/**
 * 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/.
 */

/** Angular Imports */
import { Component, OnInit, inject } from '@angular/core';
import { UntypedFormBuilder, UntypedFormGroup, Validators } from '@angular/forms';
import { Router } from '@angular/router';
import { MatDialog } from '@angular/material/dialog';
import { MatTooltip } from '@angular/material/tooltip';
import { DateAdapter, MAT_DATE_FORMATS } from '@angular/material/core';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';
import { ConfirmationDialogComponent } from 'app/shared/confirmation-dialog/confirmation-dialog.component';
import { DdsDateAdapter, DDS_DATE_FORMATS } from './dds-date-adapter';

/** Custom Services */
import { OrganizationService } from 'app/organization/organization.service';
import { AlertService } from 'app/core/alert/alert.service';
import { SettingsService } from 'app/settings/settings.service';
import { Dates } from 'app/core/utils/dates';
import { announceHeldForApproval, heldForApproval } from 'app/deposits/dds-approvals/dds-approval-notice';

/**
 * DDS Interest & Commission batch processing — the legacy Interest Part menu.
 *
 * Eight menu entries, which are four Calculate/Post pairs. A *calculation* job works out what has
 * been earned since the last one and parks it: interest against the customer's account, commission
 * against the agent. Neither is spendable yet. The matching *posting* job then moves that parked
 * figure where it belongs — into the customer's balance, or out to the agent.
 *
 * Every job is itself a two-step Generate then Post. Generate saves what it worked out and changes
 * nothing else, so a figure that looks wrong is discarded by simply not posting it.
 */
@Component({
  selector: 'mifosx-dds-batch-processing',
  templateUrl: './dds-batch-processing.component.html',
  styleUrls: ['./dds-batch-processing.component.scss'],
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    // The reason a run failed is too long to sit in the column, and too useful to leave out.
    MatTooltip
  ],
  // Day-first dates, as the legacy screen showed them. Declared here rather than application-wide:
  // a @Component's providers reach only this component, so no other screen's datepicker changes.
  providers: [
    { provide: DateAdapter, useClass: DdsDateAdapter },
    { provide: MAT_DATE_FORMATS, useValue: DDS_DATE_FORMATS }
  ]
})
export class DdsBatchProcessingComponent implements OnInit {
  private formBuilder = inject(UntypedFormBuilder);
  private router = inject(Router);
  private organizationService = inject(OrganizationService);
  private alertService = inject(AlertService);
  private dialog = inject(MatDialog);
  private settingsService = inject(SettingsService);
  private dateUtils = inject(Dates);

  /**
   * The menu as the legacy system lists it, paired with what the API calls each job. Ordered as
   * calculate-then-post within each pair, matching the numbering on the legacy screen.
   */
  jobTypes: Array<{ label: string; code: string }> = [
    { label: 'Interest Calculation', code: 'INTEREST_CALCULATION' },
    { label: 'Interest Posting', code: 'INTEREST_POSTING' },
    { label: 'OD Interest Calculation', code: 'OD_INTEREST_CALCULATION' },
    { label: 'OD Interest Posting', code: 'OD_INTEREST_POSTING' },
    { label: 'Commission Calculation', code: 'COMMISSION_CALCULATION' },
    { label: 'Commission Posting', code: 'COMMISSION_POSTING' },
    // Last, and on its own: the others move money onto accounts that stay open, while this one pays
    // an account out and shuts it. Listing it beside a calculate/post pair would suggest it is the
    // second half of one.
    { label: 'Maturity Auto Close', code: 'MATURITY_AUTO_CLOSE' }
  ];

  branchScopes = [
    'All',
    'Selected'
  ];

  private static readonly MONEY = new Intl.NumberFormat('en-IN', {
    minimumFractionDigits: 2,
    maximumFractionDigits: 2
  });

  offices: any[] = [];
  selectedOfficeNames = new Set<string>();

  /** The run currently previewed on screen, or null once it has been posted or discarded. */
  generatedRun: any = null;
  previewRows: any[] = [];

  recentRuns: any[] = [];

  batchForm: UntypedFormGroup = this.formBuilder.group({
    jobType: [
      'INTEREST_CALCULATION',
      Validators.required
    ],
    branchScope: [
      'All',
      Validators.required
    ],
    jobDate: [
      new Date(),
      Validators.required
    ],
    agentFrom: [
      1,
      Validators.required
    ],
    agentTo: [
      99999,
      Validators.required
    ],
    partyFrom: [
      1,
      Validators.required
    ],
    partyTo: [
      99999999,
      Validators.required
    ]
  });

  get jobType(): string {
    return this.batchForm.get('jobType').value;
  }

  get jobTypeLabel(): string {
    return this.jobTypes.find((type) => type.code === this.jobType)?.label ?? this.jobType;
  }

