package encode

import (
	"encoding/base64"
	"encoding/json"
)

const (
	standardBase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
	customBase64   = "KLMPQRSTUVWXYZABCGHdefIJjkNOlmnopqrstuvwxyzabcghiDEF34501289+67/"
)

var base64Map = func() map[byte]byte {
	m := make(map[byte]byte, len(standardBase64))
	for i := 0; i < len(standardBase64); i++ {
		m[standardBase64[i]] = customBase64[i]
	}
	return m
}()

// CustomBase64Encode 使用自定义字符映射对标准 Base64 进行转换
func CustomBase64Encode(data []byte) string {
	standard := base64.StdEncoding.EncodeToString(data)
	result := make([]byte, len(standard))
	for i := 0; i < len(standard); i++ {
		if c, ok := base64Map[standard[i]]; ok {
			result[i] = c
		} else {
			result[i] = standard[i]
		}
	}
	return string(result)
}

// EncodeJSON 将任意数据编码为 JSON 后，再进行自定义 Base64 编码
func EncodeJSON(v any) (string, error) {
	jsonBytes, err := json.Marshal(v)
	if err != nil {
		return "", err
	}
	return CustomBase64Encode(jsonBytes), nil
}

// ParseBase64Param 解析 base64Resp 参数，默认为 true
func ParseBase64Param(c interface{ Query(string) string }) bool {
	v := c.Query("base64Resp")
	if v == "" || v == "true" || v == "1" {
		return true
	}
	return false
}