/**
 * Application wiring.
 *
 * Flow:  user text -> POST /api/robot/speak -> backend -> robot
 *        robot lifecycle -> backend event bus -> WebSocket -> this file -> UI
 *
 * The POST returns as soon as the robot acknowledges the utterance; everything
 * after that ("speaking", "completed", failures) arrives over the socket.
 */

import { api, ApiError } from './api.js';
import { RobotSocket } from './socket.js';
import * as ui from './ui.js';

const DRAFT_KEY = 'agibot-a3:draft';
const RESET_DELAY = 2200;

const state = {
  config: { maxLength: 1000, mode: 'mock' },
  status: { state: 'connecting', connected: false },
  history: [],
  audio: { items: [], stats: {} },
  auditioning: null,
  activeRequestId: null,
  stage: 'idle',
  resetTimer: null,
};

const socket = new RobotSocket();

// =========================================================================
// derived UI state
// =========================================================================
function syncControls() {
  const length = ui.el.textInput.value.trim().length;
  const busy = Boolean(state.activeRequestId);
  const connected = Boolean(state.status.connected);

  ui.setControls({
    canSpeak: connected && length > 0 && length <= state.config.maxLength,
    busy,
    canStop: busy,
  });
  ui.renderCounter(ui.el.textInput.value.length, state.config.maxLength);
}

function applyStatus(status) {
  state.status = { ...state.status, ...status };
  ui.renderConnection(state.status);
  ui.renderFacts(state.status);

  // The robot vanished mid-utterance: stop pretending it is still speaking.
  if (!state.status.connected && state.activeRequestId) {
    finishUtterance('error', 'Robot disconnected during speech.');
  }

  // Page opened (or reloaded) while the robot is mid-sentence - adopt it rather
  // than showing "Ready" over a talking robot.
  if (state.status.busy && state.status.activeRequestId && !state.activeRequestId) {
    state.activeRequestId = state.status.activeRequestId;
    state.stage = 'speaking';
    clearTimeout(state.resetTimer);
    ui.renderPipeline('speaking');
    ui.renderLive('speaking', 'Speaking…');
  }

  syncControls();
}

// =========================================================================
// speech lifecycle
// =========================================================================
const STAGE_VIEW = {
  queued:     { tone: 'busy',     text: 'Queued…' },
  sending:    { tone: 'busy',     text: 'Sending to robot…' },
  processing: { tone: 'busy',     text: 'Robot is preparing speech…' },
  speaking:   { tone: 'speaking', text: 'Speaking…' },
  completed:  { tone: 'ok',       text: 'Completed' },
  cancelled:  { tone: 'error',    text: 'Stopped' },
  failed:     { tone: 'error',    text: 'Speech failed' },
};

function onProgress(progress) {
  if (state.activeRequestId && progress.requestId !== state.activeRequestId) return;
  state.activeRequestId = progress.requestId;

  const stage = progress.stage;
  state.stage = stage;
  ui.renderPipeline(stage);

  const view = STAGE_VIEW[stage] || { tone: 'busy', text: stage };
  const detail = progress.detail
    || (typeof progress.elapsedMs === 'number' ? `${progress.elapsedMs} ms` : '');
  ui.renderLive(view.tone, progress.message || view.text, detail);

  if (['completed', 'failed', 'cancelled'].includes(stage)) {
    if (stage === 'completed') refreshAudio();
    if (stage === 'failed') ui.toast(progress.message || 'Speech request failed.', 'error');
    finishUtterance(view.tone, progress.message || view.text, detail);
  }
  syncControls();
}

function finishUtterance(tone, message, detail = '') {
  state.activeRequestId = null;
  ui.renderLive(tone, message, detail);
  syncControls();

  clearTimeout(state.resetTimer);
  state.resetTimer = setTimeout(() => {
    if (state.activeRequestId) return;   // a new utterance already started
    state.stage = 'idle';
    ui.renderPipeline('idle');
    ui.renderLive('idle', state.status.connected ? 'Ready' : 'Robot offline');
  }, RESET_DELAY);
}

