const topicInput = document.getElementById("topic");
const generateBtn = document.getElementById("generate-btn");
const exportBtn = document.getElementById("export-btn");
const statusEl = document.getElementById("status");
const outputEl = document.getElementById("output");

let current = { topic: "", markdown: "" };

function setStatus(text, isError = false) {
  statusEl.textContent = text;
  statusEl.classList.toggle("error", isError);
}

async function generate() {
  const topic = topicInput.value.trim();
  if (!topic) {
    setStatus("请先输入主题", true);
    return;
  }

  generateBtn.disabled = true;
  exportBtn.disabled = true;
  setStatus("生成中，请稍候…");
  outputEl.textContent = "正在生成…";

  try {
    const resp = await fetch("/api/generate", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ topic }),
    });
    const data = await resp.json();

    if (!resp.ok) {
      throw new Error(data.error || "生成失败");
    }

    current = { topic: data.topic, markdown: data.markdown };
    outputEl.textContent = data.markdown;
    exportBtn.disabled = false;
    setStatus("生成完成");
  } catch (err) {
    outputEl.textContent = "生成失败";
    setStatus(err.message, true);
  } finally {
    generateBtn.disabled = false;
  }
}

async function exportMarkdown() {
  if (!current.markdown) return;

  try {
    const resp = await fetch("/api/export", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(current),
    });

    if (!resp.ok) {
      const data = await resp.json().catch(() => ({}));
      throw new Error(data.error || "导出失败");
    }

    const blob = await resp.blob();
    const url = URL.createObjectURL(blob);
    const a = document.createElement("a");
    a.href = url;
    a.download = `${current.topic}-登记手册.md`;
    document.body.appendChild(a);
    a.click();
    a.remove();
    URL.revokeObjectURL(url);
    setStatus("已开始下载");
  } catch (err) {
    setStatus(err.message, true);
  }
}

generateBtn.addEventListener("click", generate);
exportBtn.addEventListener("click", exportMarkdown);
topicInput.addEventListener("keydown", (e) => {
  if (e.key === "Enter") generate();
});