components/calendar.js

class CustomCalendar extends HTMLElement {
  connectedCallback() {
    this.attachShadow({ mode: 'open' });
    this.renderCalendar(new Date());
  }

  renderCalendar(date) {
    const monthNames = ["January", "February", "March", "April", "May", "June",
      "July", "August", "September", "October", "November", "December"
    ];

    const firstDay = new Date(date.getFullYear(), date.getMonth(), 1);
    const lastDay = new Date(date.getFullYear(), date.getMonth() + 1, 0);
    const daysInMonth = lastDay.getDate();
    const startingDay = firstDay.getDay();

    let calendarHTML = '';
    let day = 1;

    this.shadowRoot.innerHTML = `
      <style>
        .calendar {
          width: 100%;
          max-width: 400px;
          background: white;
          border-radius: 0.75rem;
          box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
          padding: 1rem;
        }
        .calendar-header {
          display: flex;
          justify-content: space-between;
          align-items: center;
          margin-bottom: 1rem;
        }
        .calendar-title {
          font-size: 1.25rem;
          font-weight: 600;
          color: #1a365d;
        }
        .calendar-nav {
          display: flex;
          gap: 0.5rem;
        }
        .calendar-nav button {
          background: #edf2f7;
          border: none;
          border-radius: 0.375rem;
          padding: 0.25rem 0.5rem;
          cursor: pointer;
        }
        .calendar-weekdays {
          display: grid;
          grid-template-columns: repeat(7, 1fr);
          text-align: center;
          font-weight: 500;
          margin-bottom: 0.5rem;
        }
        .calendar-days {
          display: grid;
          grid-template-columns: repeat(7, 1fr);
          gap: 0.25rem;
        }
        .calendar-day {
          padding: 0.5rem;
          text-align: center;
          border-radius: 0.375rem;
          cursor: pointer;
        }
        .calendar-day:hover {
          background: #ebf8ff;
        }
        .calendar-day.empty {
          visibility: hidden;
        }
        .calendar-day.today {
          background: #4299e1;
          color: white;
        }
        .calendar-day.selected {
          background: #3182ce;
          color: white;
        }
      </style>
      <div class="calendar">
        <div class="calendar-header">
          <div class="calendar-title">${monthNames[date.getMonth()]} ${date.getFullYear()}</div>
          <div class="calendar-nav">
            <button id="prevMonth">&lt;</button>
            <button id="nextMonth">&gt;</button>
          </div>
        </div>
        <div class="calendar-weekdays">
          <div>Sun</div>
          <div>Mon</div>
          <div>Tue</div>
          <div>Wed</div>
          <div>Thu</div>
          <div>Fri</div>
          <div>Sat</div>
        </div>
        <div class="calendar-days">
          ${Array(42).fill().map((_, i) => {
            if (i < startingDay || day > daysInMonth) {
              return `<div class="calendar-day empty"></div>`;
            }
            const currentDay = day;
            const isToday = currentDay === new Date().getDate() && 
                          date.getMonth() === new Date().getMonth() && 
                          date.getFullYear() === new Date().getFullYear();
            day++;
            return `<div class="calendar-day ${isToday ? 'today' : ''}">${currentDay}</div>`;
          }).join('')}
        </div>
      </div>
    `;

    this.shadowRoot.getElementById('prevMonth').addEventListener('click', () => {
      this.renderCalendar(new Date(date.getFullYear(), date.getMonth() - 1, 1));
    });

    this.shadowRoot.getElementById('nextMonth').addEventListener('click', () => {
      this.renderCalendar(new Date(date.getFullYear(), date.getMonth() + 1, 1));
    });
  }
}

customElements.define('custom-calendar', CustomCalendar);