website/module.nix

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

let
  cfg = config.services.jetpham-website;
  package = cfg.package;
  qaApi = cfg.apiPackage;
  apiListen = "${cfg.apiListenAddress}:${toString cfg.apiListenPort}";
  usingDefaultWebhookSecret = cfg.webhookSecretFile == null;
  webhookSecretPath =
    if usingDefaultWebhookSecret then config.age.secrets.webhook-secret.path else cfg.webhookSecretFile;
  usingDefaultTorSecretKey = cfg.tor.onionSecretKeyFile == null;
  usingDefaultTorPublicKey = cfg.tor.onionPublicKeyFile == null;
  usingDefaultTorHostname = cfg.tor.onionHostnameFile == null;
  torOnionSecretKeyPath =
    if usingDefaultTorSecretKey then
      config.age.secrets.tor-onion-secret-key.path
    else
      cfg.tor.onionSecretKeyFile;
  torOnionPublicKeyPath =
    if usingDefaultTorPublicKey then
      config.age.secrets.tor-onion-public-key.path
    else
      cfg.tor.onionPublicKeyFile;
  torOnionHostnamePath =
    if usingDefaultTorHostname then
      config.age.secrets.tor-onion-hostname.path
    else
      cfg.tor.onionHostnameFile;
  caddyCommonConfig = ''
    header Cross-Origin-Opener-Policy "same-origin"
    header Cross-Origin-Embedder-Policy "require-corp"

    handle /api/* {
      reverse_proxy ${apiListen}
    }

    handle /qa/rss.xml {
      reverse_proxy ${apiListen}
    }

    handle {
      root * ${package}
      try_files {path} /index.html
      file_server
    }

    ${cfg.caddy.extraConfig}
  '';
in
{
  options.services.jetpham-website = {
    enable = lib.mkEnableOption "Jet Pham's personal website";

    package = lib.mkOption {
      type = lib.types.package;
      default = self.packages.${pkgs.system}.default;
      defaultText = lib.literalExpression "self.packages.${pkgs.system}.default";
      description = "Static site package served by Caddy.";
    };

    apiPackage = lib.mkOption {
      type = lib.types.package;
      default = self.packages.${pkgs.system}.qa-api;
      defaultText = lib.literalExpression "self.packages.${pkgs.system}.qa-api";
      description = "Q&A API package run by systemd.";
    };

    domain = lib.mkOption {
      type = lib.types.str;
      default = "jetpham.com";
      description = "Domain to serve the website on.";
    };

    openFirewall = lib.mkOption {
      type = lib.types.bool;
      default = true;
      description = "Open HTTP and HTTPS ports when Caddy is enabled.";
    };

    apiListenAddress = lib.mkOption {
      type = lib.types.str;
      default = "127.0.0.1";
      description = "Address for the local Q&A API listener.";
    };

    apiListenPort = lib.mkOption {
      type = lib.types.port;
      default = 3003;
      description = "Port for the local Q&A API listener.";
    };

    caddy.enable = lib.mkOption {
      type = lib.types.bool;
      default = true;
      description = "Serve the static site and reverse proxy the API through Caddy.";
    };

    caddy.extraConfig = lib.mkOption {
      type = lib.types.lines;
      default = "";
      description = "Extra Caddy directives appended inside the virtual host block.";
    };

    tor = {
      enable = lib.mkEnableOption "Tor hidden service for the website";

      port = lib.mkOption {
        type = lib.types.port;
        default = 8888;
        description = "Local Caddy port exposed through the onion service.";
      };

      onionSecretKeyFile = lib.mkOption {
        type = lib.types.nullOr lib.types.path;
        default = null;
        description = "Path to the Tor hidden service secret key file.";
      };

      onionPublicKeyFile = lib.mkOption {
        type = lib.types.nullOr lib.types.path;
        default = null;
        description = "Path to the Tor hidden service public key file.";
      };

      onionHostnameFile = lib.mkOption {
        type = lib.types.nullOr lib.types.path;
        default = null;
        description = "Path to the Tor hidden service hostname file.";
      };
    };

    qaNotifyEmail = lib.mkOption {
      type = lib.types.str;
      default = "jet@extremist.software";
      description = "Email address to receive Q&A notifications.";
    };

    qaMailDomain = lib.mkOption {
      type = lib.types.str;
      default = "extremist.software";
      description = "Mail domain for Q&A reply addresses.";
    };

    qaReplyDomain = lib.mkOption {
      type = lib.types.str;
      default = "extremist.software";
      description = "Domain used in the static Q&A Reply-To address (`qa@...`). Use a dedicated subdomain and route only that mail into the webhook to avoid impacting your main inbox if the Q&A API fails.";
    };

    webhookSecretFile = lib.mkOption {
      type = lib.types.nullOr lib.types.path;
      default = null;
      description = "File containing the WEBHOOK_SECRET for MTA Hook authentication. Defaults to the module-managed agenix secret when left unset.";
    };
  };

