EM2_ERP/em2rp/functions/aiEquipmentProposal.js

/**
 * Cloud Function : Assistant IA Logisticien
 * Utilise Gemini avec function calling côté serveur.
 * Les tools accèdent directement à Firestore via Admin SDK.
 * L'authentification Firebase est requise (pas de clé API côté client).
 */

const { GoogleGenerativeAI } = require('@google/generative-ai');
const admin = require('firebase-admin');
const logger = require('firebase-functions/logger');

const GEMINI_MODEL = 'gemini-2.5-flash';
const GEMINI_API_KEY = 'AIzaSyBdBdjFLma2pLenmFBlqZHArS4GVF-mclo';
const MAX_TOOL_ITERATIONS = 12;
const PAST_EVENTS_LIMIT = 5;
const SEARCH_RESULTS_LIMIT = 20;
const EVENT_SEARCH_SCAN_LIMIT = 100;
const MAX_TOOL_CALLS_PER_ITERATION = 5;
const AVAILABILITY_EVENTS_SCAN_LIMIT = 500;
const MAX_BATCH_AVAILABILITY_ITEMS = 50;

// Initialisation lazy de db pour éviter les erreurs si Firebase n'est pas encore initialisé
const getDb = () => admin.firestore();

// ============================================================================
// Déclarations des tools Gemini
// ============================================================================

const AI_TOOLS = [
  {
    functionDeclarations: [
      {
        name: 'search_equipment',
        description: 'Recherche du materiel par mot-cle dans la base de données.',
        parameters: {
          type: 'object',
          properties: {
            query: {
              type: 'string',
              description: 'Texte de recherche (nom, catégorie, marque, modèle).',
            },
          },
          required: ['query'],
        },
      },
      {
        name: 'check_availability',
        description: 'Vérifie si un équipement est disponible pour une période donnée.',
        parameters: {
          type: 'object',
          properties: {
            equipmentId: {
              type: 'string',
              description: 'ID exact de l\'équipement à vérifier.',
            },
            startDate: {
              type: 'string',
              description: 'Date de début ISO-8601. Exemple: 2026-03-20T08:00:00.000Z',
            },
            endDate: {
              type: 'string',
              description: 'Date de fin ISO-8601. Exemple: 2026-03-21T23:00:00.000Z',
            },
          },
          required: ['equipmentId', 'startDate', 'endDate'],
        },
      },
      {
        name: 'check_availability_batch',
        description: 'Vérifie la disponibilité d une liste d équipements pour la meme période en un seul appel.',
        parameters: {
          type: 'object',
          properties: {
            equipmentIds: {
              type: 'array',
              items: { type: 'string' },
              description: 'Liste des IDs à vérifier (max 50).',
            },
            startDate: {
              type: 'string',
              description: 'Date de début ISO-8601.',
            },
            endDate: {
              type: 'string',
              description: 'Date de fin ISO-8601.',
            },
          },
          required: ['equipmentIds', 'startDate', 'endDate'],
        },
      },
      {
        name: 'get_past_events',
        description: `Retourne les ${PAST_EVENTS_LIMIT} événements passés les plus récents similaires, avec leur liste de matériel, pour s'en inspirer.`,
        parameters: {
          type: 'object',
          properties: {
            eventTypeId: {
              type: 'string',
              description: 'ID du type d\'événement. Optionnel.',
              nullable: true,
            },
          },
        },
      },
      {
        name: 'search_event_reference',
        description: 'Recherche un evenement precise par nom (et optionnellement date) pour reutiliser son materiel et ses flight cases.',
        parameters: {
          type: 'object',
          properties: {
            query: {
              type: 'string',
              description: 'Texte du nom ou extrait du nom de l evenement recherche.',
            },
            dateHint: {
              type: 'string',
              description: 'Date cible ISO-8601 ou YYYY-MM-DD si connue.',
              nullable: true,
            },
          },
          required: ['query'],
        },
      },
      {
        name: 'search_containers',
        description: 'Recherche des flight cases / containers contenant certains equipements. Toujours appeler avant de proposer du materiel individuellement afin de privilegier les flight cases.',
        parameters: {
          type: 'object',
          properties: {
            equipmentIds: {
              type: 'array',
              items: { type: 'string' },
              description: 'Liste des IDs d equipements pour lesquels chercher des flight cases.',
            },
            query: {
              type: 'string',
              description: 'Recherche textuelle optionnelle dans le nom du container.',
              nullable: true,
            },
          },
          required: ['equipmentIds'],
        },
      },
    ],
  },
];

const SYSTEM_PROMPT = `Tu es un expert logisticien IA pour la gestion de materiel evenementiel.
Tu dois proposer une liste de materiel et de flight cases adaptee a l evenement decrit.

