const { get } = require("../../utils/api");
const { refreshMe, requireLogin } = require("../../utils/auth");
const { isModuleEnabled, visibleModules } = require("../../utils/modules");
const { getActiveClassId, getActiveClassName, getEnabledModules, showError } = require("../../utils/page-helpers");

function formatDateTime(value) {
  if (!value) return "";
  return String(value).replace("T", " ").slice(0, 16);
}

function formatScheduleTime(item) {
  const start = formatDateTime(item.start_time);
  const end = formatDateTime(item.end_time);
  if (item.type === "deadline") return `截止 ${start}`;
  if (!end) return start;
  if (start.slice(0, 10) === end.slice(0, 10)) {
    return `${start} - ${end.slice(11)}`;
  }
  return `${start} - ${end}`;
}

function scheduleTypeText(type) {
  return {
    course: "课程",
    deadline: "截止日",
    activity: "活动"
  }[type] || type || "排期";
}

function countdownText(value) {
  if (!value) return "";
  const target = new Date(value).getTime();
  if (Number.isNaN(target)) return "";
  const now = Date.now();
  const diffDays = Math.ceil((target - now) / (24 * 60 * 60 * 1000));
  if (diffDays < 0) return `已逾期 ${Math.abs(diffDays)} 天`;
  if (diffDays === 0) return "今天截止";
  if (diffDays === 1) return "明天截止";
  return `还有 ${diffDays} 天`;
}

Page({
  data: {
    className: "HKU ICB",
    homeStatus: "班级信息已同步",
    announcements: [],
    schedules: [],
    votes: [],
    timelines: [],
    quickModules: [],
    focusItems: [],
    unreadCount: 0,
    loading: false
  },

  async onShow() {
    if (!requireLogin()) return;
    await this.load();
  },

  async load() {
    this.setData({ loading: true });
    try {
      await refreshMe();
      const app = getApp();
      const user = app.globalData.user;
      const classId = getActiveClassId();
      const enabledModules = getEnabledModules();
      const className = getActiveClassName();
      this.setData({
        className,
        quickModules: [
          ...visibleModules("class", enabledModules),
          ...visibleModules("interact", enabledModules)
        ].slice(0, 4)
      });

      const tasks = [get("/api/notifications/unread-count").catch(() => ({ unread_count: 0 }))];
      const names = ["unread"];
      if (isModuleEnabled("announcements", enabledModules)) {
        names.push("announcements");
        tasks.push(get("/api/announcements/", { page_size: 3, class_id: classId }));
      }
      if (isModuleEnabled("schedule", enabledModules)) {
        names.push("schedules");
        tasks.push(get("/api/schedule/upcoming", { limit: 3, class_id: classId }));
      }
      if (isModuleEnabled("votes", enabledModules)) {
        names.push("votes");
        tasks.push(get("/api/votes/", { page_size: 3, class_id: classId }));
      }

      const results = await Promise.all(tasks);
      const next = { announcements: [], schedules: [], votes: [], timelines: [] };
      names.forEach((name, index) => {
        const value = results[index];
        if (name === "unread") next.unreadCount = value.unread_count || 0;
        if (name === "announcements") next.announcements = value.items || [];
        if (name === "schedules") {
          next.schedules = (value || []).map((item) => ({
            ...item,
            schedule_time_text: formatScheduleTime(item),
            schedule_type_text: scheduleTypeText(item.type),
            countdown_text: item.type === "deadline" ? countdownText(item.start_time) : ""
          }));
        }
        if (name === "votes") {
          next.votes = (value.items || []).map((item) => ({
            ...item,
            vote_type_text: item.vote_type === "multiple" ? "多选" : "单选",
            vote_action_text: item.has_voted ? "已参与" : "待参与"
          }));
        }
        if (name === "timelines") next.timelines = value.items || [];
      });
      const pendingVotes = next.votes.filter((item) => !item.has_voted);
      const focusItems = [];
      if (next.schedules.length) {
        const schedule = next.schedules[0];
        focusItems.push({
          id: schedule.id,
          type: "schedule",
          mark: "日",
          label: "下一项排期",
          title: schedule.title,
          detail: schedule.schedule_time_text,
          badge: schedule.countdown_text || schedule.schedule_type_text
        });
      }
      if (pendingVotes.length) {
        const vote = pendingVotes[0];
        focusItems.push({
          id: vote.id,
          type: "vote",
          mark: "选",
          label: "待参与投票",
          title: vote.title,
          detail: `${vote.vote_type_text} · ${vote.total_voters} 人参与`,
          badge: "去参与"
        });
      }
      if (next.announcements.length) {
        const announcement = next.announcements[0];
        focusItems.push({
          id: announcement.id,
          type: "announcements",
          mark: "告",
          label: "最新公告",
          title: announcement.title,
          detail: announcement.author_name || "班级公告",
          badge: "查看"
        });
      }
      next.focusItems = focusItems.slice(0, 3);
      next.homeStatus = next.unreadCount > 0
        ? `${next.unreadCount} 条未读通知`
        : "暂无未读通知";
      this.setData(next);
    } catch (error) {
      showError(error);
    } finally {
      this.setData({ loading: false });
    }
  },

  openModule(event) {
    const key = event.currentTarget.dataset.key;
    wx.navigateTo({ url: `/pages/module/index?module=${key}` });
  },

  openFocus(event) {
    const type = event.currentTarget.dataset.type;
    const id = event.currentTarget.dataset.id;
    if (type === "schedule") {
      wx.navigateTo({ url: `/pages/schedule-detail/index?id=${id}` });
      return;
    }
    if (type === "vote") {
      wx.navigateTo({ url: `/pages/vote-detail/index?id=${id}` });
      return;
    }
    if (type === "announcements") {
      wx.navigateTo({ url: `/pages/announcement-detail/index?id=${id}` });
      return;
    }
    wx.navigateTo({ url: `/pages/module/index?module=${type}` });
  },

  openSchedule(event) {
    wx.navigateTo({ url: `/pages/schedule-detail/index?id=${event.currentTarget.dataset.id}` });
  },

  openVote(event) {
    wx.navigateTo({ url: `/pages/vote-detail/index?id=${event.currentTarget.dataset.id}` });
  },

  openTimeline(event) {
    wx.navigateTo({ url: `/pages/timeline-detail/index?id=${event.currentTarget.dataset.id}` });
  }
});