Latest Chapter correction: one numeric input, owner-gated (#149)

backend/internal/web/admin_series.go

@@ -3,6 +3,7 @@ package web
 import (
 	"fmt"
 	"log"
+	"math"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -172,6 +173,58 @@ func (h *Handler) adminSeriesPoll(w http.ResponseWriter, r *http.Request) {
 	h.render(w, http.StatusOK, "series-row", seriesRow(a, band, time.Now()))
 }
 
+// adminSeriesCorrectLatest is the Latest Chapter correction: the owner types
+// one number and the Series' Latest Chapter becomes it, stamped as a
+// Correction. The number must be a finite float greater than zero — a
+// non-numeric, zero or negative value answers 400 and never reaches the
+// store, because a bad value would become every Reader's problem. The press
+// answers with the freshly rendered meta fragment, so the figures describe
+// the state after the press. The owner gate is the route's, not this
+// handler's; the body is capped like the API path caps its bodies.
+func (h *Handler) adminSeriesCorrectLatest(w http.ResponseWriter, r *http.Request) {
+	site, seriesID, ok := strings.Cut(r.PathValue("key"), ":")
+	if !ok || site == "" || seriesID == "" {
+		http.Error(w, "bad series key", http.StatusBadRequest)
+		return
+	}
+	r.Body = http.MaxBytesReader(w, r.Body, 1<<16)
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "invalid form", http.StatusBadRequest)
+		return
+	}
+	num, err := strconv.ParseFloat(r.PostFormValue("chapter"), 64)
+	if err != nil || math.IsNaN(num) || math.IsInf(num, 0) || num <= 0 {
+		http.Error(w, "chapter must be a finite number greater than zero", http.StatusBadRequest)
+		return
+	}
+	if _, found, err := h.adminSeriesByKey(site, seriesID); err != nil {
+		log.Printf("series correction %s: %v", site+":"+seriesID, err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	} else if !found {
+		http.NotFound(w, r)
+		return
+	}
+	if err := h.store.CorrectLatestChapter(site, seriesID, num, time.Now().UnixMilli()); err != nil {
+		log.Printf("series correction %s: %v", site+":"+seriesID, err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	// Re-read after the write: the answer must describe the state after the
+	// press, so the marker reads "corrected just now".
+	a, found, err := h.adminSeriesByKey(site, seriesID)
+	if err != nil {
+		log.Printf("series correction %s: %v", site+":"+seriesID, err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	if !found {
+		http.NotFound(w, r)
+		return
+	}
+	h.render(w, http.StatusOK, "series-detail-meta", h.seriesDetailView(a))
+}
+
 // seriesListView assembles one Series list view from the request's query
 // string. An unknown filter value is the absent All case, never an error: the
 // select's options are not the only way this URL can be reached.