const $ = (sel) => document.querySelector(sel);
const state = { overview: null, users: [], events: [] };

const fmtBytes = (value = 0) => {
  const units = ["B", "KB", "MB", "GB", "TB"];
  let n = Number(value) || 0;
  let i = 0;
  while (n >= 1024 && i < units.length - 1) {
    n /= 1024;
    i += 1;
  }
  return `${n.toFixed(i === 0 ? 0 : 1)} ${units[i]}`;
};

const fmtDate = (epoch) => new Date(epoch * 1000).toLocaleString();

const toast = (message) => {
  const el = $("#toast");
  el.textContent = message;
  el.classList.add("show");
  clearTimeout(toast._timer);
  toast._timer = setTimeout(() => el.classList.remove("show"), 2600);
};

const event = (title, detail = "") => {
  state.events.unshift({ title, detail, time: new Date() });
  state.events = state.events.slice(0, 8);
  renderEvents();
};

async function api(path, options = {}) {
  const headers = {
    "Accept": "application/json",
    "X-GoTelegram-Admin": "1",
    ...(options.headers || {}),
  };
  if (options.body && !headers["Content-Type"]) headers["Content-Type"] = "application/json";
  const res = await fetch(path, { ...options, headers, credentials: "same-origin" });
  const data = await res.json().catch(() => ({}));
  if (!res.ok || data.ok === false) throw new Error(data.error || `HTTP ${res.status}`);
  return data.data ?? data;
}

function renderServices(services = {}) {
  const items = [
    { key: "telemt", label: "telemt", api: "telemt" },
    { key: "nginx", label: "nginx", api: "nginx" },
    { key: "bot", label: "bot", api: "gotelegram-bot" },
    { key: "stats", label: "stats", api: "gotelegram-stats" },
    { key: "admin", label: "admin", api: "gotelegram-admin" },
  ];
  $("#services").innerHTML = items.map((item) => {
    const status = services[item.key] || "unknown";
    return `<article class="service ${status}">
      <strong>${item.label}</strong>
      <div class="status"><span class="dot"></span><span>${status}</span></div>
      <button class="soft" data-restart="${item.api}" ${item.key === "admin" ? "disabled" : ""}>Restart</button>
    </article>`;
  }).join("");
}

function renderOverview() {
  const data = state.overview;
  if (!data) return;
  const cfg = data.config || {};
  const stats = data.stats_current || {};
  $("#metricMode").textContent = cfg.mode || "--";
  $("#metricDomain").textContent = cfg.domain || cfg.mask_host || "--";
  $("#metricUsers").textContent = data.users_count ?? 0;
  $("#metricProxyTraffic").textContent = fmtBytes(stats.proxy_bytes);
  $("#metricProxyPackets").textContent = `${stats.proxy_pkts || 0} packets`;
  $("#metricSiteTraffic").textContent = fmtBytes(stats.site_bytes);
  $("#metricSitePackets").textContent = `${stats.site_pkts || 0} packets`;
  $("#runtimeBox").textContent = JSON.stringify(data.runtime_summary || {}, null, 2);
  renderServices(data.services || {});
  renderBackups(data.backups || []);
  drawTrafficChart(data.stats_history || []);
}

function renderUsers() {
  const tbody = $("#usersTable");
  if (!state.users.length) {
    tbody.innerHTML = `<tr><td colspan="4">No keys yet</td></tr>`;
    return;
  }
  tbody.innerHTML = state.users.map((user) => `
    <tr>
      <td><strong>${escapeHtml(user.name)}</strong>${user.main ? " <small>main</small>" : ""}</td>
      <td><code title="${escapeHtml(user.secret)}">${escapeHtml(user.secret)}</code></td>
      <td><button class="soft" data-copy="${escapeAttr(user.link)}">Copy link</button></td>
      <td class="actions">
        <button class="soft" data-copy="${escapeAttr(user.secret)}">Copy secret</button>
        <button class="danger" data-delete="${escapeAttr(user.name)}" ${user.main ? "disabled" : ""}>Delete</button>
      </td>
    </tr>
  `).join("");
}

function renderBackups(backups) {
  const box = $("#backupsList");
  if (!backups.length) {
    box.innerHTML = `<div class="backup-item"><strong>No backups</strong><span></span></div>`;
    return;
  }
  box.innerHTML = backups.map((item) => `
    <div class="backup-item">
      <div>
        <strong>${escapeHtml(item.name)}</strong>
        <span>${escapeHtml(item.path)} · ${fmtDate(item.mtime)}</span>
      </div>
      <div>${fmtBytes(item.size)}${item.encrypted ? " · encrypted" : ""}</div>
    </div>
  `).join("");
}

function renderEvents() {
  $("#events").innerHTML = state.events.map((item) => `
    <div class="event">
      <strong>${escapeHtml(item.title)}</strong>
      <small>${escapeHtml(item.detail || item.time.toLocaleTimeString())}</small>
    </div>
  `).join("");
}

function drawTrafficChart(rows) {
  const canvas = $("#trafficChart");
  const ctx = canvas.getContext("2d");
  const ratio = window.devicePixelRatio || 1;
  const rect = canvas.getBoundingClientRect();
  canvas.width = Math.max(320, rect.width) * ratio;
  canvas.height = 260 * ratio;
  ctx.setTransform(ratio, 0, 0, ratio, 0, 0);
  const w = canvas.width / ratio;
  const h = canvas.height / ratio;
  ctx.clearRect(0, 0, w, h);
  ctx.fillStyle = "#ffffff";
  ctx.fillRect(0, 0, w, h);

