package gziphttp

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

type GZipResponseWriter struct {
	w  http.ResponseWriter
	gz *gzip.Writer
}

func Can(r *http.Request) bool {
	if strings.HasSuffix(r.URL.Path, ".gz") {
		return false
	}
	encodings, _ := r.Header["Accept-Encoding"]
	for _, encoding := range encodings {
		items := strings.Split(encoding, ",")
		for _, item := range items {
			if strings.TrimSpace(item) == "gzip" {
				return true
			}
		}
	}
	return false
}

func New(w http.ResponseWriter) *GZipResponseWriter {
	w.Header().Add("Content-Type", "text/html")
	w.Header().Add("Content-Encoding", "gzip")
	return &GZipResponseWriter{
		w:  w,
		gz: gzip.NewWriter(w),
	}
}

func (gz *GZipResponseWriter) Header() http.Header {
	return gz.w.Header()
}

func (gz *GZipResponseWriter) WriteHeader(statusCode int) {
	gz.w.WriteHeader(statusCode)
}

func (gz *GZipResponseWriter) Write(b []byte) (int, error) {
	return gz.gz.Write(b)
}

func (gz *GZipResponseWriter) Close() error {
	return gz.gz.Close()
}