package reqline

import (
	"regexp"
	"fmt"
)


// extractHttpMethod extracts the HTTP method from a []byte
// and checks for errors
// allowed format: OPTIONS|GET|HEAD|POST|PUT|DELETE
func (r *T) extractHttpMethod(b []byte) error {

	switch string(b) {
		case "OPTIONS": r.method = OPTIONS
		case "GET":     r.method = GET
		case "HEAD":    r.method = HEAD
		case "POST":    r.method = POST
		case "PUT":     r.method = PUT
		case "DELETE":  r.method = DELETE

		default:
			return fmt.Errorf("Unknown HTTP method '%s'", b)
	}

	return nil
}


// extractURI extracts the URI from a []byte and checks for errors
// allowed format: /([^/]/)*/?
func (r *T) extractURI(b []byte) error {

	/* (1) Check format */
	checker := regexp.MustCompile("^(?:/[^/]+)*/?$")
	if !checker.Match(b) {
		return fmt.Errorf("Invalid URI format, expected an absolute path (starts with /), got '%s'", b)
	}

	/* (2) Store */
	r.uri = string(b)

	return nil

}


// extractHttpVersion extracts the version and checks for errors
// allowed format: [1-9] or [1.9].[0-9]
func (r *T) extractHttpVersion(b []byte) error {

	/* (1) Extract version parts */
	extractor := regexp.MustCompile(`^HTTP/([1-9])(?:\.([0-9]))?$`);

	if !extractor.Match(b) {
		return fmt.Errorf("Cannot parse HTTP version, expected INT or INT.INT, got '%s'", b)
	}

	/* (2) Extract version number */
	matches := extractor.FindSubmatch(b)
	var version    byte = matches[1][0] - '0'

	/* (3) Extract subversion (if exists) */
	var subVersion byte = 0
	if len(matches[2]) > 0 {
		subVersion = matches[2][0] - '0'
	}

	/* (4) Store version (x 10 to fit uint8) */
	r.version = version * 10 + subVersion

	return nil
}