  const pad = { l: 48, r: 18, t: 20, b: 34 };
  const points = rows.length ? rows : [{ proxy_delta: 0, site_delta: 0 }, { proxy_delta: 0, site_delta: 0 }];
  const max = Math.max(1, ...points.map((p) => Math.max(p.proxy_delta || 0, p.site_delta || 0)));
  const plotW = w - pad.l - pad.r;
  const plotH = h - pad.t - pad.b;

  ctx.strokeStyle = "#dfe6f1";
  ctx.lineWidth = 1;
  ctx.beginPath();
  for (let i = 0; i <= 4; i += 1) {
    const y = pad.t + (plotH / 4) * i;
    ctx.moveTo(pad.l, y);
    ctx.lineTo(w - pad.r, y);
  }
  ctx.stroke();

  const line = (key, color) => {
    ctx.strokeStyle = color;
    ctx.lineWidth = 2.4;
    ctx.beginPath();
    points.forEach((p, i) => {
      const x = pad.l + (plotW * i) / Math.max(1, points.length - 1);
      const y = pad.t + plotH - ((p[key] || 0) / max) * plotH;
      if (i === 0) ctx.moveTo(x, y);
      else ctx.lineTo(x, y);
    });
    ctx.stroke();
  };
  line("proxy_delta", "#2563eb");
  line("site_delta", "#0f9f6e");

  ctx.fillStyle = "#647087";
  ctx.font = "12px system-ui";
  ctx.fillText(`max ${fmtBytes(max)}/min`, pad.l, 14);
  ctx.fillStyle = "#2563eb";
  ctx.fillText("proxy", pad.l, h - 10);
  ctx.fillStyle = "#0f9f6e";
  ctx.fillText("site", pad.l + 58, h - 10);
}

async function refreshAll() {
  const btn = $("#refreshBtn");
  btn.disabled = true;
  try {
    state.overview = await api("/api/overview");
    state.users = await api("/api/users");
    renderOverview();
    renderUsers();
  } catch (err) {
    if (err.message !== "Unauthorized") toast(err.message);
  } finally {
    btn.disabled = false;
  }
}

async function addUser(name) {
  const data = await api("/api/users", {
    method: "POST",
    body: JSON.stringify({ name }),
  });
  event("Key created", data.name);
  toast("Key created");
  await refreshAll();
}

async function deleteUser(name) {
  await api(`/api/users/${encodeURIComponent(name)}`, { method: "DELETE" });
  event("Key deleted", name);
  toast("Key deleted");
  await refreshAll();
}

async function createBackup() {
  const btn = $("#createBackupBtn");
  btn.disabled = true;
  try {
    const data = await api("/api/backups", { method: "POST", body: "{}" });
    event("Backup created", data.path || "");
    toast("Backup created");
    await refreshAll();
  } catch (err) {
    toast(err.message);
  } finally {
    btn.disabled = false;
  }
}

async function loadLogs() {
  const service = $("#logService").value;
  $("#logsBox").textContent = "Loading...";
  try {
    $("#logsBox").textContent = await api(`/api/logs?service=${encodeURIComponent(service)}`);
  } catch (err) {
    $("#logsBox").textContent = err.message;
  }
}

async function restartService(name) {
  await api(`/api/services/${encodeURIComponent(name)}/restart`, { method: "POST", body: "{}" });
  event("Service restarted", name);
  toast(`${name} restarted`);
  await refreshAll();
}

function escapeHtml(value) {
  return String(value ?? "").replace(/[&<>"']/g, (ch) => ({
    "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#039;",
  })[ch]);
}

function escapeAttr(value) {
  return escapeHtml(value).replace(/`/g, "&#096;");
}

document.addEventListener("click", async (eventObj) => {
  const target = eventObj.target.closest("button");
  if (!target) return;

  if (target.dataset.copy) {
    await navigator.clipboard.writeText(target.dataset.copy);
    toast("Copied");
  }
  if (target.dataset.delete) {
    const name = target.dataset.delete;
    if (confirm(`Delete key ${name}?`)) deleteUser(name).catch((err) => toast(err.message));
  }
  if (target.dataset.restart) {
    const name = target.dataset.restart;
    if (confirm(`Restart ${name}?`)) restartService(name).catch((err) => toast(err.message));
  }
});

$("#addUserForm").addEventListener("submit", (eventObj) => {
  eventObj.preventDefault();
  const input = $("#userName");
  const name = input.value.trim();
  if (!/^[A-Za-z0-9_.-]{1,48}$/.test(name)) {
    toast("Use latin letters, digits, _, . or -");
    return;
  }
  input.value = "";
  addUser(name).catch((err) => toast(err.message));
});

$("#refreshBtn").addEventListener("click", refreshAll);
$("#createBackupBtn").addEventListener("click", createBackup);
$("#loadLogsBtn").addEventListener("click", loadLogs);
window.addEventListener("resize", () => state.overview && drawTrafficChart(state.overview.stats_history || []));

document.querySelectorAll("nav a").forEach((link) => {
  link.addEventListener("click", () => {
    document.querySelectorAll("nav a").forEach((item) => item.classList.remove("active"));
    link.classList.add("active");
  });
});

refreshAll();
loadLogs();