const fileInput = document.getElementById("file-input");
const statusText = document.getElementById("status-text");
const statusDetail = document.getElementById("status-detail");
const progressFill = document.getElementById("progress-fill");
const progressPercent = document.getElementById("progress-percent");
const progressLabel = document.getElementById("progress-label");
const sguidCount = document.getElementById("sguid-count");
const skuidCount = document.getElementById("skuid-count");
const productLineCount = document.getElementById("product-line-count");
const outputPath = document.getElementById("output-path");
const statToday = document.getElementById("stat-today");
const statMonth = document.getElementById("stat-month");
const statSevenDays = document.getElementById("stat-seven-days");
const resultActions = document.getElementById("sgu-result-actions");
const downloadBtn = document.getElementById("sgu-download-btn");

let currentTaskId = null;
let currentResult = null;
let pollingTimer = null;
let progressTimer = null;

async function refreshStats() {
  const response = await fetch("/api/stats");
  if (!response.ok) {
    throw new Error("统计信息刷新失败");
  }
  const data = await response.json();
  statToday.textContent = data.today ?? 0;
  statMonth.textContent = data.month ?? 0;
  statSevenDays.textContent = data.seven_days ?? 0;
}

function setProgress(value, label) {
  const safeValue = Math.max(0, Math.min(100, Math.round(value)));
  progressFill.style.width = `${safeValue}%`;
  progressPercent.textContent = `${safeValue}%`;
  progressLabel.textContent = label;
}

function startProgressSimulation() {
  let current = Math.max(18, Number.parseInt(progressPercent.textContent, 10) || 0);
  setProgress(current, "文件已上传，准备开始分析...");
  progressTimer = window.setInterval(() => {
    if (current < 72) {
      current += current < 42 ? 7 : 4;
      setProgress(current, "正在汇总数据，请稍候...");
      return;
    }
    if (current < 90) {
      current += 1;
      setProgress(current, "正在生成结果文件...");
    }
  }, 500);
}

function stopProgressSimulation() {
  if (progressTimer) {
    window.clearInterval(progressTimer);
    progressTimer = null;
  }
}

function resetView() {
  if (pollingTimer) {
    window.clearTimeout(pollingTimer);
    pollingTimer = null;
  }
  stopProgressSimulation();
  currentTaskId = null;
  currentResult = null;
  resultActions.classList.add("hidden");
  sguidCount.textContent = "0";
  skuidCount.textContent = "0";
  productLineCount.textContent = "0";
  outputPath.textContent = "尚未生成";
}

function renderCompletedResult(result) {
  currentResult = result;
  const counts = result.counts || {};
  sguidCount.textContent = counts.SGUID ?? 0;
  skuidCount.textContent = counts.SKUID ?? 0;
  productLineCount.textContent = counts.PRODUCT_LINE ?? 0;
  outputPath.textContent = result.output_file || result.output_filename || "尚未生成";
  resultActions.classList.remove("hidden");

  if (result.result_type === "success") {
    statusText.textContent = "已处理成功";
    statusDetail.textContent = `结果文件 ${result.output_filename} 已生成，请点击下方按钮下载。`;
    setProgress(100, "处理完成，结果文件已生成");
    return;
  }

  statusText.textContent = "已生成错误说明";
  statusDetail.textContent = `系统已生成错误说明文件 ${result.output_filename}，请点击下方按钮下载查看。`;
  setProgress(100, "处理完成，错误说明文件已生成");
}

async function pollStatus() {
  if (!currentTaskId) {
    return;
  }

  const response = await fetch(`/api/process/status/${currentTaskId}`);
  const payload = await response.json();
  if (!response.ok) {
    throw new Error(payload.error || "任务状态获取失败");
  }

  if (payload.status === "processing") {
    pollingTimer = window.setTimeout(pollStatus, 1000);
    return;
  }

  if (payload.status === "completed") {
    renderCompletedResult(payload.result || {});
    await refreshStats();
    return;
  }

  if (payload.status === "error") {
    throw new Error(payload.result?.error || "处理失败，请稍后重试。");
  }

  pollingTimer = window.setTimeout(pollStatus, 1000);
}

async function uploadFile(file) {
  const formData = new FormData();
  formData.append("file", file);

  resetView();
  fileInput.disabled = true;
  setProgress(6, "正在上传文件...");
  statusText.textContent = "处理中，请稍候...";
  statusDetail.textContent = `正在处理文件：${file.name}`;
  outputPath.textContent = "服务器保存中...";

  const response = await fetch("/api/process", {
    method: "POST",
    body: formData,
  });
  const payload = await response.json();
  if (!response.ok || payload.success === false) {
    throw new Error(payload.error || "上传失败");
  }

  currentTaskId = payload.task_id;
  setProgress(22, "文件上传成功，正在排队分析...");
  startProgressSimulation();
  await pollStatus();
}

fileInput.addEventListener("change", async (event) => {
  const [file] = event.target.files;
  if (!file) {
    return;
  }

  try {
    await uploadFile(file);
  } catch (error) {
    stopProgressSimulation();
    statusText.textContent = "处理失败";
    statusDetail.textContent = error.message;
    outputPath.textContent = "服务器未生成文件";
    setProgress(100, "处理失败");
  } finally {
    stopProgressSimulation();
    fileInput.disabled = false;
    fileInput.value = "";
  }
});

downloadBtn.addEventListener("click", () => {
  if (!currentResult?.output_filename) {
    return;
  }
  window.open(`/api/process/download/${currentResult.output_filename}`, "_blank");
});

window.addEventListener("beforeunload", () => {
  if (pollingTimer) {
    clearTimeout(pollingTimer);
  }
  stopProgressSimulation();
});

setProgress(0, "等待上传文件");
refreshStats().catch(() => {
  statToday.textContent = "0";
  statMonth.textContent = "0";
  statSevenDays.textContent = "0";
});