"""主页：上传入口 + 最近 10 个任务的实时进度。

共享 _shared.py 的 BASE_CSS / SHARED_JS / 上传协议 JS。
页面专属：refreshList（拉取最近任务）、makeTaskCard、pollTask（轮询进行中任务）。
"""

from __future__ import annotations

from ._shared import POLL_INTERVAL, render_page, render_upload_js

RECENT_LIMIT = 10
LIST_REFRESH_INTERVAL = 5000

_PAGE_JS = f"""
const POLL_INTERVAL = {POLL_INTERVAL};
const LIST_REFRESH_INTERVAL = {LIST_REFRESH_INTERVAL};
const RECENT_LIMIT = {RECENT_LIMIT};

const tasksEl = document.getElementById("tasks");
const emptyEl = document.getElementById("empty");
let pollingIds = new Set();

// 初始化上传区
initUpload(document.getElementById("drop"), document.getElementById("file-input"), tasksEl);

// ==================== 最近任务列表 ====================

async function refreshList() {{
  try {{
    const r = await fetch("/api/tasks?limit=" + RECENT_LIMIT);
    if (!r.ok) return;
    const data = await r.json();
    renderTasks(data.tasks);
  }} catch (e) {{}}
}}

function renderTasks(tasks) {{
  tasksEl.querySelectorAll(".server-task").forEach(el => el.remove());
  const hasUploadCards = tasksEl.querySelector(".upload-task") !== null;
  emptyEl.style.display = (tasks.length === 0 && !hasUploadCards) ? "block" : "none";

  for (const task of tasks) {{
    tasksEl.appendChild(makeTaskCard(task));
  }}
  // 对进行中的任务启动轮询（上传会话用 upload_id 去重，Task 用 id 去重）
  for (const task of tasks) {{
    if (!ACTIVE_STATES.includes(task.status)) continue;
    const pollKey = task.is_upload ? task.upload_id : String(task.id);
    if (pollingIds.has(pollKey)) continue;
    pollingIds.add(pollKey);
    pollTask(task);
  }}
}}

function downloadLinks(taskId) {{
  return `<a href="/api/tasks/${{taskId}}/subtitle?type=bilingual" class="dl">双语 SRT</a>`
    + ` <a href="/api/tasks/${{taskId}}/subtitle?type=en" class="dl">英</a>`
    + ` <a href="/api/tasks/${{taskId}}/subtitle?type=zh" class="dl">中</a>`;
}}

function makeTaskCard(task) {{
  const el = document.createElement("div");
  el.className = "card task server-task";
  el.dataset.taskId = task.id;
  if (task.is_upload) el.dataset.uploadId = task.upload_id;
  el.innerHTML = renderTaskInner(task);
  return el;
}}

function renderTaskInner(task) {{
  const label = STATUS_LABEL[task.status] || task.status;
  const stateClass = task.status === "done" ? "state-done"
    : task.status === "failed" ? "state-fail" : "state-running";

  // 上传中：created_at 可能是 naive UTC，前端按 UTC 解析
  let created;
  try {{ created = fmtDateTime24(new Date(task.created_at + "Z")); }}
  catch (e) {{ created = task.created_at; }}

  let body;
  if (task.status === "done") {{
    body = `<div class="task-meta"><b>完成</b> · ${{downloadLinks(task.id)}}</div>`;
  }} else if (task.status === "failed") {{
    body = `<div class="task-meta fail-msg">${{escapeHtml(task.error || "未知错误")}}</div>`;
  }} else {{
    const pct = (task.progress == null) ? 0 : task.progress;
    const sizeInfo = task.size_bytes ? ` · ${{fmtBytes(task.size_bytes)}}` : "";
    body = `<div class="bar"><div class="fill" style="width:${{pct}}%"></div><span class="pct">${{pct.toFixed(0)}}%${{sizeInfo}}</span></div>`;
  }}
  return `
    <div class="task-head">
      <span class="fname">${{task.is_upload ? "" : "#" + task.id + " "}}${{escapeHtml(task.filename)}}</span>
      <span class="fstate ${{stateClass}}">${{label}}</span>
    </div>
    ${{body}}
    <div class="task-time">${{created}}</div>`;
}}

async function pollTask(task) {{
  // 上传会话：轮询 upload status 接口；Task：轮询 task 接口
  const isUpload = task.is_upload === true && task.upload_id;
  const url = isUpload
    ? "/api/tasks/chunk-uploads/" + task.upload_id + "/status"
    : "/api/tasks/" + task.id;
  let backoff = POLL_INTERVAL;
  const tick = async () => {{
    try {{
      const r = await fetch(url);
      if (!r.ok) {{ pollingIds.delete(task.id); pollingIds.delete(task.upload_id); return; }}
      const data = await r.json();

      if (isUpload) {{
        // 上传会话：complete 后 task_id 出现，切换为 Task 轮询
        if (data.completed && data.task_id) {{
          pollingIds.delete(task.upload_id);
          pollingIds.add(data.task_id);
          pollTask({{ id: data.task_id, is_upload: false }});
          // 刷新列表让新 Task 卡片出现
          refreshList();
          return;
        }}
        // 更新上传进度
        const card = tasksEl.querySelector('.server-task[data-upload-id="' + task.upload_id + '"]');
        if (!card) {{ pollingIds.delete(task.upload_id); return; }}
        const uploaded = (data.uploaded_chunks || []).length;
        const total = data.total_chunks || 1;
        const pct = Math.min(4, uploaded / total * 4);
        const fakeTask = {{
          status: "uploading", progress: pct, is_upload: true,
          upload_id: task.upload_id, filename: data.filename,
          size_bytes: data.size_bytes, created_at: task.created_at,
        }};
        card.innerHTML = renderTaskInner(fakeTask);
        backoff = POLL_INTERVAL;
        setTimeout(tick, backoff);
      }} else {{
        // Task 轮询
        const card = tasksEl.querySelector('.server-task[data-task-id="' + task.id + '"]');
        if (!card) {{ pollingIds.delete(task.id); return; }}
        card.innerHTML = renderTaskInner(data);
        if (data.status === "done" || data.status === "failed") {{
          pollingIds.delete(task.id);
          return;
        }}
        backoff = POLL_INTERVAL;
        setTimeout(tick, backoff);
      }}
    }} catch (e) {{
      // 网络错误：指数退避，上限 30s
      backoff = Math.min(backoff * 1.6, 30000);
      setTimeout(tick, backoff);
    }}
  }};
  tick();
}}

// 启动
refreshList();
setInterval(refreshList, LIST_REFRESH_INTERVAL);
"""

_BODY = """
<h1>音频转字幕</h1>
<p class="sub">上传视频或音频文件，自动生成双语（英/中）SRT 字幕。支持大文件分片上传与断点续传。</p>

<div id="drop" class="drop">
  <p class="drop-hint">把文件拖到这里，或</p>
  <label class="btn">选择文件<input id="file-input" type="file" multiple hidden></label>
</div>

<h2>最近任务</h2>
<div id="tasks" class="tasks"></div>
<div id="empty" class="empty" style="display:none">暂无任务，上传文件后这里会显示进度。</div>
"""


def render() -> str:
    # 上传完成后刷新任务列表，让新任务出现在卡片中
    upload_js = render_upload_js(on_complete="refreshList();")
    return render_page(
        title="audio2text — 音频转字幕",
        nav_active="home",
        body=_BODY,
        page_js=upload_js + _PAGE_JS,
    )