ARC decision letters: launch letter editor prefilled with ARC merge fields

- ARC detail header: Decision Letter button -> Forms & Letters (Letters tab) with
  association/owner/subject + projectTitle/decisionStatus/arcDate/decisionDate/
  propertyAddress/decisionNotes context
- LetterGenerator: resolves ARC tokens (before generic ones), new {{mailingAddress}}
  token, click-to-insert merge-field palette; templates via existing Save Template flow

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/forms/LetterGenerator.jsx

@@ -1,4 +1,5 @@
 import { useState, useEffect, useRef, useMemo, useCallback } from "react";
+import { useLocation } from "react-router-dom";
 import { formatMailingAddress } from '@/lib/formatMailingAddress';
 import { FileText, Download, Users, Search, Plus, Save, Eye, FolderOpen, Trash2, UserPlus, X, FolderUp, CalendarIcon, Building2 } from "lucide-react";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
@@ -333,8 +334,27 @@ const parseHtmlToSegments = (html) => {
   return blocks;
 };
 
+// Merge fields available in the letter body. ARC-scoped tokens resolve to the
+// application the editor was launched from (ARC page → "Decision Letter");
+// elsewhere they resolve to blank, so templates can be authored any time.
+const LETTER_VARIABLES = [
+  { token: "{{ownerName}}", label: "Owner name(s)" },
+  { token: "{{mailingAddress}}", label: "Mailing address" },
+  { token: "{{propertyAddress}}", label: "Property address" },
+  { token: "{{associationName}}", label: "Association name" },
+  { token: "{{currentDate}}", label: "Letter date" },
+];
+const ARC_VARIABLES = [
+  { token: "{{projectTitle}}", label: "Project title" },
+  { token: "{{decisionStatus}}", label: "Decision status" },
+  { token: "{{arcDate}}", label: "ARC date (submitted)" },
+  { token: "{{decisionDate}}", label: "Decision date" },
+  { token: "{{decisionNotes}}", label: "Decision notes" },
+];
+
 export default function LetterGenerator() {
   const { toast } = useToast();
+  const location = useLocation();
   const quillRef = useRef(null);
   const [associations, setAssociations] = useState([]);
   const [selectedAssociation, setSelectedAssociation] = useState("");
@@ -351,6 +371,9 @@ export default function LetterGenerator() {
   // Custom variables for the association
   const [customVars, setCustomVars] = useState([]);
 
+  // ARC decision-letter context (set when launched from the ARC page)
+  const [arcVars, setArcVars] = useState(null);
+
   // Manual recipients
   const [manualRecipients, setManualRecipients] = useState([]);
   const [showManualDialog, setShowManualDialog] = useState(false);
@@ -383,6 +406,16 @@ export default function LetterGenerator() {
   const handleLoadTemplate = async (id) => { const r = await templates.loadTemplate(id); if (r?.form_data) applyFormData(r.form_data); };
   const handleNewTemplate = () => { templates.newTemplate(); setSelectedAssociation(""); setSelectedOwners([]); setSubject(""); setCertifiedMail(""); setTemplateName(""); setEditorContent(""); setManualRecipients([]); setCurrentLetterId(null); setLetterName(""); };
 
+  // Insert a {{token}} at the current cursor position in the editor
+  const insertVariable = useCallback((token) => {
+    const quill = quillRef.current?.getEditor();
+    if (!quill) return;
+    const range = quill.getSelection(true);
+    const index = range ? range.index : quill.getLength();
+    quill.insertText(index, token);
+    quill.setSelection(index + token.length);
+  }, []);
+
   // Insert page break handler
   const insertPageBreak = useCallback(() => {
     const quill = quillRef.current?.getEditor();
@@ -432,6 +465,18 @@ export default function LetterGenerator() {
     }
   }, [insertPageBreak]);
 
+  // Prefill from the ARC page ("Decision Letter" button): association, owner,
+  // subject, and the application's merge-field values.
+  useEffect(() => {
+    const ctx = location.state?.arcLetter;
+    if (!ctx) return;
+    if (ctx.associationId) setSelectedAssociation(ctx.associationId);
+    if (ctx.ownerId) setSelectedOwners([ctx.ownerId]);
+    if (ctx.subject) setSubject((prev) => prev || ctx.subject);
+    setArcVars(ctx.vars || null);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
   useEffect(() => {
     supabase.from("associations").select("id, name").eq("status", "active").order("name").then(({ data }) => {
       if (data) setAssociations(data);
@@ -798,13 +843,34 @@ export default function LetterGenerator() {
         });
       }
 
