"use client";

import { useEffect, useState } from "react";
import { useParams, useRouter } from "next/navigation";
import AuthGuard from "@/components/auth-guard";
import NavBar from "@/components/nav-bar";
import { useApi } from "@/lib/use-api";
import ReactMarkdown from "react-markdown";
import SpeakableText from "@/components/speakable-text";

interface Category {
  ID: string;
  NAME: string;
  DEPTH: number;
  FULL_PATH: string;
}

interface KnowledgeItem {
  ID: string;
  TYPE: string;
  TITLE: string;
  SOURCE_URL: string;
  RAW_TEXT: string;
  STRUCTURED_CONTENT: string | null;
  STATUS: string;
  CREATED_AT: string;
  UPDATED_AT: string;
  CATEGORIES: Category[];
}

interface Chunk {
  ID: string;
  CHUNK_INDEX: number;
  CONTENT: string;
  TOKEN_COUNT: number;
}

const statusColors: Record<string, string> = {
  PENDING: "bg-yellow-500/20 text-yellow-400",
  EXTRACTING: "bg-blue-500/20 text-blue-400",
  CHUNKING: "bg-purple-500/20 text-purple-400",
  CATEGORIZING: "bg-indigo-500/20 text-indigo-400",
  STRUCTURING: "bg-orange-500/20 text-orange-400",
  EMBEDDING: "bg-cyan-500/20 text-cyan-400",
  READY: "bg-green-500/20 text-green-400",
  FAILED: "bg-red-500/20 text-red-400",
};

const typeLabels: Record<string, string> = {
  YOUTUBE: "YouTube",
  WEB: "Web",
  TEXT: "Text",
};

function extractYouTubeVideoId(url: string): string | null {
  try {
    const u = new URL(url);
    if (u.hostname === "youtu.be") return u.pathname.slice(1);
    if (u.hostname.includes("youtube.com")) return u.searchParams.get("v");
  } catch {
    // invalid URL
  }
  return null;
}

export default function KnowledgeDetailPage() {
  const { request } = useApi();
  const router = useRouter();
  const params = useParams();
  const id = params.id as string;

  const [item, setItem] = useState<KnowledgeItem | null>(null);
  const [chunks, setChunks] = useState<Chunk[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [editingTitle, setEditingTitle] = useState(false);
  const [titleDraft, setTitleDraft] = useState("");
  const [showChunks, setShowChunks] = useState(false);
  const [deleting, setDeleting] = useState(false);
  const [generating, setGenerating] = useState(false);
  const [structuring, setStructuring] = useState(false);
  const [showStructured, setShowStructured] = useState(true);

  const fetchItem = async () => {
    try {
      const data = await request<KnowledgeItem>({ method: "GET", url: `/api/knowledge/${id}` });
      setItem(data);
    } catch (err: unknown) {
      const msg = err instanceof Error ? err.message : "Failed to load";
      setError(msg);
    } finally {
      setLoading(false);
    }
  };

  const fetchChunks = async () => {
    try {
      const data = await request<Chunk[]>({ method: "GET", url: `/api/knowledge/${id}/chunks` });
      setChunks(data);
    } catch (err) {
      console.error("Failed to load chunks:", err);
    }
  };

  useEffect(() => {
    fetchItem();
  }, [id]);

  // Poll while processing
  useEffect(() => {
    if (!item) return;
    const processing = ["PENDING", "EXTRACTING", "STRUCTURING", "CHUNKING", "CATEGORIZING", "EMBEDDING"].includes(item.STATUS);
    if (!processing) return;
    const interval = setInterval(fetchItem, 3000);
    return () => clearInterval(interval);
  }, [item?.STATUS]);

  const handleSaveTitle = async () => {
    if (!titleDraft.trim()) return;
    try {
      const updated = await request<KnowledgeItem>({
        method: "PATCH",
        url: `/api/knowledge/${id}`,
        data: { title: titleDraft.trim() },
      });
      setItem(updated);
      setEditingTitle(false);
    } catch (err) {
      console.error("Failed to update title:", err);
    }
  };

