import { computed, onBeforeUnmount, onMounted, ref } from 'vue';

const copy = {
  it: {
    pageTitle: 'Face ID',
    pageHeadline: 'Trova le tue foto con un selfie',
    pageIntro: 'Carica una tua immagine recente e lascia che Face ID cerchi le corrispondenze solo nella gara corrente.',
    userFallback: 'Sessione FaceAI',
    raceFallback: 'Gara corrente',
    statusReady: 'Pronto',
    statusProcessing: 'In lavorazione',
    statusCompleted: 'Completata',
    statusFailed: 'Errore',
    statusLabel: 'Stato',
    userLabel: 'Utente',
    raceLabel: 'Gara',
    languageLabel: 'Lingua',
    uploaderTitle: 'Carica il tuo selfie',
    uploaderHint: 'Puoi trascinare un file immagine oppure selezionarlo dal dispositivo.',
    uploaderDragIdle: 'Trascina qui il selfie',
    uploaderDragActive: 'Rilascia l’immagine per caricarla',
    uploaderBrowse: 'Scegli immagine',
    uploaderFormats: 'Formati supportati: JPG, PNG, WEBP',
    uploaderSelected: 'File selezionato',
    uploaderReplace: 'Sostituisci',
    uploaderRemove: 'Rimuovi',
    backButton: 'Torna alla pagina gara',
    uploadButton: 'Avvia ricerca Face ID',
    openSimulator: 'Apri il simulatore legacy',
    handoffMissing: 'Apri prima il simulatore legacy per generare il token firmato di handoff.',
    sessionLoading: 'Caricamento della sessione FaceAI…',
    submitLoading: 'Invio del selfie e preparazione della ricerca…',
    redirectLoading: 'Reindirizzamento alla pagina legacy filtrata in corso…',
    processingLoading: 'Ricerca biometrica in corso su tutte le foto della gara…',
    unavailableDefault: 'FaceAI non è disponibile per questa gara.',
    readyMessage: 'Seleziona un selfie per avviare una ricerca limitata alla gara corrente.',
    completedMessage: 'Ricerca completata. Trovate {count} foto corrispondenti.',
    failedMessage: 'La ricerca non è stata completata. Verifica il messaggio di errore e riprova.',
    matchesLabel: 'Foto trovate',
    redirectMessage: 'Reindirizzamento alla pagina legacy filtrata in corso…',
    noFileCta: 'Seleziona un’immagine per sbloccare la ricerca.',
    invalidImage: 'Seleziona un file immagine valido.',
    pollError: 'Impossibile leggere lo stato della ricerca.',
    searchFailed: 'La ricerca non è andata a buon fine.',
    redirectError: 'Impossibile generare il link di ritorno.',
    chooseSelfie: 'Seleziona un selfie prima di avviare la ricerca.',
    raceDataUnavailable: 'I dati FaceAI non sono disponibili per questa gara.',
    searchCreateError: 'Impossibile avviare la ricerca.',
    faceAiAlt: 'FaceAI',
    dropzoneDisabled: 'Il caricamento non è disponibile per questa gara.'
  },
  en: {
    pageTitle: 'Face ID',
    pageHeadline: 'Find your photos with a selfie',
    pageIntro: 'Upload a recent picture of yourself and Face ID will search only within the current race.',
    userFallback: 'FaceAI session',
    raceFallback: 'Current race',
    statusReady: 'Ready',
    statusProcessing: 'Processing',
    statusCompleted: 'Completed',
    statusFailed: 'Error',
    statusLabel: 'Status',
    userLabel: 'User',
    raceLabel: 'Race',
    languageLabel: 'Language',
    uploaderTitle: 'Upload your selfie',
    uploaderHint: 'Drag an image here or choose it from your device.',
    uploaderDragIdle: 'Drag your selfie here',
    uploaderDragActive: 'Drop the image to upload it',
    uploaderBrowse: 'Choose image',
    uploaderFormats: 'Supported formats: JPG, PNG, WEBP',
    uploaderSelected: 'Selected file',
    uploaderReplace: 'Replace',
    uploaderRemove: 'Remove',
    backButton: 'Back to the race page',
    uploadButton: 'Start Face ID search',
    openSimulator: 'Open the legacy simulator',
    handoffMissing: 'Open the legacy simulator first to generate the signed handoff token.',
    sessionLoading: 'Loading the FaceAI session…',
    submitLoading: 'Uploading the selfie and preparing the search…',
    redirectLoading: 'Redirecting to the filtered legacy page…',
    processingLoading: 'Biometric search in progress across all race photos…',
    unavailableDefault: 'FaceAI is not available for this race.',
    readyMessage: 'Select a selfie to start a search limited to the current race.',
    completedMessage: 'Search completed. Found {count} matching photos.',
    failedMessage: 'The search did not complete. Check the message and try again.',
    matchesLabel: 'Photos found',
    redirectMessage: 'Redirecting to the filtered legacy page…',
    noFileCta: 'Select an image to unlock the search action.',
    invalidImage: 'Select a valid image file.',
    pollError: 'Unable to read the search status.',
    searchFailed: 'The search failed.',
    redirectError: 'Unable to build the return link.',
    chooseSelfie: 'Choose a selfie before starting the search.',
    raceDataUnavailable: 'FaceAI data is not available for this race.',
    searchCreateError: 'Unable to start the search.',
    faceAiAlt: 'FaceAI',
    dropzoneDisabled: 'Upload is not available for this race.'
  }
};

