// server.js (Node.js with Express and ws)

const express = require('express');
const { WebSocketServer } = require('ws');
const cors = require('cors'); // Import CORS

const { initializeApp, cert } = require('firebase-admin/app');
const { getFirestore } = require('firebase-admin/firestore');

var admin = require("firebase-admin");

const serviceAccount = require("./serviceAcc.json");

initializeApp({
  credential: cert(serviceAccount)
});


const db = getFirestore();
const app = express();
const port = process.env.PORT || 8080;

const wss = new WebSocketServer({ noServer: true });

app.use(cors());

initialData = { devices: [], rooms: [], users: [] }; // Provide default empty data on error
let currentDeviceStates = {};

// const fetchInitialData = async () => {
//     const devices = [];
//     const rooms = [];
//     const users = [];

//     try {
//         const deviceSnapshot = await db.collection('Devices').get();
//         deviceSnapshot.forEach(doc => devices.push({ id: doc.id, ...doc.data() }));

//         const roomsSnapshot = await db.collectionGroup('Rooms').get(); // Get all rooms across hostels
//         roomsSnapshot.forEach(doc => rooms.push({ id: doc.id, ...doc.data(), hostelId: doc.ref.parent.parent.id })); // Include hostelId

//         const usersSnapshot = await db.collection('Users').get();
//         usersSnapshot.forEach(doc => users.push({ id: doc.id, ...doc.data() }));

//         initialData = { devices, rooms, users };

//         // console.log("Initial data fetched:", initialData);
//         //for each hostel id mantain a list of rooms with devices pertaining to that hostel

//         //setall to off

//         initialData.devices.forEach(device => {
//             device.state = false;
//         }  ); 

//         initialData.rooms.forEach(room => {
//             if (!currentDeviceStates[room.id]) {
//                 currentDeviceStates[room.id] = [];
//             }

//             const roomDevices = initialData.devices.filter(device => device.hostelId === room.hostelId);
//             currentDeviceStates[room.id] = { ...room, devices: roomDevices };
//         });




//     } catch (error) {
//         console.error("Error fetching initial data:", error);
//         // return { devices: [], rooms: [], users: [] };
//         initialData = { devices, rooms, users };
//     }
// };



// const fetchInitialData = async () => {
//   try {
//       const [deviceSnapshot, roomsSnapshot, usersSnapshot] = await Promise.all([
//           db.collection('Devices').get(),
//           db.collectionGroup('Rooms').get(),
//           db.collection('Users').get()
//       ]);

//       const devices = deviceSnapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
//       const rooms = roomsSnapshot.docs.map(doc => ({ id: doc.id, ...doc.data(), hostelId: doc.ref.parent.parent.id }));
//       const users = usersSnapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));

//       initialData = { devices, rooms, users };

//       initialData.devices.forEach(device => {
//           device.state = false;
//       });

//       initialData.rooms.forEach(room => {
//           const roomDevices = initialData.devices.filter(device => device.hostelId === room.hostelId);
//           currentDeviceStates[room.id] = { ...room, devices: roomDevices.map(device => ({...device})) }; // Deep copy to avoid modifying initialData
//       });


//       console.log("Initial data fetched and processed.");


//   } catch (error) {
//       console.error("Error fetching initial data:", error);
//       initialData = { devices: [], rooms: [], users: [] }; // Provide default empty data on error
//       currentDeviceStates = {};
//   }
// };



// fetchInitialData().then(() => {
//   setupFirestoreListeners();
// });




// const updateInitialData = (collectionName, snapshot) => {
//   const changes = snapshot.docChanges();
//   changes.forEach(change => {
//       const docData = { id: change.doc.id, ...change.doc.data() };
//       console.log(change.type, collectionName, "\t");
//       var index;

//       switch (change.type) {
//           case 'added':
//               index = initialData[collectionName]?.findIndex(item => item.id === change.doc.id);
//               if (index !== -1) {
//                   initialData[collectionName][index] = docData;
//               }
//               else {
//                   initialData[collectionName].push(docData);
//               }

//               console.log("Length of ", collectionName, " is ", initialData[collectionName].length);
//               console.log("DATA: ",docData);
//               break;
//           case 'modified':
//               index = initialData[collectionName].findIndex(item => item.id === change.doc.id);
//               if (index !== -1) {
//                   initialData[collectionName][index] = docData;

//                       for (const roomId in currentDeviceStates) {
//                           const roomDevices = currentDeviceStates[roomId].devices;
//                           const deviceIndex = roomDevices.findIndex(dev => dev.id === change.doc.id);
//                           if (deviceIndex !== -1) {
//                               currentDeviceStates[roomId].devices[deviceIndex] = {...docData, state: roomDevices[deviceIndex].state}
//                           }
//                       }

