"use client";

import { useState, useTransition } from "react";
import { submitHomework } from "@/lib/actions/student-actions";
import { AudioRecorder } from "@/components/curator/audio-recorder";
import { linkify } from "@/lib/linkify";

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

interface Feedback {
  id: string;
  text: string;
  files?: HWFile[];
  audioUrl?: string | null;
  createdAt: Date;
  curator: { name: string };
}

interface Submission {
  id: string;
  text: string | null;
  files: HWFile[];
  audioUrl?: string | null;
  submittedAt: Date;
  status: string;
  feedbacks: Feedback[];
}

interface Props {
  homework: { id: string; description: string };
  submission: Submission | null;
  slug: string;
  lessonId: string;
  allowAudio?: boolean;
}

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 HomeworkSection({ homework, submission, slug, lessonId, allowAudio = false }: Props) {
  const [text, setText] = useState(submission?.text ?? "");
  const [files, setFiles] = useState<HWFile[]>(submission?.files ?? []);
  const [audioUrl, setAudioUrl] = useState<string | null>(submission?.audioUrl ?? null);
  const [uploading, setUploading] = useState(false);
  const [pending, startTransition] = useTransition();
  const [editing, setEditing] = useState(!submission);

  const isReviewed = submission && submission.feedbacks.length > 0;
  const isApproved = submission?.status === "APPROVED";
  // Финализировано: есть фидбек ИЛИ ДЗ принято кнопкой без ответа. Нельзя пересдавать.
  const isLocked = Boolean(isReviewed || isApproved);

  const inputStyle = {
    border: "2px solid var(--border)",
    background: "var(--background)",
    outline: "none",
    width: "100%",
    padding: "0.5rem 0.75rem",
    fontSize: "16px",
    fontFamily: "inherit",
    resize: "vertical" as const,
    minHeight: "140px",
  };

  async function handleFileUpload(e: React.ChangeEvent<HTMLInputElement>) {
    const file = e.target.files?.[0];
    if (!file) return;
    setUploading(true);
    const fd = new FormData();
    fd.append("file", file);
    const res = await fetch("/api/student/homework-upload", { method: "POST", body: fd });
    const data = await res.json();
    if (data.url) setFiles((prev) => [...prev, data]);
    setUploading(false);
    e.target.value = "";
  }

  function removeFile(url: string) {
    setFiles((prev) => prev.filter((f) => f.url !== url));
  }

  function handleSubmit() {
    startTransition(() => submitHomework(homework.id, slug, lessonId, text, files, audioUrl));
    setEditing(false);
  }

  return (
    <div className="space-y-4">
      {/* Assignment description */}
      <div className="px-4 py-3 text-sm whitespace-pre-wrap" style={{ border: "2px solid var(--border)", background: "var(--color-surface)" }}>
        {homework.description}
      </div>

      {/* Submitted & reviewed */}
      {isReviewed && (
        <div className="space-y-3">
          <div className="space-y-2">
            <p className="text-xs font-bold uppercase tracking-widest" style={{ color: "var(--muted-foreground)" }}>Ваш ответ</p>
            <div className="px-4 py-3 text-sm whitespace-pre-wrap opacity-70" style={{ border: "2px solid var(--border)" }}>
              {submission!.text ? linkify(submission!.text) : "—"}
            </div>
            {submission!.audioUrl && (
              <div className="px-4 py-2" style={{ border: "1px solid var(--border)" }}>
                <p className="text-xs mb-1" style={{ color: "var(--muted-foreground)" }}>Аудио-ответ:</p>
                <audio controls src={submission!.audioUrl} style={{ height: 32, width: "100%" }} />
              </div>
            )}
          </div>
          {submission!.feedbacks.map((fb) => {
            const fbFiles = fb.files ?? [];
            return (
              <div key={fb.id} className="px-4 py-3 space-y-2" style={{ border: "2px solid var(--foreground)", background: "var(--accent)" }}>
                <div className="flex items-center justify-between">
                  <p className="text-xs font-bold uppercase tracking-widest">Обратная связь</p>
                  <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
                    {fb.curator.name} · {new Date(fb.createdAt).toLocaleDateString("ru-RU")}
                  </span>
                </div>
                <p className="text-sm whitespace-pre-wrap">{linkify(fb.text)}</p>
                {fbFiles.length > 0 && (
                  <div className="space-y-1">
                    {fbFiles.map((f) => (
                      <a key={f.url} href={f.url} target="_blank" rel="noopener noreferrer"
                        className="flex items-center gap-2 text-xs underline">
                        <span>📎</span><span>{f.name}</span>
                        <span style={{ color: "var(--muted-foreground)" }}>{formatSize(f.size)}</span>
                      </a>
                    ))}
                  </div>
                )}
                {fb.audioUrl && (
                  <div>
                    <p className="text-xs mb-1" style={{ color: "var(--muted-foreground)" }}>Аудио от куратора:</p>
                    <audio controls src={fb.audioUrl} style={{ height: 32 }} />
                  </div>
                )}
              </div>
            );
          })}
        </div>
      )}

