import express from 'express';
import Sessions from './Schema/sessions.schema.js'
import Teachers from '../Teachers/Schema/Teachers.schema.js';
import { Types } from 'mongoose';

const SessionsRoutes = express.Router();

// Get All Sessions
SessionsRoutes.get('/', async(req, res) => {
    
})

// Add New User for teacher
SessionsRoutes.post('/', async(req, res) => {
    const {teacherId, startTime, endTime } = req.body;

    //Check for teacher existance
    const existingTeacher = await Teachers.findOne({_id: teacherId});
    
    console.log('existingTeacher', existingTeacher)
    if(!existingTeacher){
        return res.status(400).send({message: 'Teacher Does not exist please provide valid teacherId.'})
    }

    // Check endTime must be greater then startTime
    if(new Date(endTime) <= new Date(startTime)) {
        return res.status(400).send({message: 'End time must be greater then start time.'})
    }

    const newSession = new Sessions({teacherId, startTime, endTime});
    const result = await newSession.save();

    if(result) {
        return res.status(201).send({message: 'Session Added Successfully', result})
    }

})

// Get Available Sessions 
SessionsRoutes.get('/available', async(req: any, res) => {
   const dateTimestamp = req.query.dateTimestamp;

    const dateString = dateTimestamp.slice(0, 10);

    // us standard dates we used here for simplicity
    const startOfDay = new Date(`${dateString}T00:00:00.000Z`);
    const endOfDay = new Date(`${dateString}T23:59:59.999Z`);

    const availableSessions = await Sessions.aggregate([
        {
            $match: {
                startTime: { $lte: endOfDay },
                endTime: { $gte: startOfDay },
                status: "AVAILABLE",
            }
        }
    ]);

    return res.status(200).send({message: 'Available Session', availableSessions})

})


// Book Available Sessions 
SessionsRoutes.post('/:id/book', async(req: any, res) => {
   
    const {id} = req.params;
    const {userId} = req.body;

    const existingSession = await Sessions.findOne({_id: id});
    
    if(!existingSession) {
        return res.status(400).send({message: 'Session does not exist.'})
    }
    if(existingSession.status !== 'AVAILABLE') {
        return res.status(400).send({message: 'This session is not Available'});
    }

    const result = await Sessions.findByIdAndUpdate(
        id,
        { status: "BOOKED", userId: userId },
        { new: true }
    );

    // console.log('re-------', result)

    if(result?.status === 'BOOKED') {
        return res.status(200).send({message: 'Session Booked', result})
    } else {
        return res.status(400).send({message: 'Error during Booking session.'})
    }



})

// Update Available Sessions To Complete : User Id also needed to update
SessionsRoutes.patch('/:id/complete', async(req: any, res) => {
   
    const {id} = req.params;
    const {userId} = req.body;

    const existingSession = await Sessions.findOne({_id: id, });
    
    if(!existingSession) {
        return res.status(400).send({message: 'Session does not exist.'})
    }
    if(existingSession.status !== 'BOOKED') {
        return res.status(400).send({message: 'This session is not BOOKED'});
    }

    const result = await Sessions.findByIdAndUpdate(
        id,
        { status: "COMPLETED", completedAt: Date.now() },
        { new: true }
    );

    // console.log('re-------', result)

    if(result?.status === 'COMPLETED') {
        return res.status(200).send({message: 'Session Marked Completed', result})
    } else {
        return res.status(400).send({message: 'Error during updating session.'})
    }



})


// Get Sessions for User : With Seperation
SessionsRoutes.get('/:id/sessions', async(req,res) => {

    let userId = new Types.ObjectId(req.params.id);
    console.log('userId', userId)

    const result = await Sessions.aggregate([
    {
        $match: {
        userId: userId
        }
    },
    {
        $facet: {
        upcomingSessions: [
            {
                $match: {
                    status: 'BOOKED'
                }
            }
        ],
        completedSessions: [
            {
                $match: {
                    status: 'COMPLETED'
                }
            }
        ]
        }
    }
    ]);

    res.status(200).json({
    success: true,
    data: result[0] ?? {
        upcomingSessions: [],
        completedSessions: []
    }
    });
})





export default SessionsRoutes;