//                   }
//               break;
//           case 'removed':
//               initialData[collectionName] = initialData[collectionName].filter(item => item.id !== change.doc.id);
//               break;
//       }
//   });

//   console.log(`Updated ${collectionName} in initialData.\n\n`);


//   if (collectionName === 'devices' || collectionName === 'rooms') {
//       rebuildCurrentDeviceStates();
//   }
// };


// const setupFirestoreListeners = () => {

//   db.collection('Devices').onSnapshot(snapshot => {
//       updateInitialData('devices', snapshot);
//   });
//   db.collectionGroup('Rooms').onSnapshot(snapshot => {
//       updateInitialData('rooms', snapshot);

//   });
//   db.collection('Users').onSnapshot(snapshot => {
//       updateInitialData('users', snapshot);

//   });
// }


// const rebuildCurrentDeviceStates = () => {
//   currentDeviceStates = {};
//   initialData.rooms.forEach(room => {
//       const roomDevices = initialData.devices.filter(device => device.hostelId === room.hostelId);
//       currentDeviceStates[room.id] = { ...room, devices: roomDevices.map(device => ({ ...device})) };
//       console.log("Rebuilt room: ", room.roomNumber, " with ", roomDevices.length, " devices.","all Devices", room.hostelId);
//   });
//   console.log("currentDeviceStates rebuilt.");
// }

// // fetchInitialData().then(() => {
// //   setupFirestoreListeners();
// // });



// setupFirestoreListeners();


const fetchInitialData = async () => {
  try {
    const [deviceSnapshot, roomsSnapshot, usersSnapshot] = await Promise.all([
      db.collection('Devices').get(),
      db.collectionGroup('Rooms').get(),
      db.collection('Users').get()
    ]);

    initialData.devices = deviceSnapshot.docs.map(doc => ({ id: doc.id, ...doc.data(), state: false })); // Initialize state to false
    initialData.rooms = roomsSnapshot.docs.map(doc => ({ id: doc.id, ...doc.data(), hostelId: doc.ref.parent.parent.id }));
    initialData.users = usersSnapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));

    rebuildCurrentDeviceStates(); // Rebuild after fetching initial data

    console.log("Initial data fetched and processed.");

  } catch (error) {
    console.error("Error fetching initial data:", error);
    initialData = { devices: [], rooms: [], users: [] };
    currentDeviceStates = {};
  }
};


const updateInitialData = (collectionName, snapshot) => {
  snapshot.docChanges().forEach(change => {
    let docData;
    if (collectionName === 'rooms') {
      docData = { id: change.doc.id, ...change.doc.data(), hostelId: change.doc.ref.parent.parent.id };
    } else {
      docData = { id: change.doc.id, ...change.doc.data() };
    }
    let index;

    switch (change.type) {
      case 'added':
        console.log('added', collectionName, docData);
        if (!initialData[collectionName].some(item => item.id === change.doc.id)) {
          initialData[collectionName].push(docData);
          if (collectionName === 'devices') {
            initialData[collectionName][initialData[collectionName].length - 1].state = false;
          }
        }
        break;
      case 'modified':
        console.log('modified', collectionName, docData);
        index = initialData[collectionName].findIndex(item => item.id === change.doc.id);
        if (index !== -1) {
          initialData[collectionName][index] = docData;

          if (collectionName === 'devices') {
            for (const roomId in currentDeviceStates) {
              const roomDevices = currentDeviceStates[roomId].devices;
              const deviceIndex = roomDevices?.findIndex(dev => dev.id === change.doc.id);
              if (deviceIndex !== -1) {
                console.log("Device found in room", roomId, "old state", roomDevices[deviceIndex].state, "new state", docData.state);
                currentDeviceStates[roomId].devices[deviceIndex] = { ...docData, state: roomDevices[deviceIndex].state };
                console.log(currentDeviceStates[roomId]);
              }
            }
          }
        }
        break;
      case 'removed':
        console.log('removed', collectionName, docData);
        initialData[collectionName] = initialData[collectionName].filter(item => item.id !== change.doc.id);
        break;
    }
  });

  console.log(`Updated ${collectionName} in initialData.\n\n`);

  if (collectionName === 'devices' || collectionName === 'rooms') {
    rebuildCurrentDeviceStates();
  }
};


const setupFirestoreListeners = () => {
  db.collection('Devices').onSnapshot(snapshot => updateInitialData('devices', snapshot));
  db.collectionGroup('Rooms').onSnapshot(snapshot => updateInitialData('rooms', snapshot));
  db.collection('Users').onSnapshot(snapshot => updateInitialData('users', snapshot));
};

