import {
  acceptIncomingCall,
  declineIncomingCall,
  hangupActiveCall,
  setMicMuted,
  subscribeCallState,
} from './call-service.js';

const MINIMIZED_BAR_HEIGHT_PX = 44;

let rootEl = null;
let overlayEl = null;
let panelEl = null;
let headerEl = null;
let titleEl = null;
let statusEl = null;
let muteBtn = null;
let acceptBtn = null;
let declineBtn = null;
let hangupBtn = null;
let minimizeBtn = null;
let barEl = null;
let barTextEl = null;
let unbind = null;
let tickerId = 0;
let currentSnapshot = null;
let minimized = false;

function resolveAppShell() {
  return document.querySelector('.app-shell') || document.body;
}

function pad2(value) {
  return String(Math.max(0, Number(value) || 0)).padStart(2, '0');
}

function formatElapsedMs(ms) {
  const totalSec = Math.max(0, Math.floor(Number(ms || 0) / 1000));
  const hours = Math.floor(totalSec / 3600);
  const minutes = Math.floor((totalSec % 3600) / 60);
  const seconds = totalSec % 60;
  if (hours > 0) return `${pad2(hours)}:${pad2(minutes)}:${pad2(seconds)}`;
  return `${pad2(minutes)}:${pad2(seconds)}`;
}

function getSnapshotElapsedMs(snapshot) {
  const baseMs = Number(snapshot?.connectedAtMs || snapshot?.startedAtMs || 0);
  if (!baseMs || !Number.isFinite(baseMs)) return 0;
  return Math.max(0, Date.now() - baseMs);
}

function buildBarText(snapshot) {
  const peer = String(snapshot?.peerLogin || '').trim() || 'пользователь';
  const elapsed = formatElapsedMs(getSnapshotElapsedMs(snapshot));
  return `Звонок с ${peer} · ${elapsed}`;
}

function setMinimized(nextValue) {
  minimized = Boolean(nextValue);
  render();
}

function ensureTicker() {
  const shouldTick = Boolean(currentSnapshot);
  if (shouldTick && !tickerId) {
    tickerId = window.setInterval(() => {
      if (!currentSnapshot) return;
      render();
    }, 1000);
  }
  if (!shouldTick && tickerId) {
    window.clearInterval(tickerId);
    tickerId = 0;
  }
}

function ensureUi() {
  if (rootEl) return;

  rootEl = document.createElement('section');
  rootEl.className = 'call-ui-root';
  rootEl.hidden = true;

  barEl = document.createElement('button');
  barEl.type = 'button';
  barEl.className = 'call-minimized-bar';
  barEl.hidden = true;
  barEl.addEventListener('click', () => {
    if (!currentSnapshot) return;
    setMinimized(false);
  });

  barTextEl = document.createElement('span');
  barTextEl.className = 'call-minimized-bar-text';
  barEl.append(barTextEl);

  overlayEl = document.createElement('div');
  overlayEl.className = 'call-overlay';
  overlayEl.hidden = true;

  panelEl = document.createElement('div');
  panelEl.className = 'call-overlay-panel';

  headerEl = document.createElement('div');
  headerEl.className = 'call-overlay-head';

  titleEl = document.createElement('h2');
  titleEl.className = 'call-overlay-title';

  minimizeBtn = document.createElement('button');
  minimizeBtn.type = 'button';
  minimizeBtn.className = 'secondary-btn call-overlay-minimize-btn';
  minimizeBtn.textContent = 'Свернуть';
  minimizeBtn.addEventListener('click', () => {
    if (!currentSnapshot) return;
    setMinimized(true);
  });

  statusEl = document.createElement('div');
  statusEl.className = 'call-overlay-status';

  const controls = document.createElement('div');
  controls.className = 'call-overlay-controls';

  muteBtn = document.createElement('button');
  muteBtn.type = 'button';
  muteBtn.className = 'secondary-btn';
  muteBtn.textContent = 'Микрофон';
  muteBtn.addEventListener('click', async () => {
    const nowMuted = muteBtn.dataset.muted === '1';
    await setMicMuted(!nowMuted);
  });

  acceptBtn = document.createElement('button');
  acceptBtn.type = 'button';
  acceptBtn.className = 'call-accept-btn';
  acceptBtn.textContent = 'Ответить';
  acceptBtn.addEventListener('click', async () => {
    await acceptIncomingCall();
  });

  declineBtn = document.createElement('button');
  declineBtn.type = 'button';
  declineBtn.className = 'destructive-btn';
  declineBtn.textContent = 'Сбросить';
  declineBtn.addEventListener('click', async () => {
    await declineIncomingCall();
  });

  hangupBtn = document.createElement('button');
  hangupBtn.type = 'button';
  hangupBtn.className = 'destructive-btn';
  hangupBtn.textContent = 'Положить трубку';
  hangupBtn.addEventListener('click', async () => {
    await hangupActiveCall();
  });

  controls.append(muteBtn, acceptBtn, declineBtn, hangupBtn);
  headerEl.append(titleEl, minimizeBtn);
  panelEl.append(headerEl, statusEl, controls);
  overlayEl.append(panelEl);
  rootEl.append(barEl, overlayEl);
  resolveAppShell().append(rootEl);
}

function applyExpandedState(snapshot) {
  overlayEl.hidden = false;
  barEl.hidden = true;

  titleEl.textContent = `Звонок: ${snapshot.peerLogin || 'пользователь'}`;
  statusEl.textContent = snapshot.statusText || '';

  const muted = Boolean(snapshot.muted);
  muteBtn.dataset.muted = muted ? '1' : '0';
  muteBtn.textContent = muted ? 'Включить микрофон' : 'Выключить микрофон';

  muteBtn.hidden = !snapshot.canMute;
  muteBtn.disabled = !snapshot.canMute;

  acceptBtn.hidden = !snapshot.canAnswer;
  declineBtn.hidden = !snapshot.canDecline;
  hangupBtn.hidden = !snapshot.canHangup;
}

function applyMinimizedState(snapshot) {
  overlayEl.hidden = true;
  barEl.hidden = false;
  barTextEl.textContent = buildBarText(snapshot);
}

function syncShellState() {
  const appShell = resolveAppShell();
  if (!appShell) return;
  if (currentSnapshot && minimized) {
    appShell.classList.add('has-minimized-call');
    const measuredHeight = Math.max(
      MINIMIZED_BAR_HEIGHT_PX,
      Math.ceil(Number(barEl?.offsetHeight || 0)),
    );
    appShell.style.setProperty('--call-minimized-bar-height', `${measuredHeight}px`);
  } else {
    appShell.classList.remove('has-minimized-call');
    appShell.style.removeProperty('--call-minimized-bar-height');
  }
}

function render() {
  ensureUi();
  rootEl.hidden = !currentSnapshot;
  ensureTicker();

  if (!currentSnapshot) {
    syncShellState();
    overlayEl.hidden = true;
    barEl.hidden = true;
    return;
  }

  if (minimized) {
    applyMinimizedState(currentSnapshot);
    syncShellState();
    return;
  }

  applyExpandedState(currentSnapshot);
  syncShellState();
}

function applyCallState(snapshot) {
  ensureUi();
  currentSnapshot = snapshot || null;
  if (!currentSnapshot) {
    minimized = false;
  }
  render();
}

export function initCallUiOverlay() {
  ensureUi();
  if (unbind) {
    unbind();
    unbind = null;
  }
  unbind = subscribeCallState(applyCallState);
}