package middleware

import (
	"compress/gzip"
	"io"
	"net/http"
	"strings"

	"spend-sparrow/log"
)

type gzipResponseWriter struct {
	io.Writer
	http.ResponseWriter
}

func (w gzipResponseWriter) Write(b []byte) (int, error) {
	return w.Writer.Write(b)
}

func Gzip(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
			next.ServeHTTP(w, r)
			return
		}

		w.Header().Set("Content-Encoding", "gzip")
		gz := gzip.NewWriter(w)
		wrapper := gzipResponseWriter{Writer: gz, ResponseWriter: w}

		next.ServeHTTP(wrapper, r)

		err := gz.Close()
		if err != nil && err != http.ErrBodyNotAllowed {
			// if err != nil {
			log.Error("Gzip: could not close Writer: %v", err)
		}
	})
}