  const handleDelete = async () => {
    if (!confirm("정말 삭제하시겠습니까?")) return;
    setDeleting(true);
    try {
      await request({ method: "DELETE", url: `/api/knowledge/${id}` });
      router.push("/knowledge");
    } catch (err) {
      console.error("Failed to delete:", err);
      setDeleting(false);
    }
  };

  const handleToggleChunks = () => {
    if (!showChunks && chunks.length === 0) {
      fetchChunks();
    }
    setShowChunks(!showChunks);
  };

  if (loading) {
    return (
      <AuthGuard>
        <NavBar />
        <main className="max-w-4xl mx-auto px-4 py-8">
          <p className="text-[var(--color-text-muted)]">Loading...</p>
        </main>
      </AuthGuard>
    );
  }

  if (error || !item) {
    return (
      <AuthGuard>
        <NavBar />
        <main className="max-w-4xl mx-auto px-4 py-8">
          <p className="text-red-400">{error || "Item not found"}</p>
          <button
            onClick={() => router.push("/knowledge")}
            className="mt-4 text-sm text-[var(--color-primary)] hover:underline"
          >
            ← Back to Knowledge
          </button>
        </main>
      </AuthGuard>
    );
  }

  const videoId = item.TYPE === "YOUTUBE" && item.SOURCE_URL ? extractYouTubeVideoId(item.SOURCE_URL) : null;

  return (
    <AuthGuard>
      <NavBar />
      <main className="max-w-4xl mx-auto px-4 py-8">
        {/* Back link */}
        <button
          onClick={() => router.push("/knowledge")}
          className="text-sm text-[var(--color-text-muted)] hover:text-[var(--color-primary)] mb-4 inline-block"
        >
          ← Back to Knowledge
        </button>

        {/* Header */}
        <div className="bg-[var(--color-bg-card)] rounded-xl p-6 border border-[var(--color-border)] mb-6">
          <div className="flex items-center gap-3 mb-3">
            <span className="text-xs px-2 py-0.5 rounded bg-[var(--color-bg-hover)] text-[var(--color-text-muted)]">
              {typeLabels[item.TYPE] || item.TYPE}
            </span>
            <span className={`text-xs px-2 py-0.5 rounded ${statusColors[item.STATUS] || ""}`}>
              {item.STATUS}
            </span>
          </div>

          {/* Title (editable) */}
          {editingTitle ? (
            <div className="flex gap-2 mb-3">
              <input
                type="text"
                value={titleDraft}
                onChange={(e) => setTitleDraft(e.target.value)}
                onKeyDown={(e) => e.key === "Enter" && handleSaveTitle()}
                className="flex-1 px-3 py-1 rounded-lg bg-[var(--color-bg-hover)] border border-[var(--color-border)] focus:border-[var(--color-primary)] focus:outline-none text-lg font-bold"
                autoFocus
              />
              <button
                onClick={handleSaveTitle}
                className="px-3 py-1 text-sm bg-[var(--color-primary)] rounded-lg"
              >
                저장
              </button>
              <button
                onClick={() => setEditingTitle(false)}
                className="px-3 py-1 text-sm bg-[var(--color-bg-hover)] border border-[var(--color-border)] rounded-lg"
              >
                취소
              </button>
            </div>
          ) : (
            <h1
              className="text-xl font-bold mb-3 cursor-pointer hover:text-[var(--color-primary)] transition-colors"
              onClick={() => {
                setTitleDraft(item.TITLE || "");
                setEditingTitle(true);
              }}
              title="클릭하여 제목 수정"
            >
              {item.TITLE || "Untitled"}
            </h1>
          )}

          {/* Source URL */}
          {item.SOURCE_URL && (
            <p className="text-sm text-[var(--color-text-muted)] mb-3 break-all">
              <a href={item.SOURCE_URL} target="_blank" rel="noopener noreferrer" className="hover:text-[var(--color-primary)]">
                {item.SOURCE_URL}
              </a>
            </p>
          )}

