import { NextResponse } from "next/server";
import { createSupabaseRouteClient } from "@/lib/supabase/server";
import { promises as fs } from "fs";
import path from "path";
import { getDocumentsBaseDir, getLegacyMindmapsBaseDir } from "@/lib/server/local-paths";
import { isConvexEnabled } from "@/lib/convex/enabled";
import { getAuthedConvexClient } from "@/lib/convex/route";
import { api } from "@/lib/convex/api";

const defaultMindmapData = {
  data: { text: "中心主题" },
  children: [],
};

// 新版：与页面文件夹（index.md 所在处）对齐，放在 public/documents/<docId>/mindmap.json
// 旧版遗留：public/mindmaps/<docId>/mindmap.json
const preferredBaseDir = getDocumentsBaseDir();
const legacyBaseDir = getLegacyMindmapsBaseDir();

async function ensureDir(dir: string) {
  await fs.mkdir(dir, { recursive: true });
}

async function removeFileSafe(file: string) {
  try {
    await fs.rm(file, { force: true });
  } catch {
    // 忽略删除失败（例如文件不存在）
  }
}

async function ensureIndexFile(folder: string, title = "无标题") {
  const indexFile = path.join(folder, "index.md");
  try {
    await fs.access(indexFile);
  } catch {
    await fs.writeFile(indexFile, `# ${title}\n`, "utf8");
  }
}

export async function GET(
  _req: Request,
  { params }: { params: Promise<{ docId: string }> },
) {
  const { docId: id } = await params;

  if (isConvexEnabled()) {
    const { auth, client } = getAuthedConvexClient();
    const mindmapId = `legacy-${id}`;
    const res = await client.query(api.mindmaps.get, {
      userId: auth.userId,
      docId: id,
      mindmapId,
    });
    return NextResponse.json({ data: res?.data ?? defaultMindmapData, source: "convex" });
  }

  const supabase = await createSupabaseRouteClient();
  const {
    data: { session },
  } = await supabase.auth.getSession();
  if (!session) {
    return NextResponse.json({ error: "未登录" }, { status: 401 });
  }

  const preferredFolder = path.join(preferredBaseDir, id);
  const preferredFile = path.join(preferredFolder, "mindmap.json");
  const legacyFolder = path.join(legacyBaseDir, id);
  const legacyFile = path.join(legacyFolder, "mindmap.json");

  const tryRead = async (file: string) => {
    try {
      const content = await fs.readFile(file, "utf8");
      return JSON.parse(content);
    } catch {
      return null;
    }
  };

  const localData =
    (await tryRead(preferredFile)) ??
    (await tryRead(legacyFile));

  if (localData) {
    return NextResponse.json({ data: localData, source: "local" });
  }

  // fallback Supabase
  const { data, error } = await supabase
    .from("documents")
    .select("mindmap_data")
    .eq("id", id)
    .eq("user_id", session.user.id)
    .maybeSingle();
  if (error) {
    return NextResponse.json({ error: error.message }, { status: 400 });
  }
  const payload = data?.mindmap_data ?? defaultMindmapData;
  return NextResponse.json({ data: payload, source: "supabase" });
}

export async function POST(
  request: Request,
  { params }: { params: Promise<{ docId: string }> },
) {
  const { docId: id } = await params;

  if (isConvexEnabled()) {
    const { auth, client } = getAuthedConvexClient();
    const mindmapId = `legacy-${id}`;
    const { data } = await request.json();
    const result = await client.mutation(api.mindmaps.put, {
      userId: auth.userId,
      docId: id,
      mindmapId,
      data: data ?? defaultMindmapData,
    });
    return NextResponse.json({ ok: true, ...(result ?? {}) });
  }

  const supabase = await createSupabaseRouteClient();
  const {
    data: { session },
  } = await supabase.auth.getSession();
  if (!session) {
    return NextResponse.json({ error: "未登录" }, { status: 401 });
  }

  const { data } = await request.json();
  const folder = path.join(preferredBaseDir, id);
  const file = path.join(folder, "mindmap.json");
  try {
    await ensureDir(folder);
    await ensureIndexFile(folder);
    await fs.writeFile(
      file,
      JSON.stringify(data ?? defaultMindmapData, null, 2),
      "utf8",
    );
  } catch (error) {
    return NextResponse.json({ error: String(error) }, { status: 500 });
  }

  const { error } = await supabase
    .from("documents")
    .update({ mindmap_data: data ?? defaultMindmapData })
    .eq("id", id)
    .eq("user_id", session.user.id);

  if (error) {
    return NextResponse.json({ error: error.message }, { status: 400 });
  }

  return NextResponse.json({ ok: true });
}

export async function DELETE(
  _req: Request,
  { params }: { params: Promise<{ docId: string }> },
) {
  const { docId: id } = await params;

  if (isConvexEnabled()) {
    const { auth, client } = getAuthedConvexClient();
    const mindmapId = `legacy-${id}`;
    const result = await client.mutation(api.mindmaps.softDelete, {
      userId: auth.userId,
      docId: id,
      mindmapId,
    });
    return NextResponse.json({ ok: true, ...(result ?? {}) });
  }

  const supabase = await createSupabaseRouteClient();
  const {
    data: { session },
  } = await supabase.auth.getSession();
  if (!session) {
    return NextResponse.json({ error: "未登录" }, { status: 401 });
  }

  const preferredFolder = path.join(preferredBaseDir, id);
  const preferredFile = path.join(preferredFolder, "mindmap.json");
  const legacyFolder = path.join(legacyBaseDir, id);
  const legacyFile = path.join(legacyFolder, "mindmap.json");

  await Promise.all([removeFileSafe(preferredFile), removeFileSafe(legacyFile)]);

  const { error } = await supabase
    .from("documents")
    .update({ mindmap_data: null })
    .eq("id", id)
    .eq("user_id", session.user.id);

  if (error) {
    return NextResponse.json({ error: error.message }, { status: 500 });
  }

  return NextResponse.json({ ok: true });
}