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

let
  cfg = config.eink.renderer;

  pythonEnv = pkgs.python3.withPackages (ps: with ps; [
    pillow
    numpy
    playwright
    requests
    # The Waveshare 12.48" lib is not packaged in nixpkgs; we vendor it
    # under renderer/waveshare/ and import it as a local module.
    spidev
    rpi-gpio
  ]);
in
{
  options.eink.renderer = {
    enable = lib.mkEnableOption "E-paper renderer (Playwright + Pillow + Waveshare driver)";

    dashboardUrl = lib.mkOption {
      type = lib.types.str;
      default = "http://127.0.0.1:3000";
    };

    refreshSeconds = lib.mkOption {
      type = lib.types.int;
      default = 300;
      description = "Seconds between full panel refreshes. Below 180 will wear the panel.";
    };

    panel = lib.mkOption {
      type = lib.types.enum [ "bw" "bwr" ];
      default = "bw";
      description = "Panel variant: bw = 12.48\" B/W, bwr = 12.48\" Module (B) B/W/Red.";
    };
  };

  config = lib.mkIf cfg.enable {
    # Playwright needs a Chromium and its system deps. Use the nixpkgs one
    # so the binary path is stable across rebuilds (not the npm-downloaded
    # browser, which won't find its sandbox libs on NixOS).
    systemd.services.eink-renderer = {
      description = "E-paper renderer loop";
      after = [ "eink-dashboard.service" "network-online.target" ];
      wants = [ "eink-dashboard.service" ];
      wantedBy = [ "multi-user.target" ];

      environment = {
        DASHBOARD_URL = cfg.dashboardUrl;
        REFRESH_SECONDS = toString cfg.refreshSeconds;
        PANEL_VARIANT = cfg.panel;
        PLAYWRIGHT_BROWSERS_PATH = "${pkgs.playwright-driver.browsers}";
        PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD = "1";
        PYTHONPATH = "${self}/renderer";
      };

      serviceConfig = {
        Type = "simple";
        ExecStart = "${pythonEnv}/bin/python ${self}/renderer/render.py";
        Restart = "always";
        RestartSec = "10s";

        # The Waveshare lib needs raw SPI + GPIO. Run as a dedicated user
        # in the spi/gpio groups rather than root.
        User = "eink";
        Group = "eink";
        SupplementaryGroups = [ "spi" "gpio" ];
      };
    };

    users.users.eink = {
      isSystemUser = true;
      group = "eink";
      extraGroups = [ "spi" "gpio" ];
    };
    users.groups.eink = {};
  };
}