const rebuildCurrentDeviceStates = () => {
  initialData.rooms.forEach(room => {
    if (!room.hostelId) {
      console.warn(`Room ${room.id} is missing hostelId`);
      return;
    }
    const roomDevices = initialData.devices.filter(device => device.hostelId === room.hostelId);
    if (!currentDeviceStates[room.id]) {
      currentDeviceStates[room.id] = { ...room, devices: roomDevices.map(device => ({ ...device })) };
    } else {
      currentDeviceStates[room.id] = {
        ...room,
        devices: roomDevices.map(device => ({
          ...device,
          state: currentDeviceStates[room.id].devices.find(dev => dev.id === device.id)?.state || false,
        })),
      };
    }
  });

  console.log("currentDeviceStates rebuilt.");
  broadcastRoomData();
};



const broadcastRoomData = () => {
  for (const roomId in connectedClients) {
    connectedClients[roomId].forEach(client => {
      if (currentDeviceStates[roomId]) {
        console.log(currentDeviceStates[roomId]);

        client.send(JSON.stringify({ type: 'roomData', roomData: currentDeviceStates[roomId] , roomId: roomId}));
      }
    });
  }
};

// Call fetchInitialData and then set up listeners
fetchInitialData()
  .then(setupFirestoreListeners)  // Set up listeners AFTER fetching initial data
  .catch(error => {
    console.error("Error initializing:", error);
  });



const connectedClients = {}; // Store connected clients per room

wss.on('connection', (ws) => {
  ws.on('message', async (message) => {
    try {
      const parsedMessage = JSON.parse(message);
      const { roomId, userId, apiKey } = parsedMessage;

      // Helper function to check authorization
      const isAuthorized = (roomId, userId, apiKey) => {
        return initialData.users.some(user => user.id === userId && user.roomId === roomId) || apiKey === "masterPassword@tiet@123";
      };

      switch (parsedMessage.type) {
        case 'joinRoom':
          if (!roomId || !(userId || apiKey) {
            ws.send(JSON.stringify({ error: 'Invalid room or user ID or apikey' }));
            return;
          }

          if (!isAuthorized(roomId, userId, apiKey)) {
            console.log("Unauthorized joinRoom attempt.");
            ws.send(JSON.stringify({ error: 'Unauthorized' }));
            return;
          }

          // Store the connected client
          if (!connectedClients[roomId]) {
            connectedClients[roomId] = [];
          }
          connectedClients[roomId].push(ws);


          ws.send(JSON.stringify({ type: 'roomData', roomData: currentDeviceStates[roomId], roomId: roomId }));
          break;

        case 'updateDeviceState':
          const { deviceId, state } = parsedMessage;
          if (!deviceId || state === undefined || !roomId || (!userId && !apiKey)) { // Check for undefined state or missing userId/apiKey
            ws.send(JSON.stringify({ error: 'Invalid device ID, state, room ID, user ID, or API key' }));
            return;
          }

          if (!isAuthorized(roomId, userId, apiKey)) {
            console.log("Unauthorized updateDeviceState attempt.");
            ws.send(JSON.stringify({ error: 'Unauthorized' }));
            return;
          }


          const room = currentDeviceStates[roomId];
          if (room) { // Check if the room exists
            const device = room.devices.find(dev => dev.id === deviceId);
            if (device) { // Check if the device exists
              device.state = state;

              // Broadcast to all clients in the room
              if (connectedClients[roomId]) {
                connectedClients[roomId].forEach(client => {
                  client.send(JSON.stringify({ type: 'deviceUpdate', deviceId, state, roomId: roomId }));
                });
              }


            } else {
              ws.send(JSON.stringify({ error: 'Device not found' }));
            }
          } else {
            ws.send(JSON.stringify({ error: 'Room not found' }));
          }

          break;

        default:
          console.log('Unknown message type:', parsedMessage.type);
      }

    } catch (error) {
      console.error('Error handling message:', error);
      ws.send(JSON.stringify({ error: 'Invalid message format' })); // Send error back to client
    }
  });

  ws.on('close', () => {
    for (const roomId in connectedClients) {
      connectedClients[roomId] = connectedClients[roomId].filter(client => client !== ws);
    }
  });

  ws.on('error', (error) => {
    console.error('WebSocket error:', error);
  });
});


console.log('WebSocket server started on port 8080');





const server = app.listen(port, () => console.log(`Listening on port ${port}`));

server.on('upgrade', (request, socket, head) => {
  wss.handleUpgrade(request, socket, head, ws => {
    wss.emit('connection', ws, request);
  });
});