// Import necessary modules
const express = require('express');
const http = require('http');
const fs = require('fs');
const fetch = require('isomorphic-fetch');
const path = require('path');
const cors = require('cors');
require('dotenv').config();

// Import custom modules
const msGraphHelper = require('./msGraphHelper');
const settings = require('./settings');

// Set the port
const HTTP_PORT = process.env.HTTP_PORT || 8080;

// Initialize Express app
const app = express();
const slideshowDir = path.join(__dirname, 'slideshow');

// Middleware configurations
app.use(express.static(path.join(__dirname, 'public')));
app.use(cors({
  origin: 'http://localhost:5173',
}));
app.use(express.json());

// Initialize Microsoft Graph API for App Only Auth
msGraphHelper.initializeGraphForAppOnlyAuth(settings);

// Read resource UPNs once at startup
const data = fs.readFileSync('./resourceUPNs.json', 'utf8');
const resourceUPNs = JSON.parse(data);

// Cache quotes to avoid reading the file on every request
let quotesCache = [];
const quotesFilePath = path.join(__dirname, 'quotes.json');
fs.readFile(quotesFilePath, 'utf8', (err, data) => {
  if (err) {
    console.error('Error reading quotes:', err.message);
  } else {
    try {
      const parsedData = JSON.parse(data);
      if (Array.isArray(parsedData) && parsedData.length > 0) {
        quotesCache = parsedData;
        console.log('Quotes loaded into cache.');
      } else {
        console.error('Quotes file is empty or malformed.');
      }
    } catch (parseError) {
      console.error('Error parsing quotes:', parseError.message);
    }
  }
});

// API endpoint to get events
app.get('/api/events', async (req, res) => {
  try {
    const now = new Date();
    const startDateTime = new Date(now);
    const endDateTime = new Date(now);
    endDateTime.setHours(20, 0, 0, 0);

    if (startDateTime > endDateTime) {
      // No relevant events to display
      return res.json({});
    }

    const events = {};
    for (const resource of resourceUPNs) {
      try {
        const data = await msGraphHelper.getCalendarView(
          resource,
          startDateTime.toISOString(),
          endDateTime.toISOString()
        );
        events[resource] = data;
      } catch (error) {
        console.error(`Error fetching events for ${resource}:`, error);
      }
    }
    res.json(events);
  } catch (err) {
    res.status(500).json({ message: err.message });
  }
});

// API endpoint to get weather information
app.get('/api/weather', async (req, res) => {
  try {
    const lat = 45.49;
    const lon = -73.58;
    const appId = process.env.OPENWEATHER_APPID;
    const url = `https://api.openweathermap.org/data/2.5/weather?units=metric&lat=${lat}&lon=${lon}&appid=${appId}`;

    const response = await fetch(url);

    if (response.ok) {
      const json = await response.json();
      res.json(json);
    } else {
      res.status(500).json({ message: 'Error fetching weather data' });
    }
  } catch (err) {
    res.status(500).json({ message: err.message });
  }
});

// API endpoint to get a random quote
app.get('/api/quotes', (req, res) => {
  try {
    if (quotesCache.length === 0) {
      return res.status(500).json({ message: 'No quotes available' });
    }

    const randomIndex = Math.floor(Math.random() * quotesCache.length);
    const randomQuote = quotesCache[randomIndex];

    res.json(randomQuote); // Send only one quote
  } catch (err) {
    res.status(500).json({ message: 'Error retrieving quote' });
  }
});

// Serve slideshow images
app.use('/slideshow', express.static(slideshowDir));

// API endpoint to get slideshow images
app.get('/api/slideshow', (req, res) => {
  fs.readdir(slideshowDir, (err, files) => {
    if (err) {
      console.error('Failed to list slideshow images:', err.message);
      res.status(500).json({ message: err.message });
      return;
    }

    const imagePaths = files
      .filter(file => /\.(jpg|jpeg|png|gif)$/i.test(file))
      .map(file => `slideshow/${file}`);

    res.json(imagePaths);
  });
});

// Create and start the HTTP server
const httpServer = http.createServer(app);

httpServer.listen(HTTP_PORT, () => {
  console.log(`HTTP Server listening on http://localhost:${HTTP_PORT}`);
});