/**
 * 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 { Component, OnInit, ViewChild, inject } from '@angular/core';
import { MatPaginator } from '@angular/material/paginator';
import { MatSort, MatSortHeader } from '@angular/material/sort';
import {
  MatTableDataSource,
  MatTable,
  MatColumnDef,
  MatHeaderCellDef,
  MatHeaderCell,
  MatCellDef,
  MatCell,
  MatHeaderRowDef,
  MatHeaderRow,
  MatRowDef,
  MatRow
} from '@angular/material/table';
import { MatChipsModule } from '@angular/material/chips';
import { MatProgressBarModule } from '@angular/material/progress-bar';
import { MatTooltip } from '@angular/material/tooltip';
import { MatDialog } from '@angular/material/dialog';
import { MatSnackBar } from '@angular/material/snack-bar';
import { NgClass, DatePipe } from '@angular/common';
import { FaIconComponent } from '@fortawesome/angular-fontawesome';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';
import { SanctionsLogsService } from './sanctions-logs.service';
import { SanctionsAlertReviewDialogComponent } from './sanctions-alert-review-dialog.component';

@Component({
  selector: 'mifosx-sanctions-logs',
  templateUrl: './sanctions-logs.component.html',
  styleUrls: ['./sanctions-logs.component.scss'],
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    MatTable,
    MatSort,
    MatColumnDef,
    MatHeaderCellDef,
    MatHeaderCell,
    MatSortHeader,
    MatCellDef,
    MatCell,
    MatHeaderRowDef,
    MatHeaderRow,
    MatRowDef,
    MatRow,
    MatPaginator,
    MatChipsModule,
    MatProgressBarModule,
    MatTooltip,
    NgClass,
    DatePipe,
    FaIconComponent
  ]
})
export class SanctionsLogsComponent implements OnInit {
  private sanctionsLogsService = inject(SanctionsLogsService);
  private dialog = inject(MatDialog);
  private snackBar = inject(MatSnackBar);

  displayedColumns: string[] = [
    'screenedName',
    'screeningResult',
    'disposition',
    'matchCount',
    'screeningSource',
    'client',
    'screenedBy',
    'screenedAt',
    'actions'
  ];

  dataSource = new MatTableDataSource<any>();
  searchName = '';
  activeFilter: string | null = null;
  /**
   * When set, the table shows the Principal Officer's alert queue (flagged screenings and their
   * disposition) instead of the raw screening log. 'ALL' means every alert regardless of state.
   */
  alertFilter: string | null = null;
  /**
   * Which screening run the rows came from: 'CLIENT_CREATION' for names screened while the client was being
   * created, 'RESCREEN' for the periodic sweep over existing clients, null for both. Applied in the browser
   * because neither the log nor the alert endpoint accepts a source filter.
   */
  activeSource: 'CLIENT_CREATION' | 'RESCREEN' | null = null;
  loading = false;
  rescreening = false;
  /** Full result set, kept so the source filter can be applied without another round trip. */
  private allRows: any[] = [];

  @ViewChild(MatPaginator, { static: true }) paginator: MatPaginator;
  @ViewChild(MatSort, { static: true }) sort: MatSort;

  ngOnInit() {
    this.loadLogs();
  }

  loadLogs() {
    this.loading = true;

    // The alert queue is a different endpoint, not a filter on the log list: it carries the
    // disposition columns the review dialog needs.
    // AWAITING_APPROVAL is a client-side view over all alerts rather than a disposition value:
    // an alert waiting on the Principal Officer is one that HAS been assessed but not signed off,
    // so it is identified by approvedBy being empty, not by its disposition.
    const serverFilter =
      this.alertFilter === 'ALL' || this.alertFilter === 'AWAITING_APPROVAL' ? undefined : this.alertFilter;

    const request$ = this.alertFilter
      ? this.sanctionsLogsService.getAlerts(serverFilter)
      : this.sanctionsLogsService.getLogs(this.buildLogFilters());

    request$.subscribe({
      next: (data: any) => this.applyRows(this.postFilter(data || [])),
      error: () => this.applyRows([])
    });
  }

  /** Narrows the fetched alerts for views the API has no dedicated filter for. */
  private postFilter(rows: any[]): any[] {
    if (this.alertFilter !== 'AWAITING_APPROVAL') {
      return rows;
    }
    return rows.filter((row) => this.isAwaitingApproval(row));
  }

  /**
   * True when the clerk has recorded an assessment and the Principal Officer has not yet approved
   * it. This is the state in which the freeze is pending and nothing happens until someone acts.
   */
  isAwaitingApproval(row: any): boolean {
    return !!row?.disposition && row.disposition !== 'PENDING_REVIEW' && !row.approvedBy;
  }

  private buildLogFilters() {
    const filters: any = {};
    if (this.activeFilter) {
      filters.result = this.activeFilter;
    }
    if (this.searchName?.trim()) {
      filters.name = this.searchName.trim();
    }
    return filters;
  }

  private applyRows(rows: any[]) {
    this.allRows = rows;
    this.refreshTable();
    this.loading = false;
  }

