"use client";
import { useEffect, useRef, useState } from "react";
import Link from "next/link";

type Phase = "idle" | "submitting" | "generating" | "review" | "ready" | "failed";

export default function CreateForm({ level: initialLevel, enabled }: { level: string; enabled: boolean }) {
  const [level, setLevel] = useState(initialLevel);
  const [subject, setSubject] = useState("");
  const [phase, setPhase] = useState<Phase>("idle");
  const [msg, setMsg] = useState("");
  const [slug, setSlug] = useState("");
  const poll = useRef<ReturnType<typeof setInterval> | undefined>(undefined);

  useEffect(() => () => clearInterval(poll.current), []);

  async function start(e: React.FormEvent) {
    e.preventDefault();
    setMsg("");
    setSlug("");
    setPhase("submitting");
    try {
      const res = await fetch("/api/create", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ level, subject }),
      });
      const data = await res.json();
      if (!res.ok) {
        setPhase("failed");
        setMsg(data.error || "Something went wrong.");
        return;
      }
      if (data.status === "needs_review") {
        setPhase("review");
        return;
      }
      setSlug(data.slug);
      setPhase("generating");
      watch(data.id, data.slug);
    } catch {
      setPhase("failed");
      setMsg("Couldn't reach the server.");
    }
  }

  function watch(id: number, baseSlug: string) {
    clearInterval(poll.current);
    poll.current = setInterval(async () => {
      try {
        const r = await fetch(`/api/create/${id}`);
        const d = await r.json();
        if (d.status === "ready") {
          clearInterval(poll.current);
          setSlug(baseSlug);
          setPhase("ready");
        } else if (d.status === "failed" || d.status === "blocked") {
          clearInterval(poll.current);
          setPhase("failed");
          setMsg(d.error || "The drawing couldn't be made. Try a different subject.");
        }
      } catch {
        /* keep polling */
      }
    }, 2500);
  }

  if (!enabled) {
    return (
      <div className="card" style={{ marginTop: 16 }}>
        <p className="muted" style={{ margin: 0 }}>
          The Create feature isn&apos;t turned on for this DrawIt instance yet. Ask your administrator to configure a
          drawing server (ComfyUI).
        </p>
      </div>
    );
  }

  const busy = phase === "submitting" || phase === "generating";

  return (
    <div style={{ marginTop: 16, maxWidth: 560 }}>
      <form onSubmit={start} className="card" style={{ display: "grid", gap: 12 }}>
        <label className="field">
          <span style={{ fontWeight: 700 }}>What do you want to draw?</span>
          <input
            value={subject}
            onChange={(e) => setSubject(e.target.value)}
            placeholder="e.g. Zebra"
            maxLength={30}
            disabled={busy}
            required
          />
        </label>
        <label className="field">
          <span style={{ fontWeight: 700 }}>Level</span>
          <select value={level} onChange={(e) => setLevel(e.target.value)} disabled={busy}>
            <option value="early-beginner">Early Beginner</option>
            <option value="beginner">Beginner</option>
          </select>
        </label>
        <button className="btn big" type="submit" disabled={busy || subject.trim().length < 2}>
          {busy ? "Drawing…" : "✨ Make my lesson"}
        </button>
      </form>

      {phase === "generating" && (
        <div className="card" style={{ marginTop: 12, textAlign: "center" }}>
          <p style={{ margin: 0 }}>🎨 Drawing your {subject || "picture"}… this can take a little while.</p>
          <p className="muted" style={{ marginTop: 6, fontSize: "0.9rem" }}>You can stay on this page.</p>
        </div>
      )}
      {phase === "review" && (
        <div className="card" style={{ marginTop: 12 }}>
          <p style={{ margin: 0 }}>📨 Thanks! &quot;{subject}&quot; was sent to a grown-up to approve. Check back soon.</p>
        </div>
      )}
      {phase === "ready" && (
        <div className="card" style={{ marginTop: 12, textAlign: "center" }}>
          <p style={{ marginTop: 0 }}>🎉 Your lesson is ready!</p>
          <Link className="btn big" href={`/learn/${level}/${slug}-trace`}>Start drawing</Link>
        </div>
      )}
      {phase === "failed" && (
        <div className="notice" style={{ marginTop: 12 }}>
          <p style={{ margin: 0 }}>{msg || "Something went wrong. Try a different subject."}</p>
        </div>
      )}
    </div>
  );
}