"""Страница просмотра логов в реальном времени (SSE).

Маршруты:
  GET  /ui/logs          — HTML-страница с историей + EventSource
  GET  /ui/logs/stream   — Server-Sent Events (text/event-stream)
"""

from __future__ import annotations

import asyncio
import html as _html
import json
from collections.abc import AsyncGenerator

from fastapi import APIRouter
from starlette.requests import Request
from starlette.responses import HTMLResponse, StreamingResponse

from onguard24 import log_buffer
from onguard24.modules.ui_support import APP_SHELL_CSS, nav_rail_html

router = APIRouter(include_in_schema=False, tags=["web-logs"])

_LEVEL_COLOR: dict[str, str] = {
    "DEBUG": "#71717a",
    "INFO": "#a3e635",
    "WARNING": "#fbbf24",
    "ERROR": "#f87171",
    "CRITICAL": "#ef4444",
}

_LOG_CSS = """
  .log-wrap { background:#0f0f10; border-radius:10px; padding:0.75rem; min-height:20rem;
    max-height:75vh; overflow-y:auto; font-family:monospace; font-size:0.8rem;
    line-height:1.55; color:#e4e4e7; }
  .log-line { display:flex; gap:0.5rem; border-bottom:1px solid #1e1e21; padding:0.12rem 0; }
  .log-line:last-child { border-bottom: none; }
  .log-ts { color:#52525b; flex-shrink:0; }
  .log-lv { flex-shrink:0; width:5.5rem; font-weight:600; }
  .log-name { flex-shrink:0; width:16rem; overflow:hidden; text-overflow:ellipsis;
    white-space:nowrap; color:#a1a1aa; }
  .log-msg { flex:1; word-break:break-all; white-space:pre-wrap; color:#e4e4e7; }
  .lv-DEBUG    { color:#71717a; }
  .lv-INFO     { color:#a3e635; }
  .lv-WARNING  { color:#fbbf24; }
  .lv-ERROR    { color:#f87171; }
  .lv-CRITICAL { color:#ef4444; background:#3f0000; border-radius:3px; padding:0 2px; }
  .log-controls { display:flex; gap:0.75rem; align-items:center; margin-bottom:0.75rem; }
  .log-controls label { font-size:0.85rem; color:#52525b; display:flex; align-items:center; gap:0.3rem; }
  .badge-live { display:inline-block; width:8px; height:8px; border-radius:50%;
    background:#a3e635; box-shadow:0 0 6px #a3e635; animation: pulse 1.6s infinite; }
  .badge-live.disconnected { background:#f87171; box-shadow:0 0 6px #f87171; animation:none; }
  @keyframes pulse { 0%,100%{opacity:1} 50%{opacity:.4} }
  #status-bar { font-size:0.8rem; color:#52525b; margin-bottom:0.5rem; }
"""

_LOG_JS = """
<script>
(function(){
  const wrap = document.getElementById('log-wrap');
  const cntEl = document.getElementById('log-count');
  const statusEl = document.getElementById('status-bar');
  const dot = document.getElementById('live-dot');
  const autoCheck = document.getElementById('auto-scroll');
  const levelFilter = document.getElementById('level-filter');
  let count = parseInt(cntEl.textContent || '0', 10);

  const LEVEL_COLOR = {
    DEBUG:'#71717a', INFO:'#a3e635', WARNING:'#fbbf24', ERROR:'#f87171', CRITICAL:'#ef4444'
  };

  function makeRow(d) {
    const row = document.createElement('div');
    row.className = 'log-line';
    row.dataset.level = d.level;
    const lvl = d.level || 'INFO';
    const col = LEVEL_COLOR[lvl] || '#e4e4e7';
    row.innerHTML =
      '<span class="log-ts">' + esc(d.ts || '') + '</span>' +
      '<span class="log-lv lv-' + lvl + '">' + esc(lvl) + '</span>' +
      '<span class="log-name">' + esc((d.name||'').slice(0,36)) + '</span>' +
      '<span class="log-msg">' + esc(d.msg||'') + '</span>';
    return row;
  }

  function esc(s){ const d=document.createElement('div');d.textContent=s;return d.innerHTML; }

  function applyFilter() {
    const lv = levelFilter.value;
    const ORDER = ['DEBUG','INFO','WARNING','ERROR','CRITICAL'];
    const minIdx = lv ? ORDER.indexOf(lv) : 0;
    wrap.querySelectorAll('.log-line').forEach(function(el){
      const idx = ORDER.indexOf(el.dataset.level);
      el.style.display = (idx >= minIdx) ? '' : 'none';
    });
  }

