'use strict';
const $ = id => document.getElementById(id);
let token = '', running = false, starting = false, loadingChannels = false, loadedKey = '', lastLog = -1;
const labels = {idle:'等待开始',running:'下载中',completed:'已完成',partial:'未达到目标',cancelled:'已停止',error:'任务中断'};
const key = () => $('key').value.trim();
function controls() {
  const busy = running || starting;
  $('start').disabled = busy || !loadedKey || loadedKey !== key() || !$('channel').value;
  $('stop').disabled = !running;
  $('channels').disabled = busy || loadingChannels;
  for (const id of ['key','channel','target']) $(id).disabled = busy || (id === 'channel' && !loadedKey);
}
async function post(path, body) {
  const response = await fetch('/api/' + path, {method:'POST',headers:{'Content-Type':'application/json','X-Session-Token':token},body:JSON.stringify(body)});
  const data = await response.json();
  if (!response.ok) throw new Error(data.error || '请求失败');
  return data;
}
$('key').addEventListener('input', () => {loadedKey=''; $('channel').replaceChildren(new Option('请重新获取频道','')); controls();});
$('channels').addEventListener('click', async () => {
  loadingChannels=true; controls(); $('notice').textContent='正在获取频道…';
  const submittedKey = key();
  try {
    const data = await post('channels',{key:submittedKey});
    if (key() !== submittedKey) return;
    $('channel').replaceChildren(...data.channels.map(c => new Option(c,c)));
    loadedKey=submittedKey; $('notice').textContent=`已获取 ${data.channels.length} 个频道。`;
    $('debug-channel').value=$('channel').value;
  } catch(error) {$('notice').textContent=error.message;}
  finally {loadingChannels=false; controls();}
});
$('channel').addEventListener('change', () => {$('debug-channel').value=$('channel').value; controls();});
$('download-form').addEventListener('submit', async event => {
  event.preventDefault(); starting=true; controls(); $('notice').textContent='';
  try {await post('start',{key:key(),channel:$('channel').value,target:Number($('target').value)}); await refresh();}
  catch(error) {$('notice').textContent=error.message;}
  finally {starting=false; controls();}
});
$('stop').addEventListener('click', async () => {
  $('stop').disabled=true;
  try {await post('stop',{}); $('notice').textContent='正在停止，等待当前请求或文章保存结束…';}
  catch(error) {$('notice').textContent=error.message;}
});
$('debug-form').addEventListener('submit', async event => {
  event.preventDefault(); $('debug-submit').disabled=true; $('debug-output').textContent='正在请求…';
  try {
    const data=await post('debug',{key:key(),endpoint:$('endpoint').value,channel:$('debug-channel').value,num:Number($('debug-num').value),start:Number($('debug-start').value)});
    const output=JSON.stringify(data,null,2);
    $('debug-output').textContent=output.slice(0,100000)+(output.length>100000?'\n…输出超过 100000 字符，已截断。':'');
  } catch(error) {$('debug-output').textContent=error.message;}
  finally {$('debug-submit').disabled=false;}
});
async function refresh() {
  const response=await fetch('/api/state');
  if (!response.ok) throw new Error('无法读取下载状态');
  const data=await response.json();
  running=data.status==='running'; controls();
  const percent=data.target ? Math.floor(data.saved/data.target*100) : 0;
  $('status').textContent=labels[data.status] || data.status;
  $('progress-text').textContent=`下载新闻 ${data.saved}/${data.target} 条`;
  $('percent').textContent=`已完成 ${percent}%`; $('progress').value=percent;
  for (const id of ['saved','skipped','failed','requests','message','output']) $(id).textContent=data[id];
  const latest=data.logs.length ? data.logs[data.logs.length-1].id : 0;
  if (latest!==lastLog) {
    const logs=$('logs'); const bottom=logs.scrollHeight-logs.scrollTop-logs.clientHeight<40;
    logs.replaceChildren(...data.logs.map(log => {const row=document.createElement('div'); const stamp=document.createElement('time'); stamp.textContent=log.time; row.append(stamp,document.createTextNode(log.message)); return row;}));
    if (bottom) logs.scrollTop=logs.scrollHeight;
    lastLog=latest;
  }
}
async function poll() {
  try {await refresh();}
  catch(error) {$('notice').textContent='与本地服务连接中断，请检查启动窗口。';}
  setTimeout(poll,700);
}
(async () => {
  try {const response=await fetch('/api/session'); token=(await response.json()).token; await poll();}
  catch(error) {$('notice').textContent='初始化失败，请刷新页面。';}
})();