import { NextRequest, NextResponse } from "next/server";
import { writeFile } from "node:fs/promises";
import {
  addMessage,
  clearMessages,
  createStorageKey,
  formatUploadedFileMeta,
  getOnlineUsers,
  listMessages,
  resolveUploadPath,
  touchPresence
} from "@/lib/chat-store";

export async function GET(request: NextRequest) {
  const user = request.nextUrl.searchParams.get("user") || undefined;

  touchPresence(user);

  return NextResponse.json({
    messages: listMessages(),
    onlineUsers: getOnlineUsers()
  });
}

export async function POST(request: NextRequest) {
  const contentType = request.headers.get("content-type") || "";
  let user = "局域网设备";
  let content = "";
  let fileRecord:
    | {
        name: string;
        meta: string;
        kind: "image" | "file";
        storageKey: string;
      }
    | undefined;

  if (contentType.includes("multipart/form-data")) {
    const formData = await request.formData();
    user = String(formData.get("user") || "局域网设备").trim() || "局域网设备";
    content = String(formData.get("content") || "").trim();
    const file = formData.get("file");

    if (file instanceof File && file.size > 0) {
      const storageKey = createStorageKey(file.name);
      const buffer = Buffer.from(await file.arrayBuffer());
      await writeFile(resolveUploadPath(storageKey), buffer);

      fileRecord = {
        name: file.name,
        meta: formatUploadedFileMeta(file.name, file.type, file.size),
        kind: file.type.startsWith("image/") ? "image" : "file",
        storageKey
      };
    }
  } else {
    const payload = (await request.json()) as {
      user?: string;
      content?: string;
    };

    user = payload.user?.trim() || "局域网设备";
    content = payload.content?.trim() || "";
  }

  if (!content && !fileRecord) {
    return NextResponse.json({ error: "消息不能为空" }, { status: 400 });
  }

  touchPresence(user);

  const message = addMessage({
    user,
    content,
    file: fileRecord
  });

  return NextResponse.json({
    message,
    onlineUsers: getOnlineUsers()
  });
}

export async function DELETE(request: NextRequest) {
  const payload = (await request.json().catch(() => ({}))) as {
    user?: string;
  };
  const user = payload.user?.trim() || "局域网设备";

  touchPresence(user);
  await clearMessages(user);

  return NextResponse.json({
    messages: listMessages(),
    onlineUsers: getOnlineUsers()
  });
}