/**
 * Copyright since 2025 Mifos Initiative
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

import { Injectable, inject } from '@angular/core';
import { AuthenticationService } from './authentication/authentication.service';
import { GL_BRANCHES, GlBranch } from 'app/gl-reports/gl-reports-data';

/**
 * Resolves what branch data the logged-in user is allowed to see.
 *
 * Head Office sees every branch and can drill into any one of them; a branch login is
 * locked to its own book. Previously this logic was copy-pasted into the Cash/Clearing
 * Summary and the NPA report with slightly different branch code lists; this service is
 * the single place it lives so new reports cannot drift.
 *
 * The logged-in office is matched to a branch by name, since session credentials carry
 * only officeId and officeName. Office names are seeded to match the GL branch names
 * exactly (see Liquibase 0442).
 */
@Injectable({ providedIn: 'root' })
export class BranchScopeService {
  private auth = inject(AuthenticationService);

  /** Sentinel used when a branch login cannot be matched to a known branch. */
  static readonly UNRESOLVED = '__unresolved__';

  get isHeadOffice(): boolean {
    return this.auth.isHeadOfficeUser();
  }

  /** The office name on the session, for labelling the scope in report headers. */
  get officeName(): string {
    return this.auth.getCredentials()?.officeName || 'Branch Office';
  }

  /**
   * Branch code the user is confined to, or null for Head Office.
   *
   * Deliberately returns the UNRESOLVED sentinel rather than falling back to the first
   * branch when the office cannot be matched: showing an unrecognised branch someone
   * else's figures would be worse than showing them nothing.
   */
  get ownBranchCode(): string | null {
    if (this.isHeadOffice) {
      return null;
    }
    const name = this.officeName.toLowerCase().trim();
    const match = GL_BRANCHES.find((b) => b.code !== 'HO' && name === b.name.toLowerCase());
    // Fall back to a substring match for offices named e.g. "Andheri (E) Branch".
    const loose = match ?? GL_BRANCHES.find((b) => b.code !== 'HO' && name.includes(b.name.toLowerCase()));
    return loose?.code ?? BranchScopeService.UNRESOLVED;
  }

  /** True when the user may choose which branch to view. */
  get canSelectBranch(): boolean {
    return this.isHeadOffice;
  }

  /** Branches offered in a selector — everything for Head Office, nothing for a branch login. */
  get selectableBranches(): GlBranch[] {
    return this.isHeadOffice ? GL_BRANCHES : [];
  }

  /** Branch code a report should start on. '' means all branches consolidated. */
  get defaultBranchCode(): string {
    return this.isHeadOffice ? '' : (this.ownBranchCode ?? '');
  }

  /**
   * Forces a requested branch code into what the user is actually allowed to see.
   * Call this wherever a branch code reaches a data query, so a stale or hand-edited
   * selection cannot widen the user's scope.
   */
  enforce(requested: string): string {
    return this.isHeadOffice ? requested : (this.ownBranchCode ?? BranchScopeService.UNRESOLVED);
  }

  /** True when a branch login's office matched no known branch, so it sees no data. */
  get isUnresolved(): boolean {
    return this.ownBranchCode === BranchScopeService.UNRESOLVED;
  }

  /** Human label for the current scope, for report headers. */
  scopeLabel(selectedCode: string): string {
    if (!this.isHeadOffice) {
      return this.officeName;
    }
    if (!selectedCode) {
      return 'All Branches (Consolidated)';
    }
    return GL_BRANCHES.find((b) => b.code === selectedCode)?.name ?? selectedCode;
  }
}