Regles absolues :
- Tu ne dois JAMAIS ecrire en base de donnees.
- Utilise search_equipment pour trouver du materiel, check_availability_batch en priorite pour verifier la disponibilite, check_availability pour un cas isole, get_past_events pour t inspirer.
- Si l utilisateur cite un evenement precis (nom/date), appelle d abord search_event_reference pour retrouver cet evenement et reutiliser son materiel ET ses flight cases.
- La sous-categorie du materiel est tres importante. Prends-la en compte en priorite.

Regles sur les flight cases (PRIORITAIRES) :
- Apres avoir identifie les equipements necessaires, appelle TOUJOURS search_containers avec la liste de leurs IDs.
- Si un flight case contient tous les equipements necessaires, propose le flight case uniquement. Ne mets PAS ces equipements dans items.
- Si un flight case contient plus d equipements que necessaire (ex: 5 blinders dans le case mais on en veut 2), propose les equipements individuellement, pas le flight case.
- N ajoute du materiel individuel dans items que pour les equipements sans flight case couvrant exactement le besoin.
- Si un equipement est indisponible, cherche une alternative via search_equipment, verifie sa dispo, puis search_containers sur l alternative.
- Verifie la disponibilite de CHAQUE equipement ET container propose.
- Quand une proposition courante existe deja, renvoie toujours la LISTE FINALE COMPLETE.

Reponse finale : du JSON valide strict, sans markdown, avec ce format exact :
{"assistantMessage":"...","proposal":{"summary":"...","containers":[{"containerId":"ID-EXACT","rationale":"..."}],"items":[{"equipmentId":"ID-EXACT","quantity":1,"rationale":"..."}]}}
- containers : flight cases proposes (les equipements couverts par un container ne doivent pas etre dans items)
- items : equipements individuels non couverts par un container
- Si impossible, renvoie proposal a null.`;

// ============================================================================
// Implémentation des tools côté serveur (Firestore Admin SDK)
// ============================================================================

/**
 * Recherche des équipements dans Firestore par mot-clé.
 */
async function toolSearchEquipment(query) {
  if (!query || query.trim().length < 2) {
    return { query, count: 0, results: [] };
  }

  const normalizedQuery = query.trim().toLowerCase();

  const snapshot = await getDb().collection('equipments').limit(200).get();
  const results = [];

  snapshot.docs.forEach((doc) => {
    const data = doc.data();
    const searchableText = [
      data.name,
      doc.id,
      data.model,
      data.brand,
      data.category,
      data.subCategory,
    ]
      .filter(Boolean)
      .join(' ')
      .toLowerCase();

    if (searchableText.includes(normalizedQuery)) {
      results.push({
        id: doc.id,
        name: data.name || doc.id,
        category: data.category || '',
        subCategory: data.subCategory || '',
        brand: data.brand || null,
        model: data.model || null,
        status: data.status || '',
        availableQuantity: data.availableQuantity ?? null,
        totalQuantity: data.totalQuantity ?? null,
      });
    }
  });

  const limited = results.slice(0, SEARCH_RESULTS_LIMIT);

  return {
    query,
    count: limited.length,
    results: limited,
  };
}

/**
 * Vérifie la disponibilité d'un équipement sur une période donnée.
 */
async function toolCheckAvailability(equipmentId, startDate, endDate, excludeEventId, sharedContext) {
  if (!equipmentId || !startDate || !endDate) {
    return { error: 'equipmentId, startDate et endDate sont requis.' };
  }

  const start = new Date(startDate);
  const end = new Date(endDate);

  if (isNaN(start.getTime()) || isNaN(end.getTime())) {
    return { error: 'Dates invalides.' };
  }

  const batchResult = await toolCheckAvailabilityBatch(
    [equipmentId],
    startDate,
    endDate,
    excludeEventId,
    sharedContext,
  );

  if (!batchResult || !Array.isArray(batchResult.results) || batchResult.results.length === 0) {
    return {
      equipmentId,
      available: true,
      conflictCount: 0,
      conflicts: [],
    };
  }

  return batchResult.results[0];
}

async function loadAvailabilityCandidates(start, sharedContext) {
  const windowKey = start.toISOString().slice(0, 10);
  const contextCache = sharedContext?.availabilityCandidatesByWindow;

  if (contextCache && contextCache.has(windowKey)) {
    return contextCache.get(windowKey);
  }

  let candidateDocs = [];

  try {
    const filteredSnapshot = await getDb().collection('events')
      .where('EndDateTime', '>=', start)
      .orderBy('EndDateTime', 'asc')
      .limit(AVAILABILITY_EVENTS_SCAN_LIMIT)
      .get();
    candidateDocs = filteredSnapshot.docs;
  } catch (error) {
    logger.warn('[AI] Availability optimized query failed, fallback to full scan', {
      message: error?.message || 'unknown',
    });

    const fallbackSnapshot = await getDb().collection('events').get();
    candidateDocs = fallbackSnapshot.docs;
  }

  if (contextCache) {
    contextCache.set(windowKey, candidateDocs);
  }

  return candidateDocs;
}

function buildAvailabilityResultForEquipment({
  equipmentId,
  start,
  end,
  candidateDocs,
  excludeEventId,
}) {
  const conflicts = [];

