package codec

import (
	"fmt"
	"net/http"
	"reflect"
)

type pathCodec struct {
	req *http.Request
}

// NewPathCodec ...
func NewPathCodec(r *http.Request) *pathCodec {
	c := &pathCodec{req: r}
	return c
}

// Decode ...
func (c *pathCodec) Decode(field reflect.StructField, fv reflect.Value, tag *Tag) error {
	pv := c.req.PathValue(tag.Name)
	if pv == "" {
		return nil
	}

	rv, err := getFieldValue(field.Type, tag, []string{pv})
	if err != nil {
		return err
	}
	if !rv.IsValid() {
		return fmt.Errorf("%s not valid", rv)
	}

	fv.Set(rv)
	return nil
}