Add TFR warning banner for airspace restrictions

Fetches active Temporary Flight Restrictions from the FAA website,
filters by configured state (LOCATION_STATE env var), and displays
a red warning banner at the top of the dashboard when TFRs are present.
Data is cached for 30 minutes and degrades gracefully if the FAA is unreachable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/cmd/api/main.go

@@ -8,6 +8,8 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strings"
+	"sync"
 	"syscall"
 	"time"
 
@@ -78,6 +80,9 @@ func main() {
 		Logger: logger,
 	})
 
+	// Create FAA TFR client
+	faaClient := client.NewFAAClient()
+
 	// Create HTTP server
 	srv := server.New(cfg.Addr(), logger)
 
@@ -88,6 +93,7 @@ func main() {
 		config:        cfg,
 		weatherSvc:    weatherSvc,
 		assessmentSvc: assessmentSvc,
+		faaClient:     faaClient,
 	}
 	srv.SetupRoutes(handler)
 
@@ -194,6 +200,12 @@ type Handler struct {
 	config        *config.Config
 	weatherSvc    *service.WeatherService
 	assessmentSvc *service.AssessmentService
+	faaClient     *client.FAAClient
+
+	// TFR cache
+	tfrCache   []model.TFR
+	tfrCacheAt time.Time
+	tfrCacheMu sync.RWMutex
 }
 
 // Health handles health check requests
@@ -371,6 +383,63 @@ func (h *Handler) AssessConditions(w http.ResponseWriter, r *http.Request) {
 	server.RespondJSON(w, 200, response)
 }
 
+const tfrCacheTTL = 30 * time.Minute
+
+// GetTFRs handles airspace TFR requests
+func (h *Handler) GetTFRs(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	// Check cache
+	h.tfrCacheMu.RLock()
+	if h.tfrCache != nil && time.Since(h.tfrCacheAt) < tfrCacheTTL {
+		tfrs := h.tfrCache
+		h.tfrCacheMu.RUnlock()
+		server.RespondJSON(w, 200, map[string]interface{}{
+			"tfrs":         tfrs,
+			"count":        len(tfrs),
+			"last_checked": h.tfrCacheAt.UTC(),
+		})
+		return
+	}
+	h.tfrCacheMu.RUnlock()
+
+	// Fetch from FAA
+	allTfrs, err := h.faaClient.FetchTFRs(ctx)
+	if err != nil {
+		h.logger.Error("failed to fetch TFRs", "error", err)
+		// Return empty on error — don't show banner
+		server.RespondJSON(w, 200, map[string]interface{}{
+			"tfrs":         []model.TFR{},
+			"count":        0,
+			"last_checked": time.Now().UTC(),
+		})
+		return
+	}
+
+	// Filter by configured state
+	var filtered []model.TFR
+	for _, tfr := range allTfrs {
+		if strings.EqualFold(tfr.State, h.config.LocationState) {
+			filtered = append(filtered, tfr)
+		}
+	}
+	if filtered == nil {
+		filtered = []model.TFR{}
+	}
+
+	// Update cache
+	h.tfrCacheMu.Lock()
+	h.tfrCache = filtered
+	h.tfrCacheAt = time.Now()
+	h.tfrCacheMu.Unlock()
+
+	server.RespondJSON(w, 200, map[string]interface{}{
+		"tfrs":         filtered,
+		"count":        len(filtered),
+		"last_checked": time.Now().UTC(),
+	})
+}
+
 // WeatherFetcher runs background weather fetching
 type WeatherFetcher struct {
 	logger     *slog.Logger