  for (const eventDoc of candidateDocs) {
    if (excludeEventId && eventDoc.id === excludeEventId) {
      continue;
    }

    const event = eventDoc.data();
    if (isCancelledStatus(event.status)) {
      continue;
    }

    const eventStart = toDateSafe(event.StartDateTime);
    const eventEnd = toDateSafe(event.EndDateTime);

    if (!eventStart || !eventEnd) {
      continue;
    }

    // Vérifier si l'équipement est assigné à cet événement
    const assignedEquipment = Array.isArray(event.assignedEquipment)
      ? event.assignedEquipment
      : [];
    const isDirectlyAssigned = assignedEquipment.some(
      (eq) => String(eq.equipmentId || '') === String(equipmentId),
    );

    if (!isDirectlyAssigned) {
      continue;
    }

    // Vérifier le chevauchement de dates
    const hasOverlap = start < eventEnd && end > eventStart;
    if (!hasOverlap) {
      continue;
    }

    const overlapStart = new Date(Math.max(start.getTime(), eventStart.getTime()));
    const overlapEnd = new Date(Math.min(end.getTime(), eventEnd.getTime()));
    const overlapDays = Math.ceil((overlapEnd - overlapStart) / (1000 * 60 * 60 * 24));

    conflicts.push({
      eventId: eventDoc.id,
      eventName: event.name || event.Name || 'Événement sans nom',
      overlapDays: Math.max(overlapDays, 1),
    });
  }

  return {
    equipmentId,
    available: conflicts.length === 0,
    conflictCount: conflicts.length,
    conflicts,
  };
}

/**
 * Vérifie la disponibilité d'une liste d'équipements pour la même période.
 */
async function toolCheckAvailabilityBatch(equipmentIds, startDate, endDate, excludeEventId, sharedContext) {
  if (!Array.isArray(equipmentIds) || equipmentIds.length === 0 || !startDate || !endDate) {
    return { error: 'equipmentIds (array), startDate et endDate sont requis.' };
  }

  const start = new Date(startDate);
  const end = new Date(endDate);

  if (isNaN(start.getTime()) || isNaN(end.getTime())) {
    return { error: 'Dates invalides.' };
  }

  const normalizedIds = Array.from(new Set(
    equipmentIds
      .map((id) => String(id || '').trim())
      .filter((id) => id.length > 0),
  )).slice(0, MAX_BATCH_AVAILABILITY_ITEMS);

  if (normalizedIds.length === 0) {
    return { error: 'Aucun equipmentId valide.' };
  }

  const candidateDocs = await loadAvailabilityCandidates(start, sharedContext);

  const results = normalizedIds.map((equipmentId) => buildAvailabilityResultForEquipment({
    equipmentId,
    start,
    end,
    candidateDocs,
    excludeEventId,
  }));

  return {
    startDate,
    endDate,
    count: results.length,
    results,
  };
}

/**
 * Retourne les N derniers événements passés similaires avec leur matériel.
 */
async function toolGetPastEvents(eventTypeId) {
  const now = new Date();
  let query = getDb().collection('events').orderBy('StartDateTime', 'desc').limit(50);

  if (eventTypeId) {
    query = getDb().collection('events')
      .where('eventTypeId', '==', eventTypeId)
      .orderBy('StartDateTime', 'desc')
      .limit(50);
  }

  const snapshot = await query.get();

  const pastEvents = snapshot.docs
    .map((doc) => {
      const data = doc.data();
      const startDate = data.StartDateTime?.toDate
        ? data.StartDateTime.toDate()
        : new Date(data.StartDateTime);
      return { doc, data, startDate };
    })
    .filter(({ startDate }) => !isNaN(startDate.getTime()) && startDate < now)
    .slice(0, PAST_EVENTS_LIMIT)
    .map(({ doc, data }) => {
      const assignedEquipment = data.assignedEquipment || [];
      return {
        id: doc.id,
        name: data.name || data.Name || 'Sans nom',
        startDate: data.StartDateTime?.toDate
          ? data.StartDateTime.toDate().toISOString()
          : data.StartDateTime,
        endDate: data.EndDateTime?.toDate
          ? data.EndDateTime.toDate().toISOString()
          : data.EndDateTime,
        assignedEquipment: assignedEquipment.map((eq) => ({
          equipmentId: eq.equipmentId,
          quantity: eq.quantity || 1,
        })),
        assignedEquipmentCount: assignedEquipment.length,
      };
    });

  return {
    count: pastEvents.length,
    events: pastEvents,
  };
}

function toDateSafe(value) {
  if (!value) return null;
  if (value.toDate && typeof value.toDate === 'function') {
    return value.toDate();
  }
  const parsed = new Date(value);
  return Number.isNaN(parsed.getTime()) ? null : parsed;
}

function isCancelledStatus(status) {
  const normalized = (status || '').toString().trim().toUpperCase();
  return normalized === 'CANCELLED' || normalized === 'CANCELED';
}

