'use client';

// Mira Wiki 索引頁
// SDD: polaris/mira/.agents/specs/mira-app/design.md §5.2 + §3.5.10
// 對應 task: 7C.1
// 階段 7-A 已建：mira-wiki-schema、mira-wiki-index(+4 children)、mira-wiki-log(+1 child)
// 此頁列出這些 infra block 與既有 wiki-page，方便 leo 在瀏覽器確認 schema 寫得對不對

import { useEffect, useMemo, useState } from 'react';
import Link from 'next/link';
import '../mira.css';

const KBDB_BASE = 'https://kbdb.finally.click';
const API_BASE = process.env.NEXT_PUBLIC_API_BASE ?? 'https://cypher.arcrun.dev';

type Block = {
  id: string;
  page_name: string;
  content: string;
  type: string;
  parent_id: string | null;
  tags_json: string | null;
  created_at: number;
};

export default function WikiIndexPage() {
  const [schema, setSchema] = useState<Block | null>(null);
  const [indexChildren, setIndexChildren] = useState<Block[]>([]);
  const [logEntries, setLogEntries] = useState<Block[]>([]);
  const [otherWikiPages, setOtherWikiPages] = useState<Block[]>([]);
  const [indexEntries, setIndexEntries] = useState<Block[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    let cancelled = false;
    async function load() {
      try {
        // 先拿 ak_ partner key（同 page.tsx pattern）
        const meRes = await fetch(`${API_BASE}/me`, { credentials: 'include' });
        if (!meRes.ok) throw new Error('未登入');
        const me = (await meRes.json()) as { api_key: string };
        const headers = { Authorization: `Bearer ${me.api_key}` };

        // 撈所有 type=wiki-page，再 client 端過濾 tags 含 'mira-wiki'
        // 原本 ?tag=mira-wiki 撞 KBDB worker D1 bug（malformed JSON），改 type filter
        // 待 KBDB 修 tag filter 後可改回（SDD 待開 kbdb-tag-filter-fix）
        const res = await fetch(
          `${KBDB_BASE}/blocks?type=wiki-page&limit=200`,
          { headers },
        );
        if (!res.ok) throw new Error(`KBDB ${res.status}`);
        const data = await res.json();
        if (cancelled) return;
        const allWikiBlocks: Block[] = data.blocks ?? [];
        // Client 端過濾：只留 tags 含 'mira-wiki'
        const blocks: Block[] = allWikiBlocks.filter((b) => {
          if (!b.tags_json) return false;
          try {
            const tags = JSON.parse(b.tags_json) as string[];
            return tags.includes('mira-wiki');
          } catch {
            return false;
          }
        });

        const tagsOf = (b: Block): string[] => {
          if (!b.tags_json) return [];
          try {
            return JSON.parse(b.tags_json) as string[];
          } catch {
            return [];
          }
        };
        const hasSubtype = (b: Block, st: string) =>
          tagsOf(b).includes(`subtype:${st}`);
        const hasAnyInfraSubtype = (b: Block) =>
          ['schema', 'index', 'index-child', 'log', 'log-child'].some((st) => hasSubtype(b, st));
        const hasMetaTag = (b: Block) =>
          tagsOf(b).some((t) => t === 'data-source-config' || t === 'source-skill');

        setSchema(blocks.find((b) => hasSubtype(b, 'schema')) ?? null);
        setIndexChildren(
          blocks
            .filter((b) => hasSubtype(b, 'index-child'))
            .sort((a, b) => a.page_name.localeCompare(b.page_name)),
        );
        setLogEntries(
          blocks
            .filter((b) => hasSubtype(b, 'log-child'))
            .sort((a, b) => b.page_name.localeCompare(a.page_name)),
        );
        // 真正的 wiki-page paragraphs（排除 infra 跟 meta 配置）
        setOtherWikiPages(
          blocks
            .filter((b) => !hasAnyInfraSubtype(b) && !hasMetaTag(b))
            .sort((a, b) => (b.created_at ?? 0) - (a.created_at ?? 0)),
        );

