chart/static/app.js

const { createApp, ref, computed, watch, onMounted, onUnmounted } = Vue;

// Shared access token. Blank when the server runs without CHART_AUTH_TOKEN,
// which is the normal local-development case — nothing prompts.
const TOKEN_KEY = 'chart-token';
let authToken = localStorage.getItem(TOKEN_KEY) || '';

// Reconnects and the status poll both hit 401s, so without this a visitor
// who cancels gets asked again every couple of seconds.
let promptDeclined = false;

function promptForToken() {
  if (promptDeclined) return false;
  const entered = window.prompt('Access token for this chart', '');
  if (entered === null) {
    promptDeclined = true;
    return false;
  }
  authToken = entered.trim();
  localStorage.setItem(TOKEN_KEY, authToken);
  return true;
}

async function apiFetch(url, options = {}) {
  const send = () => fetch(url, {
    ...options,
    headers: authToken
      ? { ...(options.headers || {}), 'X-Chart-Token': authToken }
      : { ...(options.headers || {}) },
  });
  const response = await send();
  // A 401 means nothing was written, so retrying the same request is safe.
  if (response.status === 401 && promptForToken()) return send();
  return response;
}

const defaultPrefs = {
  base_tf: '1m',
  enabled: { ma: { '1d': [10, 20, 50, 100, 200], '1h': [] }, manual: true, auto: false },
  hidden_levels_score: false,
};

// Stored preferences outlive the shape they were written in. Anything added to
// defaultPrefs later would otherwise be missing for every existing visitor —
// and a missing `enabled.ma` is a crash, not a cosmetic gap.
function mergePrefs(defaults, stored) {
  if (!stored || typeof stored !== 'object' || Array.isArray(stored)) return structuredClone(defaults);
  const merged = structuredClone(defaults);
  for (const [key, value] of Object.entries(stored)) {
    if (!(key in merged)) continue;
    const fallback = merged[key];
    if (fallback && typeof fallback === 'object' && !Array.isArray(fallback)) {
      merged[key] = mergePrefs(fallback, value);
    } else if (Array.isArray(fallback)) {
      if (Array.isArray(value)) merged[key] = value;
    } else if (value !== null && typeof value !== 'object') {
      merged[key] = value;
    }
  }
  return merged;
}

function loadPrefs() {
  try {
    return mergePrefs(defaultPrefs, JSON.parse(localStorage.getItem('chart-layer-prefs')));
  } catch {
    return structuredClone(defaultPrefs);
  }
}

createApp({
  setup() {
    const status = ref({ stream: 'disconnected', bars_held: {} });
    const price = ref(null);
    const prefs = ref(loadPrefs());
    const timeframe = ref(prefs.value.base_tf || '1m');
    const levels = ref([]);
    const clusters = ref([]);
    const alerts = ref([]);
    let alertSequence = 0;
    const drawMode = ref(false);
    const drawName = ref('');
    const drawColor = ref('#65b7cf');
    const drawWidth = ref(2);
    const drawSide = ref('support');
    const snap = ref(true);
    const drawPoints = ref([]);
    const selectedLine = ref(null);
    const selectedLines = ref([]);
    const timeframes = ['1m', '5m', '15m', '30m', '1h', '1d'];
    const now = ref(Date.now());
    let chartApi = null;
    let socket = null;
    let retryDelay = 2000;
    let timer = null;

    const barAge = computed(() => {
      if (!status.value.last_bar_t) return '—';
      const seconds = Math.max(0, Math.floor(now.value / 1000 - status.value.last_bar_t));
      return seconds < 60 ? `${seconds}s` : `${Math.floor(seconds / 60)}m`;
    });
    const manualLines = computed(() => levels.value.filter(level => level.kind === 'manual'));
    const hasLineSelection = computed(() => selectedLines.value.length > 0 || selectedLine.value != null);
    const allManualSelected = computed(() => manualLines.value.length > 0 && selectedLines.value.length === manualLines.value.length);

    async function refreshStatus() {
      const response = await apiFetch('/api/status');
      if (response.ok) status.value = await response.json();
    }