backend/internal/client/faa.go

@@ -0,0 +1,136 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/scottyah/paragliding/internal/model"
+)
+
+const (
+	faaTFRListURL = "https://tfr.faa.gov/tfr2/list.jsp"
+	faaBaseURL    = "https://tfr.faa.gov"
+)
+
+// FAAClient fetches TFR data from the FAA website
+type FAAClient struct {
+	httpClient *http.Client
+}
+
+// NewFAAClient creates a new FAA TFR client
+func NewFAAClient() *FAAClient {
+	return &FAAClient{
+		httpClient: &http.Client{
+			Timeout: 15 * time.Second,
+		},
+	}
+}
+
+var (
+	anchorRe  = regexp.MustCompile(`(?is)<a\s+([^>]*)>(.*?)</a>`)
+	hrefRe    = regexp.MustCompile(`(?i)href="([^"]*)"`)
+	dateRe    = regexp.MustCompile(`^\d{2}/\d{2}/\d{4}$`)
+	htmlTagRe = regexp.MustCompile(`<[^>]*>`)
+)
+
+type anchor struct {
+	href string
+	text string
+}
+
+// FetchTFRs retrieves the list of active TFRs from the FAA website
+func (c *FAAClient) FetchTFRs(ctx context.Context) ([]model.TFR, error) {
+	req, err := http.NewRequestWithContext(ctx, "GET", faaTFRListURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("create request: %w", err)
+	}
+	req.Header.Set("User-Agent", "ParaglidingWeatherApp/1.0")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("fetch TFR list: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("TFR list returned status %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("read response: %w", err)
+	}
+
+	return parseTFRList(string(body)), nil
+}
+
+// extractAnchors finds all <a> tags in HTML and returns their href and text content
+func extractAnchors(html string) []anchor {
+	matches := anchorRe.FindAllStringSubmatch(html, -1)
+	anchors := make([]anchor, 0, len(matches))
+	for _, m := range matches {
+		text := htmlTagRe.ReplaceAllString(m[2], "")
+		text = strings.TrimSpace(text)
+		a := anchor{text: text}
+		if hrefMatch := hrefRe.FindStringSubmatch(m[1]); hrefMatch != nil {
+			a.href = hrefMatch[1]
+		}
+		anchors = append(anchors, a)
+	}
+	return anchors
+}
+
+// parseTFRList extracts TFR entries from the FAA list page HTML.
+// The page contains a table where each row has anchor tags for:
+// date, notam ID (with detail link), facility, state, type, description, zoom link
+func parseTFRList(html string) []model.TFR {
+	rows := strings.Split(html, "<tr")
+	var tfrs []model.TFR
+
+	for _, row := range rows {
+		anchors := extractAnchors(row)
+		if len(anchors) < 6 {
+			continue
+		}
+
+		// First anchor should contain a date (mm/dd/yyyy)
+		if !dateRe.MatchString(anchors[0].text) {
+			continue
+		}
+
+		// Build detail URL from the NOTAM anchor's href
+		detailURL := anchors[1].href
+		if detailURL != "" {
+			detailURL = strings.Replace(detailURL, "..", faaBaseURL, 1)
+			detailURL = strings.ReplaceAll(detailURL, "\n", "")
+			detailURL = strings.ReplaceAll(detailURL, "\r", "")
+		}
+
+		desc := anchors[5].text
+		desc = strings.ReplaceAll(desc, "\n", "")
+		desc = strings.ReplaceAll(desc, "\r", "")
+		// Collapse multiple spaces
+		for strings.Contains(desc, "  ") {
+			desc = strings.ReplaceAll(desc, "  ", " ")
+		}
+
+		tfr := model.TFR{
+			Date:        anchors[0].text,
+			NotamID:     anchors[1].text,
+			Facility:    anchors[2].text,
+			State:       anchors[3].text,
+			Type:        anchors[4].text,
+			Description: strings.TrimSpace(desc),
+			DetailURL:   detailURL,
+		}
+
+		tfrs = append(tfrs, tfr)
+	}
+
+	return tfrs
+}

backend/internal/config/config.go

@@ -20,6 +20,9 @@ type Config struct {
 	LocationLon  float64 `envconfig:"LOCATION_LON" default:"-122.4194"`
 	LocationName string  `envconfig:"LOCATION_NAME" default:"San Francisco"`
 