          {/* Meta */}
          <div className="flex gap-4 text-xs text-[var(--color-text-muted)]">
            <span>생성: {new Date(item.CREATED_AT).toLocaleString("ko-KR")}</span>
            <span>수정: {new Date(item.UPDATED_AT).toLocaleString("ko-KR")}</span>
          </div>
        </div>

        {/* YouTube Embed */}
        {videoId && (
          <div className="rounded-xl overflow-hidden border border-[var(--color-border)] mb-6">
            <div className="relative w-full" style={{ paddingBottom: "56.25%" }}>
              <iframe
                className="absolute inset-0 w-full h-full"
                src={`https://www.youtube.com/embed/${videoId}`}
                allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
                allowFullScreen
              />
            </div>
          </div>
        )}

        {/* Processing indicator */}
        {/* Categories */}
        {item.CATEGORIES && item.CATEGORIES.length > 0 && (
          <div className="flex flex-wrap gap-2 mb-6">
            {item.CATEGORIES.map((cat) => (
              <span
                key={cat.ID}
                className="text-xs px-2.5 py-1 rounded-full bg-[var(--color-primary)]/15 text-[var(--color-primary)] border border-[var(--color-primary)]/30"
              >
                {cat.FULL_PATH}
              </span>
            ))}
          </div>
        )}

        {["PENDING", "EXTRACTING", "STRUCTURING", "CHUNKING", "CATEGORIZING", "EMBEDDING"].includes(item.STATUS) && (
          <div className="bg-blue-500/10 border border-blue-500/30 rounded-xl p-4 mb-6 flex items-center gap-3">
            <div className="w-4 h-4 border-2 border-blue-400 border-t-transparent rounded-full animate-spin" />
            <span className="text-sm text-blue-400">
              {item.STATUS === "PENDING" && "파이프라인 대기 중..."}
              {item.STATUS === "EXTRACTING" && "텍스트 추출 중..."}
              {item.STATUS === "STRUCTURING" && "내용 정리 중..."}
              {item.STATUS === "CHUNKING" && "청킹 처리 중..."}
              {item.STATUS === "CATEGORIZING" && "카테고리 분류 중..."}
              {item.STATUS === "EMBEDDING" && "벡터 임베딩 중..."}
            </span>
          </div>
        )}

        {/* Structured Content */}
        {item.STRUCTURED_CONTENT && (
          <div className="mb-6">
            <button
              onClick={() => setShowStructured(!showStructured)}
              className="text-sm text-[var(--color-primary)] hover:underline mb-3"
            >
              {showStructured ? "▼ 정리된 내용 숨기기" : "▶ 정리된 내용 보기"}
            </button>
            {showStructured && (
              <div className="bg-[var(--color-bg-card)] rounded-xl p-6 border border-[var(--color-border)] max-w-none">
                <div className="structured-content text-sm leading-relaxed">
                  <ReactMarkdown
                    components={{
                      h1: ({children}) => <h1 className="text-xl font-bold mt-6 mb-3">{children}</h1>,
                      h2: ({children}) => <h2 className="text-lg font-bold mt-5 mb-2">{children}</h2>,
                      h3: ({children}) => <h3 className="text-base font-bold mt-4 mb-2">{children}</h3>,
                      p: ({children, node}) => {
                        // eslint-disable-next-line @typescript-eslint/no-explicit-any
                        const txt = node?.children?.map((c: any) => c.type === 'text' ? c.value : '').join('') || '';
                        return <p className="mb-3"><SpeakableText text={txt}>{children}</SpeakableText></p>;
                      },
                      ul: ({children}) => <ul className="list-disc ml-5 mb-3 space-y-1">{children}</ul>,
                      ol: ({children}) => <ol className="list-decimal ml-5 mb-3 space-y-1">{children}</ol>,
                      li: ({children, node}) => {
                        // eslint-disable-next-line @typescript-eslint/no-explicit-any
                        const txt = node?.children?.map((c: any) => c.type === 'text' ? c.value : '').join('') || '';
                        return <li className="leading-relaxed"><SpeakableText text={txt}>{children}</SpeakableText></li>;
                      },
                      strong: ({children}) => <strong className="font-bold">{children}</strong>,
                      blockquote: ({children}) => <blockquote className="border-l-2 border-[var(--color-primary)] pl-4 my-3 italic text-[var(--color-text-muted)]">{children}</blockquote>,
                      code: ({children}) => <code className="bg-[var(--color-bg-hover)] px-1.5 py-0.5 rounded text-xs">{children}</code>,
                    }}
                  >
                    {item.STRUCTURED_CONTENT}
                  </ReactMarkdown>
                </div>
              </div>
            )}
          </div>
        )}