-      // Resolve variables in HTML before parsing
-      let resolvedHtml = (editorContent || "")
+      // Single-line mailing address so {{mailingAddress}} flows inside a sentence
+      const mailingAddressInline = (recipientAddr || "")
+        .split(/\n+/).map((l) => l.trim()).filter(Boolean).join(", ");
+
+      // Resolve variables in HTML before parsing. ARC decision-letter tokens
+      // resolve FIRST so {{propertyAddress}} means the ARC property (not the
+      // recipient's mailing address) when launched from an ARC application.
+      let resolvedHtml = editorContent || "";
+      if (arcVars) {
+        resolvedHtml = resolvedHtml
+          .replace(/\{\{projectTitle\}\}/gi, arcVars.projectTitle || "")
+          .replace(/\{\{decisionStatus\}\}/gi, arcVars.decisionStatus || "")
+          .replace(/\{\{arcDate\}\}/gi, arcVars.arcDate || "")
+          .replace(/\{\{decisionDate\}\}/gi, arcVars.decisionDate || "")
+          .replace(/\{\{decisionNotes\}\}/gi, arcVars.decisionNotes || "")
+          .replace(/\{\{propertyAddress\}\}/gi, arcVars.propertyAddress || "");
+      } else {
+        // Authored-anywhere templates: ARC tokens resolve to blank outside ARC mode
+        resolvedHtml = resolvedHtml
+          .replace(/\{\{(projectTitle|decisionStatus|arcDate|decisionDate|decisionNotes)\}\}/gi, "");
+      }
+      resolvedHtml = resolvedHtml
         .replace(/\{\{clientName\}\}/gi, association?.name || "")
         .replace(/\{\{AssociationName\}\}/gi, association?.name || "")
         .replace(/\{\{ownerName\}\}/gi, recipientName || "")
         .replace(/\{\{ownersNames\}\}/gi, recipientName || "")
         .replace(/\{\{Owners\}\}/gi, recipientName || "")
+        .replace(/\{\{mailingAddress\}\}/gi, mailingAddressInline)
         .replace(/\{\{propertyAddress\}\}/gi, recipientAddr || "")
         .replace(/\{\{currentDate\}\}/gi, dateStr)
         .replace(/\{\{Date\}\}/gi, dateStr)
@@ -1332,6 +1398,45 @@ export default function LetterGenerator() {
             />
           </div>
 
+          {/* Merge fields — click to insert at the cursor */}
+          <div className="rounded-md border border-border bg-muted/30 px-3 py-2">
+            <p className="text-[10px] font-semibold uppercase text-muted-foreground mb-1.5">Merge Fields</p>
+            <div className="flex flex-wrap gap-1">
+              {LETTER_VARIABLES.map((v) => (
+                <button
+                  key={v.token}
+                  type="button"
+                  onClick={() => insertVariable(v.token)}
+                  title={`Insert ${v.token}`}
+                  className="px-1.5 py-0.5 rounded border border-border bg-background font-mono text-[10px] text-primary hover:bg-primary/10 transition-colors"
+                >
+                  {v.label}
+                </button>
+              ))}
+            </div>
+            <p className="text-[10px] font-semibold uppercase text-muted-foreground mt-2 mb-1.5">
+              ARC Decision Fields
+              {arcVars?.projectTitle ? (
+                <span className="ml-1 normal-case font-normal text-primary">· loaded: {arcVars.projectTitle}</span>
+              ) : (
+                <span className="ml-1 normal-case font-normal">· filled when opened from an ARC application</span>
+              )}
+            </p>
+            <div className="flex flex-wrap gap-1">
+              {ARC_VARIABLES.map((v) => (
+                <button
+                  key={v.token}
+                  type="button"
+                  onClick={() => insertVariable(v.token)}
+                  title={`Insert ${v.token}`}
+                  className="px-1.5 py-0.5 rounded border border-border bg-background font-mono text-[10px] text-primary hover:bg-primary/10 transition-colors"
+                >
+                  {v.label}
+                </button>
+              ))}
+            </div>
+          </div>
+
           {/* QR Code hint */}
           <div className="rounded-md border border-border bg-muted/30 px-3 py-2">
             <p className="text-[10px] font-semibold uppercase text-muted-foreground mb-1">QR Code Variable</p>

src/pages/ARCApplicationsPage.tsx

@@ -19,7 +19,7 @@ import { useDropzone } from "react-dropzone";
 import {
   Plus, Search, Gavel, Filter, FileText, Calendar, Building2, User,
   Home, Clock, ChevronRight, CheckCircle2, XCircle, AlertCircle,
-  MessageSquare, Image, Paperclip, RefreshCw, Download, UploadCloud, X, File, Trash2,
+  MessageSquare, Image, Paperclip, RefreshCw, Download, UploadCloud, X, File, Trash2, Mail,
 } from "lucide-react";
 import {
   AlertDialog, AlertDialogAction, AlertDialogCancel, AlertDialogContent,
@@ -835,6 +835,7 @@ function ARCDetailPanel({
 }) {
   const st = getStatus(app.status);
   const StIcon = st.icon;
+  const navigate = useNavigate();
   const [decisionNotes, setDecisionNotes] = useState(app.decision_notes || "");
   const [activeSection, setActiveSection] = useState<"details" | "review" | "timeline">("details");
   const [voteRefreshKey, setVoteRefreshKey] = useState(0);
@@ -938,6 +939,38 @@ function ARCDetailPanel({
             <StIcon className="h-3 w-3" /> {st.label}
           </Badge>
           <div className="flex items-center gap-2">
+            <Button
+              size="sm"
+              variant="outline"
+              className="h-7 text-[11px] gap-1"
+              title="Open the letter editor prefilled with this application's owner and merge fields"
+              onClick={() => {
+                const decisionLabel =
+                  app.status === "approved" ? "Approved" :
+                  app.status === "denied" ? "Denied" :
+                  st.label;
+                const fmt = (d: string | null | undefined) => (d ? format(new Date(d), "MMMM d, yyyy") : "");
+                navigate("/dashboard/forms-letters?tab=letters", {
+                  state: {
+                    arcLetter: {
+                      associationId: app.association_id,
+                      ownerId: app.owner_id || null,
+                      subject: `ARC Application ${decisionLabel}: ${app.title || ""}`,
+                      vars: {
+                        projectTitle: app.title || "",
+                        decisionStatus: decisionLabel,
+                        arcDate: fmt(app.submitted_date || app.created_at),
+                        decisionDate: fmt(app.review_date),
+                        propertyAddress: app.units?.address || app.owners?.property_address || "",
+                        decisionNotes: app.decision_notes || "",
+                      },
+                    },
+                  },
+                });
+              }}
+            >
+              <Mail className="h-3 w-3" /> Decision Letter
+            </Button>
             <Button
               size="sm"
               variant="outline"