  config = lib.mkIf cfg.enable {
    age.secrets.webhook-secret = lib.mkIf usingDefaultWebhookSecret {
      file = "${self}/secrets/webhook-secret.age";
      mode = "0400";
    };

    age.secrets.tor-onion-secret-key = lib.mkIf (cfg.tor.enable && usingDefaultTorSecretKey) {
      file = "${self}/secrets/tor-onion-secret-key.age";
      owner = "tor";
      group = "tor";
      mode = "0400";
    };

    age.secrets.tor-onion-public-key = lib.mkIf (cfg.tor.enable && usingDefaultTorPublicKey) {
      file = "${self}/secrets/tor-onion-public-key.age";
      owner = "tor";
      group = "tor";
      mode = "0444";
    };

    age.secrets.tor-onion-hostname = lib.mkIf (cfg.tor.enable && usingDefaultTorHostname) {
      file = "${self}/secrets/tor-onion-hostname.age";
      owner = "tor";
      group = "tor";
      mode = "0444";
    };

    assertions = [
      {
        assertion =
          !cfg.tor.enable
          || (torOnionSecretKeyPath != null && torOnionPublicKeyPath != null && torOnionHostnamePath != null);
        message = "services.jetpham-website.tor requires onionSecretKeyFile, onionPublicKeyFile, and onionHostnameFile.";
      }
    ];

    networking.firewall.allowedTCPPorts = lib.mkIf (cfg.caddy.enable && cfg.openFirewall) [
      80
      443
    ];

    services.caddy.enable = cfg.caddy.enable;

    services.tor = lib.mkIf cfg.tor.enable {
      enable = true;
      relay.onionServices.jetpham-website = {
        map = [
          {
            port = 80;
            target = {
              addr = "127.0.0.1";
              port = cfg.tor.port;
            };
          }
        ];
      };
    };

    systemd.services.tor-onion-keys = lib.mkIf cfg.tor.enable {
      description = "Copy Tor onion keys into place";
      after = lib.optional (
        usingDefaultTorSecretKey || usingDefaultTorPublicKey || usingDefaultTorHostname
      ) "agenix.service";
      before = [ "tor.service" ];
      wantedBy = [ "tor.service" ];
      serviceConfig.Type = "oneshot";
      script = ''
        dir="/var/lib/tor/onion/jetpham-website"
        mkdir -p "$dir"
        cp ${torOnionSecretKeyPath} "$dir/hs_ed25519_secret_key"
        cp ${torOnionPublicKeyPath} "$dir/hs_ed25519_public_key"
        cp ${torOnionHostnamePath} "$dir/hostname"
        chown -R tor:tor "$dir"
        chmod 700 "$dir"
        chmod 400 "$dir/hs_ed25519_secret_key"
        chmod 444 "$dir/hs_ed25519_public_key" "$dir/hostname"
      '';
    };

    systemd.services.jetpham-qa-api = {
      description = "Jet Pham Q&A API";
      after = [ "network-online.target" ] ++ lib.optional usingDefaultWebhookSecret "agenix.service";
      wants = [ "network-online.target" ] ++ lib.optional usingDefaultWebhookSecret "agenix.service";
      wantedBy = [ "multi-user.target" ];
      serviceConfig = {
        DynamicUser = true;
        StateDirectory = "jetpham-qa";
        WorkingDirectory = "/var/lib/jetpham-qa";
        Environment = [
          "QA_DB_PATH=/var/lib/jetpham-qa/qa.db"
          "QA_NOTIFY_EMAIL=${cfg.qaNotifyEmail}"
          "QA_MAIL_DOMAIN=${cfg.qaMailDomain}"
          "QA_REPLY_DOMAIN=${cfg.qaReplyDomain}"
        ];
        NoNewPrivileges = true;
        PrivateTmp = true;
        ProtectHome = true;
        ProtectSystem = "strict";
        ReadWritePaths = [ "/var/lib/jetpham-qa" ];
        Restart = "on-failure";
        RestartSec = 5;
        LoadCredential = "webhook-secret:${webhookSecretPath}";
      };
      script = ''
        if [ ! -s "$CREDENTIALS_DIRECTORY/webhook-secret" ]; then
          echo "WEBHOOK_SECRET credential is empty" >&2
          exit 1
        fi

        export WEBHOOK_SECRET="$(cat "$CREDENTIALS_DIRECTORY/webhook-secret")"
        exec ${qaApi}/bin/jetpham-qa-api
      '';
    };

    services.caddy.virtualHosts.${cfg.domain} = lib.mkIf cfg.caddy.enable {
      extraConfig = caddyCommonConfig;
    };

    services.caddy.virtualHosts."http://:${toString cfg.tor.port}" =
      lib.mkIf (cfg.caddy.enable && cfg.tor.enable)
        {
          extraConfig = ''
            bind 127.0.0.1
            ${caddyCommonConfig}
          '';
        };
  };
}