package textio

import (
	"errors"
	"net/url"
	"runtime"
	"strings"

	"github.com/fumiama/tienyik"
)

func API() string {
	pc, f, _, ok := runtime.Caller(1)
	if !ok {
		panic("cannot get api of caller")
	}
	if strings.Contains(f, "\\") {
		f = strings.ReplaceAll(f, "\\", "/")
	}
	_, p, ok := strings.Cut(f, "/tienyik/")
	if !ok {
		panic("cannot cut api " + f + " of caller")
	}
	f = strings.TrimSuffix(p, ".go")
	fn := runtime.FuncForPC(pc)
	if fn == nil {
		panic("cannot get func name of caller, api: " + f)
	}
	p = fn.Name()
	i := strings.LastIndex(p, ".")
	if i < 0 {
		panic("func name of caller '" + p + " has no '.', api: " + f)
	}
	p = p[i+1:]
	if len(p) <= 1 {
		panic("func name of caller '" + p + " too short', api: " + f)
	}
	sb := strings.Builder{}
	sb.WriteString(f)
	sb.WriteByte('/')
	sb.WriteString(strings.ToLower(p[:1]))
	sb.WriteString(p[1:])
	return sb.String()
}

func EUrlParams(tya *tienyik.AES, params url.Values) string {
	return url.Values{
		FuncName(1, true): {BytesToString(tya.Encrypt(
			StringToBytes(params.Encode()),
		))},
	}.Encode()
}

func ParseQuery(tya *tienyik.AES, eparams string) (url.Values, error) {
	q, err := url.ParseQuery(eparams)
	if err != nil {
		return nil, err
	}
	if len(q) != 1 {
		return nil, errors.New("len(q) must be 1")
	}
	for _, v := range q {
		dec, err := tya.Decrypt(StringToBytes(v[0]))
		if err != nil {
			return nil, err
		}
		return url.ParseQuery(BytesToString(dec))
	}
	panic("unexpected")
}