    function connect() {
      const protocol = location.protocol === 'https:' ? 'wss' : 'ws';
      const query = authToken ? `?token=${encodeURIComponent(authToken)}` : '';
      socket = new WebSocket(`${protocol}://${location.host}/ws${query}`);
      socket.onopen = () => {
        retryDelay = 2000;
        socket.send(JSON.stringify({ type: 'subscribe', tf: timeframe.value }));
        sendPrefs();
      };
      socket.onmessage = ({ data }) => {
        const message = JSON.parse(data);
        if (message.type === 'snapshot') {
          chartApi.setBars(message.bars);
          levels.value = message.levels || [];
          syncVisibleLevels();
          price.value = message.price;
        } else if (message.type === 'bar') {
          chartApi.updateBar(message.bar);
          price.value = message.bar.c;
          status.value.last_bar_t = message.bar.t;
        } else if (message.type === 'levels') {
          levels.value = message.levels;
          syncVisibleLevels();
        } else if (message.type === 'clusters') {
          clusters.value = message.clusters;
          price.value = message.price;
        } else if (message.type === 'alert') {
          // Keyed on a counter, not the timestamp: two alerts inside the same
          // second would collide and Vue would reuse the wrong row.
          alerts.value = [
            { key: ++alertSequence, at: new Date().toLocaleTimeString(), message: message.message },
            ...alerts.value,
          ].slice(0, 20);
          playAlert();
        }
      };
      socket.onclose = async () => {
        status.value.stream = 'disconnected';
        // A refused upgrade reaches the browser as 1006, not 1008: the server
        // rejects the handshake with HTTP 403 before any close frame exists.
        // So the close code cannot distinguish "bad token" from "server
        // restarting". Re-check over HTTP instead — apiFetch prompts for a
        // token when that is what is actually wrong — and back off so a
        // visitor without one is not reconnecting twice a second forever.
        await refreshStatus();
        retryDelay = Math.min(retryDelay * 2, 30000);
        setTimeout(connect, retryDelay);
      };
    }

    // One context for the page, not one per alert. Browsers cap how many a
    // document may hold (~6), after which alerts silently stop making a sound.
    let audioContext = null;

    function playAlert() {
      const Context = window.AudioContext || window.webkitAudioContext;
      if (!Context) return;
      if (!audioContext) audioContext = new Context();
      // Autoplay policy suspends a context created before any user gesture.
      if (audioContext.state === 'suspended') audioContext.resume();
      const oscillator = audioContext.createOscillator();
      const gain = audioContext.createGain();
      oscillator.frequency.value = 740;
      gain.gain.setValueAtTime(0.12, audioContext.currentTime);
      gain.gain.exponentialRampToValueAtTime(0.001, audioContext.currentTime + 0.35);
      oscillator.connect(gain).connect(audioContext.destination);
      oscillator.start();
      oscillator.stop(audioContext.currentTime + 0.35);
      // Nodes are single-use; release them rather than letting them pile up.
      oscillator.onended = () => { oscillator.disconnect(); gain.disconnect(); };
    }

    function toggleDraw() {
      drawMode.value = !drawMode.value;
      drawPoints.value = [];
      selectedLine.value = null;
      chartApi.clearLinePreview();
    }

    function handleChartMove(param) {
      if (!drawMode.value || drawPoints.value.length !== 1) return;
      chartApi.setLinePreview(drawPoints.value[0], chartApi.pointFromClick(param, snap.value), drawColor.value, drawWidth.value);
    }

