package kite

import (
	"bufio"
	"fmt"
	"net"
	"net/http"
)

type responseWriter struct {
	http.ResponseWriter
	statusCode int
	written    bool
}

func newResponseWriter(w http.ResponseWriter) *responseWriter {
	return &responseWriter{
		ResponseWriter: w,
		statusCode:     http.StatusOK,
	}
}

func (rw *responseWriter) WriteHeader(statusCode int) {
	if rw.written {
		return
	}

	rw.statusCode = statusCode
	rw.written = true
	rw.ResponseWriter.WriteHeader(statusCode)
}

func (rw *responseWriter) Write(b []byte) (int, error) {
	if !rw.written {
		rw.WriteHeader(http.StatusOK)
	}
	return rw.ResponseWriter.Write(b)
}

func (rw *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
	h, ok := rw.ResponseWriter.(http.Hijacker)
	if !ok {
		return nil, nil, fmt.Errorf("underlying ResponseWriter does not implement http.Hijacker")
	}
	return h.Hijack()
}

func (rw *responseWriter) Flush() {
	if f, ok := rw.ResponseWriter.(http.Flusher); ok {
		f.Flush()
	}
}

func (rw *responseWriter) Push(target string, opts *http.PushOptions) error {
	if p, ok := rw.ResponseWriter.(http.Pusher); ok {
		return p.Push(target, opts)
	}
	return http.ErrNotSupported
}