  /** Commission is per agent, so the party range does not narrow it. */
  get isCommissionJob(): boolean {
    return this.jobType.startsWith('COMMISSION');
  }

  get isPostingJob(): boolean {
    return this.jobType.endsWith('_POSTING');
  }

  get isBranchSelected(): boolean {
    return this.batchForm.get('branchScope')?.value === 'Selected';
  }

  /**
   * Only a commission calculation has a breakdown worth showing: it is the one job where the figure
   * applied is not the figure worked out, because TDS and the standing deductions come off it.
   */
  get showsCommissionBreakdown(): boolean {
    return this.jobType === 'COMMISSION_CALCULATION';
  }

  /** What Generate found, in words — the same figure the Post button is about to apply. */
  get previewTotal(): number {
    return this.previewRows.reduce((total, row) => total + Number(row.amount || 0), 0);
  }

  ngOnInit(): void {
    this.organizationService.getOffices().subscribe((offices: any[]) => {
      this.offices = offices || [];
    });
    this.loadRecentRuns();
  }

  money(value: any): string {
    if (value === null || value === undefined || value === '') {
      return '—';
    }
    return DdsBatchProcessingComponent.MONEY.format(Number(value));
  }

  labelOf(code: string): string {
    return this.jobTypes.find((type) => type.code === code)?.label ?? code;
  }

  toggleOffice(officeName: string): void {
    if (this.selectedOfficeNames.has(officeName)) {
      this.selectedOfficeNames.delete(officeName);
    } else {
      this.selectedOfficeNames.add(officeName);
    }
  }

  /**
   * What every past run did and whether it was applied. Without this a generated-but-unposted run is
   * invisible the moment the page is left, and there is no way to tell whether a month's interest
   * was ever actually posted.
   */
  private loadRecentRuns(): void {
    this.organizationService.getDdsBatchRuns().subscribe((runs: any[]) => {
      this.recentRuns = runs || [];
    });
  }

  generate(): void {
    const raw = this.batchForm.getRawValue();
    const dateFormat = this.settingsService.dateFormat;

    const payload: any = {
      jobType: raw.jobType,
      branchScope: raw.branchScope,
      jobDate: this.dateUtils.formatDate(raw.jobDate, dateFormat),
      agentFrom: raw.agentFrom,
      agentTo: raw.agentTo,
      dateFormat,
      locale: this.settingsService.language.code
    };

    // The party range narrows an interest job to particular accounts; commission is worked out per
    // agent on their whole collection, so sending a range there would only imply a filter that has
    // no effect.
    if (!this.isCommissionJob) {
      payload.partyFrom = raw.partyFrom;
      payload.partyTo = raw.partyTo;
    }

    if (raw.branchScope === 'Selected') {
      payload.officeNames = Array.from(this.selectedOfficeNames);
    }

    this.organizationService.generateDdsBatchRun(payload).subscribe((result: any) => {
      this.organizationService.getDdsBatchRun(result.resourceId).subscribe((batchRun: any) => {
        this.generatedRun = batchRun;
        this.previewRows = batchRun.rows || [];

        // A run that found nothing is the normal outcome of a period already processed, not a
        // failure — but it has to say so, or an empty table reads as the screen being broken.
        if (this.previewRows.length === 0) {
          this.alertService.alert({
            type: 'Information',
            message: `${this.jobTypeLabel} found nothing to apply. Either this period has already been processed, or there was no activity in it.`
          });
        } else {
          this.alertService.alert({
            type: 'Success',
            message: `${this.jobTypeLabel}: ${this.previewRows.length} ${this.previewRows.length === 1 ? 'entry' : 'entries'} totalling ${this.money(this.previewTotal)} calculated. Nothing has been applied yet — review and press Post.`
          });
        }

        this.loadRecentRuns();
      });
    });
  }

  post(): void {
    if (!this.generatedRun || this.previewRows.length === 0) {
      return;
    }

    const count = this.previewRows.length;
    const total = this.money(this.previewTotal);
    const isPosting = this.isPostingJob;