    async function handleChartClick(param) {
      if (!drawMode.value) {
        selectedLine.value = chartApi.hitTest(param);
        selectedLines.value = selectedLine.value ? [selectedLine.value] : [];
        return;
      }
      const point = chartApi.pointFromClick(param, snap.value);
      if (point.snappedSide) drawSide.value = point.snappedSide;
      drawPoints.value.push(point);
      if (drawPoints.value.length < 2) return;
      chartApi.clearLinePreview();
      const [start, end] = drawPoints.value.sort((a, b) => a.t - b.t);
      if (start.t === end.t) { drawPoints.value = []; return; }
      const temporaryId = `tmp_${Date.now()}`;
      const optimistic = {
        id: temporaryId, kind: 'manual', tf: timeframe.value, side: drawSide.value,
        weight: 1, score: 1, label: drawName.value || `${timeframe.value} ${drawSide.value}`,
        anchor_t: start.t, anchor_p: start.p, slope: (end.p - start.p) / (end.t - start.t),
        points: null, first_t: start.t, last_t: end.t, provisional: false, hidden: false,
        color: drawColor.value, line_width: drawWidth.value,
      };
      levels.value.push(optimistic);
      syncVisibleLevels();
      drawPoints.value = [];
      drawMode.value = false;
      try {
        const response = await apiFetch('/api/lines', {
          method: 'POST', headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ tf: timeframe.value, side: drawSide.value, anchor_t: start.t, anchor_p: start.p, end_t: end.t, end_p: end.p, note: drawName.value, color: drawColor.value, line_width: drawWidth.value }),
        });
        if (!response.ok) throw new Error(`HTTP ${response.status}`);
        const saved = await response.json();
        levels.value = levels.value.filter(level => level.id !== temporaryId);
        if (!levels.value.some(level => level.id === saved.id)) levels.value.push(saved);
        selectedLine.value = saved.id;
        selectedLines.value = [saved.id];
      } catch (error) {
        levels.value = levels.value.filter(level => level.id !== temporaryId);
        console.error('Unable to save line', error);
      }
      syncVisibleLevels();
    }

    async function deleteSelected() {
      const ids = selectedLines.value.length ? selectedLines.value : [selectedLine.value].filter(Boolean);
      await deleteLines(ids);
    }

    async function deleteLine(id) {
      await deleteLines([id]);
    }

    async function deleteLines(ids) {
      if (!ids.length) return;
      const deleting = new Set(ids);
      levels.value = levels.value.filter(level => !deleting.has(level.id));
      if (selectedLine.value && deleting.has(selectedLine.value)) selectedLine.value = null;
      selectedLines.value = selectedLines.value.filter(id => !deleting.has(id));
      syncVisibleLevels();
      const responses = [];
      for (const id of ids) {
        responses.push(await apiFetch(`/api/lines/${encodeURIComponent(id)}`, { method: 'DELETE' }));
      }
      responses.forEach(response => {
        if (!response.ok) console.error(`Unable to delete line: HTTP ${response.status}`);
      });
    }

    function selectLine(id) {
      selectedLine.value = id;
      selectedLines.value = [id];
    }

    function toggleLineSelection(id) {
      selectedLines.value = selectedLines.value.includes(id)
        ? selectedLines.value.filter(value => value !== id)
        : [...selectedLines.value, id];
      selectedLine.value = selectedLines.value.length === 1 ? selectedLines.value[0] : null;
    }

    function toggleSelectAll() {
      selectedLines.value = allManualSelected.value ? [] : manualLines.value.map(line => line.id);
      selectedLine.value = selectedLines.value.length === 1 ? selectedLines.value[0] : null;
    }

    async function deleteSelectedLines() {
      await deleteLines([...selectedLines.value]);
    }

    async function renameLine(line, name) {
      await updateLineStyle(line, { note: name.trim() });
    }

    async function updateLineStyle(line, changes) {
      const response = await apiFetch(`/api/lines/${encodeURIComponent(line.id)}`, {
        method: 'PATCH', headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(changes),
      });
      if (!response.ok) { console.error(`Unable to update line: HTTP ${response.status}`); return; }
      const saved = await response.json();
      levels.value = levels.value.map(level => level.id === line.id ? saved : level);
      syncVisibleLevels();
    }