      {/* Принято без письменного ответа */}
      {isApproved && !isReviewed && submission && (
        <div className="space-y-3">
          <div className="flex items-center gap-2">
            <span className="text-xs px-2 py-0.5 font-bold uppercase tracking-widest" style={{ border: "2px solid var(--foreground)", background: "var(--accent)" }}>
              ДЗ принято ✓
            </span>
            <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
              Сдано {new Date(submission.submittedAt).toLocaleDateString("ru-RU")}
            </span>
          </div>
          {submission.text && (
            <div className="px-4 py-3 text-sm whitespace-pre-wrap opacity-70" style={{ border: "2px solid var(--border)" }}>
              {linkify(submission.text)}
            </div>
          )}
          {submission.audioUrl && (
            <div className="px-4 py-2" style={{ border: "1px solid var(--border)" }}>
              <p className="text-xs mb-1" style={{ color: "var(--muted-foreground)" }}>Аудио-ответ:</p>
              <audio controls src={submission.audioUrl} style={{ height: 32, width: "100%" }} />
            </div>
          )}
          {submission.files.length > 0 && (
            <div className="space-y-1">
              {submission.files.map((f) => (
                <a key={f.url} href={f.url} target="_blank" rel="noopener noreferrer"
                  className="flex items-center gap-2 px-3 py-2 text-xs" style={{ border: "2px solid var(--border)" }}>
                  <span>📎</span>
                  <span className="flex-1 underline">{f.name}</span>
                  <span style={{ color: "var(--muted-foreground)" }}>{formatSize(f.size)}</span>
                </a>
              ))}
            </div>
          )}
        </div>
      )}

      {/* Submitted, pending review */}
      {submission && !isLocked && !editing && (
        <div className="space-y-3">
          <div className="flex items-center justify-between">
            <div className="flex items-center gap-2">
              <span className="text-xs px-2 py-0.5 font-bold uppercase tracking-widest" style={{ border: "2px solid var(--border)", background: "var(--color-surface)", color: "var(--muted-foreground)" }}>
                На проверке
              </span>
              <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
                Сдано {new Date(submission.submittedAt).toLocaleDateString("ru-RU")}
              </span>
            </div>
            <button onClick={() => setEditing(true)} className="text-xs underline" style={{ color: "var(--muted-foreground)" }}>
              Изменить
            </button>
          </div>
          {submission.text && (
            <div className="px-4 py-3 text-sm whitespace-pre-wrap" style={{ border: "2px solid var(--border)" }}>
              {linkify(submission.text)}
            </div>
          )}
          {submission.audioUrl && (
            <div className="px-4 py-2" style={{ border: "1px solid var(--border)" }}>
              <p className="text-xs mb-1" style={{ color: "var(--muted-foreground)" }}>Аудио-ответ:</p>
              <audio controls src={submission.audioUrl} style={{ height: 32, width: "100%" }} />
            </div>
          )}
          {submission.files.length > 0 && (
            <div className="space-y-1">
              {submission.files.map((f) => (
                <a key={f.url} href={f.url} target="_blank" rel="noopener noreferrer"
                  className="flex items-center gap-2 px-3 py-2 text-xs"
                  style={{ border: "2px solid var(--border)" }}>
                  <span>📎</span>
                  <span className="flex-1 underline">{f.name}</span>
                  <span style={{ color: "var(--muted-foreground)" }}>{formatSize(f.size)}</span>
                </a>
              ))}
            </div>
          )}
        </div>
      )}

      {/* Form */}
      {editing && !isLocked && (
        <div className="space-y-3">
          <textarea
            value={text}
            onChange={(e) => setText(e.target.value)}
            style={inputStyle}
            placeholder="Напишите ваш ответ..."
            onFocus={(e) => (e.currentTarget.style.borderColor = "var(--foreground)")}
            onBlur={(e) => (e.currentTarget.style.borderColor = "var(--border)")}
          />

          {/* File list */}
          {files.length > 0 && (
            <div className="space-y-1">
              {files.map((f) => (
                <div key={f.url} className="flex items-center gap-2 px-3 py-2 text-xs" style={{ border: "2px solid var(--border)" }}>
                  <span>📎</span>
                  <span className="flex-1">{f.name}</span>
                  <span style={{ color: "var(--muted-foreground)" }}>{formatSize(f.size)}</span>
                  <button onClick={() => removeFile(f.url)} style={{ color: "oklch(0.577 0.245 27.325)" }}>✕</button>
                </div>
              ))}
            </div>
          )}

          {/* Audio recorder */}
          {allowAudio && (
            <AudioRecorder
              value={audioUrl}
              onChange={setAudioUrl}
              uploadUrl="/api/student/audio-upload"
            />
          )}

          <div className="flex items-center gap-2 flex-wrap">
            <button
              onClick={handleSubmit}
              disabled={pending || (!text.trim() && files.length === 0 && !audioUrl)}
              className="btn-aubade btn-aubade-accent text-sm px-5 py-2"
              style={{ opacity: pending || (!text.trim() && files.length === 0 && !audioUrl) ? 0.6 : 1 }}
            >
              {pending ? "Отправка..." : submission ? "Обновить ответ" : "Сдать работу"}
            </button>
            <label className="btn-aubade text-xs px-3 py-2 cursor-pointer">
              {uploading ? "Загрузка..." : "📎 Прикрепить файл"}
              <input type="file" className="sr-only" onChange={handleFileUpload} disabled={uploading} />
            </label>
            {submission && (
              <button onClick={() => setEditing(false)} className="text-xs" style={{ color: "var(--muted-foreground)" }}>
                Отмена
              </button>
            )}
          </div>
        </div>
      )}
    </div>
  );
}