# NixOS module for phone-recorder server
# Add to your configuration.nix imports or use as a standalone module
#
# Usage in configuration.nix:
#   imports = [ ./phone-recorder.nix ];
#   services.phone-recorder.enable = true;

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

let
  cfg = config.services.phone-recorder;
in
{
  options.services.phone-recorder = {
    enable = lib.mkEnableOption "Phone Recorder server";

    port = lib.mkOption {
      type = lib.types.port;
      default = 8000;
      description = "Port for the API server";
    };

    dataDir = lib.mkOption {
      type = lib.types.path;
      default = "/var/lib/phone-recorder";
      description = "Directory for recordings and database";
    };

    user = lib.mkOption {
      type = lib.types.str;
      default = "phone-recorder";
      description = "User to run the service as";
    };

    domain = lib.mkOption {
      type = lib.types.str;
      default = "recordings.hallocks.xyz";
      description = "Domain for HTTPS access";
    };

    enableCaddy = lib.mkOption {
      type = lib.types.bool;
      default = true;
      description = "Enable Caddy reverse proxy with automatic HTTPS";
    };

    enableFail2ban = lib.mkOption {
      type = lib.types.bool;
      default = true;
      description = "Enable fail2ban protection";
    };

    sourceDir = lib.mkOption {
      type = lib.types.path;
      default = /home/thallock/phone-recorder;
      description = "Path to the server source code";
    };
  };

  config = lib.mkIf cfg.enable {
    # Create user and group
    users.users.${cfg.user} = {
      isSystemUser = true;
      group = cfg.user;
      home = cfg.dataDir;
      createHome = true;
    };
    users.groups.${cfg.user} = {};

    # Systemd service
    systemd.services.phone-recorder = {
      description = "Phone Recorder API Server";
      after = [ "network.target" ];
      wantedBy = [ "multi-user.target" ];

      environment = {
        HOST = "127.0.0.1";  # Only listen locally, Caddy handles external
        PORT = toString cfg.port;
        BASE_DIR = toString cfg.sourceDir;
        RECORDINGS_DIR = "${cfg.dataDir}/recordings";
        DATABASE_PATH = "${cfg.dataDir}/recordings.db";
      };

      serviceConfig = {
        Type = "simple";
        User = cfg.user;
        Group = cfg.user;
        WorkingDirectory = cfg.sourceDir;
        ExecStart = "${pkgs.uv}/bin/uv run python main.py";
        Restart = "always";
        RestartSec = 5;

        # Hardening
        NoNewPrivileges = true;
        ProtectSystem = "strict";
        ProtectHome = "read-only";
        PrivateTmp = true;
        ReadWritePaths = [ cfg.dataDir ];
      };

      preStart = ''
        mkdir -p ${cfg.dataDir}/recordings
        mkdir -p ${cfg.dataDir}/keys
      '';
    };

    # Caddy reverse proxy
    services.caddy = lib.mkIf cfg.enableCaddy {
      enable = true;
      virtualHosts = {
        "${cfg.domain}" = {
          extraConfig = ''
            # API endpoints
            handle /api/* {
              reverse_proxy localhost:${toString cfg.port}
            }
            handle /health {
              reverse_proxy localhost:${toString cfg.port}
            }

            # Static frontend (if you have one)
            handle {
              root * /var/www/recordings-viewer
              file_server
              try_files {path} /index.html
            }

            # Security headers
            header {
              X-Content-Type-Options nosniff
              X-Frame-Options DENY
              Referrer-Policy strict-origin-when-cross-origin
            }

            # Rate limiting for uploads
            @upload path /api/v1/recordings/upload
            handle @upload {
              rate_limit {remote.ip} 10r/m
              reverse_proxy localhost:${toString cfg.port}
            }

            # Logging
            log {
              output file /var/log/caddy/recordings.log
              format json
            }
          '';
        };
      };
    };

    # Open firewall
    networking.firewall.allowedTCPPorts = [ 80 443 ]
      ++ lib.optional (!cfg.enableCaddy) cfg.port;

    # Fail2ban
    services.fail2ban = lib.mkIf cfg.enableFail2ban {
      enable = true;
      maxretry = 5;
      bantime = "1h";

      jails = {
        caddy-auth = lib.mkIf cfg.enableCaddy ''
          enabled = true
          filter = caddy-auth
          logpath = /var/log/caddy/recordings.log
          maxretry = 5
          bantime = 3600
        '';
      };
    };

    # Fail2ban filter for Caddy
    environment.etc."fail2ban/filter.d/caddy-auth.conf" = lib.mkIf (cfg.enableFail2ban && cfg.enableCaddy) {
      text = ''
        [Definition]
        failregex = ^.*"remote_ip":"<HOST>".*"status":40[13].*$
        ignoreregex =
      '';
    };
  };
}