/**
 * 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, inject } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule } from '@angular/forms';
import { Router } from '@angular/router';
import { catchError } from 'rxjs/operators';
import { of } from 'rxjs';

import { DividendDashboardService } from '../dividend-dashboard.service';

/**
 * Bank Manager's Dividend Dashboard: summary stats, every dividend ever declared, full 3-year lock
 * history, and members whose unclaimed dividend sits alongside an overdue loan EMI (with a
 * proactive "Apply to Loan" action).
 *
 * Claiming a dividend hands off to the DD inventory, because a dividend is only ever collected as a
 * Demand Draft. The draft is then approved on the DD Issuance Approvals screen alongside every
 * other draft, so there is no separate claim queue here — the lock history shows the DD number once
 * it has been drawn.
 */
@Component({
  selector: 'mifosx-dividend-dashboard',
  templateUrl: './dividend-dashboard.component.html',
  styleUrls: [
    '../../cashier/cashier-shared.scss',
    '../clerk-shared.scss',
    './dividend-dashboard.component.scss'
  ],
  standalone: true,
  imports: [
    CommonModule,
    FormsModule
  ]
})
export class DividendDashboardComponent implements OnInit {
  private service = inject(DividendDashboardService);
  private router = inject(Router);

  /**
   * Which list the clerk is looking at.
   *
   * The three lists answer unrelated questions — what has been declared, who is blocked by an
   * overdue EMI, and the full lock history — and a clerk is only ever in one of them. Stacked on one
   * page they made the screen long enough that the section a clerk came for was usually below the
   * fold, so they are tabbed instead.
   *
   * Every list is still loaded on init rather than on first view: the counts in the tab strip have
   * to be right before a tab is opened, or the strip would be advertising numbers it does not know.
   */
  activeTab: 'declarations' | 'overdue' | 'locks' = 'declarations';

  rows: any[] = [];
  loading = false;
  loaded = false;

  expandedLockId: number | null = null;
  selectedLoanId: Record<number, number | null> = {};
  applyAmount: Record<number, number | null> = {};
  applying = false;
  applyError: string | null = null;

  summary: any = null;
  summaryLoading = false;

  declarations: any[] = [];
  declarationsLoading = false;
  declarationsLoaded = false;

  /**
   * Free-text search, one box per table.
   *
   * Kept separate rather than shared because the three tables answer different questions and a
   * clerk is usually in one of them: narrowing the lock history to a member should not blank out
   * the declarations table above it, which has nothing to do with that member.
   *
   * Filtering is done here rather than server-side because every row is already loaded — these are
   * a society's dividends, not a transaction ledger — so a round trip per keystroke would be slower
   * than the filter itself and would blank the table while it ran.
   */
  declarationSearch = '';
  overdueSearch = '';
  lockSearch = '';

  /** Every lock the status filter returned, before the year filter narrows it. */
  locks: any[] = [];
  locksLoading = false;
  locksLoaded = false;
  lockStatusFilter = 'ALL';

  /**
   * Financial years that actually have locks, newest first — derived from the data rather than
   * listed anywhere, so a new declaration adds its year on its own and a year whose locks are all
   * gone stops being offered. No maintenance as years roll over.
   */
  lockYears: string[] = [];
  lockYearFilter = 'ALL';

  ngOnInit(): void {
    this.loadSummary();
    this.loadDeclarations();
    this.load();
    this.loadLocks();
  }

  /**
   * Takes the clerk to the DD inventory to draw the draft this dividend is paid out as.
   *
   * A dividend is only ever collected as a Demand Draft, so the claim is really a request to issue
   * one — and the place a draft is issued is the leaflet inventory, where the clerk can see which
   * numbered leaflet they are about to commit. Gathering the draft's details on this dashboard
   * instead meant filling a second, thinner version of the DD form and never seeing the DD number
   * until after approval.
   *
   * The dividend travels in the query string rather than in a service, so a reloaded or
   * bookmarked page still knows which lock it is drawing against instead of silently issuing an
   * ordinary counter draft.
   */
  claimAsDemandDraft(lock: any): void {
    this.router.navigate(
      [
        '/sponsor-dd',
        'inventory'
      ],
      {
        queryParams: {
          dividendLockId: lock.lockId,
          dividendAmount: Number(lock.amount),
          dividendBeneficiary: lock.clientName ?? '',
          dividendFinancialYear: lock.financialYear ?? ''
        }
      }
    );
  }

  loadSummary(): void {
    this.summaryLoading = true;
    this.service
      .getSummary()
      .pipe(catchError(() => of(null)))
      .subscribe((res: any) => {
        this.summary = res;
        this.summaryLoading = false;
      });
  }

  loadDeclarations(): void {
    this.declarationsLoading = true;
    this.service
      .getDeclarations()
      .pipe(catchError(() => of([])))
      .subscribe((res: any[]) => {
        this.declarations = res ?? [];
        this.declarationsLoading = false;
        this.declarationsLoaded = true;
      });
  }

  /**
   * Whether any of a row's searchable fields contains the term.
   *
   * Substring rather than prefix matching, because a clerk reading an account number off a passbook
   * often types the distinctive tail of it rather than the branch prefix every account shares. Null
   * fields are skipped — a lock with no share account still has to be findable by member name.
   */
  private matches(term: string, ...fields: (string | number | null | undefined)[]): boolean {
    const needle = term.trim().toLowerCase();
    if (!needle) {
      return true;
    }
    return fields.some((field) => field != null && String(field).toLowerCase().includes(needle));
  }

