------------------------------------------------
# Vault Server Security Group
#----------------------------------------------------------------------------

resource "aws_security_group" "instance_security_group" {
  name        = "${var.instance_name}_security_group"
  description = "Security Group for ${var.instance_name}(s)"
  vpc_id      = var.vpc_id
  tags        = merge(local.standard_tags, var.tags)
}

#----------------------------------------------------------------------------
# INGRESS
#----------------------------------------------------------------------------
resource "aws_security_group_rule" "vault_server_from_alb" {
  type                     = "ingress"
  description              = "Allows the servers to receive traffic for troubleshooting"
  from_port                = 443
  to_port                  = 443
  protocol                 = "tcp"
  source_security_group_id = aws_security_group.vault_ALB_server.id
  security_group_id        = aws_security_group.instance_security_group.id
}


#----------------------------------------------------------------------------
# EGRESS
#----------------------------------------------------------------------------
resource "aws_security_group_rule" "https-out" {
  type              = "egress"
  description       = "For endpoints and troubleshooting"
  from_port         = 443
  to_port           = 443
  protocol          = "tcp"
  cidr_blocks       = ["10.0.0.0/8"]
  security_group_id = aws_security_group.instance_security_group.id
}

resource "aws_security_group_rule" "vault_server_to_alb" {
  type                     = "egress"
  description              = "Allow Vault to communicate via HTTPS w/ other members in cluster"
  from_port                = 443
  to_port                  = 443
  protocol                 = "tcp"
  source_security_group_id = aws_security_group.vault_ALB_server.id
  security_group_id        = aws_security_group.instance_security_group.id
}

#grab the dynamodb endpoint
data "aws_prefix_list" "private_dynamodb" {
  name = "com.amazonaws.*.dynamodb"
}

resource "aws_security_group_rule" "vault_server_egress_dynamodb" {
  type              = "egress"
  description       = "Vault HTTPS - Outbound to Dynamodb"
  from_port         = 443
  to_port           = 443
  protocol          = "tcp"
  security_group_id = aws_security_group.instance_security_group.id
  prefix_list_ids   = [data.aws_prefix_list.private_dynamodb.id]
}