package response

import (
	"fmt"
	"io"
	"encoding/base64"
	"crypto/sha1"
)



// SetStatusCode sets the status code
func (r *T) SetStatusCode(sc StatusCode) {
	r.code = sc
}

// SetProtocols sets the protocols
func (r *T) SetProtocol(p []byte) {
	r.protocol = p
}

// ProcessKey processes the accept token according
// to the rfc from the Sec-WebSocket-Key
func (r *T) ProcessKey(k []byte) {

	/* (1) Concat with constant salt */
	mix := append(k, WSSalt...)

	/* (2) Hash with sha1 algorithm */
	digest := sha1.Sum(mix)

	/* (3) Base64 encode it */
	r.accept = []byte( base64.StdEncoding.EncodeToString( digest[:sha1.Size] ) )

}


// Send sends the response through an io.Writer
// typically a socket
func (r T) Send(w io.Writer) (int, error) {

	/* (1) Build response line */
	responseLine := fmt.Sprintf("HTTP/%s %d %s\r\n", HttpVersion, r.code, r.code.Message())

	/* (2) Build headers */
	optionalProtocol := ""
	if len(r.protocol) > 0 {
		optionalProtocol = fmt.Sprintf("Sec-WebSocket-Protocol: %s\r\n", r.protocol)
	}

	headers := fmt.Sprintf("Upgrade: websocket\t\nConnection: Upgrade\r\nSec-WebSocket-Accept: %s\r\nSec-WebSocket-Version: %d\r\n%s", r.accept, WSVersion, optionalProtocol)

	/* (3) Build all */
	raw := []byte(fmt.Sprintf("%s%s\r\n", responseLine, headers))

	/* (4) Write */
	written, err := w.Write(raw)

	return written, err

}

// GetProtocol returns the choosen protocol if set, else nil
func (r T) GetProtocol() []byte {
	return r.protocol
}