function normalizeSearchText(value) {
  return (value || '')
    .toString()
    .toLowerCase()
    .normalize('NFD')
    .replace(/[\u0300-\u036f]/g, '')
    .replace(/[^a-z0-9\s-]/g, ' ')
    .replace(/\s+/g, ' ')
    .trim();
}

function parseDateHintFlexible(value) {
  const directDate = toDateSafe(value);
  if (directDate) {
    return directDate;
  }

  const normalized = normalizeSearchText(value);
  if (!normalized) return null;

  const monthMap = {
    janvier: 0,
    fevrier: 1,
    fevr: 1,
    mars: 2,
    avril: 3,
    avr: 3,
    mai: 4,
    juin: 5,
    juillet: 6,
    juil: 6,
    aout: 7,
    septembre: 8,
    sept: 8,
    octobre: 9,
    oct: 9,
    novembre: 10,
    nov: 10,
    decembre: 11,
    dec: 11,
  };

  const frDateMatch = normalized.match(/(\d{1,2})\s+([a-z]+)\s+(\d{4})/);
  if (frDateMatch) {
    const day = parseInt(frDateMatch[1], 10);
    const monthKey = frDateMatch[2];
    const year = parseInt(frDateMatch[3], 10);
    const month = monthMap[monthKey];

    if (!Number.isNaN(day) && !Number.isNaN(year) && month !== undefined) {
      const parsed = new Date(Date.UTC(year, month, day));
      return Number.isNaN(parsed.getTime()) ? null : parsed;
    }
  }

  return null;
}

function dateToYmd(dateValue) {
  if (!dateValue) return null;
  return dateValue.toISOString().slice(0, 10);
}

function dateToYmdInTimezone(dateValue, timeZone) {
  if (!dateValue) return null;

  const formatter = new Intl.DateTimeFormat('en-CA', {
    timeZone,
    year: 'numeric',
    month: '2-digit',
    day: '2-digit',
  });

  const parts = formatter.formatToParts(dateValue);
  const year = parts.find((part) => part.type === 'year')?.value;
  const month = parts.find((part) => part.type === 'month')?.value;
  const day = parts.find((part) => part.type === 'day')?.value;

  if (!year || !month || !day) {
    return null;
  }

  return `${year}-${month}-${day}`;
}

function parseYmdToUtcDate(ymd) {
  if (!ymd || !/^\d{4}-\d{2}-\d{2}$/.test(ymd)) {
    return null;
  }

  const [year, month, day] = ymd.split('-').map((value) => parseInt(value, 10));
  return new Date(Date.UTC(year, month - 1, day));
}

function buildToolCacheKey(name, args) {
  const safeArgs = args && typeof args === 'object' ? args : {};
  return `${name}:${JSON.stringify(safeArgs)}`;
}

function isDateMatchingHint(eventDate, hintedYmd) {
  if (!eventDate || !hintedYmd) {
    return true;
  }

  const eventUtcYmd = dateToYmd(eventDate);
  const eventParisYmd = dateToYmdInTimezone(eventDate, 'Europe/Paris');

  if (eventUtcYmd === hintedYmd || eventParisYmd === hintedYmd) {
    return true;
  }

  const hintedDate = parseYmdToUtcDate(hintedYmd);
  if (!hintedDate) {
    return false;
  }

  const eventDateUtc = parseYmdToUtcDate(eventUtcYmd);
  const eventDateParis = parseYmdToUtcDate(eventParisYmd);
  const oneDayInMs = 24 * 60 * 60 * 1000;

  const utcDelta = eventDateUtc
    ? Math.abs(eventDateUtc.getTime() - hintedDate.getTime())
    : Number.MAX_SAFE_INTEGER;
  const parisDelta = eventDateParis
    ? Math.abs(eventDateParis.getTime() - hintedDate.getTime())
    : Number.MAX_SAFE_INTEGER;

  return Math.min(utcDelta, parisDelta) <= oneDayInMs;
}

function extractQueryTokens(rawQuery) {
  const monthWords = new Set([
    'janvier', 'fevrier', 'fevr', 'mars', 'avril', 'avr', 'mai', 'juin',
    'juillet', 'juil', 'aout', 'septembre', 'sept', 'octobre', 'oct',
    'novembre', 'nov', 'decembre', 'dec',
  ]);
  const stopWords = new Set([
    'de', 'du', 'des', 'le', 'la', 'les', 'un', 'une', 'en', 'date', 'sur',
    'pour', 'avec', 'et', 'a', 'au', 'aux',
  ]);

  return normalizeSearchText(rawQuery)
    .split(' ')
    .filter((token) => token.length >= 2)
    .filter((token) => !/^\d+$/.test(token))
    .filter((token) => !monthWords.has(token))
    .filter((token) => !stopWords.has(token));
}