+	// Location state (for filtering TFRs)
+	LocationState string `envconfig:"LOCATION_STATE" default:"CA"`
+
 	// Timezone configuration
 	Timezone string `envconfig:"TIMEZONE" default:"America/Los_Angeles"`
 

backend/internal/model/tfr.go

@@ -0,0 +1,12 @@
+package model
+
+// TFR represents a Temporary Flight Restriction
+type TFR struct {
+	Date        string `json:"date"`
+	NotamID     string `json:"notam_id"`
+	Facility    string `json:"facility"`
+	State       string `json:"state"`
+	Type        string `json:"type"`
+	Description string `json:"description"`
+	DetailURL   string `json:"detail_url"`
+}

backend/internal/server/routes.go

@@ -14,6 +14,7 @@ type RouteHandler interface {
 	GetForecast(w http.ResponseWriter, r *http.Request)
 	GetHistorical(w http.ResponseWriter, r *http.Request)
 	AssessConditions(w http.ResponseWriter, r *http.Request)
+	GetTFRs(w http.ResponseWriter, r *http.Request)
 }
 
 // SetupRoutes configures all API routes
@@ -30,6 +31,11 @@ func (s *Server) SetupRoutes(handler RouteHandler) {
 			r.Get("/historical", handler.GetHistorical)
 			r.Post("/assess", handler.AssessConditions)
 		})
+
+		// Airspace routes
+		r.Route("/airspace", func(r chi.Router) {
+			r.Get("/tfrs", handler.GetTFRs)
+		})
 	})
 }
 

frontend/app/page.tsx

@@ -1,12 +1,13 @@
 'use client'
 
-import { useCurrentWeather, useForecast, useHistorical } from '@/hooks/use-weather'
+import { useCurrentWeather, useForecast, useHistorical, useTfrs } from '@/hooks/use-weather'
 import { AssessmentBadge } from '@/components/weather/assessment-badge'
 import { WindSpeedChart } from '@/components/weather/wind-speed-chart'
 import { WindDirectionChart } from '@/components/weather/wind-direction-chart'
 import { ThresholdControls } from '@/components/weather/threshold-controls'
 import { RefreshCountdown } from '@/components/weather/refresh-countdown'
 import { StaleDataBanner } from '@/components/weather/stale-data-banner'
+import { TfrBanner } from '@/components/weather/tfr-banner'
 import { Collapsible } from '@/components/ui/collapsible'
 import { useQueryClient } from '@tanstack/react-query'
 import { Loader2, AlertCircle } from 'lucide-react'
@@ -28,6 +29,9 @@ export default function DashboardPage() {
     error: forecastError,
   } = useForecast()
 
+  // Fetch TFR data
+  const { data: tfrData } = useTfrs()
+
   // Fetch yesterday's data for comparison
   const yesterday = format(subDays(new Date(), 1), 'yyyy-MM-dd')
   const {
@@ -111,6 +115,11 @@ export default function DashboardPage() {
           )}
         </div>
 
+        {/* TFR Warning */}
+        {tfrData && tfrData.tfrs.length > 0 && (
+          <TfrBanner tfrs={tfrData.tfrs} />
+        )}
+
         {/* Stale Data Warning */}
         <StaleDataBanner lastUpdated={currentWeather.last_updated} />
 

frontend/components/weather/index.ts

@@ -4,3 +4,4 @@ export { WindDirectionChart } from './wind-direction-chart'
 export { ThresholdControls } from './threshold-controls'
 export { RefreshCountdown } from './refresh-countdown'
 export { StaleDataBanner } from './stale-data-banner'
+export { TfrBanner } from './tfr-banner'

