feat: add WinnerSelectionPayout with escrow signing flow

components/bounty/WinnerSelectionPayout.tsx

@@ -0,0 +1,127 @@
+
+"use client";
+import { useState } from "react";
+import { Button } from "@/components/ui/button";
+import { Card, CardContent, CardHeader, CardTitle, CardDescription } from "@/components/ui/card";
+import { Badge } from "@/components/ui/badge";
+import { Trophy, Loader2, CheckCircle, Hash } from "lucide-react";
+
+interface WinnerSlot {
+  position: number;
+  label: string;
+  amount: number;
+  submissionId?: string;
+  applicantAddress?: string;
+  applicantName?: string;
+}
+
+interface WinnerSelectionPayoutProps {
+  bountyId: string;
+  slots: WinnerSlot[];
+  escrowMode: "managed" | "external";
+  onSelectWinnersAndPay: (winners: { applicantAddress: string; position: number }[]) => Promise<{ txHash: string }>;
+}
+
+type Step = "review" | "confirm" | "paying" | "complete";
+
+export function WinnerSelectionPayout({ bountyId, slots, escrowMode, onSelectWinnersAndPay }: WinnerSelectionPayoutProps) {
+  const [step, setStep] = useState<Step>("review");
+  const [txHash, setTxHash] = useState("");
+  const [error, setError] = useState("");
+
+  const filled = slots.filter(s => s.applicantAddress);
+  const allFilled = filled.length === slots.length;
+  const totalPayout = slots.reduce((sum, s) => sum + s.amount, 0);
+
+  const handlePay = async () => {
+    setStep("paying");
+    setError("");
+    try {
+      const winners = filled.map(s => ({ applicantAddress: s.applicantAddress!, position: s.position }));
+      const result = await onSelectWinnersAndPay(winners);
+      setTxHash(result.txHash);
+      setStep("complete");
+    } catch (e: any) {
+      setError(e.message ?? "Payout failed");
+      setStep("confirm");
+    }
+  };
+
+  if (step === "complete") {
+    return (
+      <Card className="border-green-500">
+        <CardContent className="py-8 text-center space-y-3">
+          <CheckCircle className="mx-auto h-12 w-12 text-green-500" />
+          <p className="font-semibold text-lg">Bounty Completed!</p>
+          <p className="text-sm text-muted-foreground">Winners paid. Bounty is now COMPLETED.</p>
+          {txHash && (
+            <a href={}
+              target="_blank" rel="noopener noreferrer"
+              className="inline-flex items-center gap-1 text-xs text-primary hover:underline">
+              <Hash className="h-3 w-3" />{txHash.slice(0,16)}...
+            </a>
+          )}
+        </CardContent>
+      </Card>
+    );
+  }
+
+  return (
+    <div className="space-y-4">
+      <Card>
+        <CardHeader>
+          <CardTitle className="flex items-center gap-2">
+            <Trophy className="h-5 w-5 text-yellow-500" />Winner Selection
+          </CardTitle>
+          <CardDescription>
+            {escrowMode === "managed" ? "Payout signs server-side" : "Payout requires your wallet"}
+          </CardDescription>
+        </CardHeader>
+        <CardContent className="space-y-3">
+          {slots.map(slot => (
+            <div key={slot.position} className="flex items-center justify-between p-3 border rounded-md">
+              <div className="flex items-center gap-3">
+                <Badge variant={slot.position === 1 ? "default" : "secondary"}>
+                  {slot.label}
+                </Badge>
+                <span className="text-sm">
+                  {slot.applicantName ?? <span className="text-muted-foreground italic">Not selected</span>}
+                </span>
+              </div>
+              <span className="text-sm font-semibold">{slot.amount} USDC</span>
+            </div>
+          ))}
+          <div className="border-t pt-3 flex justify-between text-sm font-semibold">
+            <span>Total payout</span>
+            <span>{totalPayout} USDC</span>
+          </div>
+        </CardContent>
+      </Card>
+
+      {error && <p className="text-sm text-destructive">{error}</p>}
+
+      {step === "review" && (
+        <Button onClick={() => setStep("confirm")} disabled={!allFilled} className="w-full">
+          Review & Pay Winners
+        </Button>
+      )}
+      {step === "confirm" && (
+        <div className="space-y-2">
+          <p className="text-sm text-muted-foreground text-center">
+            This will pay {totalPayout} USDC on-chain and mark the bounty COMPLETED.
+          </p>
+          <div className="flex gap-2">
+            <Button variant="outline" onClick={() => setStep("review")} className="flex-1">Back</Button>
+            <Button onClick={handlePay} className="flex-1">Confirm &amp; Pay</Button>
+          </div>
+        </div>
+      )}
+      {step === "paying" && (
+        <Button disabled className="w-full">
+          <Loader2 className="mr-2 h-4 w-4 animate-spin" />Processing payout...
+        </Button>
+      )}
+    </div>
+  );
+}
+export default WinnerSelectionPayout;