        {/* Chunks toggle */}
        {item.STATUS === "READY" && (
          <div className="mb-6">
            <button
              onClick={handleToggleChunks}
              className="text-sm text-[var(--color-primary)] hover:underline"
            >
              {showChunks ? "▼ 청크 숨기기" : "▶ 청크 보기"}
            </button>

            {showChunks && (
              <div className="mt-3 space-y-3">
                {chunks.length === 0 ? (
                  <p className="text-sm text-[var(--color-text-muted)]">Loading chunks...</p>
                ) : (
                  chunks.map((chunk) => (
                    <div
                      key={chunk.ID}
                      className="bg-[var(--color-bg-card)] rounded-lg p-4 border border-[var(--color-border)]"
                    >
                      <div className="flex justify-between items-center mb-2">
                        <span className="text-xs text-[var(--color-text-muted)]">
                          Chunk #{chunk.CHUNK_INDEX}
                        </span>
                        <span className="text-xs text-[var(--color-text-muted)]">
                          ~{chunk.TOKEN_COUNT} tokens
                        </span>
                      </div>
                      <p className="text-sm whitespace-pre-wrap">{chunk.CONTENT}</p>
                    </div>
                  ))
                )}
              </div>
            )}
          </div>
        )}

        {/* Actions */}
        <div className="pt-4 border-t border-[var(--color-border)] flex items-center gap-4">
          {item.STATUS === "READY" && (
            <>
              <button
                onClick={async () => {
                  setStructuring(true);
                  setShowStructured(true);
                  try {
                    // 비동기 요청: 서버가 STRUCTURING 상태로 변경 후 백그라운드 처리
                    // 폴링이 자동으로 진행 상태를 갱신함
                    await request({
                      method: "POST",
                      url: `/api/knowledge/${id}/structure`,
                      data: {},
                    });
                    // 완료 후 최종 상태 갱신
                    await fetchItem();
                  } catch (err) {
                    console.error("Failed to structure:", err);
                    alert("내용 정리에 실패했습니다.");
                    await fetchItem();
                  } finally {
                    setStructuring(false);
                  }
                }}
                disabled={structuring}
                className="text-sm text-[var(--color-primary)] hover:underline disabled:opacity-40"
              >
                {structuring ? "정리 중..." : item.STRUCTURED_CONTENT ? "다시 정리하기" : "내용 정리하기"}
              </button>
              <button
                onClick={async () => {
                  setGenerating(true);
                  try {
                    const result = await request<{ generated: number }>({
                      method: "POST",
                      url: `/api/study-cards/generate/${id}`,
                    });
                    alert(`${result.generated}개의 스터디 카드가 생성되었습니다.`);
                  } catch (err) {
                    console.error("Failed to generate cards:", err);
                    alert("카드 생성에 실패했습니다.");
                  } finally {
                    setGenerating(false);
                  }
                }}
                disabled={generating}
                className="text-sm text-[var(--color-primary)] hover:underline disabled:opacity-40"
              >
                {generating ? "카드 생성 중..." : "스터디 카드 생성"}
              </button>
            </>
          )}
          <button
            onClick={handleDelete}
            disabled={deleting}
            className="text-sm text-red-400 hover:text-red-300 disabled:opacity-40"
          >
            {deleting ? "삭제 중..." : "삭제"}
          </button>
        </div>
      </main>
    </AuthGuard>
  );
}