/**
 * 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 { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';

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

/**
 * Commission Slab Master component.
 *
 * Two kinds of slab: ACCOUNT (commission percentage on collection volume)
 * and COMMISSION (a senior-agent override on another agent's commission -
 * deferred: there is no agent hierarchy modelled yet, see the DDS punch
 * list). Modelled directly on the legacy Commission Slab Master screen this
 * replaces.
 *
 * Backed by its own DDS Commission Slab API (`/dds/commissionslabs`) - an
 * append-only chart, same as the legacy screen: existing rows load on open,
 * newly-added rows post on Save, and there is no edit/delete of a
 * previously-saved row.
 */
@Component({
  selector: 'mifosx-commission-slab-master',
  templateUrl: './commission-slab-master.component.html',
  styleUrls: ['./commission-slab-master.component.scss'],
  imports: [...STANDALONE_SHARED_IMPORTS]
})
export class CommissionSlabMasterComponent implements OnInit {
  private formBuilder = inject(UntypedFormBuilder);
  private router = inject(Router);
  private organizationService = inject(OrganizationService);
  private alertService = inject(AlertService);

  private static readonly SLAB_TYPE_CODES: Record<string, string> = {
    Account: 'ACCOUNT',
    Commission: 'COMMISSION'
  };
  private static readonly SLAB_TYPE_LABELS: Record<string, string> = {
    ACCOUNT: 'Account',
    COMMISSION: 'Commission'
  };

  slabTypes = [
    'Account',
    'Commission'
  ];

  displayedColumns: string[] = [
    'slabType',
    'slabFrom',
    'slabTo',
    'commissionPercent',
    'actions'
  ];

  slabs: Array<{ id?: number; slabType: string; slabFrom: number; slabTo: number; commissionPercent: number }> = [];

  newSlabForm: UntypedFormGroup = this.formBuilder.group({
    slabType: [
      '',
      Validators.required
    ],
    slabFrom: [
      0,
      Validators.required
    ],
    slabTo: [
      0,
      Validators.required
    ],
    commissionPercent: [
      0,
      Validators.required
    ]
  });

  ngOnInit(): void {
    this.loadSlabs();
  }

  private loadSlabs(): void {
    this.organizationService.getCommissionSlabs().subscribe((slabs: any[]) => {
      this.slabs = (slabs || []).map((slab) => ({
        id: slab.id,
        slabType: CommissionSlabMasterComponent.SLAB_TYPE_LABELS[slab.slabType] || slab.slabType,
        slabFrom: slab.slabFrom,
        slabTo: slab.slabTo,
        commissionPercent: slab.commissionPercent
      }));
    });
  }

  /**
   * Where each slab type's coverage begins and ends, and any figure in between that no slab claims.
   *
   * A gap is not an error - a bank may well decide there is no commission below some floor - but it
   * has to be visible. The commission run simply finds no slab for a volume that falls in a gap and
   * moves on, so the agent is paid nothing for that month with nothing on screen to say why.
   */
  get coverage(): Array<{ slabType: string; from: number; to: number; gaps: string[] }> {
    return this.slabTypes
      .map((slabType) => {
        const rows = this.slabs
          .filter((slab) => slab.slabType === slabType)
          .map((slab) => ({ from: Number(slab.slabFrom), to: Number(slab.slabTo) }))
          .sort((a, b) => a.from - b.from);

        if (rows.length === 0) {
          return null;
        }

        const gaps: string[] = [];
        for (let i = 1; i < rows.length; i++) {
          const previousEnd = rows[i - 1].to;
          const nextStart = rows[i].from;
          if (nextStart > previousEnd + 1) {
            gaps.push(`${previousEnd + 1} - ${nextStart - 1}`);
          }
        }

        return { slabType, from: rows[0].from, to: rows[rows.length - 1].to, gaps };
      })
      .filter((entry): entry is { slabType: string; from: number; to: number; gaps: string[] } => entry !== null);
  }

  /**
   * The slab already on the table that this range would collide with, if any.
   *
   * The backend refuses overlapping slabs, but only when Save is pressed - by then the officer may
   * have keyed several rows and has to work out which one it objected to. Catching it as the row is
   * added names the clash while it is still the row in front of them.
   */
  private clashingSlab(candidate: { slabType: string; slabFrom: number; slabTo: number }): any {
    return this.slabs.find(
      (slab) =>
        slab.slabType === candidate.slabType &&
        Number(candidate.slabFrom) <= Number(slab.slabTo) &&
        Number(candidate.slabTo) >= Number(slab.slabFrom)
    );
  }

  addSlab(): void {
    if (this.newSlabForm.invalid) {
      // Marking the controls touched is what makes Material show which one is missing; without it
      // the button simply does nothing and the officer has no idea what the screen is waiting for.
      this.newSlabForm.markAllAsTouched();
      this.alertService.alert({ type: 'Error', message: 'Fill the slab type, range and percentage first' });
      return;
    }

    const candidate = this.newSlabForm.getRawValue();

    if (Number(candidate.slabFrom) > Number(candidate.slabTo)) {
      this.alertService.alert({ type: 'Error', message: 'Slab From cannot be greater than Slab To' });
      return;
    }
    if (Number(candidate.commissionPercent) > 100) {
      this.alertService.alert({ type: 'Error', message: 'Commission cannot be more than 100%' });
      return;
    }

    const clash = this.clashingSlab(candidate);
    if (clash) {
      this.alertService.alert({
        type: 'Error',
        message: `Overlaps the existing ${clash.slabType} slab ${clash.slabFrom} to ${clash.slabTo}`
      });
      return;
    }

    this.slabs.push(candidate);
    this.newSlabForm.reset({
      slabType: '',
      slabFrom: 0,
      slabTo: 0,
      commissionPercent: 0
    });
  }

