{ pkgs, config, lib, ... }:
{

  nix = {
    package = pkgs.nix;
    # SEE: https://github.com/NixOS/nix/issues/4119#issuecomment-1734738812
    settings.sandbox = "relaxed";
    extraOptions = ''
      experimental-features = nix-command flakes repl-flake
      extra-platforms = x86_64-darwin aarch64-darwin x86_64-linux
    '';
  };

  # Right now the documentation build is broken.
  # TODO(jwall): Add this back when they work again.
  documentation.enable = false;

  # I'm not a zealot about this one.
  nixpkgs.config.allowUnfree = true;

  nixpkgs.overlays = [
   (self: super: {
     neovim = super.neovim.override {
       viAlias = true;
       vimAlias = true;
     };
   })
  ];

  # TODO(zaphar): Move this to a module.
  launchd.user.agents.ipfs = {
    serviceConfig = {
      ProgramArguments = [
        "${pkgs.kubo}/bin/ipfs"
        "daemon"
        "--init"
      ];
      KeepAlive = true;
      RunAtLoad = true;
    };
  };

  services.durnitisp.enable = true;
  services.node-exporter.enable = true;
  services.prometheus.enable = true;
  services.heracles.enable = true;
  services.heracles.settings = [
        {
            title = "Metrics";
            span = {
                end = "now";
                duration = "1d";
                step_duration = "5min";
            };
            graphs = [
                {
                    title = "CPU and Mem Used";
                    query_type = "Range";
                    yaxes = [
                        {
                            anchor = "y";
                            tickformat = "~%";
                        }
                    ];
                    plots = [
                        { # Memory Usage
                            source = "http://${config.services.prometheus.listen}";
                            query = ''
                              (node_memory_wired_bytes
                               + node_memory_compressed_bytes
                               + node_memory_active_bytes)
                              / node_memory_total_bytes
                            '';
                            config = {
                                name_format = "`\${labels.instance} - Memory`";
                                yaxis = "y";
                                fill = "tozeroy";
                            };
                        }
                        { # CPU plot
                            source = "http://${config.services.prometheus.listen}";
                            query = ''
                              sum by (job,instance, mode)(irate(node_cpu_seconds_total{mode!="idle"}[5m]))
                              / ignoring(mode) group_left
                              sum by (job,instance)(irate(node_cpu_seconds_total[5m]))
                            '';
                            config = {
                                name_format = "`\${labels.instance} - \${labels.mode}`";
                                axis = "y";
                            };
                        }
                    ];
                }
                {
                    title = "Network Quality";
                    query_type = "Range";
                    d3_tick_format = "~s";
                    yaxes = [
                        {
                            anchor = "y";
                            type = "log";
                        }
                    ];
                    plots = [
                        {
                            source = "http://${config.services.prometheus.listen}";
                            query = ''
                                stun_attempt_latency_ms
                            '';
                            config = {
                                name_format = "`UDP \${labels.domain} latency`";
                                yaxis = "y";
                            };
                        }
                        {
                            source = "http://${config.services.prometheus.listen}";
                            query = ''
                                ping_latency
                            '';
                            config = {
                                name_format = "`Ping \${labels.domain} latency`";
                                yaxis = "y";
                            };
                        }
                    ];
                }
                {
                    title = "Network Traffic Bytes";
                    query_type = "Range";
                    d3_tick_format = "~s";
                    yaxes = [
                        {
                            anchor = "y";
                            type = "log";
                        }
                    ];
                    plots = [
                        {
                            source = "http://${config.services.prometheus.listen}";
                            query = ''
                                irate(node_network_receive_bytes_total{device=~"(lo|en).*"}[5m])
                            '';
                            config = {
                                name_format = "`\${labels.device} Rx`";
                                yaxis = "y";
                            };
                        }
                        {
                            source = "http://${config.services.prometheus.listen}";
                            query = ''
                                irate(node_network_transmit_bytes_total{device=~"(lo|en).*"}[5m])
                            '';
                            config = {
                                name_format = "`\${labels.device} Tx`";
                                yaxis = "y";
                            };
                        }
                    ];
                }
            ];
        }
    ];

    services.victoria-logs.enable = true;
    services.vector.enable = true;
    services.vector.settings = {
        data_dir = "/var/lib/vector";
        sources = {
            prometheus = {
                type = "file";
                include = [
                    config.services.prometheus.stdoutPath
                    config.services.prometheus.stderrPath
                ];
            };
            heracles = {
                type = "file";
                include = [
                    config.services.heracles.stdoutPath
                    config.services.heracles.stderrPath
                ];
            };
            # TODO(zaphar): We should remap durnitisp output to strip the TTY control characters.
            durnitisp = {
                type = "file";
                include = [
                    config.services.durnitisp.stdoutPath
                    config.services.durnitisp.stderrPath
                ];
            };
            vector = {
                type = "file";
                include = [
                    config.services.vector.stdoutPath
                    config.services.vector.stderrPath
                ];
            };
        };
        transforms = {
            strip_tty = {
                type = "remap";
                inputs = [
                    "durnitisp"
                ];
                source = "_msg = strip_ansi_escape_codes(_msg)";
            };
        };
        sinks = {
            victoria = {
                type = "elasticsearch";
                mode = "bulk";
                endpoints = [
                    "http://${config.services.victoria-logs.listenAddr}/insert/elasticsearch/"
                ];
                inputs = [
                    "prometheus"
                    "heracles"
                    "durnitisp"
                    "vector"
                ];
                api_version = "v8";
                healthcheck.enabled = false;
                query = {
                    _msg_field = "message";
                    _time_field = "timestamp";
                    _stream_fields = "host,file";
                };
            };
        };
    };

  # TODO launchd.user.agents.prometheus;
  # Use a custom configuration.nix location.
  # $ darwin-rebuild switch -I darwin-config=$HOME/.config/nixpkgs/darwin/configuration.nix
  # environment.darwinConfig = "$HOME/.config/nixpkgs/darwin/configuration.nix";

  # Auto upgrade nix package and the daemon service.
  services.nix-daemon.enable = true;

  #services.spacebar.enable = true;
  #services.spacebar.package = "${pkgs.spacebar}";

  # Create /etc/bashrc that loads the nix-darwin environment.
  # programs.bash.enable = true;  # default shell on catalina
  # programs.fish.enable = true;

   system.defaults = {
     finder.AppleShowAllExtensions = true;
   };
   system.systemBuilderArgs = lib.mkIf (config.nix.settings.sandbox == "relaxed") {
      sandboxProfile = ''
        (allow file-read* file-write* process-exec mach-lookup (subpath "${builtins.storeDir}"))
      '';
    };
  # Used for backwards compatibility, please read the changelog before changing.
  # $ darwin-rebuild changelog
  system.stateVersion = 4;
}