// =========================================================================
// history
// =========================================================================
function applyHistoryEvent(payload) {
  if (payload.action === 'clear') {
    state.history = [];
  } else if (payload.entry) {
    const index = state.history.findIndex((item) => item.id === payload.entry.id);
    if (index === -1) state.history.unshift(payload.entry);
    else state.history[index] = payload.entry;
    const limit = state.config.historyLimit || 100;
    if (state.history.length > limit) state.history.length = limit;
  }
  ui.renderHistory(state.history, useHistoryText, replayLine);
}

/** Speak a history line again. Its audio is saved, so this is instant. */
async function replayLine(item) {
  ui.el.textInput.value = item.text;
  saveDraft();
  await speak();
}

function useHistoryText(text) {
  ui.el.textInput.value = text;
  ui.el.textInput.focus();
  ui.el.textInput.setSelectionRange(text.length, text.length);
  saveDraft();
  syncControls();
}

// =========================================================================
// actions
// =========================================================================
async function speak() {
  const text = ui.el.textInput.value.trim();
  if (!text) {
    ui.toast('Type something for the robot to say first.', 'error');
    ui.el.textInput.focus();
    return;
  }
  if (!state.status.connected) {
    ui.toast(
      state.status.error || 'Robot is offline. Check the robot IP and network connection.',
      'error',
    );
    return;
  }

  clearTimeout(state.resetTimer);
  ui.renderPipeline('sending');
  ui.renderLive('busy', 'Sending to robot…');
  ui.setControls({ canSpeak: false, busy: true, canStop: true });

  try {
    const result = await api.speak(text);
    state.activeRequestId = result.requestId;
    syncControls();
  } catch (err) {
    state.activeRequestId = null;
    const message = err instanceof ApiError ? err.message : 'Speech request failed.';
    ui.toast(message, 'error');
    ui.renderPipeline('failed');
    finishUtterance('error', message);
  }
}

async function stop() {
  try {
    await api.stop();
    ui.renderLive('error', 'Stopping…');
  } catch (err) {
    ui.toast(err.message || 'Could not stop the robot.', 'error');
  }
}

function clearText() {
  ui.el.textInput.value = '';
  saveDraft();
  ui.el.textInput.focus();
  syncControls();
}

// =========================================================================
// saved audio
// =========================================================================
async function refreshAudio() {
  try {
    const data = await api.audio();
    state.audio = { items: data.items || [], stats: data.stats || {} };
    ui.renderAudio(state.audio.items, state.audio.stats, {
      fileUrl: api.audioUrl,
      onPlayState: (audio) => {
        // Only one clip auditions at a time.
        if (state.auditioning && state.auditioning !== audio) {
          state.auditioning.pause();
          state.auditioning.currentTime = 0;
        }
        state.auditioning = audio;
      },
    });
  } catch {
    /* the panel is a convenience; never let it break the page */
  }
}

async function clearAudio() {
  try {
    const result = await api.clearAudio();
    ui.toast(`Deleted ${result.removed} saved clip(s).`, 'ok', 3000);
    await refreshAudio();
    // Rows can no longer promise instant replay.
    state.history = state.history.map((item) => ({ ...item, audioSaved: false }));
    ui.renderHistory(state.history, useHistoryText, replayLine);
  } catch (err) {
    ui.toast(err.message || 'Could not clear saved audio.', 'error');
  }
}

async function clearHistory() {
  try {
    await api.clearHistory();
    state.history = [];
    ui.renderHistory(state.history, useHistoryText, replayLine);
  } catch (err) {
    ui.toast(err.message || 'Could not clear history.', 'error');
  }
}

async function reconnect() {
  ui.el.reconnectBtn.dataset.spin = 'true';
  try {
    await api.reconnect();
    ui.toast('Reconnecting to the robot…', 'info', 2500);
  } catch (err) {
    ui.toast(err.message || 'Reconnect failed.', 'error');
  } finally {
    setTimeout(() => { ui.el.reconnectBtn.dataset.spin = 'false'; }, 900);
  }
}

