# Status monitoring module - serves /status endpoints for shields.io badges
{
  config,
  lib,
  pkgs,
  ...
}:

with lib;

let
  cfg = config.atelier.services.status;

  # Script to check services and write status JSON
  statusScript = pkgs.writeShellScript "status-check" ''
    set -euo pipefail
    STATUS_DIR="/var/lib/status"
    mkdir -p "$STATUS_DIR"

    # Check each configured service
    ${concatStringsSep "\n" (
      map (svc: ''
        if systemctl is-active --quiet ${escapeShellArg svc}; then
          echo "ok" > "$STATUS_DIR/${svc}"
        else
          rm -f "$STATUS_DIR/${svc}"
        fi
      '') cfg.services
    )}

    # Always write host status (if this runs, host is up)
    echo "ok" > "$STATUS_DIR/${cfg.hostname}"

    # Check remote hosts via ping (Tailscale)
    ${concatStringsSep "\n" (
      map (host: ''
        if ${pkgs.iputils}/bin/ping -c 1 -W 2 ${escapeShellArg host} >/dev/null 2>&1; then
          echo "ok" > "$STATUS_DIR/${host}"
        else
          rm -f "$STATUS_DIR/${host}"
        fi
      '') cfg.remoteHosts
    )}

    # Build services JSON
    SERVICES_JSON="{"
    ${concatStringsSep "\n" (
      imap0 (i: svc: ''
        if systemctl is-active --quiet ${escapeShellArg svc}; then
          SERVICES_JSON="$SERVICES_JSON${if i > 0 then "," else ""}\"${svc}\":true"
        else
          SERVICES_JSON="$SERVICES_JSON${if i > 0 then "," else ""}\"${svc}\":false"
        fi
      '') cfg.services
    )}
    SERVICES_JSON="$SERVICES_JSON}"

    # Write full status JSON
    cat > "$STATUS_DIR/status.json" << EOF
    {
      "hostname": "${cfg.hostname}",
      "timestamp": "$(date -Iseconds)",
      "services": $SERVICES_JSON
    }
    EOF
  '';
in
{
  options.atelier.services.status = {
    enable = mkEnableOption "status monitoring endpoints";

    hostname = mkOption {
      type = types.str;
      description = "Hostname for this machine's status endpoint";
    };

    domain = mkOption {
      type = types.str;
      description = "Domain to serve status on";
    };

    services = mkOption {
      type = types.listOf types.str;
      default = [ ];
      description = "List of systemd services to monitor";
    };

    remoteHosts = mkOption {
      type = types.listOf types.str;
      default = [ ];
      description = "List of remote hosts to check via ping (e.g. Tailscale hosts)";
    };

    cloudflareCredentialsFile = mkOption {
      type = types.nullOr types.path;
      default = null;
      description = "Path to Cloudflare credentials file for DNS challenge";
    };
  };

  config = mkIf cfg.enable {
    # Timer to update status every minute
    systemd.services.status-check = {
      description = "Update status endpoints";
      serviceConfig = {
        Type = "oneshot";
        ExecStart = statusScript;
      };
    };

    systemd.timers.status-check = {
      description = "Run status check every minute";
      wantedBy = [ "timers.target" ];
      timerConfig = {
        OnBootSec = "30s";
        OnUnitActiveSec = "1min";
      };
    };

    # Ensure status directory exists
    systemd.tmpfiles.rules = [
      "d /var/lib/status 0755 root root -"
    ];

    # Caddy virtual host for status
    services.caddy.virtualHosts."${cfg.domain}".extraConfig = ''
      ${optionalString (cfg.cloudflareCredentialsFile != null) ''
        tls {
          dns cloudflare {env.CLOUDFLARE_API_TOKEN}
        }
      ''}

      # Individual host status (returns 200 if file exists)
      @status_host path /status/${cfg.hostname}
      handle @status_host {
        @online file /var/lib/status/${cfg.hostname}
        handle @online {
          respond "ok" 200
        }
        handle {
          respond "offline" 503
        }
      }

      # Service status endpoints
      ${concatStringsSep "\n" (
        map (svc: ''
          @status_${svc} path /status/service/${svc}
          handle @status_${svc} {
            @online_${svc} file /var/lib/status/${svc}
            handle @online_${svc} {
              respond "ok" 200
            }
            handle {
              respond "offline" 503
            }
          }
        '') cfg.services
      )}

      # Remote host status endpoints (Tailscale)
      ${concatStringsSep "\n" (
        map (host: ''
          @status_${host} path /status/${host}
          handle @status_${host} {
            @online_${host} file /var/lib/status/${host}
            handle @online_${host} {
              respond "ok" 200
            }
            handle {
              respond "offline" 503
            }
          }
        '') cfg.remoteHosts
      )}

      # Full status JSON
      @status_json path /status
      handle @status_json {
        root * /var/lib/status
        rewrite * /status.json
        file_server
        header Content-Type application/json
      }

      # Root redirect to status
      handle {
        respond "alastor.hogwarts.channel - see /status" 200
      }
    '';
  };
}