  /** Only ever an unsaved row - a saved slab is corrected, not taken away. */
  removeSlab(index: number): void {
    this.slabs.splice(index, 1);
  }

  /** Which saved row is currently open for correction, or -1 when none is. */
  editingIndex = -1;

  editSlabForm: UntypedFormGroup = this.formBuilder.group({
    slabType: [
      '',
      Validators.required
    ],
    slabFrom: [
      0,
      Validators.required
    ],
    slabTo: [
      0,
      Validators.required
    ],
    commissionPercent: [
      0,
      Validators.required
    ]
  });

  startEdit(index: number): void {
    const slab = this.slabs[index];
    this.editingIndex = index;
    this.editSlabForm.setValue({
      slabType: slab.slabType,
      slabFrom: slab.slabFrom,
      slabTo: slab.slabTo,
      commissionPercent: slab.commissionPercent
    });
  }

  cancelEdit(): void {
    this.editingIndex = -1;
  }

  saveEdit(): void {
    const slab = this.slabs[this.editingIndex];
    const corrected = this.editSlabForm.getRawValue();

    if (this.editSlabForm.invalid) {
      this.editSlabForm.markAllAsTouched();
      this.alertService.alert({ type: 'Error', message: 'Fill the slab type, range and percentage' });
      return;
    }
    if (Number(corrected.slabFrom) > Number(corrected.slabTo)) {
      this.alertService.alert({ type: 'Error', message: 'Slab From cannot be greater than Slab To' });
      return;
    }
    if (Number(corrected.commissionPercent) > 100) {
      this.alertService.alert({ type: 'Error', message: 'Commission cannot be more than 100%' });
      return;
    }

    this.organizationService
      .updateCommissionSlab(slab.id, {
        slabType: CommissionSlabMasterComponent.SLAB_TYPE_CODES[corrected.slabType] || corrected.slabType,
        slabFrom: corrected.slabFrom,
        slabTo: corrected.slabTo,
        commissionPercent: corrected.commissionPercent,
        locale: 'en'
      })
      .subscribe({
        next: (response: any) => {
          if (heldForApproval(response)) {
            announceHeldForApproval(response, 'The slab correction', this.organizationService, this.alertService);
          } else {
            this.alertService.alert({ type: 'Success', message: 'Slab corrected' });
          }
          this.editingIndex = -1;
          this.loadSlabs();
        },
        // The backend refuses a correction that overlaps another slab; the reason has to reach the
        // officer, not vanish.
        error: (error: any) => {
          this.alertService.alert({
            type: 'Error',
            message:
              error?.error?.errors?.[0]?.defaultUserMessage ||
              error?.error?.defaultUserMessage ||
              'Could not correct the slab'
          });
        }
      });
  }

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

  save(): void {
    const newSlabs = this.slabs.filter((slab) => !slab.id);
    if (newSlabs.length === 0) {
      // Save used to return here without a word, so a slab typed into the entry row but never added
      // looked exactly like a slab that had been saved.
      this.alertService.alert({
        type: 'Error',
        message: 'Nothing new to save — add the slab to the table with + first'
      });
      return;
    }

    const payload = newSlabs.map((slab) => ({
      slabType: CommissionSlabMasterComponent.SLAB_TYPE_CODES[slab.slabType] || slab.slabType,
      slabFrom: slab.slabFrom,
      slabTo: slab.slabTo,
      commissionPercent: slab.commissionPercent
    }));

    this.organizationService.createCommissionSlabs(payload).subscribe({
      next: (response: any) => {
        if (heldForApproval(response)) {
          announceHeldForApproval(
            response,
            `${newSlabs.length} ${newSlabs.length === 1 ? 'slab' : 'slabs'}`,
            this.organizationService,
            this.alertService
          );
        } else {
          this.alertService.alert({
            type: 'Success',
            message: `${newSlabs.length} ${newSlabs.length === 1 ? 'slab' : 'slabs'} saved`
          });
        }
        this.loadSlabs();
      },
      // The backend refuses an overlapping range; the officer needs to read why, not watch nothing
      // happen and assume the save went through.
      error: (error: any) => {
        this.alertService.alert({
          type: 'Error',
          message:
            error?.error?.errors?.[0]?.defaultUserMessage ||
            error?.error?.defaultUserMessage ||
            'Could not save the slabs'
        });
      }
    });
  }
}