/**
 * Recherche des containers/flight cases contenant des equipements donnes.
 */
async function toolSearchContainers(equipmentIds, query) {
  if (!Array.isArray(equipmentIds) || equipmentIds.length === 0) {
    return { error: 'equipmentIds (array) est requis.' };
  }

  const normalizedEquipmentIds = new Set(
    equipmentIds.map((id) => String(id || '').trim()).filter((id) => id.length > 0),
  );

  if (normalizedEquipmentIds.size === 0) {
    return { error: 'Aucun equipmentId valide.' };
  }

  const normalizedQuery = query ? normalizeSearchText(query) : null;

  const snapshot = await getDb().collection('containers').limit(300).get();
  const results = [];

  for (const doc of snapshot.docs) {
    const data = doc.data();
    if (isCancelledStatus(data.status)) continue;

    const containerEquipmentIds = Array.isArray(data.equipmentIds)
      ? data.equipmentIds.map((id) => String(id || '').trim()).filter(Boolean)
      : [];

    if (containerEquipmentIds.length === 0) continue;

    const matchingIds = containerEquipmentIds.filter((id) => normalizedEquipmentIds.has(id));
    if (matchingIds.length === 0) continue;

    if (normalizedQuery) {
      const searchableText = normalizeSearchText(data.name || doc.id);
      if (!searchableText.includes(normalizedQuery)) continue;
    }

    results.push({
      id: doc.id,
      name: data.name || doc.id,
      type: data.type || '',
      status: data.status || '',
      equipmentIds: containerEquipmentIds,
      totalItemCount: containerEquipmentIds.length,
      matchingEquipmentIds: matchingIds,
      matchingCount: matchingIds.length,
      coverageRatio: matchingIds.length / normalizedEquipmentIds.size,
    });
  }

  // Trier par meilleure couverture (plus de matching ET ratio le plus proche de 1)
  results.sort((a, b) => {
    if (b.matchingCount !== a.matchingCount) return b.matchingCount - a.matchingCount;
    return b.coverageRatio - a.coverageRatio;
  });

  const limited = results.slice(0, 15);

  return {
    requestedEquipmentIds: Array.from(normalizedEquipmentIds),
    count: limited.length,
    containers: limited,
  };
}

/**
 * Recherche un evenement de reference par nom/date, meme s'il est futur.
 */
async function toolSearchEventReference(query, dateHint) {
  const normalizedQuery = normalizeSearchText(query);
  if (!normalizedQuery) {
    return { query, count: 0, events: [] };
  }

  const hintedDate = parseDateHintFlexible(dateHint) || parseDateHintFlexible(query);
  const hintedYmd = hintedDate ? dateToYmd(hintedDate) : null;
  const queryTokens = extractQueryTokens(query);

  let docs = [];

  // Priorite a une recherche ciblee autour de la date demandee.
  if (hintedDate) {
    const dayStart = new Date(Date.UTC(
      hintedDate.getUTCFullYear(),
      hintedDate.getUTCMonth(),
      hintedDate.getUTCDate(),
      0,
      0,
      0,
      0,
    ));
    const dayEnd = new Date(Date.UTC(
      hintedDate.getUTCFullYear(),
      hintedDate.getUTCMonth(),
      hintedDate.getUTCDate(),
      23,
      59,
      59,
      999,
    ));
    const rangeStart = new Date(dayStart.getTime() - (24 * 60 * 60 * 1000));
    const rangeEnd = new Date(dayEnd.getTime() + (24 * 60 * 60 * 1000));

    try {
      const byDateSnapshot = await getDb().collection('events')
        .where('StartDateTime', '>=', rangeStart)
        .where('StartDateTime', '<=', rangeEnd)
        .orderBy('StartDateTime', 'desc')
        .limit(Math.max(EVENT_SEARCH_SCAN_LIMIT, 150))
        .get();
      docs = byDateSnapshot.docs;
    } catch (error) {
      logger.warn('[AI] search_event_reference date query failed, fallback to scan', {
        message: error?.message || 'unknown',
      });
    }
  }

  if (docs.length === 0) {
    const snapshot = await getDb().collection('events')
      .orderBy('StartDateTime', 'desc')
      .limit(EVENT_SEARCH_SCAN_LIMIT)
      .get();
    docs = snapshot.docs;
  }

  const candidates = docs.map((doc) => {
    const data = doc.data();
    const startDate = toDateSafe(data.StartDateTime);
    const endDate = toDateSafe(data.EndDateTime);
    const eventName = (data.name || data.Name || '').toString();
    const searchableText = normalizeSearchText([eventName, doc.id, data.eventTypeId || ''].join(' '));

    const assignedEquipment = Array.isArray(data.assignedEquipment) ? data.assignedEquipment : [];
    const assignedContainers = Array.isArray(data.assignedContainers) ? data.assignedContainers : [];
    const matchedTokenCount = queryTokens.filter((token) => searchableText.includes(token)).length;
    const hasTokenMatch = queryTokens.length === 0
      ? searchableText.includes(normalizedQuery)
      : matchedTokenCount >= Math.min(2, queryTokens.length);
    const matchesDate = isDateMatchingHint(startDate, hintedYmd);
    const eventYmd = startDate ? dateToYmd(startDate) : null;

