import { randomUUID } from "crypto";
import { NextResponse } from "next/server";
import { createSupabaseRouteClient } from "@/lib/supabase/server";
import { ensureDefaultWorkspace, resolveActiveWorkspaceId } from "@/lib/workspaces";
import type { Json } from "@/types/supabase";
import { composeContentWithBlocks, extractBlocksFromContent } from "@/lib/document-content";
import path from "path";
import { promises as fs } from "fs";
import { getDocumentsBaseDir } from "@/lib/server/local-paths";
import { isConvexEnabled } from "@/lib/convex/enabled";
import { getConvexHttpClient } from "@/lib/convex/server";
import { api } from "@/lib/convex/api";
import { requireAuthContext } from "@/lib/auth/authContext";

const documentsBaseDir = getDocumentsBaseDir();

async function ensureDocumentScaffold(id: string, title: string | null) {
  const folder = path.join(documentsBaseDir, id);
  const indexFile = path.join(folder, "index.md");
  await fs.mkdir(folder, { recursive: true });
  try {
    await fs.access(indexFile);
  } catch {
    const safeTitle = title && title.trim() ? title.trim() : "无标题";
    const content = `# ${safeTitle}\n`;
    await fs.writeFile(indexFile, content, "utf8");
  }
}

export async function POST(request: Request) {
  try {
    if (isConvexEnabled()) {
      return await handleCreateRequestConvex(request);
    }
    return await handleCreateRequest(request);
  } catch (error) {
    console.error("创建页面失败", error);
    const message = error instanceof Error ? error.message : "创建页面失败，请稍后再试";
    return NextResponse.json({ error: message }, { status: 500 });
  }
}

async function handleCreateRequestConvex(request: Request) {
  const auth = requireAuthContext();
  const client = getConvexHttpClient();

  const { parentId }: { parentId?: string | null } = await request.json();

  const workspaceBootstrap = await client.mutation(api.workspaces.ensureDefaultWorkspace, {
    userId: auth.userId,
    fallbackName: auth.email ?? auth.name ?? "我的空间",
    workspaceIdIfCreate: randomUUID(),
  });

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

  if (parentId) {
    const parentDoc = await client.query(api.documents.getMeta, {
      userId: auth.userId,
      id: parentId,
    });

    if (!parentDoc) {
      return NextResponse.json({ error: "父页面不存在或无权限" }, { status: 404 });
    }

    workspaceId = parentDoc.workspace_id;
    accessScope = (parentDoc.access_scope ?? "private") as typeof accessScope;
    const parentContentRes = await client.query(api.documents.getContent, { userId: auth.userId, id: parentId });
    parentContent = (parentContentRes?.content as Json | null) ?? null;
  } else {
    workspaceId = workspaceBootstrap.activeWorkspaceId || null;
  }

  if (!workspaceId) {
    return NextResponse.json({ error: "缺少目标工作空间" }, { status: 400 });
  }

  const id = randomUUID();
  const data = await client.mutation(api.documents.create, {
    userId: auth.userId,
    id,
    workspaceId,
    parentId: parentId ?? null,
    title: "无标题",
    accessScope,
    content: [],
  });

  // 为文件树创建本地目录和 index.md
  if (data?.id) {
    await ensureDocumentScaffold(data.id, data.title ?? "无标题");
  }

  if (parentId && data) {
    const existingBlocks = extractBlocksFromContent(parentContent);
    const pageReferenceBlock = {
      id: randomUUID(),
      type: "pageReference",
      props: {
        pageId: data.id,
        title: data.title ?? "无标题",
      },
    };
    const nextBlocks = [...existingBlocks, pageReferenceBlock as Json];
    const payload = composeContentWithBlocks(parentContent, nextBlocks);

    await client.mutation(api.documents.updateContent, {
      userId: auth.userId,
      id: parentId,
      content: payload,
    });
  }

  return NextResponse.json(data);
}

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

  if (!session) {
    return NextResponse.json({ error: "未登录" }, { status: 401 });
  }

  const { parentId }: { parentId?: string | null } = await request.json();

  await ensureDefaultWorkspace(supabase, session.user.id, session.user.email ?? "我的空间");

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

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

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

  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: rawSiblingCount, error: countError } = await siblingQuery;
  const siblingCount = rawSiblingCount ?? 0;

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

  const { data, error } = await supabase
    .from("documents")
    .insert({
      user_id: session.user.id,
      parent_id: parentId ?? null,
      workspace_id: workspaceId,
      title: "无标题",
      content: { blocks: [] },
      access_scope: accessScope,
      sort_order: siblingCount,
    })
    .select(
      "id,title,parent_id,sort_order,is_starred,created_at,updated_at,workspace_id,access_scope,is_template",
    )
    .single();

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

  // 为文件树创建本地目录和 index.md
  if (data?.id) {
    await ensureDocumentScaffold(data.id, data.title ?? "无标题");
  }

  if (parentId && data) {
    const existingBlocks = extractBlocksFromContent(parentContent);
    const pageReferenceBlock = {
      id: randomUUID(),
      type: "pageReference",
      props: {
        pageId: data.id,
        title: data.title ?? "无标题",
      },
    };
    const nextBlocks = [...existingBlocks, pageReferenceBlock as Json];
    const payload = composeContentWithBlocks(parentContent, nextBlocks);
    const timestamp = new Date().toISOString();
    const { error: parentUpdateError } = await supabase
      .from("documents")
      .update({ content: payload, updated_at: timestamp })
      .eq("id", parentId)
      .eq("user_id", session.user.id);

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

  return NextResponse.json(data);
}