// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
// Use of this source code is governed by a MIT style
// license that can be found in the LICENSE file.

package gin

import (
	"encoding/xml"
	"log"
	"reflect"
	"runtime"
	"strings"
)

const (
	methodGET     = iota
	methodPOST    = iota
	methodPUT     = iota
	methodAHEAD   = iota
	methodOPTIONS = iota
	methodDELETE  = iota
	methodCONNECT = iota
	methodTRACE   = iota
	methodUnknown = iota
)

type H map[string]interface{}

// Allows type H to be used with xml.Marshal
func (h H) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	start.Name = xml.Name{
		Space: "",
		Local: "map",
	}
	if err := e.EncodeToken(start); err != nil {
		return err
	}
	for key, value := range h {
		elem := xml.StartElement{
			Name: xml.Name{Space: "", Local: key},
			Attr: []xml.Attr{},
		}
		if err := e.EncodeElement(value, elem); err != nil {
			return err
		}
	}
	if err := e.EncodeToken(xml.EndElement{Name: start.Name}); err != nil {
		return err
	}
	return nil
}

func filterFlags(content string) string {
	for i, char := range content {
		if char == ' ' || char == ';' {
			return content[:i]
		}
	}
	return content
}

func chooseData(custom, wildcard interface{}) interface{} {
	if custom == nil {
		if wildcard == nil {
			log.Panic("negotiation config is invalid")
		}
		return wildcard
	}
	return custom
}

func parseAccept(acceptHeader string) (parts []string) {
	parts = strings.Split(acceptHeader, ",")
	for i, part := range parts {
		index := strings.IndexByte(part, ';')
		if index >= 0 {
			part = part[0:index]
		}
		parts[i] = strings.TrimSpace(part)
	}
	return
}

func lastChar(str string) uint8 {
	size := len(str)
	if size == 0 {
		log.Panic("The length of the string can't be 0")
	}
	return str[size-1]
}

func nameOfFunction(f interface{}) string {
	return runtime.FuncForPC(reflect.ValueOf(f).Pointer()).Name()
}

func codeForHTTPMethod(method string) int {
	switch method {
	case "GET":
		return methodGET
	case "POST":
		return methodPOST
	case "PUT":
		return methodPUT
	case "AHEAD":
		return methodAHEAD
	case "OPTIONS":
		return methodOPTIONS
	case "DELETE":
		return methodDELETE
	case "TRACE":
		return methodTRACE
	case "CONNECT":
		return methodCONNECT
	default:
		return methodUnknown
	}
}