    return {
      id: doc.id,
      name: eventName || 'Sans nom',
      startDate,
      endDate,
      eventYmd,
      assignedEquipment,
      assignedContainers,
      assignedEquipmentCount: assignedEquipment.length,
      matchesQuery: hasTokenMatch,
      matchedTokenCount,
      matchesDate,
    };
  });

  const strictMatched = candidates
    .filter((event) => event.matchesQuery && event.matchesDate);
  const fallbackMatched = candidates
    .filter((event) => event.matchesQuery);
  const selectedCandidates = strictMatched.length > 0 ? strictMatched : fallbackMatched;

  const matched = selectedCandidates
    .sort((a, b) => {
      const aScore = (a.matchesDate ? 3 : 0) + (a.assignedEquipmentCount > 0 ? 1 : 0) + a.matchedTokenCount;
      const bScore = (b.matchesDate ? 3 : 0) + (b.assignedEquipmentCount > 0 ? 1 : 0) + b.matchedTokenCount;
      if (bScore !== aScore) return bScore - aScore;

      const aTime = a.startDate ? a.startDate.getTime() : 0;
      const bTime = b.startDate ? b.startDate.getTime() : 0;
      return bTime - aTime;
    })
    .slice(0, 5)
    .map((event) => ({
      id: event.id,
      name: event.name,
      startDate: event.startDate ? event.startDate.toISOString() : null,
      endDate: event.endDate ? event.endDate.toISOString() : null,
      assignedEquipment: event.assignedEquipment.map((eq) => ({
        equipmentId: eq.equipmentId,
        quantity: eq.quantity || 1,
      })),
      assignedContainers: event.assignedContainers,
      assignedEquipmentCount: event.assignedEquipmentCount,
    }));

  return {
    query,
    dateHint: hintedYmd || null,
    usedDateFallback: strictMatched.length === 0 && Boolean(hintedYmd),
    count: matched.length,
    events: matched,
  };
}

/**
 * Exécute un tool Gemini et retourne le résultat.
 */
async function executeTool(toolCall, excludeEventId, sharedContext) {
  const { name, args } = toolCall;
  logger.info(`[AI] Executing tool: ${name}`, { args });

  try {
    switch (name) {
      case 'search_equipment':
        return await toolSearchEquipment(args.query);

      case 'check_availability':
        return await toolCheckAvailability(
          args.equipmentId,
          args.startDate,
          args.endDate,
          excludeEventId,
          sharedContext,
        );

      case 'check_availability_batch':
        return await toolCheckAvailabilityBatch(
          args.equipmentIds,
          args.startDate,
          args.endDate,
          excludeEventId,
          sharedContext,
        );

      case 'get_past_events':
        return await toolGetPastEvents(args.eventTypeId || null);

      case 'search_event_reference':
        return await toolSearchEventReference(args.query, args.dateHint || null);

      case 'search_containers':
        return await toolSearchContainers(args.equipmentIds, args.query || null);

      default:
        return { error: `Tool inconnu: ${name}` };
    }
  } catch (err) {
    logger.error(`[AI] Tool error (${name}):`, err);
    return { error: err.message };
  }
}

// ============================================================================
// Gestionnaire principal
// ============================================================================

/**
 * Construit le prompt utilisateur avec le contexte de l'événement.
 */
function buildUserPrompt({
  userMessage,
  eventTypeId,
  startDate,
  endDate,
  currentEquipment,
  workingProposal,
}) {
  const currentEquipmentStr = currentEquipment && currentEquipment.length > 0
    ? currentEquipment.map((eq) => `${eq.equipmentId} x${eq.quantity || 1}`).join(', ')
    : 'aucun';
  const workingProposalStr = workingProposal && workingProposal.length > 0
    ? workingProposal.map((eq) => `${eq.equipmentId} x${eq.quantity || 1}`).join(', ')
    : 'aucune';

  const isAutoMode = !userMessage || userMessage.trim().length === 0;
  const finalMessage = isAutoMode
    ? 'Génère automatiquement une proposition de matériel adaptée à cet événement, basée sur les événements similaires passés.'
    : userMessage.trim();

  return [
    'Contexte de l\'événement :',
    `- Type d'événement (ID): ${eventTypeId || 'non renseigné'}`,
    `- Date de début : ${startDate}`,
    `- Date de fin : ${endDate}`,
    `- Matériel déjà assigné : ${currentEquipmentStr}`,
    `- Proposition courante à modifier : ${workingProposalStr}`,
    '',
    'Demande :',
    finalMessage,
    '',
    'Si la demande cite un evenement precis (nom/date), commence par search_event_reference avant de proposer du materiel.',
    'Si une proposition courante existe, traite-la comme base de travail et renvoie toujours la liste finale complete apres modification.',
    'Rappel : vérifier la disponibilité avant de recommander. Privilégier check_availability_batch pour contrôler plusieurs équipements en un appel.',
    'En cas d\'indisponibilité, chercher une alternative via search_equipment puis revérifier.',
  ].join('\n');
}