  /** Applies the source filter over the rows already fetched. */
  private refreshTable() {
    const rows = this.activeSource
      ? this.allRows.filter((row) => (this.activeSource === 'RESCREEN' ? this.isRescreen(row) : !this.isRescreen(row)))
      : this.allRows;

    this.dataSource = new MatTableDataSource(rows);
    this.dataSource.paginator = this.paginator;
    this.dataSource.sort = this.sort;
  }

  /**
   * A row came from the periodic sweep when the backend stamped it PERIODIC_RESCREEN; everything else was
   * screened as the name was entered during client creation.
   */
  isRescreen(row: any): boolean {
    return (row?.screeningSource || '').toUpperCase().includes('RESCREEN');
  }

  sourceLabel(row: any): string {
    return this.isRescreen(row) ? 'Re-screening' : 'Client Creation';
  }

  sourceClass(row: any): string {
    return this.isRescreen(row) ? 'source-rescreen' : 'source-onboarding';
  }

  filterBySource(source: 'CLIENT_CREATION' | 'RESCREEN' | null) {
    this.activeSource = this.activeSource === source ? null : source;
    this.refreshTable();
  }

  /** Row counts behind each source chip, so the split is visible before filtering. */
  get creationCount(): number {
    return this.allRows.filter((row) => !this.isRescreen(row)).length;
  }

  get rescreenCount(): number {
    return this.allRows.filter((row) => this.isRescreen(row)).length;
  }

  applySearch(value: string) {
    this.searchName = value;
    // Name search only exists on the log endpoint, so leave the alert queue when searching.
    this.alertFilter = null;
    this.loadLogs();
  }

  filterByResult(result: string | null) {
    this.activeFilter = this.activeFilter === result ? null : result;
    this.alertFilter = null;
    this.loadLogs();
  }

  filterByAlert(status: string) {
    this.alertFilter = this.alertFilter === status ? null : status;
    this.activeFilter = null;
    this.loadLogs();
  }

  clearFilters() {
    this.searchName = '';
    this.activeFilter = null;
    this.alertFilter = null;
    this.activeSource = null;
    this.loadLogs();
  }

  /** Only flagged rows carry a case to review. */
  isAlert(row: any): boolean {
    return !!row?.disposition;
  }

  dispositionLabel(row: any): string {
    switch (row?.disposition) {
      case 'PENDING_REVIEW':
        return 'Pending Review';
      case 'FALSE_POSITIVE':
        return row.approvedBy ? 'False Positive — Approved' : 'False Positive — Awaiting PO';
      case 'CONFIRMED_MATCH':
        if (!row.approvedBy) {
          return 'Confirmed — Awaiting PO';
        }
        // An onboarding match has no client and therefore no accounts to freeze — saying
        // "Frozen" there would claim an action that never happened.
        return row.frozenAccountIds ? 'Confirmed — Frozen' : 'Confirmed — Blocked';
      default:
        return '—';
    }
  }

  dispositionClass(row: any): string {
    if (row?.disposition === 'CONFIRMED_MATCH') return 'badge-flagged';
    if (row?.disposition === 'FALSE_POSITIVE') return row.approvedBy ? 'badge-clear' : 'badge-pending';
    if (row?.disposition === 'PENDING_REVIEW') return 'badge-pending';
    return '';
  }

  reviewAlert(row: any) {
    this.dialog
      .open(SanctionsAlertReviewDialogComponent, { width: '600px', data: { ...row }, autoFocus: false })
      .afterClosed()
      .subscribe((changed: boolean) => {
        if (changed) {
          this.loadLogs();
        }
      });
  }

  /**
   * Screens every existing client against the currently loaded list snapshot. This is what
   * detects a customer who was added to the UN list after they were onboarded — the only
   * situation in which there are accounts to freeze.
   */
  rescreenExistingClients() {
    this.rescreening = true;
    this.sanctionsLogsService.rescreenExistingClients().subscribe({
      next: (res: any) => {
        this.rescreening = false;
        this.snackBar.open(`Re-screening complete — ${res?.clientsFlagged ?? 0} client(s) flagged.`, 'Close', {
          duration: 6000
        });
        this.filterByAlert('PENDING_REVIEW');
      },
      error: (err: any) => {
        this.rescreening = false;
        this.snackBar.open(err?.error?.defaultUserMessage || 'Re-screening failed.', 'Close', { duration: 6000 });
      }
    });
  }
}