  levelFilter.addEventListener('change', applyFilter);
  applyFilter();

  function scrollBottom() {
    if (autoCheck.checked) wrap.scrollTop = wrap.scrollHeight;
  }

  scrollBottom();

  const src = new EventSource('/ui/logs/stream');

  src.onopen = function(){
    dot.className = 'badge-live';
    statusEl.textContent = 'Live — соединение установлено';
  };

  src.onmessage = function(e){
    try {
      const d = JSON.parse(e.data);
      const row = makeRow(d);
      wrap.appendChild(row);
      count++;
      cntEl.textContent = count;
      // keep DOM manageable: trim oldest
      while (wrap.children.length > 1000) wrap.removeChild(wrap.firstChild);
      const lv = levelFilter.value;
      if (lv) {
        const ORDER = ['DEBUG','INFO','WARNING','ERROR','CRITICAL'];
        if (ORDER.indexOf(d.level) < ORDER.indexOf(lv)) row.style.display='none';
      }
      scrollBottom();
    } catch(ex){}
  };

  src.onerror = function(){
    dot.className = 'badge-live disconnected';
    statusEl.textContent = 'Соединение потеряно — попытка переподключения…';
  };
})();
</script>
"""


def _line_html(entry: dict) -> str:
    ts = _html.escape(entry.get("ts", ""))
    lvl = entry.get("level", "INFO")
    name = _html.escape((entry.get("name") or "")[:36])
    msg = _html.escape(entry.get("msg") or "")
    return (
        f'<div class="log-line" data-level="{_html.escape(lvl)}">'
        f'<span class="log-ts">{ts}</span>'
        f'<span class="log-lv lv-{_html.escape(lvl)}">{_html.escape(lvl)}</span>'
        f'<span class="log-name">{name}</span>'
        f'<span class="log-msg">{msg}</span>'
        f"</div>"
    )


@router.get("/ui/logs", response_class=HTMLResponse)
async def logs_page(request: Request) -> HTMLResponse:
    history = log_buffer.get_history()
    lines_html = "\n".join(_line_html(e) for e in history)
    count = len(history)
    rail = nav_rail_html("__logs__")

    page = f"""<!DOCTYPE html>
<html lang="ru">
<head>
  <meta charset="utf-8"/>
  <meta name="viewport" content="width=device-width,initial-scale=1"/>
  <title>Логи — onGuard24</title>
  <style>
    {APP_SHELL_CSS}
    {_LOG_CSS}
  </style>
</head>
<body>
<div class="app-shell">
<main class="app-main module-page-main">
  <h1>Логи приложения</h1>
  <div class="log-controls">
    <span><span id="live-dot" class="badge-live"></span> real-time</span>
    <span>Записей: <strong id="log-count">{count}</strong></span>
    <label><input type="checkbox" id="auto-scroll" checked> авто-прокрутка</label>
    <label>
      Уровень:
      <select id="level-filter">
        <option value="">Все</option>
        <option value="DEBUG">DEBUG+</option>
        <option value="INFO">INFO+</option>
        <option value="WARNING">WARNING+</option>
        <option value="ERROR">ERROR+</option>
        <option value="CRITICAL">CRITICAL</option>
      </select>
    </label>
    <a href="/ui/logs" class="og-btn" style="text-decoration:none;padding:0.3rem 0.7rem;font-size:0.8rem">Обновить</a>
  </div>
  <div id="status-bar">Подключаемся к потоку…</div>
  <div class="log-wrap" id="log-wrap">
{lines_html}
  </div>
</main>
{rail}
</div>
{_LOG_JS}
</body>
</html>"""
    return HTMLResponse(page)


@router.get("/ui/logs/stream")
async def logs_stream(request: Request) -> StreamingResponse:
    q = log_buffer.subscribe()

    async def generator() -> AsyncGenerator[bytes, None]:
        try:
            while True:
                if await request.is_disconnected():
                    break
                try:
                    entry = await asyncio.wait_for(q.get(), timeout=20.0)
                    payload = json.dumps(entry, ensure_ascii=False)
                    yield f"data: {payload}\n\n".encode()
                except asyncio.TimeoutError:
                    yield b": keepalive\n\n"
        finally:
            log_buffer.unsubscribe(q)

    return StreamingResponse(
        generator(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "X-Accel-Buffering": "no",
            "Connection": "keep-alive",
        },
    )