import {
  ChangeDetectionStrategy,
  Component,
  computed,
  HostListener,
  inject,
  input,
  output,
} from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormBuilder, ReactiveFormsModule, Validators } from '@angular/forms';
import {
  passwordMatchValidator,
  PasswordPolicy,
} from './change-password-modal.validators';

export type ChangePasswordMode = 'self' | 'admin-reset';

export interface ChangePasswordSubmitPayload {
  oldPassword: string;
  newPassword: string;
  confirmNewPassword: string;
}

const DEFAULT_POLICY: PasswordPolicy = {
  minLength: 12,
  requireMixed: true,
  description: 'At least 12 characters with upper, lower, digit and symbol',
};

@Component({
  selector: 'app-change-password-modal',
  standalone: true,
  changeDetection: ChangeDetectionStrategy.OnPush,
  imports: [CommonModule, ReactiveFormsModule],
  template: `
    @if (open()) {
      <div class="modal-overlay" data-testid="change-password-overlay" (click)="onCancel()">
        <div
          class="modal-card"
          role="dialog"
          aria-modal="true"
          aria-labelledby="cp-title"
          data-testid="change-password-modal"
          (click)="$event.stopPropagation()"
        >
          <h2 id="cp-title">Change Password</h2>

          <form [formGroup]="form" (ngSubmit)="onSubmit()">
            @if (mode() === 'self') {
              <label class="field">
                <span>Old password</span>
                <input
                  type="password"
                  autocomplete="current-password"
                  formControlName="oldPassword"
                  data-testid="cp-old"
                />
              </label>
            }

            <label class="field">
              <span>New password</span>
              <input
                type="password"
                autocomplete="new-password"
                formControlName="newPassword"
                data-testid="cp-new"
              />
              @if (fieldErrorFor('newPassword'); as msg) {
                <span class="error" data-testid="cp-new-error">{{ msg }}</span>
              }
            </label>

            <label class="field">
              <span>Confirm new password</span>
              <input
                type="password"
                autocomplete="new-password"
                formControlName="confirmNewPassword"
                data-testid="cp-confirm"
              />
              @if (fieldErrorFor('confirmPassword'); as msg) {
                <span class="error" data-testid="cp-confirm-error">{{ msg }}</span>
              }
              @if (fieldErrorFor('confirmNewPassword'); as msg) {
                <span class="error" data-testid="cp-confirm-error">{{ msg }}</span>
              }
            </label>

            @if (errorMessage()) {
              <p class="error" data-testid="cp-error">{{ errorMessage() }}</p>
            }
            @if (formError()) {
              <p class="error" data-testid="cp-form-error">{{ formError() }}</p>
            }
            <p class="hint" data-testid="cp-policy">{{ policy().description }}</p>

            <div class="actions">
              <button
                type="button"
                data-testid="cp-cancel"
                (click)="onCancel()"
                [disabled]="submitting()"
              >
                Cancel
              </button>
              <button
                type="submit"
                data-testid="cp-ok"
                [disabled]="submitting()"
              >
                OK
              </button>
            </div>
          </form>
        </div>
      </div>
    }
  `,
})
export class ChangePasswordModalComponent {
  private readonly fb = inject(FormBuilder);

  readonly open = input<boolean>(false);
  readonly mode = input<ChangePasswordMode>('self');
  readonly policy = input<PasswordPolicy>(DEFAULT_POLICY);
  readonly errorMessage = input<string | null>(null);
  readonly submitting = input<boolean>(false);
  readonly fieldErrors = input<Record<string, string> | null>(null);

  readonly cancel = output<void>();
  readonly submit = output<ChangePasswordSubmitPayload>();

  readonly form = this.fb.nonNullable.group(
    {
      oldPassword: this.fb.nonNullable.control(''),
      newPassword: this.fb.nonNullable.control('', [Validators.required]),
      confirmNewPassword: this.fb.nonNullable.control('', [Validators.required]),
    },
    { validators: passwordMatchValidator },
  );

  readonly formError = computed<string | null>(() => {
    const errs = this.form.errors;
    if (errs?.['passwordMismatch']) return 'Passwords do not match';
    return null;
  });

  fieldErrorFor(path: string): string | null {
    const map = this.fieldErrors();
    if (!map) return null;
    return map[path] ?? null;
  }

  @HostListener('document:keydown.escape')
  onEscape(): void {
    if (this.open() && !this.submitting()) this.onCancel();
  }

  onCancel(): void {
    if (this.submitting()) return;
    this.form.reset({ oldPassword: '', newPassword: '', confirmNewPassword: '' });
    this.cancel.emit();
  }

  onSubmit(): void {
    if (this.submitting()) return;
    const v = this.form.getRawValue();
    if (this.mode() === 'self' && !v.oldPassword) return;
    if (!v.newPassword || !v.confirmNewPassword) return;
    if (this.form.invalid) return;
    this.submit.emit({
      oldPassword: v.oldPassword,
      newPassword: v.newPassword,
      confirmNewPassword: v.confirmNewPassword,
    });
  }
}