import { NextResponse } from "next/server";
import { createSupabaseRouteClient } from "@/lib/supabase/server";
import { ensureDefaultWorkspace, resolveActiveWorkspaceId } from "@/lib/workspaces";

type CreateChildPayload = {
  parentId: string | null;
  title?: string;
  blocks?: unknown;
};

export const dynamic = "force-dynamic";

export async function POST(request: Request) {
  const supabase = await createSupabaseRouteClient();
  const {
    data: { session },
  } = await supabase.auth.getSession();

  if (!session) {
    return NextResponse.json({ error: "未登录无法创建页面" }, { status: 401 });
  }

  const { parentId, title, blocks }: CreateChildPayload = await request.json();

  if (typeof parentId === "undefined") {
    return NextResponse.json({ error: "缺少 parentId" }, { status: 400 });
  }

  let workspaceId: string;
  let accessScope: "private" | "shared" | "public" = "private";

  if (parentId) {
    const { data: parentDoc, error: parentError } = await supabase
      .from("documents")
      .select("workspace_id,access_scope")
      .eq("id", parentId)
      .single();

    if (parentError || !parentDoc) {
      return NextResponse.json({ error: "父页面不存在" }, { status: 404 });
    }
    workspaceId = parentDoc.workspace_id;
    accessScope = (parentDoc.access_scope ?? "private") as typeof accessScope;
  } else {
    await ensureDefaultWorkspace(supabase, session.user.id, session.user.email ?? "我的空间");
    workspaceId = await resolveActiveWorkspaceId(supabase, session.user.id);
    if (!workspaceId) {
      return NextResponse.json({ error: "缺少目标工作空间" }, { status: 400 });
    }
  }

  const siblingQuery = supabase
    .from("documents")
    .select("id", { head: true, count: "exact" })
    .eq("workspace_id", workspaceId);

  if (parentId) {
    siblingQuery.eq("parent_id", parentId);
  } else {
    siblingQuery.is("parent_id", null);
  }

  const { count: siblingCount = 0, error: countError } = await siblingQuery;

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

  const resolvedTitle =
    title && title.trim().length > 0 ? title.trim() : "未命名页面";

  const contentPayload = Array.isArray(blocks) ? blocks : [];

  const { data, error } = await supabase
    .from("documents")
    .insert({
      user_id: session.user.id,
      parent_id: parentId,
      workspace_id: workspaceId,
      access_scope: accessScope,
      title: resolvedTitle,
      content: contentPayload,
      sort_order: siblingCount,
    })
    .select("id,title")
    .single();

  if (error || !data) {
    return NextResponse.json(
      { error: error?.message ?? "创建子页面失败" },
      { status: 500 },
    );
  }

  return NextResponse.json({
    pageId: data.id,
    title: data.title ?? resolvedTitle,
  });
}