package request

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


// parseHeader parses any http request line
// (header and request-line)
func (r *T) parseHeader(b []byte) error {

	/* (1) First line -> GET {uri} HTTP/{version}
	---------------------------------------------------------*/
	if !r.first {

		err := r.request.Parse(b)

		if err != nil {
			return fmt.Errorf("Error while parsing first line: %s", err)
		}

		r.first = true
		return nil

	}



	/* (2) Other lines -> Header-Name: Header-Value
	---------------------------------------------------------*/
	/* (1) Try to parse header */
	head, err := header.Parse(b)
	if err != nil {
		return fmt.Errorf("Error parsing header: %s", err)
	}

	/* (2) Manage header */
	switch head.Name {

		case header.HOST:       fmt.Printf("[host]                   ")
			err = r.extractHostPort(head.Values[0])

		case header.UPGRADE:    fmt.Printf("[upgrade]                ")
			err = r.checkUpgrade(head.Values)

		case header.CONNECTION: fmt.Printf("[connection]             ")
			err = r.checkConnection(head.Values)

		case header.WSKEY:      fmt.Printf("[sec-websocket-key]      ")
		case header.ORIGIN:     fmt.Printf("[origin]                 ")
		case header.WSPROTOCOL: fmt.Printf("[sec-websocket-protocol] ")
		case header.WSVERSION:  fmt.Printf("[sec-websocket-version]  ")
		default:
			return nil
	}

	if err != nil { return err }


	for i, v := range head.Values {
		if i == 0 {
			fmt.Printf("[ '%s'", v)
		} else {
			fmt.Printf(", '%s'", v)
		}
	}
	fmt.Printf(" ]\n");

	return nil

}

// checkHost checks and extracts the Host header
func (r *T) extractHostPort(b []byte) error {

	split := strings.Split(string(b), ":")

	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)

	return nil

}


// checkConnection checks the 'Connection' header
// it MUST contain 'Upgrade'
func (r T) checkConnection(bb [][]byte) 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 [][]byte) 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])

}