const { Op } = require('sequelize');

class IdentityManager {
  constructor(adManager, AuthenticationModel) {
    this.ad = adManager || null;
    this.Authentication = AuthenticationModel;
  }

  /**
   * -----------------------------------------------------
   * REQUIRED FIELDS (MANUAL USER)
   * -----------------------------------------------------
   */
  REQUIRED_FIELDS = [
    'sAMAccountName',
    'mail',
    'givenName',
    'sn',
    'password'
  ];

  /**
   * -----------------------------------------------------
   * VALIDATE MANUAL USER
   * -----------------------------------------------------
   */
  validateManualUser(user) {
    const missing = [];

    for (const field of this.REQUIRED_FIELDS) {
      if (
        user[field] === undefined ||
        user[field] === null ||
        user[field] === ''
      ) {
        missing.push(field);
      }
    }

    if (missing.length) {
      throw new Error(
        `Fehlende Pflichtfelder: ${missing.join(', ')}`
      );
    }

    // 🔍 Optional: einfache Zusatzvalidierungen
    if (user.mail && !user.mail.includes('@')) {
      throw new Error('Ungültige E-Mail-Adresse');
    }

    if (user.password && user.password.length < 6) {
      throw new Error('Passwort muss mindestens 6 Zeichen lang sein');
    }
  }

  /**
   * -----------------------------------------------------
   * FIXED MAPPING (AD → Authentication)
   * -----------------------------------------------------
   */
  mapAdObject(obj) {
    if (!obj || !obj.objectGUID) return null;

    return {
      ObjectGUID: obj.objectGUID,
      sAMAccountName: obj.sAMAccountName || obj.cn || null,
      mail: obj.mail || null,
      givenName: obj.givenName || null,
      sn: obj.sn || null,
      employeeID: obj.employeeID || null,
      title: obj.title || null,
      department: obj.department || null,
      streetAddress: obj.streetAddress || null,
      userAccountControl_ID: obj.userAccountControl || null,
      authenticationType_ID: 1,
      telephoneNumber: obj.telephoneNumber || null,
      physicalDeliveryOfficeName: obj.physicalDeliveryOfficeName || null,
      distinguishedName: obj.dn || null,
      password: null,
      refreshtoken: null,
      active: true,
      online: false
    };
  }

  /**
   * -----------------------------------------------------
   * DEDUP (wie SQL UNION)
   * -----------------------------------------------------
   */
  deduplicateByGUID(items) {
    const map = new Map();

    for (const item of items) {
      if (!item?.ObjectGUID) continue;
      map.set(item.ObjectGUID, item);
    }

    return Array.from(map.values());
  }

  /**
   * -----------------------------------------------------
   * TABLE CHECK / CREATE
   * -----------------------------------------------------
   */
  async ensureTable() {
    const qi = this.Authentication.sequelize.getQueryInterface();
    const tables = await qi.showAllTables();

    const exists = tables.includes('Authentication');

    if (!exists) {
      await this.Authentication.sync();
      return false;
    }

    return true;
  }

  /**
   * -----------------------------------------------------
   * CORE SYNC (INTELLIGENT)
   * -----------------------------------------------------
   */
  async syncFromAD() {
    if (!this.ad) {
      throw new Error('AD nicht konfiguriert');
    }

    const [users, groups, computers] = await Promise.all([
      this.ad.findUsers('*'),
      this.ad.findGroups('*'),
      this.ad.getComputers()
    ]);

    const mapped = this.deduplicateByGUID([
      ...users.map(u => this.mapAdObject(u)),
      ...groups.map(g => this.mapAdObject(g)),
      ...computers.map(c => this.mapAdObject(c))
    ].filter(Boolean));

    if (!mapped.length) {
      return { total: 0, deactivated: 0 };
    }

    await this.Authentication.bulkCreate(mapped, {
      updateOnDuplicate: [
        'mail',
        'givenName',
        'sn',
        'employeeID',
        'title',
        'department',
        'streetAddress',
        'userAccountControl_ID',
        'telephoneNumber',
        'physicalDeliveryOfficeName',
        'distinguishedName',
        'active'
      ]
    });

    const existing = await this.Authentication.findAll({
      where: { authenticationType_ID: 1 },
      attributes: ['ObjectGUID']
    });

    const adGuids = new Set(mapped.map(u => u.ObjectGUID));

    const toDeactivate = existing
      .filter(e => !adGuids.has(e.ObjectGUID))
      .map(e => e.ObjectGUID);

    if (toDeactivate.length) {
      await this.Authentication.update(
        { active: false },
        {
          where: {
            ObjectGUID: toDeactivate
          }
        }
      );
    }

    return {
      total: mapped.length,
      deactivated: toDeactivate.length,
      adGuids: Array.from(adGuids)
    };
  }

  /**
   * -----------------------------------------------------
   * OPTIONAL: HARD DELETE
   * -----------------------------------------------------
   */
  async removeDeletedADObjects(adGuids) {
    return this.Authentication.destroy({
      where: {
        authenticationType_ID: 1,
        ObjectGUID: {
          [Op.notIn]: adGuids
        }
      }
    });
  }

  /**
   * -----------------------------------------------------
   * RECREATE
   * -----------------------------------------------------
   */
  async recreateAuthentications(hardReset = false) {
    let message = '';

    const exists = await this.ensureTable();

    if (!exists) {
      message = 'Tabelle wurde neu erstellt ';
    }

    try {
      const result = await this.syncFromAD();

      message += `Sync abgeschlossen (${result.total} Objekte)`;

      if (result.deactivated) {
        message += `, ${result.deactivated} deaktiviert`;
      }

      if (hardReset) {
        const deleted = await this.removeDeletedADObjects(result.adGuids);
        message += `, ${deleted} gelöscht`;
      }

    } catch (err) {
      message += 'Fehler: ' + err.message;
    }

    return message;
  }

  /**
   * -----------------------------------------------------
   * MANUAL USER (MIT VALIDATION)
   * -----------------------------------------------------
   */
  async createManualUser(user) {
    this.validateManualUser(user);

    return this.Authentication.create({
      ...user,
      authenticationType_ID: 2,
      active: true,
      online: false
    });
  }

  /**
   * -----------------------------------------------------
   * MANUAL BULK (MIT VALIDATION)
   * -----------------------------------------------------
   */
  async createManualUsers(users) {
    const errors = [];

    users.forEach((user, index) => {
      try {
        this.validateManualUser(user);
      } catch (err) {
        errors.push(`User ${index}: ${err.message}`);
      }
    });

    if (errors.length) {
      throw new Error(errors.join(' | '));
    }

    return this.Authentication.bulkCreate(
      users.map(user => ({
        ...user,
        authenticationType_ID: 2,
        active: true,
        online: false
      }))
    );
  }

  /**
   * -----------------------------------------------------
   * GET USER
   * -----------------------------------------------------
   */
  async getUser(username) {
    return this.Authentication.findOne({
      where: { sAMAccountName: username }
    });
  }
}

module.exports = IdentityManager;