const form = document.querySelector("#login-form");
const nextInput = document.querySelector("#next-url");
const statusEl = document.querySelector("#login-status");

const params = new URLSearchParams(window.location.search);
const requestedNext = params.get("next") || "/software.html";

function safeNext(value) {
  if (!value) return "/software.html";
  if (value.startsWith("/") && !value.startsWith("//")) return value;
  if (/^[a-z0-9._/-]+$/i.test(value)) return value;
  return "/software.html";
}

function setStatus(message, type = "") {
  statusEl.textContent = message;
  statusEl.classList.toggle("is-error", type === "error");
  statusEl.classList.toggle("is-ok", type === "ok");
}

async function checkExistingLogin() {
  try {
    const response = await fetch("/api/auth/me", { headers: { Accept: "application/json" } });
    const payload = await response.json();
    if (payload.authenticated) {
      window.location.href = safeNext(requestedNext);
    }
  } catch {
    setStatus("");
  }
}

nextInput.value = safeNext(requestedNext);

form.addEventListener("submit", async (event) => {
  event.preventDefault();
  const formData = new FormData(form);
  const payload = Object.fromEntries(formData.entries());

  try {
    setStatus("正在登录...");
    const response = await fetch("/api/auth/login", {
      method: "POST",
      headers: {
        Accept: "application/json",
        "Content-Type": "application/json",
      },
      body: JSON.stringify(payload),
    });
    const data = await response.json();
    if (!response.ok) {
      throw new Error(data.error || "登录失败");
    }
    setStatus("登录成功，正在跳转。", "ok");
    window.location.href = safeNext(data.next || payload.next);
  } catch (error) {
    setStatus(error.message, "error");
  }
});

checkExistingLogin();