frontend/components/weather/tfr-banner.tsx

@@ -0,0 +1,57 @@
+'use client'
+
+import { AlertTriangle, ExternalLink } from 'lucide-react'
+import { cn } from '@/lib/utils'
+import type { TFR } from '@/lib/types'
+
+interface TfrBannerProps {
+  tfrs: TFR[]
+  className?: string
+}
+
+export function TfrBanner({ tfrs, className }: TfrBannerProps) {
+  if (!tfrs || tfrs.length === 0) return null
+
+  return (
+    <div
+      className={cn(
+        'flex items-start gap-3 rounded-lg border border-red-500 bg-red-50 dark:bg-red-950 p-4',
+        className
+      )}
+      role="alert"
+    >
+      <AlertTriangle className="h-5 w-5 text-red-600 dark:text-red-400 flex-shrink-0 mt-0.5" />
+      <div className="flex-1">
+        <p className="text-sm font-medium text-red-800 dark:text-red-200">
+          {tfrs.length} Active TFR{tfrs.length !== 1 ? 's' : ''} in Area
+        </p>
+        <ul className="mt-1 space-y-1">
+          {tfrs.map((tfr) => (
+            <li key={tfr.notam_id} className="text-xs text-red-700 dark:text-red-300">
+              <span className="font-medium">{tfr.type}</span>
+              {tfr.description && <> &mdash; {tfr.description}</>}
+              {tfr.detail_url && (
+                <a
+                  href={tfr.detail_url}
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="ml-1 inline-flex items-center gap-0.5 text-red-600 dark:text-red-400 hover:underline"
+                >
+                  Details <ExternalLink className="h-3 w-3" />
+                </a>
+              )}
+            </li>
+          ))}
+        </ul>
+        <a
+          href="https://tfr.faa.gov/tfr3/"
+          target="_blank"
+          rel="noopener noreferrer"
+          className="mt-2 inline-flex items-center gap-1 text-xs font-medium text-red-600 dark:text-red-400 hover:underline"
+        >
+          View all TFRs on FAA website <ExternalLink className="h-3 w-3" />
+        </a>
+      </div>
+    </div>
+  )
+}

frontend/hooks/use-weather.ts

@@ -1,8 +1,8 @@
 'use client'
 
 import { useQuery } from '@tanstack/react-query'
-import { getCurrentWeather, getForecast, getHistorical } from '@/lib/api'
-import type { CurrentWeatherResponse, ForecastResponse, HistoricalResponse } from '@/lib/types'
+import { getCurrentWeather, getForecast, getHistorical, getTfrs } from '@/lib/api'
+import type { CurrentWeatherResponse, ForecastResponse, HistoricalResponse, TFRResponse } from '@/lib/types'
 
 const STALE_TIME = 5 * 60 * 1000 // 5 minutes
 const REFETCH_INTERVAL = 5 * 60 * 1000 // 5 minutes
@@ -35,3 +35,15 @@ export function useHistorical(date: string, lat?: number, lon?: number) {
     enabled: !!date,
   })
 }
+
+const TFR_STALE_TIME = 30 * 60 * 1000 // 30 minutes
+const TFR_REFETCH_INTERVAL = 30 * 60 * 1000 // 30 minutes
+
+export function useTfrs() {
+  return useQuery<TFRResponse>({
+    queryKey: ['airspace', 'tfrs'],
+    queryFn: () => getTfrs(),
+    staleTime: TFR_STALE_TIME,
+    refetchInterval: TFR_REFETCH_INTERVAL,
+  })
+}

frontend/lib/api.ts

@@ -3,6 +3,7 @@ import {
   ForecastResponse,
   HistoricalResponse,
   AssessmentResponse,
+  TFRResponse,
   Thresholds,
   APIError,
 } from './types'
@@ -166,6 +167,13 @@ class APIClient {
     }
   }
 
+  /**
+   * Get active TFRs (Temporary Flight Restrictions) near the configured location
+   */
+  async getTfrs(): Promise<TFRResponse> {
+    return this.request<TFRResponse>('/airspace/tfrs')
+  }
+
   /**
    * Assess current conditions with custom thresholds
    */
@@ -200,6 +208,8 @@ export const getForecast = (lat?: number, lon?: number) =>
 export const getHistorical = (date: string, lat?: number, lon?: number) =>
   apiClient.getHistorical(date, lat, lon)
 
+export const getTfrs = () => apiClient.getTfrs()
+
 export const assessWithThresholds = (
   thresholds: Thresholds,
   lat?: number,

frontend/lib/types.ts

@@ -85,6 +85,24 @@ export interface AssessmentResponse {
   thresholds_used: Thresholds
 }
 
+// TFR (Temporary Flight Restriction) types
+
+export interface TFR {
+  date: string
+  notam_id: string
+  facility: string
+  state: string
+  type: string
+  description: string
+  detail_url: string
+}
+
+export interface TFRResponse {
+  tfrs: TFR[]
+  count: number
+  last_checked: string
+}
+
 // Error response type
 export interface APIError {
   error: string