    async function updateLineGeometry(line) {
      const response = await apiFetch(`/api/lines/${encodeURIComponent(line.id)}`, {
        method: 'PATCH', headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          anchor_t: line.anchor_t, anchor_p: line.anchor_p,
          slope: line.slope, last_t: line.last_t,
        }),
      });
      if (!response.ok) { console.error(`Unable to move line: HTTP ${response.status}`); return; }
      const saved = await response.json();
      levels.value = levels.value.map(level => level.id === line.id ? saved : level);
      syncVisibleLevels();
    }

    async function endLineHere(line) {
      const response = await apiFetch(`/api/lines/${encodeURIComponent(line.id)}`, {
        method: 'PATCH', headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ cutoff_t: line.cutoff_t }),
      });
      if (!response.ok) { console.error(`Unable to end line: HTTP ${response.status}`); return; }
      const saved = await response.json();
      levels.value = levels.value.map(level => level.id === line.id ? saved : level);
      syncVisibleLevels();
    }

    // Backspace is a normal editing key inside a field. Without this guard,
    // fixing a typo in a trendline's name deletes the trendline.
    function isEditing(target) {
      if (!target) return false;
      return target.isContentEditable || ['INPUT', 'TEXTAREA', 'SELECT'].includes(target.tagName);
    }

    function handleKeydown(event) {
      if (isEditing(event.target)) return;
      if ((event.key === 'Delete' || event.key === 'Backspace') && hasLineSelection.value) {
        event.preventDefault();
        deleteSelected();
      }
    }

    function selectTimeframe(tf) {
      timeframe.value = tf;
      prefs.value.base_tf = tf;
      if (socket?.readyState === WebSocket.OPEN) {
        socket.send(JSON.stringify({ type: 'subscribe', tf }));
      }
    }

    function enabled(level) {
      if (level.kind === 'ma') return (prefs.value.enabled.ma[level.tf] || []).includes(level.period);
      if (level.kind === 'manual') return prefs.value.enabled.manual;
      return prefs.value.enabled.auto;
    }

    function syncVisibleLevels() {
      if (chartApi) chartApi.syncLevels(levels.value.filter(enabled));
    }

    function sendPrefs() {
      if (socket?.readyState === WebSocket.OPEN) {
        socket.send(JSON.stringify({ type: 'prefs', ...prefs.value }));
      }
    }

    function allEnabled(tf) {
      const available = tf === '1d' ? [10, 20, 50, 100, 200] : [9, 21];
      return available.every(period => (prefs.value.enabled.ma[tf] || []).includes(period));
    }

    function toggleGroup(tf, checked) {
      prefs.value.enabled.ma[tf] = checked ? (tf === '1d' ? [10, 20, 50, 100, 200] : [9, 21]) : [];
    }

    watch(prefs, () => {
      localStorage.setItem('chart-layer-prefs', JSON.stringify(prefs.value));
      syncVisibleLevels();
      sendPrefs();
    }, { deep: true });

    watch(selectedLine, id => {
      if (chartApi) chartApi.setSelectedLine(id);
    });

    onMounted(() => {
      chartApi = new ConfluenceChart();
      chartApi.create(document.getElementById('chart'));
      chartApi.setClickHandler(handleChartClick);
      chartApi.setMoveHandler(handleChartMove);
      chartApi.setLineChangeHandler(updateLineGeometry);
      chartApi.setLineEndHandler(endLineHere);
      window.addEventListener('keydown', handleKeydown);
      refreshStatus();
      connect();
      timer = setInterval(() => { now.value = Date.now(); refreshStatus(); }, 5000);
    });
    onUnmounted(() => {
      clearInterval(timer);
      if (socket) socket.close();
      if (chartApi) chartApi.destroy();
      window.removeEventListener('keydown', handleKeydown);
    });

    return { status, price, barAge, timeframe, timeframes, prefs, clusters, alerts, drawMode, drawName, drawColor, drawWidth, drawSide, snap, drawPoints, selectedLine, selectedLines, manualLines, hasLineSelection, allManualSelected, selectTimeframe, allEnabled, toggleGroup, toggleDraw, deleteSelected, deleteLine, selectLine, toggleLineSelection, toggleSelectAll, deleteSelectedLines, renameLine, updateLineStyle };
  },
}).mount('#app');