const crypto = require('crypto');

class VaultifyManager {

  constructor({
    vaultModel,
    publicKey
  }) {
    this.Vault = vaultModel;
    this.publicKey = publicKey;

    this.cache = new Map(); // feature cache per customer
  }


  createMiddleware() {

    return async (req, res, next) => {

      const customerId = req.user?.Customer_ID;

      if (!customerId) {
        return res.status(403).send('No customer');
      }

      await this.loadCustomer(customerId);

      req.vault = {
        has: (f) => this.has(customerId, f),
        get: (f, p) => this.get(customerId, f, p)
      };

      next();
    };
  }

  // =========================================================
  // LOAD ALL LICENSES FOR CUSTOMER
  // =========================================================

  async loadCustomer(customerId) {

    const records = await this.Vault.findAll({
      where: {
        Customer_ID: customerId,
        Active: true
      }
    });

    const resultMap = new Map();

    for (const record of records) {

      const valid = this.verify(record);
      if (!valid) continue;

      const payload = this.parsePayload(record.Payload);

      resultMap.set(record.Feature, {
        payload,
        expiresAt: record.ExpiresAt
      });
    }

    this.cache.set(customerId, resultMap);

    return {
      customerId,
      features: [...resultMap.keys()]
    };
  }

  // =========================================================
  // VERIFY SIGNATURE
  // =========================================================

  verify(record) {
    try {
      const payload = this.parsePayload(record.Payload);

      const data = {
        Customer_ID: record.Customer_ID,
        Feature: record.Feature,
        Payload: payload,
        ExpiresAt: record.ExpiresAt ?? null
      };

      const verifier = crypto.createVerify('RSA-SHA256');
      verifier.update(JSON.stringify(data));
      verifier.end();

      const isValid = verifier.verify(
        this.publicKey,
        record.Signature,
        'base64'
      );

      if (!isValid) return false;

      // 🔥 WICHTIG: Ablaufdatum HIER erzwingen
      if (payload.expiresAt && record.ExpiresAt) {
        if (payload.expiresAt !== record.ExpiresAt) {
          return false;
        }
      }
      if (record.ExpiresAt && new Date(record.ExpiresAt) < new Date()) {
        return false;
      }

      return true;

    } catch {
      return false;
    }
  }

  // =========================================================
  // SAFE JSON PARSER
  // =========================================================

  parsePayload(payload) {
    try {
      return typeof payload === 'string'
        ? JSON.parse(payload)
        : payload;
    } catch {
      return {};
    }
  }

  // =========================================================
  // FEATURE CHECK
  // =========================================================

  has(customerId, feature) {

    const customer = this.cache.get(customerId);
    if (!customer) return false;

    const entry = customer.get(feature);
    if (!entry) return false;

    if (entry.expiresAt && new Date(entry.expiresAt) < new Date()) {
      return false;
    }

    return true;
  }

  // =========================================================
  // GET FEATURE CONFIG
  // =========================================================

  get(customerId, feature, path = null) {

    const customer = this.cache.get(customerId);
    if (!customer) return undefined;

    const entry = customer.get(feature);
    if (!entry) return undefined;

    if (!path) return entry.payload;

    return path
      .split('.')
      .reduce((obj, key) => obj?.[key], entry.payload);
  }

  // =========================================================
  // REFRESH SINGLE FEATURE
  // =========================================================

  async refreshFeature(customerId, feature) {

    const record = await this.Vault.findOne({
      where: {
        Customer_ID: customerId,
        Feature: feature,
        Active: true
      }
    });

    if (!record) return false;

    if (!this.verify(record)) return false;

    const customer = this.cache.get(customerId) || new Map();

    customer.set(feature, {
      payload: this.parsePayload(record.Payload),
      expiresAt: record.ExpiresAt
    });

    this.cache.set(customerId, customer);

    return true;
  }

  // =========================================================
  // STATUS
  // =========================================================

  status(customerId) {
    const customer = this.cache.get(customerId);

    return {
      customerId,
      features: customer ? [...customer.keys()] : []
    };
  }
}

module.exports = VaultifyManager;