display last updated timestamp parsed from Excel filename

main.go

@@ -9,8 +9,11 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"path"
+	"regexp"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/xuri/excelize/v2"
 )
@@ -36,6 +39,11 @@ type Station struct {
 	Diesel     float64 `json:"diesel"`
 }
 
+type StationsResponse struct {
+	LastUpdated string    `json:"lastUpdated"`
+	Stations    []Station `json:"stations"`
+}
+
 func main() {
 	port := os.Getenv("PORT")
 	if port == "" {
@@ -61,9 +69,14 @@ func handleStations(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	resp := StationsResponse{
+		LastUpdated: parseTimestampFromURL(dataURL),
+		Stations:    stations,
+	}
+
 	w.Header().Set("Content-Type", "application/json")
 	w.Header().Set("Cache-Control", "public, max-age=3600")
-	json.NewEncoder(w).Encode(stations)
+	json.NewEncoder(w).Encode(resp)
 }
 
 func fetchAndParse() ([]Station, error) {
@@ -169,3 +182,27 @@ func parsePrice(s string) float64 {
 	}
 	return v
 }
+
+var tsRegex = regexp.MustCompile(`(\d{14})`)
+
+// parseTimestampFromURL extracts a YYYYMMDDHHmmSS timestamp from the URL
+// filename and returns it as a human-readable string.
+func parseTimestampFromURL(rawURL string) string {
+	base := path.Base(rawURL)
+	match := tsRegex.FindString(base)
+	if match == "" {
+		return ""
+	}
+
+	loc, err := time.LoadLocation("America/Montreal")
+	if err != nil {
+		loc = time.UTC
+	}
+
+	t, err := time.ParseInLocation("20060102150405", match, loc)
+	if err != nil {
+		return ""
+	}
+
+	return t.Format(time.RFC3339)
+}

static/index.html

@@ -64,6 +64,13 @@
     .legend-labels { display: flex; justify-content: space-between; font-size: 11px; color: #666; }
     #stats { margin-top: 8px; font-size: 11px; color: #888; }
 
+    #last-updated {
+      position: fixed; bottom: 8px; left: 56px;
+      background: white; padding: 5px 10px;
+      border-radius: 6px; box-shadow: 0 1px 4px rgba(0,0,0,0.15);
+      z-index: 2000; font-size: 11px; color: #666;
+    }
+
     /* Colored pin markers */
     .pin-icon {
       filter: drop-shadow(0 1px 3px rgba(0,0,0,0.35));
@@ -89,6 +96,8 @@
     <div id="visible-count"></div>
   </div>
 
+  <div id="last-updated"></div>
+
   <div id="legend">
     <h3>Prix régulier (¢/L)</h3>
     <div class="legend-gradient"></div>
@@ -126,10 +135,21 @@
 
     fetch('/api/stations')
       .then(r => r.json())
-      .then(stations => {
+      .then(data => {
         document.getElementById('loading').style.display = 'none';
+        const stations = data.stations;
         allStations = stations;
 
+        // Last updated
+        if (data.lastUpdated) {
+          const d = new Date(data.lastUpdated);
+          document.getElementById('last-updated').textContent =
+            'Dernière mise à jour: ' + d.toLocaleString('fr-CA', {
+              year: 'numeric', month: 'long', day: 'numeric',
+              hour: '2-digit', minute: '2-digit',
+            });
+        }
+
         const prices = stations.map(s => s.regular).filter(p => p > 0);
         minPrice = Math.min(...prices);
         maxPrice = Math.max(...prices);