package heleket

import (
	"crypto/md5"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"strings"
)

// encodeBody matches PHP json_encode default (slashes escaped, unicode unescaped).
func encodeBody(v any) ([]byte, error) {
	b, err := json.Marshal(v)
	if err != nil {
		return nil, err
	}
	return []byte(strings.ReplaceAll(string(b), "/", `\/`)), nil
}

func SignBody(body []byte, apiKey string) string {
	escaped := strings.ReplaceAll(string(body), "/", `\/`)
	sum := md5.Sum([]byte(base64.StdEncoding.EncodeToString([]byte(escaped)) + apiKey))
	return hex.EncodeToString(sum[:])
}

func VerifyWebhook(body []byte, apiKey string) (map[string]any, bool) {
	var raw map[string]json.RawMessage
	if err := json.Unmarshal(body, &raw); err != nil {
		return nil, false
	}
	signRaw, ok := raw["sign"]
	if !ok {
		return nil, false
	}
	var sign string
	if err := json.Unmarshal(signRaw, &sign); err != nil {
		return nil, false
	}
	delete(raw, "sign")

	payload, err := encodeBody(raw)
	if err != nil {
		return nil, false
	}
	if SignBody(payload, apiKey) != sign {
		return nil, false
	}

	var data map[string]any
	if err := json.Unmarshal(body, &data); err != nil {
		return nil, false
	}
	delete(data, "sign")
	return data, true
}