    // Post is the step that moves money, and it cannot be undone from this screen — so it names
    // exactly what is about to change rather than asking a generic "are you sure".
    this.dialog
      .open(ConfirmationDialogComponent, {
        data: {
          type: 'warn',
          heading: `Post ${this.jobTypeLabel}?`,
          dialogContext:
            `${count} ${count === 1 ? 'entry' : 'entries'} totalling ${total} will be applied. ` +
            (isPosting
              ? 'This credits the customers or pays the agents, and appears on the ledger. '
              : 'This records what has been earned against each account. ') +
            'It cannot be undone from this screen.'
        }
      })
      .afterClosed()
      .subscribe((response: any) => {
        if (response?.confirm) {
          this.applyRun(count, total);
        }
      });
  }

  /**
   * Applies the run, and says what actually happened rather than assuming it finished.
   *
   * A crediting run costs what a savings deposit costs on every account it touches, so the server
   * takes it off the request and does it in the background - the reply comes back in a moment while
   * the work is still going on. Reporting that as "posted" would tell the clerk a run had finished
   * seconds after it began, and they would go looking for credits that were still being written.
   *
   * So the run is followed until it settles. A calculation run is done by the time the reply lands
   * and says so at once; a crediting run says it is under way, and the list beneath refreshes itself
   * until the server marks it posted - or failed, with the reason the server recorded.
   */
  private applyRun(count: number, total: string): void {
    const label = this.jobTypeLabel;
    const runId = this.generatedRun.id;
    const crediting = this.isPostingJob;

    this.organizationService.postDdsBatchRun(runId).subscribe((response: any) => {
      this.generatedRun = null;
      this.previewRows = [];
      this.loadRecentRuns();

      if (heldForApproval(response)) {
        announceHeldForApproval(
          response,
          `${label} (${count} ${count === 1 ? 'entry' : 'entries'}, ${total})`,
          this.organizationService,
          this.alertService
        );
        return;
      }

      if (!crediting) {
        this.alertService.alert({
          type: 'Success',
          message: `${label} posted — ${count} ${count === 1 ? 'entry' : 'entries'}, ${total}.`
        });
        return;
      }

      this.postingRunId = runId;
      this.alertService.alert({
        type: 'Posting',
        message:
          `${label} is running — ${count} ${count === 1 ? 'entry' : 'entries'}, ${total}. ` +
          'It continues in the background; this list will update when it is done.'
      });
      this.followRun(runId, label);
    });
  }

  /** The crediting run being followed, if one is. The screen reads this to show it is under way. */
  postingRunId: number | null = null;

  /**
   * Watches a background run until the server marks it settled.
   *
   * Polled rather than pushed: a batch that takes minutes needs no faster news than this, and a poll
   * costs nothing when the answer is one row. It gives up after a while rather than asking forever -
   * the run is still on the list either way, and a clerk can read its status there.
   */
  private followRun(runId: number, label: string): void {
    let checksLeft = DdsBatchProcessingComponent.MAX_STATUS_CHECKS;

    const check = () => {
      this.organizationService.getDdsBatchRuns().subscribe({
        next: (runs: any[]) => {
          const run = (runs || []).find((each: any) => each.id === runId);
          const status = run?.status;

          if (status === 'POSTED' || status === 'FAILED') {
            this.postingRunId = null;
            this.loadRecentRuns();
            this.alertService.alert(
              status === 'POSTED'
                ? { type: 'Success', message: `${label} posted — ${run.rowsPosted ?? run.totalRows} entries applied.` }
                : { type: 'Error', message: `${label} failed: ${run.failureReason || 'see the run for details'}` }
            );
            return;
          }

          if (--checksLeft > 0) {
            setTimeout(check, DdsBatchProcessingComponent.STATUS_CHECK_INTERVAL_MS);
          } else {
            // Still going after the wait. Left on the list rather than reported either way - saying
            // "failed" for a run that is merely long would be worse than saying nothing.
            this.postingRunId = null;
            this.loadRecentRuns();
          }
        },
        // A failed status check says nothing about the run itself, which carries on regardless.
        error: () => {
          if (--checksLeft > 0) {
            setTimeout(check, DdsBatchProcessingComponent.STATUS_CHECK_INTERVAL_MS);
          } else {
            this.postingRunId = null;
          }
        }
      });
    };

    setTimeout(check, DdsBatchProcessingComponent.STATUS_CHECK_INTERVAL_MS);
  }

  private static readonly STATUS_CHECK_INTERVAL_MS = 4000;
  /** Twenty minutes of checking, which is longer than any run measured here has taken. */
  private static readonly MAX_STATUS_CHECKS = 300;

  /** Drops the preview without applying it — the safe way out of a calculation that looks wrong. */
  discard(): void {
    this.generatedRun = null;
    this.previewRows = [];
  }

  exit(): void {
    this.router.navigate(['/organization']);
  }
}