// --- FT4 Decoder Plugin (server-side decode) ---
// SPDX-FileCopyrightText: 2026 Stanislaw Grams <stanislawgrams@gmail.com>
// SPDX-License-Identifier: BSD-2-Clause

function ft8RenderMessage(message) {
  if (typeof renderFt8Message === "function") return renderFt8Message(message);
  if (typeof ft8EscapeHtml === "function") return ft8EscapeHtml(message);
  return message;
}

const ft4Status = document.getElementById("ft4-status");
const ft4PeriodEl = document.getElementById("ft4-period");
const ft4MessagesEl = document.getElementById("ft4-messages");
const ft4FilterInput = document.getElementById("ft4-filter");
const ft4PauseBtn = document.getElementById("ft4-pause-btn");
const FT4_PERIOD_MS = 7500;
let ft4FilterText = "";
let ft4MessageHistory = [];
let ft4Paused = false;
let ft4BufferedWhilePaused = 0;

function currentFt4HistoryRetentionMs() {
  return typeof window.getDecodeHistoryRetentionMs === "function"
    ? window.getDecodeHistoryRetentionMs()
    : 24 * 60 * 60 * 1000;
}

function pruneFt4MessageHistory() {
  const cutoffMs = Date.now() - currentFt4HistoryRetentionMs();
  ft4MessageHistory = ft4MessageHistory.filter((msg) => Number(msg?._tsMs ?? msg?.ts_ms) >= cutoffMs);
}

function scheduleFt4Ui(key, job) {
  if (typeof window.trxScheduleUiFrameJob === "function") {
    window.trxScheduleUiFrameJob(key, job);
    return;
  }
  job();
}

function scheduleFt4HistoryRender() { scheduleFt4Ui("ft4-history", () => renderFt4History()); }

function normalizeFt4DisplayFreqHz(freqHz) {
  const rawHz = Number(freqHz);
  if (!Number.isFinite(rawHz)) return null;
  const baseHz = Number.isFinite(window.ft8BaseHz) ? Number(window.ft8BaseHz) : null;
  if (Number.isFinite(baseHz) && baseHz > 0 && rawHz >= 0 && rawHz < 100000) {
    return baseHz + rawHz;
  }
  return rawHz;
}

function updateFt4PeriodTimer() {
  if (!ft4PeriodEl) return;
  const nowMs = Date.now();
  const remaining = (FT4_PERIOD_MS - nowMs % FT4_PERIOD_MS) / 1000;
  ft4PeriodEl.textContent = `Next slot ${remaining.toFixed(1)}s`;
}

updateFt4PeriodTimer();
setInterval(updateFt4PeriodTimer, 250);

function renderFt4Row(msg) {
  const row = document.createElement("div");
  row.className = "ft8-row";
  const rawMessage = (msg.message || "").toString();
  row.dataset.message = rawMessage.toUpperCase();
  row.dataset.decoder = "ft4";
  row.dataset.storedFreqHz = Number.isFinite(msg.freq_hz) ? String(msg.freq_hz) : "";
  const snr = Number.isFinite(msg.snr_db) ? msg.snr_db.toFixed(1) : "--";
  const dt = Number.isFinite(msg.dt_s) ? msg.dt_s.toFixed(2) : "--";
  const displayFreqHz = normalizeFt4DisplayFreqHz(msg.freq_hz);
  const freq = Number.isFinite(displayFreqHz) ? displayFreqHz.toFixed(0) : "--";
  const renderedMessage = ft8RenderMessage(rawMessage);
  const tsMs = msg._tsMs ?? msg.ts_ms;
  const timeStr = tsMs ? new Date(tsMs).toLocaleTimeString([], { hour: "2-digit", minute: "2-digit", second: "2-digit" }) : "--:--:--";
  row.innerHTML = `<span class="ft8-time">${timeStr}</span><span class="ft8-snr">${snr}</span><span class="ft8-dt">${dt}</span><span class="ft8-freq">${freq}</span><span class="ft8-msg">${renderedMessage}</span>`;
  return row;
}

function updateFt4PauseUi() {
  if (!ft4PauseBtn) return;
  ft4PauseBtn.textContent = ft4Paused ? "Resume" : "Pause";
  ft4PauseBtn.classList.toggle("active", ft4Paused);
}

function renderFt4History() {
  pruneFt4MessageHistory();
  if (!ft4MessagesEl || ft4Paused) { updateFt4PauseUi(); return; }
  const filter = ft4FilterText;
  const fragment = document.createDocumentFragment();
  for (let i = 0; i < ft4MessageHistory.length; i++) {
    const msg = ft4MessageHistory[i];
    if (filter && !(msg.message || "").toString().toUpperCase().includes(filter)) continue;
    fragment.appendChild(renderFt4Row(msg));
  }
  ft4MessagesEl.replaceChildren(fragment);
  updateFt4PauseUi();
}

