package main

import (
	"fmt"
	"net/http"
)

func (app *application) recoverPanic(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Create a deferred function (which will always be run in the event of a panic as Go unwinds the stack).
		defer func() {
			// Use the builtin recover function to check if there has been a panic or not.
			if err := recover(); err != nil {
				// If there was a panic, set a "Connection: close" header on the response. This acts as a trigger to make Go's HTTP server automatically close the current connection after a response has been sent.
				w.Header().Set("Connection", "close")

				// The value returned by recover() has the type any, so we use fmt.Errorf() to normalize it into an error and call our serverErrorResponse() helper. In turn, this will log the error using our custom Logger type at the ERROR level and send the client a 500 Internal Server Error response.
				app.serverErrorResponse(w, r, fmt.Errorf("%s", err))
			}
		}()

		next.ServeHTTP(w, r)
	})
}