const knownServerMessages = {
  'No training dataset available for this race.': 'raceDataUnavailable',
  'FaceAI data is not available for this race.': 'raceDataUnavailable',
  'FaceAI is not available for this race.': 'unavailableDefault',
  'Unable to read search status.': 'pollError',
  'The search failed.': 'searchFailed',
  'Unable to build return URL.': 'redirectError',
  'Unable to create the search.': 'searchCreateError',
  'Choose a selfie before starting the search.': 'chooseSelfie'
};

const simulatorUrl = 'http://localhost:8080/faceai_simulator.php?raceId=101&lang=it';

export function useFaceAiHome() {
  const session = ref(null);
  const loading = ref(true);
  const errorMessage = ref('');
  const selectedFile = ref(null);
  const activeSearch = ref(null);
  const redirectUrl = ref('');
  const isSubmitting = ref(false);
  const isRedirecting = ref(false);
  const isDragging = ref(false);
  const fileInput = ref(null);
  let pollTimer = null;
  let dragDepth = 0;

  const currentLocale = computed(() => {
    const language = (session.value?.lang || document.documentElement.lang || 'it').toLowerCase();
    return language.startsWith('en') ? 'en' : 'it';
  });

  function t(key, params = {}) {
    const message = copy[currentLocale.value][key] || copy.it[key] || key;
    return Object.keys(params).reduce((text, paramKey) => text.replace(`{${paramKey}}`, String(params[paramKey])), message);
  }

  function localizeServerMessage(message, fallbackKey) {
    if (!message) {
      return t(fallbackKey);
    }

    if (currentLocale.value === 'en') {
      return message;
    }

    const mappedKey = knownServerMessages[message];
    if (mappedKey) {
      return t(mappedKey);
    }

    return t(fallbackKey);
  }

  function shouldLogFaceAiDebug() {
    return import.meta.env.DEV || window.location.hostname === 'localhost' || window.location.hostname === '127.0.0.1';
  }

  function logFaceAiDebug(label, extra = null) {
    if (!shouldLogFaceAiDebug()) {
      return;
    }

    const payload = {
      pageUrl: window.location.href,
      session: session.value,
      availability: raceAvailability.value,
      activeSearch: activeSearch.value,
      redirectUrl: redirectUrl.value,
      extra
    };