  /** Declarations the table renders. Product-level rows, so there is no member to search on. */
  get visibleDeclarations(): any[] {
    return this.declarations.filter((d) =>
      this.matches(this.declarationSearch, d.productName, d.periodStartDate, d.periodEndDate, d.status)
    );
  }

  /** Members with an overdue EMI, narrowed to the one the clerk is dealing with. */
  get visibleOverdueRows(): any[] {
    return this.rows.filter((r) => this.matches(this.overdueSearch, r.clientName, r.shareAccountNo));
  }

  declarationStatusLabel(status: string): string {
    return status === 'PENDING_APPROVAL' ? 'Pending Approval' : 'Approved';
  }

  declarationStatusClass(status: string): string {
    return status === 'PENDING_APPROVAL' ? 'dd-badge--pending' : 'dd-badge--posted';
  }

  loadLocks(): void {
    this.locksLoading = true;
    this.service
      .getLocks(this.lockStatusFilter)
      .pipe(catchError(() => of([])))
      .subscribe((res: any[]) => {
        this.locks = res ?? [];
        this.rebuildLockYears();
        this.locksLoading = false;
        this.locksLoaded = true;
      });
  }

  /**
   * Rebuilds the year chips from whatever locks came back, newest first.
   *
   * A year the current status filter has no locks for disappears from the chips, so the selected
   * year is reset to ALL when that happens — otherwise the table would show nothing with no
   * indication why.
   */
  private rebuildLockYears(): void {
    this.lockYears = [...new Set(this.locks.map((l) => l.financialYear).filter((y) => !!y))].sort((a, b) =>
      b.localeCompare(a)
    );
    if (this.lockYearFilter !== 'ALL' && !this.lockYears.includes(this.lockYearFilter)) {
      this.lockYearFilter = 'ALL';
    }
  }

  /**
   * Locks the table actually renders — the status filter is applied server-side, the year and the
   * search here. All three narrow together, so a clerk can hold a year and still search within it.
   */
  get visibleLocks(): any[] {
    return this.locks.filter(
      (l) =>
        (this.lockYearFilter === 'ALL' || l.financialYear === this.lockYearFilter) &&
        this.matches(this.lockSearch, l.clientName, l.shareAccountNo, l.productName, l.appliedLoanAccountNo)
    );
  }

  /** Total of what is on screen, so a year's worth of dividend can be read off directly. */
  get visibleLocksTotal(): number {
    return this.visibleLocks.reduce((sum, l) => sum + (Number(l.amount) || 0), 0);
  }

  setLockStatusFilter(status: string): void {
    this.lockStatusFilter = status;
    this.loadLocks();
  }

  setLockYearFilter(year: string): void {
    this.lockYearFilter = year;
  }

  lockStatusClass(status: string): string {
    switch (status) {
      case 'UNCLAIMED':
        return 'dd-badge--pending';
      case 'CLAIMED':
        return 'dd-badge--posted';
      case 'FORFEITED':
        return 'dd-badge--failed';
      default:
        return 'dd-badge--pending';
    }
  }

  load(): void {
    this.loading = true;
    this.expandedLockId = null;
    this.service
      .getDashboard()
      .pipe(catchError(() => of([])))
      .subscribe((res: any[]) => {
        this.rows = res ?? [];
        this.loading = false;
        this.loaded = true;
      });
  }

  totalOverdue(row: any): number {
    return (row.overdueLoans || []).reduce((sum: number, l: any) => sum + Number(l.overdueAmount || 0), 0);
  }

  toggleApply(row: any): void {
    if (this.expandedLockId === row.lockId) {
      this.expandedLockId = null;
      return;
    }
    this.expandedLockId = row.lockId;
    this.applyError = null;
    const firstLoan = (row.overdueLoans || [])[0];
    this.selectedLoanId[row.lockId] = firstLoan ? firstLoan.loanId : null;
    this.applyAmount[row.lockId] = firstLoan
      ? Math.min(Number(row.lockedAmount), Number(firstLoan.overdueAmount))
      : Number(row.lockedAmount);
  }

  maxAmountFor(row: any): number {
    const loanId = this.selectedLoanId[row.lockId];
    const loan = (row.overdueLoans || []).find((l: any) => l.loanId === loanId);
    const overdue = loan ? Number(loan.overdueAmount) : Number(row.lockedAmount);
    return Math.min(Number(row.lockedAmount), overdue);
  }

  onLoanChange(row: any): void {
    this.applyAmount[row.lockId] = this.maxAmountFor(row);
  }

  submitApply(row: any): void {
    const loanId = this.selectedLoanId[row.lockId];
    const amount = this.applyAmount[row.lockId];
    if (!loanId || !amount || amount <= 0) {
      this.applyError = 'Select a loan and enter a valid amount.';
      return;
    }
    this.applying = true;
    this.applyError = null;
    this.service.applyToLoan(row.lockId, loanId, amount).subscribe({
      next: () => {
        this.applying = false;
        this.load();
        this.loadLocks();
        this.loadSummary();
      },
      error: (err: any) => {
        this.applying = false;
        this.applyError = err?.error?.message || 'Failed to apply dividend to loan.';
      }
    });
  }
}