variable "domain" {
  type = string
  default = "fediversity.net"
}

variable "mastodon" {
  type = object({
    enable = bool
  })
  default = {
    enable = false
  }
}

variable "pixelfed" {
  type = object({
    enable = bool
  })
  default = {
    enable = false
  }
}

variable "peertube" {
  type = object({
    enable = bool
  })
  default = {
    enable = false
  }
}

variable "initialUser" {
  type = object({
    displayName = string
    username = string
    email = string
    # TODO: mark (nested) credentials as sensitive
    # https://discuss.hashicorp.com/t/is-it-possible-to-mark-an-attribute-of-an-object-as-sensitive/24649/2
    password = string
  })
  default = {
    displayName = "Testy McTestface"
    username = "test"
    email = "test@test.com"
    password = "testtest"
  }
}

variable "ssh_private_key_file" {
  type        = string
  description = "Path to private key used to connect to the target_host"
  default     = ""
}

variable "deploy_environment" {
  type        = map(string)
  description = "Extra environment variables to be set during deployment."
  default     = {}
}

locals {
  system = "x86_64-linux"
  pins = jsondecode(file("${path.module}/.npins.json"))
  peripheral_configs = {
    garage = "test01"
  }
  application_configs = {
    mastodon = {
      cfg = var.mastodon
      hostname = "test06"
    }
    pixelfed = {
      cfg = var.pixelfed
      hostname = "test04"
    }
    peertube = {
      cfg = var.peertube
      hostname = "test05"
    }
  }
  peripherals = { for name, inst in local.peripheral_configs : name => {
      hostname = inst
      cfg = {
        enable = anytrue([for _, app in local.application_configs: app.cfg.enable])
      }
    }
  }
  applications = { for name, inst in local.application_configs : name => merge(inst, {
      # depends_on = [for name in local.peripheral_configs : module.deploy[name]]
    })
  }
}

# FIXME settle for pwd when in /nix/store?
# FIXME calculate separately to reduce false positives
data "external" "hash" {
  program = ["sh", "-c", "echo '{\"hash\":\"$(nix-hash ..)\"}'"]
}

# merged instantiate/deploy to prevent 24+s instantiates when nothing changed.
# terraform-nixos separates these to only deploy if instantiate changed.
# FIXME find a better solution for this. current considerations were:
# - generic resources cannot have outputs, while we want info from the instantiation (unless built on host?).
# - `data` always runs, which is slow for deploy/instantiation.
resource "terraform_data" "nixos" {
  for_each = {for name, inst in merge(
    local.peripherals,
    local.applications,
  ) : name => inst if inst.cfg.enable}

  triggers_replace = [
    data.external.hash.result,
    var.deploy_environment,
    var.domain,
    var.initialUser,
    local.system,
    each.key,
    each.value,
  ]

  provisioner "local-exec" {
    working_dir = path.root
    environment = merge(var.deploy_environment, {
      NIX_PATH = join(":", [for name, path in local.pins : "${name}=${path}"]),
    })
    # TODO: refactor back to command="ignoreme" interpreter=concat([]) to protect sensitive data from error logs?
    # TODO: build on target?
    command = <<-EOF
      set -euo pipefail

      # INSTANTIATE
      command=(
        nix-instantiate
        --expr
        'let
          os = import <nixpkgs/nixos> {
            system = "${local.system}";
            configuration = {
              terraform = builtins.fromJSON "${replace(jsonencode({
                domain = var.domain
                hostname = each.value.hostname
                initialUser = var.initialUser
              }), "\"", "\\\"")}";
              imports = [
                ${path.root}/options.nix
                ${path.root}/shared.nix
                ${path.root}/${each.key}.nix
                # FIXME: get VM details from TF
                ${path.root}/../infra/test-machines/${each.value.hostname}
              ];
            };
          };
        in {
          substituters = builtins.concatStringsSep " " os.config.nix.settings.substituters;
          trusted_public_keys = builtins.concatStringsSep " " os.config.nix.settings.trusted-public-keys;
          drv_path = os.config.system.build.toplevel.drvPath;
          out_path = os.config.system.build.toplevel;
        }'
      )
      "$${command[@]}" -A out_path
      json="$("$${command[@]}" --eval --strict --json)"

      # DEPLOY
      declare substituters trusted_public_keys drv_path
      eval "export $(echo $json | jaq -r 'to_entries | map("\(.key)=\(.value)") | @sh')"
      host="root@${each.value.hostname}.abundos.eu" # FIXME: #24
      buildArgs=(
        --option extra-binary-caches https://cache.nixos.org/
        --option substituters $substituters
        --option trusted-public-keys $trusted_public_keys
      )
      sshOpts=(
        -o StrictHostKeyChecking=no
        -o BatchMode=yes
        -o "IdentityFile='${var.ssh_private_key_file}'"
      )
      outPath=$(nix-store --realize "$drv_path" "$${buildArgs[@]}")
      NIX_SSHOPTS="$${sshOpts[*]}" nix-copy-closure --to "$host" "$outPath" --gzip --use-substitutes
      ssh "$${sshOpts[@]}" "$host" "nix-env --profile /nix/var/nix/profiles/system --set $outPath; $outPath/bin/switch-to-configuration switch"
    EOF
  }
}