// Unified [tag] log scrollback — consumes /ws/logs (backlog once, then new
// lines as they're appended to lidar.log/camera.log/recording.log).

const MAX_RENDERED_LINES = 2000;

export function initLogPanel() {
  const body = document.getElementById("log-body");
  const autoscrollChk = document.getElementById("log-autoscroll");
  const clearBtn = document.getElementById("btn-log-clear");

  function appendLine({ tag, line }) {
    const row = document.createElement("div");
    row.className = `log-line tag-${tag}`;
    const tagSpan = document.createElement("span");
    tagSpan.className = "log-tag";
    tagSpan.textContent = `[${tag}]`;
    const textSpan = document.createElement("span");
    textSpan.className = "log-text";
    textSpan.textContent = line;
    row.appendChild(tagSpan);
    row.appendChild(textSpan);
    body.appendChild(row);
    while (body.childElementCount > MAX_RENDERED_LINES) {
      body.removeChild(body.firstChild);
    }
    if (autoscrollChk.checked) {
      body.scrollTop = body.scrollHeight;
    }
  }

  clearBtn.onclick = () => { body.innerHTML = ""; };

  const proto = location.protocol === "https:" ? "wss:" : "ws:";
  function connect() {
    const ws = new WebSocket(`${proto}//${location.host}/ws/logs`);
    ws.onmessage = (ev) => {
      const msg = JSON.parse(ev.data);
      if (msg.backlog) msg.backlog.forEach(appendLine);
      if (msg.lines) msg.lines.forEach(appendLine);
    };
    ws.onclose = () => setTimeout(connect, 1500);
    ws.onerror = () => ws.close();
  }
  connect();
}