    console.groupCollapsed(`[FaceAI] ${label}`);
    console.log(payload);
    console.groupEnd();
  }

  const isWorking = computed(() => loading.value || isSubmitting.value || isRedirecting.value || activeSearch.value?.status === 'processing');
  const isProcessingSearch = computed(() => isSubmitting.value || activeSearch.value?.status === 'processing');
  const raceAvailability = computed(() => session.value?.availability || null);
  const canPickFile = computed(() => Boolean(session.value) && raceAvailability.value?.available === true && !isWorking.value);

  const canStartSearch = computed(() => {
    if (!session.value || !selectedFile.value) {
      return false;
    }

    if (!session.value.access?.faceAiAllowed) {
      return false;
    }

    return raceAvailability.value?.available === true && !isWorking.value;
  });

  const selectedFileSizeLabel = computed(() => {
    if (!selectedFile.value?.size) {
      return '';
    }

    const sizeInMb = selectedFile.value.size / (1024 * 1024);
    if (sizeInMb >= 1) {
      return `${sizeInMb.toFixed(1)} MB`;
    }

    return `${Math.max(1, Math.round(selectedFile.value.size / 1024))} KB`;
  });

  const activeSearchStatusLabel = computed(() => {
    const status = activeSearch.value?.status;

    if (status === 'processing') {
      return t('statusProcessing');
    }
    if (status === 'completed') {
      return t('statusCompleted');
    }
    if (status === 'failed') {
      return t('statusFailed');
    }

    return t('statusReady');
  });

  const busyLabel = computed(() => {
    if (loading.value) {
      return t('sessionLoading');
    }

    if (isSubmitting.value) {
      return t('submitLoading');
    }

    if (isRedirecting.value) {
      return t('redirectLoading');
    }

    if (activeSearch.value?.status === 'processing') {
      return t('processingLoading');
    }

    return '';
  });

  const statusLabel = computed(() => {
    if (!activeSearch.value) {
      if (session.value && raceAvailability.value && !raceAvailability.value.available) {
        return localizeServerMessage(raceAvailability.value.message, 'unavailableDefault');
      }

      return t('readyMessage');
    }

    if (activeSearch.value.status === 'completed') {
      return t('completedMessage', { count: activeSearch.value.matchCount ?? 0 });
    }

    if (activeSearch.value.status === 'failed') {
      return localizeServerMessage(activeSearch.value.errorMessage, 'failedMessage');
    }

    return t('processingLoading');
  });

  function openFilePicker() {
    if (!canPickFile.value) {
      return;
    }

    fileInput.value?.click();
  }

  function setSelectedFile(file) {
    if (!file) {
      selectedFile.value = null;
      return;
    }

    if (!file.type || !file.type.startsWith('image/')) {
      selectedFile.value = null;
      errorMessage.value = t('invalidImage');
      if (fileInput.value) {
        fileInput.value.value = '';
      }
      return;
    }

    selectedFile.value = file;
    errorMessage.value = '';
  }

  function clearSelectedFile() {
    selectedFile.value = null;
    if (fileInput.value) {
      fileInput.value.value = '';
    }
  }

  function onFileChange(event) {
    setSelectedFile(event.target.files?.[0] || null);
  }

  function onDragEnter(event) {
    if (!canPickFile.value) {
      return;
    }

    event.preventDefault();
    dragDepth += 1;
    isDragging.value = true;
  }

  function onDragOver(event) {
    if (!canPickFile.value) {
      return;
    }

    event.preventDefault();
    isDragging.value = true;
  }

  function onDragLeave(event) {
    if (!canPickFile.value) {
      return;
    }

    event.preventDefault();
    dragDepth = Math.max(0, dragDepth - 1);
    if (dragDepth === 0) {
      isDragging.value = false;
    }
  }