        // 平行撈 index-entry blocks（per-entity 摘要，CC navigation entry point）
        // 對應 design.md §3.5.12.4.1 / 7B.3f
        const idxRes = await fetch(
          `${KBDB_BASE}/blocks?type=index-entry&limit=200`,
          { headers },
        );
        if (idxRes.ok) {
          const idxData = await idxRes.json();
          if (!cancelled) {
            const idxBlocks: Block[] = idxData.blocks ?? [];
            setIndexEntries(
              idxBlocks.sort((a, b) => (a.page_name ?? '').localeCompare(b.page_name ?? '')),
            );
          }
        }
      } catch (e: any) {
        if (!cancelled) setError(e?.message ?? 'load failed');
      } finally {
        if (!cancelled) setLoading(false);
      }
    }
    load();
    return () => {
      cancelled = true;
    };
  }, []);

  // Dedupe wiki-pages by entity（content）— 累積式設計每個 raw 各建一個 wiki-page，
  // 同 entity 多版只在 listing 顯示最新一張卡 + 版本數提示
  const dedupedWikiPages = useMemo(() => {
    const groups = new Map<string, { entity: string; latest: Block; versionCount: number }>();
    for (const p of otherWikiPages) {
      const entity = (p.content || '').trim() || p.page_name || '?';
      const existing = groups.get(entity);
      if (!existing) {
        groups.set(entity, { entity, latest: p, versionCount: 1 });
      } else {
        existing.versionCount++;
        if ((p.created_at ?? 0) > (existing.latest.created_at ?? 0)) {
          existing.latest = p;
        }
      }
    }
    return Array.from(groups.values()).sort(
      (a, b) => (b.latest.created_at ?? 0) - (a.latest.created_at ?? 0),
    );
  }, [otherWikiPages]);

  return (
    <main className="mira-app">
      <div className="mira-content">
        <header style={{ padding: '24px 0 16px', borderBottom: '1px solid #2a2a2a' }}>
          <div style={{ display: 'flex', alignItems: 'center', gap: 12, marginBottom: 4 }}>
            <Link
              href="/mira"
              style={{ color: '#888', fontSize: 14, textDecoration: 'none' }}
            >
              ← Mira 首頁
            </Link>
          </div>
          <h1 style={{ fontSize: 28, fontWeight: 700, color: '#fff', margin: 0 }}>
            📚 Mira Wiki
          </h1>
          <p style={{ color: '#888', fontSize: 14, marginTop: 4 }}>
            leo 的個人觀點累積（Karpathy LLM Wiki 風格）
          </p>
        </header>

        {loading && <div style={{ padding: 24, color: '#666' }}>載入中⋯</div>}
        {error && (
          <div style={{ padding: 24, color: '#e66' }}>讀取失敗：{error}</div>
        )}

        {!loading && !error && (
          <>
            <Section title="📋 Schema（合成規則）">
              {schema ? (
                <WikiCardLink page_name={schema.page_name} title="mira-wiki-schema" excerpt="ingest 規則手冊：cypher binding、17 predicates、entity normalize⋯" />
              ) : (
                <Empty>尚未建立 schema</Empty>
              )}
            </Section>

            <Section title="🗂 Index（4 個分類）">
              {indexChildren.length > 0 ? (
                <div style={{ display: 'grid', gap: 8 }}>
                  {indexChildren.map((b) => {
                    const tags = b.tags_json ? (JSON.parse(b.tags_json) as string[]) : [];
                    const key = tags.find((t) => t.startsWith('index-key:'))?.replace('index-key:', '') ?? '?';
                    return (
                      <WikiCardLink
                        key={b.id}
                        page_name={b.page_name}
                        title={`${iconForKey(key)} ${key}`}
                        excerpt={firstLineOf(b.content)}
                      />
                    );
                  })}
                </div>
              ) : (
                <Empty>index children 尚未建立</Empty>
              )}
            </Section>

