/**
 * 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, ElementRef, ViewChild, forwardRef } from '@angular/core';
import { CommonModule } from '@angular/common';
import { ControlValueAccessor, FormsModule, NG_VALUE_ACCESSOR } from '@angular/forms';

/**
 * Drop-in replacement for `<input type="text" placeholder="DD-MM-YYYY">` used throughout the
 * Investment module. Keeps the DD-MM-YYYY string every date field/helper in investment-data.ts
 * already expects (parseDDMMYYYY, addPeriod, etc.), but adds a calendar button that opens the
 * browser's native date picker and converts the picked value back to DD-MM-YYYY — so users can
 * either type the date or pick it, without changing any consuming component's data model.
 *
 * Usage: <mifosx-date-ddmmyyyy [(ngModel)]="someField"></mifosx-date-ddmmyyyy>
 */
@Component({
  selector: 'mifosx-date-ddmmyyyy',
  standalone: true,
  imports: [
    CommonModule,
    FormsModule
  ],
  providers: [
    {
      provide: NG_VALUE_ACCESSOR,
      useExisting: forwardRef(() => DateDdmmyyyyPickerComponent),
      multi: true
    }
  ],
  template: `
    <div class="inv-date-field">
      <input
        type="text"
        class="inv-date-field__text"
        [ngModel]="value"
        (ngModelChange)="onTextChange($event)"
        (blur)="onTouched()"
        placeholder="DD-MM-YYYY"
        [disabled]="disabled"
      />
      <button
        type="button"
        class="inv-date-field__btn"
        tabindex="-1"
        [disabled]="disabled"
        (click)="openPicker()"
        aria-label="Pick a date"
        title="Pick a date"
      >
        📅
      </button>
      <input
        #native
        type="date"
        class="inv-date-field__native"
        tabindex="-1"
        [ngModel]="isoValue"
        (ngModelChange)="onPickerChange($event)"
      />
    </div>
  `,
  styles: [
    `
      /* Angular view encapsulation stops the host page's .inv-form-field styles from reaching
       * inside this component's own template, so the look of the surrounding form fields
       * (height, border, radius, font) is deliberately re-declared here instead of inherited. */
      :host {
        display: block;
        width: 100%;
      }
      .inv-date-field {
        position: relative;
        display: flex;
        align-items: center;
        gap: 6px;
        width: 100%;
      }
      .inv-date-field__text {
        flex: 1;
        min-width: 0;
        width: 100%;
        height: 36px;
        padding: 0 10px;
        border: 1px solid #e2e8f0;
        border-radius: 8px;
        font-size: 13px;
        color: #0d1b2a;
        font-family: inherit;
        background: #fff;
        box-sizing: border-box;
      }
      .inv-date-field__btn {
        flex: 0 0 auto;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        height: 36px;
        width: 36px;
        padding: 0;
        border: 1px solid #e2e8f0;
        border-radius: 8px;
        background: #fff;
        cursor: pointer;
        font-size: 14px;
        line-height: 1;
      }
      .inv-date-field__btn:hover:not(:disabled) {
        background: #f2f4f7;
      }
      .inv-date-field__btn:disabled {
        cursor: not-allowed;
        opacity: 0.5;
      }
      .inv-date-field__native {
        position: absolute;
        width: 0;
        height: 0;
        padding: 0;
        border: none;
        opacity: 0;
        pointer-events: none;
      }
    `
  ]
})
export class DateDdmmyyyyPickerComponent implements ControlValueAccessor {
  @ViewChild('native') private nativeInput?: ElementRef<HTMLInputElement>;

  value = '';
  disabled = false;

  private onChangeFn: (v: string) => void = () => {};
  onTouched: () => void = () => {};

  /** DD-MM-YYYY -> yyyy-MM-dd, the format <input type="date"> requires. */
  get isoValue(): string {
    const parts = (this.value || '').split('-');
    if (parts.length !== 3) {
      return '';
    }
    const [
      dd,
      mm,
      yyyy
    ] = parts;
    if (!/^\d{2}$/.test(dd) || !/^\d{2}$/.test(mm) || !/^\d{4}$/.test(yyyy)) {
      return '';
    }
    return `${yyyy}-${mm}-${dd}`;
  }

  writeValue(v: string): void {
    this.value = v ?? '';
  }

  registerOnChange(fn: (v: string) => void): void {
    this.onChangeFn = fn;
  }

  registerOnTouched(fn: () => void): void {
    this.onTouched = fn;
  }

  setDisabledState(isDisabled: boolean): void {
    this.disabled = isDisabled;
  }

  onTextChange(v: string): void {
    this.value = v;
    this.onChangeFn(v);
  }

  /** yyyy-MM-dd (from the native picker) -> DD-MM-YYYY, the format the rest of the app expects. */
  onPickerChange(iso: string): void {
    const parts = (iso || '').split('-');
    if (parts.length !== 3) {
      return;
    }
    const [
      yyyy,
      mm,
      dd
    ] = parts;
    const ddmmyyyy = `${dd}-${mm}-${yyyy}`;
    this.value = ddmmyyyy;
    this.onChangeFn(ddmmyyyy);
    this.onTouched();
  }

  openPicker(): void {
    const el = this.nativeInput?.nativeElement;
    if (!el || this.disabled) {
      return;
    }
    const showPicker = (el as HTMLInputElement & { showPicker?: () => void }).showPicker;
    if (typeof showPicker === 'function') {
      try {
        showPicker.call(el);
        return;
      } catch {
        // Some browsers throw if not called from a "user gesture" context they recognise —
        // fall back to a plain click(), which still opens the native picker.
      }
    }
    el.click();
  }
}