"use client";

import { useState, useTransition, useRef } from "react";
import { useRouter } from "next/navigation";
import Link from "next/link";
import { submitFeedback, setReviewing, approveWithoutFeedback } from "./actions";
import { AudioRecorder } from "@/components/curator/audio-recorder";

interface FileItem {
  name: string;
  url: string;
  size: number;
}

function formatSize(bytes: number) {
  if (bytes < 1024) return `${bytes} Б`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(0)} КБ`;
  return `${(bytes / 1024 / 1024).toFixed(1)} МБ`;
}

export function FeedbackForm({
  submissionId,
  currentStatus,
}: {
  submissionId: string;
  currentStatus: string;
}) {
  const [text, setText] = useState("");
  const [files, setFiles] = useState<FileItem[]>([]);
  const [audioUrl, setAudioUrl] = useState<string | null>(null);
  const [uploading, setUploading] = useState(false);
  const [pending, startTransition] = useTransition();
  const fileInputRef = useRef<HTMLInputElement>(null);
  const router = useRouter();

  async function handleFileChange(e: React.ChangeEvent<HTMLInputElement>) {
    const picked = Array.from(e.target.files ?? []);
    if (!picked.length) return;
    setUploading(true);
    const uploaded: FileItem[] = [];
    for (const f of picked) {
      const form = new FormData();
      form.append("file", f);
      const res = await fetch("/api/curator/upload", { method: "POST", body: form });
      const data = await res.json();
      if (data.url) uploaded.push({ name: data.name, url: data.url, size: data.size });
    }
    setFiles((prev) => [...prev, ...uploaded]);
    setUploading(false);
    if (fileInputRef.current) fileInputRef.current.value = "";
  }

  function handleAction(action: "approve" | "reject") {
    if (!text.trim()) return;
    startTransition(async () => {
      await submitFeedback(submissionId, {
        text: text.trim(),
        files,
        audioUrl,
        action,
      });
      router.push("/curator/homework");
    });
  }

  function handleReviewing() {
    startTransition(async () => {
      await setReviewing(submissionId);
    });
  }

  function handleApproveNoFeedback() {
    startTransition(async () => {
      await approveWithoutFeedback(submissionId);
      router.push("/curator/homework");
    });
  }

  const isWorking = pending || uploading;

  return (
    <div className="space-y-4">
      <p
        className="text-xs font-bold uppercase tracking-widest"
        style={{ color: "var(--muted-foreground)" }}
      >
        Ваш ответ
      </p>

      {/* Text */}
      <textarea
        value={text}
        onChange={(e) => setText(e.target.value)}
        placeholder="Напишите обратную связь студенту..."
        disabled={isWorking}
        style={{
          border: "2px solid var(--border)",
          background: "var(--background)",
          outline: "none",
          width: "100%",
          padding: "0.5rem 0.75rem",
          fontSize: "16px",
          fontFamily: "inherit",
          resize: "vertical",
          minHeight: "120px",
        }}
        onFocus={(e) => (e.currentTarget.style.borderColor = "var(--foreground)")}
        onBlur={(e) => (e.currentTarget.style.borderColor = "var(--border)")}
      />

      {/* File upload */}
      <div className="space-y-2">
        <div className="flex items-center gap-2">
          <label
            className="btn-aubade text-xs px-3 py-1.5 cursor-pointer"
            style={{ opacity: isWorking ? 0.5 : 1 }}
          >
            📎 Прикрепить файл
            <input
              ref={fileInputRef}
              type="file"
              multiple
              className="hidden"
              onChange={handleFileChange}
              disabled={isWorking}
            />
          </label>
          {uploading && (
            <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
              Загрузка...
            </span>
          )}
        </div>

        {files.length > 0 && (
          <div className="space-y-1">
            {files.map((f, i) => (
              <div
                key={f.url}
                className="flex items-center gap-2 px-3 py-1.5 text-xs"
                style={{ border: "1px solid var(--border)" }}
              >
                <span>📎</span>
                <span className="flex-1 truncate">{f.name}</span>
                <span style={{ color: "var(--muted-foreground)" }}>{formatSize(f.size)}</span>
                <button
                  type="button"
                  onClick={() => setFiles((prev) => prev.filter((_, j) => j !== i))}
                  style={{ color: "oklch(0.577 0.245 27.325)" }}
                >
                  ×
                </button>
              </div>
            ))}
          </div>
        )}
      </div>

      {/* Audio recorder */}
      <AudioRecorder value={audioUrl} onChange={setAudioUrl} />

      {/* Action buttons */}
      <div className="flex items-center gap-2 flex-wrap pt-1">
        <button
          type="button"
          onClick={() => handleAction("approve")}
          disabled={isWorking || !text.trim()}
          className="btn-aubade-accent px-4 py-2 text-sm"
          style={{ opacity: isWorking || !text.trim() ? 0.5 : 1 }}
        >
          {pending ? "Отправка..." : "Отправить ответ"}
        </button>

        <button
          type="button"
          onClick={handleApproveNoFeedback}
          disabled={isWorking}
          className="btn-aubade px-4 py-2 text-sm"
          style={{ opacity: isWorking ? 0.5 : 1 }}
          title="Засчитать ДЗ без письменного ответа"
        >
          Принять и отметить выполненным
        </button>

        {currentStatus !== "REVIEWING" && (
          <button
            type="button"
            onClick={handleReviewing}
            disabled={isWorking}
            className="px-4 py-2 text-sm"
            style={{
              border: "2px solid var(--border)",
              background: "oklch(0.9 0.08 80)",
              color: "oklch(0.4 0.1 80)",
              opacity: isWorking ? 0.5 : 1,
            }}
          >
            На рассмотрение
          </button>
        )}

        <button
          type="button"
          onClick={() => handleAction("reject")}
          disabled={isWorking || !text.trim()}
          className="px-4 py-2 text-sm"
          style={{
            border: "2px solid var(--border)",
            background: "oklch(0.9 0.06 27)",
            color: "oklch(0.45 0.2 27)",
            opacity: isWorking || !text.trim() ? 0.5 : 1,
          }}
        >
          Отклонить и отправить
        </button>

        <Link
          href="/curator/homework"
          className="px-4 py-2 text-sm"
          style={{ border: "2px solid var(--border)", color: "var(--muted-foreground)" }}
        >
          К списку ДЗ
        </Link>
      </div>
    </div>
  );
}