            <Section title={`🧭 Index Entries（${indexEntries.length}）— CC 看的 entity 摘要`}>
              {indexEntries.length > 0 ? (
                <div style={{ display: 'grid', gap: 8 }}>
                  {indexEntries.map((b) => {
                    const entity = (b.page_name ?? '').replace(/^index-/, '');
                    const firstLine = firstLineOf(b.content)
                      .replace(/^#+\s*/, '')
                      .slice(0, 80);
                    return (
                      <WikiCardLink
                        key={b.id}
                        page_name={b.page_name ?? ''}
                        title={entity}
                        excerpt={firstLine || `index for ${entity}`}
                      />
                    );
                  })}
                </div>
              ) : (
                <Empty>尚未有 index-entry（wiki_synthesis 跑完後自動建）</Empty>
              )}
            </Section>

            <Section title="📜 Log（每月一筆）">
              {logEntries.length > 0 ? (
                <div style={{ display: 'grid', gap: 8 }}>
                  {logEntries.map((b) => (
                    <WikiCardLink
                      key={b.id}
                      page_name={b.page_name}
                      title={b.page_name}
                      excerpt={firstLineOf(b.content)}
                    />
                  ))}
                </div>
              ) : (
                <Empty>尚未有 log</Empty>
              )}
            </Section>

            <Section title={`📖 Wiki Pages（${dedupedWikiPages.length}，原 ${otherWikiPages.length} 筆累積版本）`}>
              {dedupedWikiPages.length > 0 ? (
                <div style={{ display: 'grid', gap: 8 }}>
                  {dedupedWikiPages.map((g) => (
                    <WikiCardLink
                      key={g.latest.id}
                      page_name={g.latest.page_name}
                      title={g.entity}
                      excerpt={
                        g.versionCount > 1
                          ? `${g.versionCount} 版累積 ・ 最新 ${new Date((g.latest.created_at ?? 0) * 1000).toLocaleString('zh-TW')}`
                          : `建立 ${new Date((g.latest.created_at ?? 0) * 1000).toLocaleString('zh-TW')}`
                      }
                    />
                  ))}
                </div>
              ) : (
                <Empty>尚未有 wiki page（待 7-B ai-canon-wiki workflow 跑出第一張）</Empty>
              )}
            </Section>
          </>
        )}
      </div>
    </main>
  );
}

function Section({ title, children }: { title: string; children: React.ReactNode }) {
  return (
    <section style={{ padding: '20px 0', borderBottom: '1px solid #1f1f1f' }}>
      <h2 style={{ fontSize: 16, fontWeight: 600, color: '#ddd', marginBottom: 12 }}>
        {title}
      </h2>
      {children}
    </section>
  );
}

function Empty({ children }: { children: React.ReactNode }) {
  return (
    <div style={{ color: '#555', fontStyle: 'italic', fontSize: 13 }}>{children}</div>
  );
}

function WikiCardLink({
  page_name,
  title,
  excerpt,
}: {
  page_name: string;
  title: string;
  excerpt: string;
}) {
  return (
    <Link
      href={`/mira/wiki/${encodeURIComponent(page_name)}`}
      style={{
        display: 'block',
        padding: '12px 14px',
        background: '#1a1a1a',
        border: '1px solid #2a2a2a',
        borderRadius: 6,
        textDecoration: 'none',
        color: 'inherit',
      }}
    >
      <div style={{ color: '#ddd', fontWeight: 500, marginBottom: 4 }}>{title}</div>
      {excerpt && (
        <div
          style={{
            color: '#888',
            fontSize: 13,
            overflow: 'hidden',
            textOverflow: 'ellipsis',
            whiteSpace: 'nowrap',
          }}
        >
          {excerpt}
        </div>
      )}
    </Link>
  );
}

function iconForKey(key: string): string {
  return (
    {
      entities: '🧩',
      topics: '📂',
      sources: '🔗',
      stale: '⚠️',
    }[key] ?? '•'
  );
}

function firstLineOf(content: string): string {
  if (!content) return '';
  const firstNonHeader = content
    .split('\n')
    .map((l) => l.trim())
    .find((l) => l && !l.startsWith('#') && !l.startsWith('>'));
  return firstNonHeader ?? '';
}