/**
 * Extrait un texte exploitable depuis la réponse Gemini, même si response.text() est vide.
 */
function extractResponseText(modelResponse) {
  if (!modelResponse) return '';

  try {
    const directText = modelResponse.text?.();
    if (directText && directText.trim().length > 0) {
      return directText.trim();
    }
  } catch (_) {
    // Fallback via candidates/parts ci-dessous.
  }

  const candidates = Array.isArray(modelResponse.candidates) ? modelResponse.candidates : [];
  const textParts = [];

  for (const candidate of candidates) {
    const parts = candidate?.content?.parts;
    if (!Array.isArray(parts)) continue;

    for (const part of parts) {
      if (typeof part?.text === 'string' && part.text.trim().length > 0) {
        textParts.push(part.text.trim());
      }
    }
  }

  return textParts.join('\n').trim();
}

/**
 * Extrait et parse le JSON de la réponse IA.
 */
function parseAiResponse(rawText) {
  if (!rawText || rawText.trim().length === 0) {
    throw new Error('Réponse IA vide.');
  }

  // Tentative directe
  try {
    const parsed = JSON.parse(rawText.trim());
    if (parsed && typeof parsed === 'object') return parsed;
  } catch (_) {
    // Continuer avec extraction depuis markdown
  }

  // Extraction depuis un bloc markdown ```json ... ```
  const fencedMatch = rawText.match(/```(?:json)?\s*([\s\S]*?)```/);
  if (fencedMatch) {
    try {
      const parsed = JSON.parse(fencedMatch[1]);
      if (parsed && typeof parsed === 'object') return parsed;
    } catch (_) {
      // Continuer
    }
  }

  // Extraction du premier objet JSON brut dans le texte
  const jsonMatch = rawText.match(/\{[\s\S]*\}/);
  if (jsonMatch) {
    try {
      const parsed = JSON.parse(jsonMatch[0]);
      if (parsed && typeof parsed === 'object') return parsed;
    } catch (_) {
      // Échoue
    }
  }

  throw new Error('JSON IA invalide ou introuvable dans la réponse.');
}

/**
 * Handler principal de la Cloud Function aiEquipmentProposal.
 */
async function handleAiEquipmentProposal(req, res) {
  const {
    eventTypeId,
    startDate,
    endDate,
    userMessage,
    history = [],
    currentEquipment = [],
    workingProposal = [],
    excludeEventId,
  } = req.body.data || {};

  if (!startDate || !endDate) {
    res.status(400).json({ error: 'startDate et endDate sont requis.' });
    return;
  }

  const genAI = new GoogleGenerativeAI(GEMINI_API_KEY);
  const model = genAI.getGenerativeModel({
    model: GEMINI_MODEL,
    systemInstruction: SYSTEM_PROMPT,
    tools: AI_TOOLS,
    toolConfig: { functionCallingConfig: { mode: 'AUTO' } },
    generationConfig: { temperature: 0.2 },
  });

  // Reconstruire l'historique de conversation
  const chatHistory = (history || [])
    .filter((turn) => turn.text && turn.text.trim().length > 0)
    .map((turn) => ({
      role: turn.isUser ? 'user' : 'model',
      parts: [{ text: turn.text.trim() }],
    }));

  const chat = model.startChat({ history: chatHistory });
  const toolResultCache = new Map();
  const sharedToolContext = {
    availabilityCandidatesByWindow: new Map(),
  };

  const userPrompt = buildUserPrompt({
    userMessage,
    eventTypeId,
    startDate,
    endDate,
    currentEquipment,
    workingProposal,
  });

  logger.info('[AI] Starting conversation', { eventTypeId, startDate, endDate });

  let response;

  try {
    response = await chat.sendMessage(userPrompt);

    // Boucle de function calling avec cache local.
    for (let iteration = 0; iteration < MAX_TOOL_ITERATIONS; iteration++) {
      const functionCalls = response.response.functionCalls();

      if (!functionCalls || functionCalls.length === 0) {
        break;
      }

      const limitedCalls = functionCalls.slice(0, MAX_TOOL_CALLS_PER_ITERATION);
      const availabilityCalls = limitedCalls.filter(
        (call) => call.name === 'check_availability'
          && call.args?.equipmentId
          && call.args?.startDate
          && call.args?.endDate,
      );

      let batchAvailabilityMap = null;
      let batchWindow = null;

      if (availabilityCalls.length >= 2) {
        const firstStartDate = availabilityCalls[0].args.startDate;
        const firstEndDate = availabilityCalls[0].args.endDate;
        const hasSameWindow = availabilityCalls.every(
          (call) => call.args.startDate === firstStartDate && call.args.endDate === firstEndDate,
        );

