package router

import (
	"fmt"
	"reflect"
	"strconv"
	"strings"
)

func bindObj(obj interface{}, kvmap map[string]string, sTag string) error {
	var err error
	vElem := reflect.ValueOf(obj).Elem()
	sElem := reflect.TypeOf(obj).Elem()
	for i := 0; i < vElem.NumField(); i++ {
		vField := vElem.Field(i)
		tag := sElem.Field(i).Tag.Get(sTag)
		if tag != "" {
			sVal, exists := kvmap[tag]
			if exists {
				switch vField.Kind() {
				case reflect.String:
					vField.SetString(sVal)
				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
					iVal, err := strconv.ParseInt(sVal, 10, 64)
					if err != nil {
						return err
					}
					vField.SetInt(iVal)
				case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
					iVal, err := strconv.ParseUint(sVal, 10, 64)
					if err != nil {
						return err
					}
					vField.SetUint(iVal)
				case reflect.Bool:
					bVal, err := strconv.ParseBool(sVal)
					if err != nil {
						return err
					}
					vField.SetBool(bVal)
				case reflect.Float32, reflect.Float64:
					fVal, err := strconv.ParseFloat(sVal, 64)
					if err != nil {
						return err
					}
					vField.SetFloat(fVal)
				}
			}
		}
	}
	return err
}

const (
	defaultItemPattern = `(?P<%s>[a-zA-Z0-9_][\-\.a-zA-Z0-9_=:~]+)`
	itemRegexepPattern = `(?P<%s>%s)`
)

func pathComp(path string) string {
	convFunc := func(item []byte) []byte {
		itemData := strings.Split(string(item), ":")
		var convItem string
		if len(itemData) > 1 {
			convItem = fmt.Sprintf(itemRegexepPattern, itemData[0], itemData[1])
		} else {
			convItem = fmt.Sprintf(defaultItemPattern, string(item))
		}
		return []byte(convItem)
	}
	return string(replaceTemplates([]byte(path), convFunc))
}

func replaceTemplates(path []byte, convFunc func([]byte) []byte) []byte {
	convPath := make([]byte, 0)
	tmpBuf := make([]byte, 0)
	var lsPos int
	lbFound := false
	var rsPos int
	for i := 0; i < len(path); i++ {
		switch {
		case path[i] == '{':
			lsPos = i + 1
			if lbFound {
				convPath = append(convPath, tmpBuf...)
			}
			lbFound = true
			tmpBuf = make([]byte, 0)
			tmpBuf = append(tmpBuf, path[i])
		case path[i] == '}':
			rsPos = i
			if lbFound {
				subst := convFunc(path[lsPos:rsPos])
				convPath = append(convPath, subst...)
				lbFound = false
			} else {
				convPath = append(convPath, path[i])
			}
		default:
			if !lbFound {
				convPath = append(convPath, path[i])
			} else {
				tmpBuf = append(tmpBuf, path[i])
			}
		}
	}
	return convPath
}