// =========================================================================
// draft persistence (per-browser convenience only)
// =========================================================================
function saveDraft() {
  try { localStorage.setItem(DRAFT_KEY, ui.el.textInput.value); } catch { /* private mode */ }
}

function loadDraft() {
  try {
    const draft = localStorage.getItem(DRAFT_KEY);
    if (draft) ui.el.textInput.value = draft;
  } catch { /* ignore */ }
}

// =========================================================================
// events
// =========================================================================
function bindDom() {
  ui.el.speakBtn.addEventListener('click', speak);
  ui.el.stopBtn.addEventListener('click', stop);
  ui.el.clearBtn.addEventListener('click', clearText);
  ui.el.clearHistoryBtn.addEventListener('click', clearHistory);
  ui.el.clearAudioBtn.addEventListener('click', clearAudio);
  ui.el.reconnectBtn.addEventListener('click', reconnect);

  ui.el.textInput.addEventListener('input', () => { saveDraft(); syncControls(); });

  // Ctrl/Cmd+Enter speaks. A bare Enter inserts a newline, on purpose - nobody
  // wants a half-typed sentence going out of the robot's speaker mid-demo.
  ui.el.textInput.addEventListener('keydown', (event) => {
    if ((event.ctrlKey || event.metaKey) && event.key === 'Enter') {
      event.preventDefault();
      speak();
    }
  });

  document.addEventListener('keydown', (event) => {
    if (event.key === 'Escape' && state.activeRequestId) {
      event.preventDefault();
      stop();
    }
  });
}

function bindSocket() {
  socket.addEventListener('hello', (event) => {
    const { config, status, history } = event.detail;
    state.config = { ...state.config, ...config };
    ui.renderConfig(state.config);
    applyStatus(status);
    state.history = history || [];
    ui.renderHistory(state.history, useHistoryText, replayLine);
    refreshAudio();
    document.documentElement.removeAttribute('data-loading');
  });

  socket.addEventListener('robot.status', (event) => applyStatus(event.detail));
  socket.addEventListener('speech.progress', (event) => onProgress(event.detail));
  socket.addEventListener('history.updated', (event) => applyHistoryEvent(event.detail));
  socket.addEventListener('config.updated', (event) => {
    state.config = { ...state.config, ...event.detail };
    ui.renderConfig(state.config);
  });

  socket.addEventListener('rtt', (event) => {
    const rtt = event.detail.rtt;
    if (typeof rtt === 'number') {
      ui.el.latencyChip.title = `Robot round-trip. Browser to backend: ${rtt} ms`;
    }
  });

  socket.addEventListener('link', (event) => {
    if (event.detail.up) return;
    // The backend went away - say so rather than leaving a stale green light.
    applyStatus({
      state: 'disconnected',
      connected: false,
      error: 'Lost connection to the local server.',
    });
  });
}

// =========================================================================
// boot
// =========================================================================
async function boot() {
  bindDom();
  bindSocket();
  loadDraft();
  syncControls();
  socket.connect();

  // Fallback for the rare case the socket cannot open at all.
  setTimeout(async () => {
    if (socket.isOpen) return;
    try {
      const [config, status, history] = await Promise.all([
        api.config(), api.status(), api.history(),
      ]);
      state.config = { ...state.config, ...config };
      ui.renderConfig(state.config);
      applyStatus(status);
      state.history = history.items || [];
      ui.renderHistory(state.history, useHistoryText, replayLine);
      refreshAudio();
      document.documentElement.removeAttribute('data-loading');
    } catch {
      ui.toast('Cannot reach the local server. Is backend/main.py running?', 'error', 12000);
    }
  }, 1200);

  ui.el.textInput.focus();
}

boot();