        if (hasSameWindow) {
          const equipmentIds = Array.from(new Set(
            availabilityCalls.map((call) => String(call.args.equipmentId)),
          )).sort();
          const batchArgs = {
            equipmentIds,
            startDate: firstStartDate,
            endDate: firstEndDate,
          };
          const batchCacheKey = buildToolCacheKey('check_availability_batch', batchArgs);

          let batchResult = toolResultCache.get(batchCacheKey);
          if (!batchResult) {
            batchResult = await executeTool(
              { name: 'check_availability_batch', args: batchArgs },
              excludeEventId,
              sharedToolContext,
            );
            toolResultCache.set(batchCacheKey, batchResult);
          }

          if (batchResult && Array.isArray(batchResult.results)) {
            batchAvailabilityMap = new Map(
              batchResult.results.map((item) => [String(item.equipmentId), item]),
            );
            batchWindow = { startDate: firstStartDate, endDate: firstEndDate };
            logger.info('[AI] Consolidated check_availability calls into one batch call', {
              iteration: iteration + 1,
              itemCount: equipmentIds.length,
            });
          }
        }
      }

      logger.info(`[AI] Tool calls (iteration ${iteration + 1}):`, limitedCalls.map((c) => c.name));

      const toolResults = await Promise.all(
        limitedCalls.map(async (toolCall) => {
          const cacheKey = buildToolCacheKey(toolCall.name, toolCall.args);
          if (toolResultCache.has(cacheKey)) {
            return {
              functionResponse: {
                name: toolCall.name,
                response: toolResultCache.get(cacheKey),
              },
            };
          }

          let toolResult;
          try {
            if (
              batchAvailabilityMap
              && batchWindow
              && toolCall.name === 'check_availability'
              && toolCall.args?.startDate === batchWindow.startDate
              && toolCall.args?.endDate === batchWindow.endDate
            ) {
              toolResult = batchAvailabilityMap.get(String(toolCall.args.equipmentId)) || {
                equipmentId: toolCall.args.equipmentId,
                available: true,
                conflictCount: 0,
                conflicts: [],
              };
            } else {
              toolResult = await executeTool(toolCall, excludeEventId, sharedToolContext);
            }
          } catch (toolError) {
            logger.warn('[AI] Tool call failed, returning degraded tool response', {
              tool: toolCall.name,
              message: toolError?.message || 'unknown',
            });
            toolResult = { error: toolError?.message || `Echec du tool ${toolCall.name}` };
          }

          toolResultCache.set(cacheKey, toolResult);

          return {
            functionResponse: {
              name: toolCall.name,
              response: toolResult,
            },
          };
        }),
      );

      response = await chat.sendMessage(toolResults);
    }
  } catch (error) {
    logger.error('[AI] Conversation timeout/error', {
      message: error?.message || 'unknown',
    });
    res.status(200).json({
      assistantMessage: 'La generation IA a rencontre une erreur technique. Reessaie dans quelques secondes.',
      proposal: null,
    });
    return;
  }

  const rawText = extractResponseText(response.response);
  logger.info('[AI] Raw response received, parsing...', {
    hasText: rawText.length > 0,
    candidateCount: response.response?.candidates?.length || 0,
  });

  // Fallback non bloquant: éviter un 500 quand Gemini ne renvoie pas de texte exploitable.
  if (!rawText) {
    res.status(200).json({
      assistantMessage: 'Je n\'ai pas pu générer une réponse exploitable pour le moment. Réessaie avec une consigne plus précise.',
      proposal: null,
    });
    return;
  }

  let payload;
  try {
    payload = parseAiResponse(rawText);
  } catch (error) {
    logger.error('[AI] JSON parsing failed, returning degraded response', error);
    res.status(200).json({
      assistantMessage: rawText,
      proposal: null,
    });
    return;
  }

  const assistantMessage = payload.assistantMessage?.toString().trim() || rawText;

  // Normaliser la proposition (items + containers)
  let proposal = null;
  if (payload.proposal) {
    const rawItems = Array.isArray(payload.proposal.items) ? payload.proposal.items : [];
    const rawContainers = Array.isArray(payload.proposal.containers) ? payload.proposal.containers : [];

    const items = rawItems
      .filter((item) => item.equipmentId && item.quantity > 0)
      .map((item) => ({
        equipmentId: String(item.equipmentId).trim(),
        quantity: Math.max(1, parseInt(item.quantity) || 1),
        rationale: (item.rationale || 'Proposition IA').trim(),
      }));

    const containers = rawContainers
      .filter((c) => c.containerId)
      .map((c) => ({
        containerId: String(c.containerId).trim(),
        rationale: (c.rationale || 'Proposition IA').trim(),
      }));

    if (items.length > 0 || containers.length > 0) {
      proposal = {
        summary: payload.proposal.summary?.toString().trim() || 'Proposition generee automatiquement.',
        items,
        containers,
      };
    }
  }

  res.status(200).json({ assistantMessage, proposal });
}

module.exports = { handleAiEquipmentProposal };