  function onDrop(event) {
    if (!canPickFile.value) {
      return;
    }

    event.preventDefault();
    dragDepth = 0;
    isDragging.value = false;
    setSelectedFile(event.dataTransfer?.files?.[0] || null);
  }

  async function loadSession() {
    loading.value = true;
    const response = await fetch('/api/session', { credentials: 'include' });

    if (!response.ok) {
      loading.value = false;
      logFaceAiDebug('Session load failed', { status: response.status });
      return;
    }

    session.value = await response.json();
    loading.value = false;
    logFaceAiDebug('Session loaded');
  }

  async function pollSearch(searchId) {
    const response = await fetch(`/api/searches/${searchId}`, { credentials: 'include' });
    if (!response.ok) {
      errorMessage.value = t('pollError');
      isSubmitting.value = false;
      logFaceAiDebug('Search polling failed', { searchId, status: response.status });
      return;
    }

    activeSearch.value = await response.json();
    logFaceAiDebug('Search status updated', { searchId, status: activeSearch.value.status });
    if (activeSearch.value.status === 'failed') {
      isSubmitting.value = false;
      errorMessage.value = localizeServerMessage(activeSearch.value.errorMessage, 'searchFailed');
      return;
    }

    if (activeSearch.value.status === 'completed') {
      isSubmitting.value = false;
      const redirectResponse = await fetch(`/api/searches/${searchId}/redirect`, { credentials: 'include' });
      const payload = await redirectResponse.json();
      if (!redirectResponse.ok) {
        errorMessage.value = localizeServerMessage(payload.error, 'redirectError');
        logFaceAiDebug('Redirect build failed', { searchId, payload });
        return;
      }
      redirectUrl.value = payload.url;
      isRedirecting.value = true;
      logFaceAiDebug('Redirect URL ready', { searchId, url: payload.url });
      window.setTimeout(() => {
        window.location.href = payload.url;
      }, 1200);
      return;
    }

    pollTimer = window.setTimeout(() => {
      pollSearch(searchId);
    }, 1500);
  }

  async function submitSearch() {
    errorMessage.value = '';
    redirectUrl.value = '';
    isRedirecting.value = false;

    if (!selectedFile.value) {
      errorMessage.value = t('chooseSelfie');
      return;
    }

    if (!session.value?.access?.faceAiAllowed || !raceAvailability.value?.available) {
      errorMessage.value = localizeServerMessage(raceAvailability.value?.message, 'raceDataUnavailable');
      return;
    }

    isSubmitting.value = true;

    const formData = new FormData();
    formData.set('raceId', session.value.race.id);
    formData.set('selfie', selectedFile.value);

    const response = await fetch('/api/searches', {
      method: 'POST',
      credentials: 'include',
      body: formData
    });

    const payload = await response.json();
    if (!response.ok) {
      errorMessage.value = localizeServerMessage(payload.error, 'searchCreateError');
      isSubmitting.value = false;
      logFaceAiDebug('Search creation failed', { status: response.status, payload });
      return;
    }

    activeSearch.value = payload;
    logFaceAiDebug('Search created', { payload });
    pollSearch(payload.id);
  }

  onMounted(loadSession);
  onBeforeUnmount(() => {
    if (pollTimer) {
      window.clearTimeout(pollTimer);
    }
  });

  return {
    activeSearch,
    activeSearchStatusLabel,
    busyLabel,
    canPickFile,
    canStartSearch,
    clearSelectedFile,
    currentLocale,
    errorMessage,
    fileInput,
    isDragging,
    isProcessingSearch,
    isRedirecting,
    isSubmitting,
    isWorking,
    loading,
    onDragEnter,
    onDragLeave,
    onDragOver,
    onDrop,
    onFileChange,
    openFilePicker,
    redirectUrl,
    selectedFile,
    selectedFileSizeLabel,
    session,
    simulatorUrl,
    statusLabel,
    submitSearch,
    t
  };
}