const express = require('express');
const bodyParser = require('body-parser');
const MTree = require('./m-tree/mtree');

// Generator used to generate random points for the MTree
const Generator = require('./data/generator');

// Express app
const app = express();
app.use(bodyParser.json());

// Euclidean distance function used as the distance metric for the MTree
function euclideanDistance(a, b) {
    return Math.sqrt(a.reduce((acc, val, i) => acc + (val - b[i]) ** 2, 0));
}

// Create an MTree with the given dimensions and capacity, using the Euclidean distance
let mtree = null;

// Serve static files from the 'public' directory
app.use(express.static(__dirname + '/public'));

// Respond to favicon requests with no content
app.get('/favicon.ico', (req, res) => { res.status(204).end(); });

// Serve the index.html file
app.get('/', (req, res) => { res.sendFile(__dirname + '/public/index.html'); });

// Return the MTree
app.get('/tree', (req, res) => {
    res.send(JSON.parse(JSON.stringify(mtree, (key, value) => {
        if (key === 'parent' || key === 'mtree')
            return value && value.id;
        return value;
    })));
});

// Endpoint to check if the MTree has been initialized
app.get('/isInitialized', (req, res) => { res.send(!!mtree); });

// Insert a point into the MTree
app.post('/insert', (req, res) => {
    let point = req.body.point;
    if (!point)
        return res.status(400).send('Missing point');
    if (point.length !== mtree.dimension)
        return res.status(400).send('Point has the wrong dimension');
    
    mtree.insert(point);
    res.send('Point inserted');
});

// Perform a range query on the MTree
app.get('/rangeQuery', (req, res) => {
    const { queryPoint, radius } = req.query;
    if (!queryPoint)
        return res.status(400).send('Missing query point');
    if (!radius || isNaN(radius))
        return res.status(400).send('Missing radius');
    if (JSON.parse(queryPoint).length !== mtree.dimension)
        return res.status(400).send('Query point has the wrong dimension');
    let parsedQueryPoint;
    try { 
        parsedQueryPoint = JSON.parse(queryPoint);
    } catch (e) {
        return res.status(400).send('Invalid query point');
    }
    const parsedRadius = parseFloat(radius);

    if (parsedQueryPoint.length !== mtree.dimension)
        return res.status(400).send('Query point has the wrong dimension');
    
    console.time('mtreeRangeQuery');
    const result = mtree.rangeQuery(parsedQueryPoint, parsedRadius);
    console.timeEnd('mtreeRangeQuery');
    //console.log(result.length);

    console.time('sequentialSearch');
    const sequentialResult = points.filter(point => euclideanDistance(point, parsedQueryPoint) <= parsedRadius);
    console.timeEnd('sequentialSearch');
    //console.log(sequentialResult.length);

    res.send(result);
});

// Perform a k-NN query on the MTree
app.get('/kNNQuery', (req, res) => {
    const { queryPoint, k } = req.query;
    if (!queryPoint)
        return res.status(400).send('Missing query point');
    if (!k || isNaN(k))
        return res.status(400).send('Missing k');
    if (JSON.parse(queryPoint).length !== mtree.dimension)
        return res.status(400).send('Query point has the wrong dimension');
    let parsedQueryPoint;
    try { 
        parsedQueryPoint = JSON.parse(queryPoint);
    } catch (e) {
        return res.status(400).send('Invalid query point');
    }
    const kInt = parseInt(k, 10);

    console.time('mtreeKNNQuery');
    const result = mtree.kNNQuery(parsedQueryPoint, kInt);
    console.timeEnd('mtreeKNNQuery');
    //console.log(result);

    console.time('sequentialSearch');
    const sequentialResult = points.sort((a, b) => euclideanDistance(a, parsedQueryPoint) - euclideanDistance(b, parsedQueryPoint)).slice(0, kInt);
    console.timeEnd('sequentialSearch');
    //console.log(sequentialResult);

    res.send(result);
});

// Recreate the MTree with the given dimensions
app.post('/recreate', (req, res) => {
    let { dimensions, pointCount } = req.body;
    dimensions = parseInt(dimensions);
    pointCount = parseInt(pointCount);
    console.log(dimensions, pointCount);
    if (isNaN(dimensions) || dimensions <= 0)
        return res.status(400).send('Invalid dimensions');
    if (isNaN(pointCount) || pointCount <= 0)
        return res.status(400).send('Invalid point count');

    const generator = new Generator(dimensions);
    mtree = new MTree(dimensions, 10);
    points = generator.generateMany(pointCount);

    // points.forEach(point => mtree.insert(point));
    points.forEach((point, i) => {
        if (i % 100 === 0) {
            console.time(`insertion of next 100 points`);
            console.log(`inserted ${i} points`);
        }
        mtree.insert(point);
        if (i % 100 === 99)
            console.timeEnd(`insertion of next 100 points`);
    })

    res.send('MTree recreated');
});

// Start the server
app.listen(3000, () => { console.log('MTree API is running on port 3000'); });