import state from './state.js';
import { fetchCalendar, saveCalendar, ApiError } from './api.js';
import { showToast } from './toast.js';

export default class CalendarView {
  constructor({ onUnauthorized } = {}) {
    this.calendarEl = document.getElementById('calendar');
    this.monthDisplayEl = document.getElementById('currentMonth');
    this.prevBtn = document.getElementById('prevMonth');
    this.nextBtn = document.getElementById('nextMonth');
    this.todayBtn = document.getElementById('todayBtn');
    this.weekdays = ['日', '一', '二', '三', '四', '五', '六'];
    this.monthNames = ['一月', '二月', '三月', '四月', '五月', '六月', '七月', '八月', '九月', '十月', '十一月', '十二月'];
    this.onUnauthorized = onUnauthorized;
    this.saveDelay = 500;
  }

  init() {
    this.bindNavigation();
    this.renderCalendar();
  }

  bindNavigation() {
    if (this.prevBtn) {
      this.prevBtn.addEventListener('click', () => {
        state.currentDate.setMonth(state.currentDate.getMonth() - 1);
        this.renderCalendar();
      });
    }

    if (this.nextBtn) {
      this.nextBtn.addEventListener('click', () => {
        state.currentDate.setMonth(state.currentDate.getMonth() + 1);
        this.renderCalendar();
      });
    }

    if (this.todayBtn) {
      this.todayBtn.addEventListener('click', () => {
        state.currentDate = new Date();
        this.renderCalendar();
      });
    }
  }

  async loadData() {
    if (!state.currentServer || !state.token) {
      return;
    }

    try {
      showToast('正在加载...', 'info');
      const result = await fetchCalendar(state.currentServer, state.token);
      state.markedDates = result.markedDates || {};
      this.renderCalendar();
      showToast('数据加载成功', 'success');
    } catch (error) {
      if (error instanceof ApiError && (error.status === 401 || error.status === 403)) {
        showToast('认证已过期，请重新登录', 'error');
        if (this.onUnauthorized) {
          this.onUnauthorized();
        }
        return;
      }
      showToast(error.message || '加载失败', 'error');
    }
  }

  clearData() {
    state.markedDates = {};
    this.renderCalendar();
  }

  renderCalendar() {
    if (!this.calendarEl || !this.monthDisplayEl) return;

    const currentDate = state.currentDate;
    const year = currentDate.getFullYear();
    const month = currentDate.getMonth();

    this.calendarEl.innerHTML = '';

    this.weekdays.forEach(day => {
      const weekdayEl = document.createElement('div');
      weekdayEl.className = 'weekday';
      weekdayEl.textContent = day;
      this.calendarEl.appendChild(weekdayEl);
    });

    this.monthDisplayEl.textContent = `${year}年 ${this.monthNames[month]}`;

    const firstDay = this.getFirstDayOfMonth(currentDate);
    const daysInMonth = this.getDaysInMonth(currentDate);

    const prevMonthDate = new Date(year, month, 0);
    const daysInPrevMonth = prevMonthDate.getDate();

    for (let i = firstDay - 1; i >= 0; i--) {
      const day = daysInPrevMonth - i;
      const date = new Date(year, month - 1, day);
      this.calendarEl.appendChild(this.createDayElement(date, day, true));
    }

    for (let day = 1; day <= daysInMonth; day++) {
      const date = new Date(year, month, day);
      this.calendarEl.appendChild(this.createDayElement(date, day, false));
    }

    const totalCells = this.calendarEl.children.length - this.weekdays.length;
    const remainingCells = 42 - totalCells;

    for (let day = 1; day <= remainingCells; day++) {
      const date = new Date(year, month + 1, day);
      this.calendarEl.appendChild(this.createDayElement(date, day, true));
    }
  }

  createDayElement(date, dayNumber, isOtherMonth) {
    const dayEl = document.createElement('div');
    dayEl.className = 'day';

    if (isOtherMonth) {
      dayEl.classList.add('other-month');
    }

    // Check if the day is in the future
    if (this.isFutureDate(date)) {
      dayEl.classList.add('future-day');
    }

    if (this.isToday(date)) {
      dayEl.classList.add('today');
    }

    const status = this.getDateStatus(date);
    if (status !== 'none') {
      dayEl.classList.add(status);
    }

    const dayNumberEl = document.createElement('div');
    dayNumberEl.className = 'day-number';
    dayNumberEl.textContent = dayNumber;
    dayEl.appendChild(dayNumberEl);

    if (status !== 'none') {
      const markEl = document.createElement('div');
      markEl.className = 'day-mark';
      markEl.textContent = status === 'completed' ? '✓' : '○';
      dayEl.appendChild(markEl);
    }

    dayEl.addEventListener('click', () => {
      if (!isOtherMonth) {
        this.toggleDateStatus(date);
      }
    });

    return dayEl;
  }

  toggleDateStatus(date) {
    if (!state.currentServer || !state.token) {
      showToast('请先选择服务器并登录', 'error');
      return;
    }

    const dateKey = this.formatDate(date);
    const currentStatus = state.markedDates[dateKey] || 'none';
    let nextStatus;

    switch (currentStatus) {
      case 'none':
        nextStatus = 'completed';
        break;
      case 'completed':
        nextStatus = 'partial';
        break;
      case 'partial':
      default:
        nextStatus = 'none';
        break;
    }

    if (nextStatus === 'none') {
      delete state.markedDates[dateKey];
    } else {
      state.markedDates[dateKey] = nextStatus;
    }

    this.renderCalendar();
    this.scheduleSave();
  }

  scheduleSave() {
    if (!state.currentServer || !state.token) return;

    if (state.saveTimeoutId) {
      clearTimeout(state.saveTimeoutId);
    }

    state.saveTimeoutId = setTimeout(() => {
      this.persistMarkedDates();
    }, this.saveDelay);
  }

  async persistMarkedDates() {
    state.saveTimeoutId = null;
    try {
      await saveCalendar(state.currentServer, state.token, state.markedDates);
      showToast('数据已保存', 'success');
    } catch (error) {
      if (error instanceof ApiError && (error.status === 401 || error.status === 403)) {
        showToast('认证已过期，请重新登录', 'error');
        if (this.onUnauthorized) {
          this.onUnauthorized();
        }
        return;
      }
      showToast(error.message || '保存失败', 'error');
    }
  }

  getFirstDayOfMonth(date) {
    return new Date(date.getFullYear(), date.getMonth(), 1).getDay();
  }

  getDaysInMonth(date) {
    return new Date(date.getFullYear(), date.getMonth() + 1, 0).getDate();
  }

  getDateStatus(date) {
    const dateKey = this.formatDate(date);
    return state.markedDates[dateKey] || 'none';
  }

  isToday(date) {
    const today = new Date();
    return date.getFullYear() === today.getFullYear() &&
      date.getMonth() === today.getMonth() &&
      date.getDate() === today.getDate();
  }

  // Check if a date is in the future
  isFutureDate(date) {
    const today = new Date();
    today.setHours(0, 0, 0, 0);
    const checkDate = new Date(date);
    checkDate.setHours(0, 0, 0, 0);
    return checkDate > today;
  }

  formatDate(date) {
    const year = date.getFullYear();
    const month = String(date.getMonth() + 1).padStart(2, '0');
    const day = String(date.getDate()).padStart(2, '0');
    return `${year}-${month}-${day}`;
  }
}