const express = require('express')

const morgan = require('morgan')

const app = express();

const requestLogger = (request, response, next) => {

console.log(`${request.method} url:: ${request.url}`);

next()

}

app.use(express.static('images'))

app.use(express.static('htmls'))

app.use(requestLogger)

app.use(morgan('tiny'))

app.use('/products', express.json({ limit: 100 }))

// Error handling Middleware functions

const errorLogger = (error, request, response, next) => {

console.log( `error ${error.message}`)

next(error) // calling next middleware

}

const errorResponder = (error, request, response, next) => {

response.header("Content-Type", 'application/json')

const status = error.status || 400

response.status(status).send(error.message)

}

const invalidPathHandler = (request, response, next) => {

response.status(400)

response.send('invalid path')

}

app.get('product', (request, response)=>{

response.sendFile("productsample.html")

})

// handle get request for path /

app.get('/', (request, response) => {

response.send('response for GET request');

})

const requireJsonContent = (request, response, next) => {

if (request.headers['content-type'] !== 'application/json') {

response.status(400).send('Server requires application/json')

} else {

next()

}

}

// handle post request for path /products

app.post('/products', requireJsonContent, (request, response) => {

const products = []

const name = request.body.name

const brand = request.body.brand

const category = request.body.category

console.log(name + " " + brand)

products.push({name: request.body.name, brand: request.body.brand, price: request.body.price})

const productCreationResponse = {productID: "12345", result: "success"}

response.json(productCreationResponse)

})

app.get('/productswitherror', (request, response) => {

let error = new Error(`processing error in request at ${request.url}`)

error.statusCode = 400

throw error

})

app.use(errorLogger)

app.use(errorResponder)

app.use(invalidPathHandler)

const port = 3000

app.listen(3000,

() => console.log(`Server listening on port ${port}.`));