function addFt4Message(msg) {
  msg._tsMs = Number.isFinite(msg?.ts_ms) ? Number(msg.ts_ms) : Date.now();
  ft4MessageHistory.unshift(msg);
  pruneFt4MessageHistory();
  if (ft4Paused) { ft4BufferedWhilePaused += 1; updateFt4PauseUi(); return; }
  scheduleFt4HistoryRender();
}

function normalizeServerFt4Message(msg) {
  const raw = (msg.message || "").toString();
  const locatorDetails = typeof ft8ExtractLocatorDetails === "function" ? ft8ExtractLocatorDetails(raw) : [];
  const grids = locatorDetails.length > 0
    ? locatorDetails.map((d) => d.grid)
    : (typeof ft8ExtractAllGrids === "function" ? ft8ExtractAllGrids(raw) : []);
  const station = typeof ft8ExtractLikelyCallsign === "function" ? ft8ExtractLikelyCallsign(raw) : null;
  const rfHz = normalizeFt4DisplayFreqHz(msg.freq_hz);
  return {
    raw, grids, station, rfHz, locatorDetails,
    history: {
      receiver: window.getDecodeRigMeta ? window.getDecodeRigMeta() : null,
      ts_ms: msg.ts_ms, snr_db: msg.snr_db, dt_s: msg.dt_s,
      freq_hz: Number.isFinite(rfHz) ? rfHz : msg.freq_hz,
      message: msg.message,
    },
  };
}

window.onServerFt4Batch = function(messages) {
  if (!Array.isArray(messages) || messages.length === 0) return;
  if (ft4Status) ft4Status.textContent = ft4Paused ? "Paused" : "Receiving";
  const normalized = [];
  for (const msg of messages) {
    const next = normalizeServerFt4Message(msg);
    if (next.grids.length > 0 && window.ft8MapAddLocator) {
      window.ft8MapAddLocator(next.raw, next.grids, "ft4", next.station, { ...msg, freq_hz: next.rfHz, locator_details: next.locatorDetails });
    }
    next.history._tsMs = Number.isFinite(next.history?.ts_ms) ? Number(next.history.ts_ms) : Date.now();
    normalized.push(next.history);
  }
  normalized.reverse();
  ft4MessageHistory = normalized.concat(ft4MessageHistory);
  pruneFt4MessageHistory();
  if (ft4Paused) { ft4BufferedWhilePaused += messages.length; updateFt4PauseUi(); return; }
  scheduleFt4HistoryRender();
};

window.restoreFt4History = function(messages) { window.onServerFt4Batch(messages); };
window.pruneFt4HistoryView = function() { pruneFt4MessageHistory(); renderFt4History(); };

window.resetFt4HistoryView = function() {
  if (ft4MessagesEl) ft4MessagesEl.innerHTML = "";
  ft4MessageHistory = [];
  ft4BufferedWhilePaused = 0;
  renderFt4History();
};

if (ft4FilterInput) {
  ft4FilterInput.addEventListener("input", () => {
    ft4FilterText = ft4FilterInput.value.trim().toUpperCase();
    renderFt4History();
  });
}

if (ft4PauseBtn) {
  ft4PauseBtn.addEventListener("click", () => {
    ft4Paused = !ft4Paused;
    if (!ft4Paused) { ft4BufferedWhilePaused = 0; renderFt4History(); } else { updateFt4PauseUi(); }
  });
}

document.getElementById("ft4-decode-toggle-btn")?.addEventListener("click", async () => {
  try { await postPath("/toggle_ft4_decode"); } catch (e) { console.error("FT4 toggle failed", e); }
});

document.getElementById("ft4-clear-btn")?.addEventListener("click", async () => {
  try {
    await postPath("/clear_ft4_decode");
    window.resetFt4HistoryView();
  } catch (e) { console.error("FT4 clear failed", e); }
});

window.onServerFt4 = function(msg) {
  if (ft4Status) ft4Status.textContent = ft4Paused ? "Paused" : "Receiving";
  const next = normalizeServerFt4Message(msg);
  if (next.grids.length > 0 && window.ft8MapAddLocator) {
    window.ft8MapAddLocator(next.raw, next.grids, "ft4", next.station, { ...msg, freq_hz: next.rfHz, locator_details: next.locatorDetails });
  }
  addFt4Message(next.history);
};

updateFt4PauseUi();