package request

import (
	"git.xdrm.io/gws/internal/http/upgrade/request/parser/header"
	"fmt"
	"strconv"
	"strings"
)



// checkHost checks and extracts the Host header
func (r *T) extractHostPort(bb header.HeaderValue) error {

	if len(bb) != 1 {
		return fmt.Errorf("Host header must have a unique value")
	}

	split := strings.Split(string(bb[0]), ":")

	r.host = split[0]

	// no port
	if len(split) < 2 {
		return nil
	}

	// extract port
	readPort, err := strconv.ParseUint(split[1], 10, 16)
	if err != nil {
		return fmt.Errorf("Cannot read port number '%s'", split[1])
	}

	r.port = uint16(readPort)

	// if 'Origin' header is already read, check it
	if len(r.origin) > 0 {
		err = r.checkOriginPolicy()
		if err != nil {
			return err
		}
	}

	return nil

}


// checkOrigin checks the Origin Header
func (r *T) extractOrigin(bb header.HeaderValue) error {

	if len(bb) != 1 {
		return fmt.Errorf("Origin header must have a unique value")
	}

	r.origin = string(bb[0])

	// if host already stored, check origin policy
	if len(r.host) > 0 {
		err := r.checkOriginPolicy()
		if err != nil {
			return err
		}
	}

	return nil

}

// checkOriginPolicy origin policy based on 'host' value
func (r T) checkOriginPolicy() error {
	// TODO: Origin policy, for now BYPASS
	return nil
}

// checkConnection checks the 'Connection' header
// it MUST contain 'Upgrade'
func (r T) checkConnection(bb header.HeaderValue) error {

	for _, b := range bb {

		if strings.ToLower( string(b) ) == "upgrade" {
			return nil
		}

	}

	return fmt.Errorf("Connection header must be 'Upgrade'")

}

// checkUpgrade checks the 'Upgrade' header
// it MUST be 'websocket'
func (r T) checkUpgrade(bb header.HeaderValue) error {

	if len(bb) != 1 {
		return fmt.Errorf("Upgrade header must have only 1 element")
	}

	if strings.ToLower( string(bb[0]) ) == "websocket" {
		return nil
	}

	return fmt.Errorf("Upgrade header must be 'websocket', got '%s'", bb[0])

}

// checkVersion checks the 'Sec-WebSocket-Version' header
// it MUST be '13'
func (r T) checkVersion(bb header.HeaderValue) error {

	if len(bb) != 1 || string(bb[0]) != "13" {
		return fmt.Errorf("Sec-WebSocket-Version header must be '13'")
	}

	return nil

}

// extractKey extracts the 'Sec-WebSocket-Key' header
// it MUST be 24 bytes (base64)
func (r *T) extractKey(bb header.HeaderValue) error {

	if len(bb) != 1 || len(bb[0]) != 24 {
		return fmt.Errorf("Sec-WebSocket-Key header must be a unique 24 bytes base64 value, got %d bytes", len(bb[0]))
	}

	return nil

}