// frontend/src/shell/NewSessionDialog.tsx
import { useState } from "react";
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
} from "../components/ui/dialog";
import { Button } from "../components/ui/button";
import { createSession } from "../api/sessions";

interface Props {
  onCreated: (id: string) => void;
}

export function NewSessionDialog({ onCreated }: Props) {
  const [open, setOpen] = useState(false);
  const [question, setQuestion] = useState("");
  const [error, setError] = useState<string | null>(null);
  const [busy, setBusy] = useState(false);

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    setError(null);
    if (!question.trim()) {
      setError("The question cannot be empty.");
      return;
    }
    setBusy(true);
    try {
      const { id } = await createSession({ question: question.trim() });
      setOpen(false);
      setQuestion("");
      onCreated(id);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to create the session.");
    } finally {
      setBusy(false);
    }
  }

  return (
    <Dialog open={open} onOpenChange={setOpen}>
      <Button
        variant="default"
        size="sm"
        className="w-full"
        onClick={() => setOpen(true)}
      >
        New session
      </Button>
      <DialogContent showCloseButton={false}>
        <DialogHeader>
          <DialogTitle>New session</DialogTitle>
        </DialogHeader>
        <form onSubmit={handleSubmit} className="flex flex-col gap-3">
          <div>
            <label className="mb-1.5 block text-xs font-medium text-muted-foreground" htmlFor="nsd-question">
              Question
            </label>
            <textarea
              id="nsd-question"
              value={question}
              onChange={(e) => setQuestion(e.target.value)}
              rows={3}
              className="w-full resize-none rounded-lg border border-input bg-card px-3 py-2 text-sm shadow-xs outline-none transition-[border-color,box-shadow] placeholder:text-muted-foreground focus:border-primary/50 focus:ring-3 focus:ring-ring/15"
              placeholder="Enter your question…"
            />
          </div>

          {error && (
            <p className="text-xs text-destructive" role="alert">
              {error}
            </p>
          )}

          <div className="flex justify-end gap-2 pt-1">
            <Button
              type="button"
              variant="outline"
              size="sm"
              onClick={() => setOpen(false)}
            >
              Cancel
            </Button>
            <Button type="submit" size="sm" disabled={busy}>
              {busy ? "Creating…" : "Create"}
            </Button>
          </div>
        </form>
      </DialogContent>
    </Dialog>
  );
}