"use client";

import { useRouter } from "next/navigation";
import { useState } from "react";
import { Button } from "@/components/ui/button";
import { Label } from "@/components/ui/label";
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";

type Target = { id: number | string; username?: string | null; displayName?: string | null };

export function ImpersonationControl({ users }: { users: Target[] }) {
  const router = useRouter();
  const [userId, setUserId] = useState("");
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);

  async function start() {
    if (!userId) return;
    setBusy(true);
    setError(null);
    try {
      const response = await fetch("/api/impersonation/start", {
        method: "POST",
        headers: { "content-type": "application/json" },
        body: JSON.stringify({ userId }),
      });
      const body = await response.json().catch(() => null);
      if (!response.ok) throw new Error(body?.error ?? "Unable to start impersonation.");
      router.push("/");
      router.refresh();
    } catch (e) {
      setError(e instanceof Error ? e.message : "Unable to start impersonation.");
    } finally {
      setBusy(false);
    }
  }

  return (
    <div className="max-w-xl rounded-xl border border-border bg-card p-6 shadow-sm">
      <h1 className="text-xl font-semibold">Impersonate a user</h1>
      <p className="mt-2 text-sm text-muted-foreground">All requests will use the selected user&apos;s identity and permissions until you return to your account.</p>
      <div className="mt-6 flex flex-col gap-2">
        <Label htmlFor="impersonation-user">User</Label>
        <Select value={userId} onValueChange={setUserId}>
          <SelectTrigger id="impersonation-user"><SelectValue placeholder="Select a user" /></SelectTrigger>
          <SelectContent>
            {users.map((user) => <SelectItem key={String(user.id)} value={String(user.id)}>{user.displayName || user.username || `User ${user.id}`} {user.username ? `(${user.username})` : ""}</SelectItem>)}
          </SelectContent>
        </Select>
      </div>
      {error && <p className="mt-3 text-sm text-destructive">{error}</p>}
      <Button className="mt-6" onClick={start} disabled={!userId || busy}>{busy ? "Starting..." : "Start impersonation"}</Button>
    </div>
  );
}