package i18n

import (
	"context"
	"net/http"
)

type HttpKeyConfig struct {
	ParamKey  string `json:",optional,default=lang"`   // 参数中的语言Key
	HeaderKey string `json:",optional,default=X-LANG"` // Header中的语言Key
}

var (
	paramKey  = "lang"
	headerKey = "X-LANG"
)

// WithHttpConfig 基于配置文件设置Keys
func WithHttpConfig(config HttpKeyConfig) {
	WithHttpParamKey(config.ParamKey)
	WithHttpHeaderKey(config.HeaderKey)
}

// WithHttpParamKey 设置参数key
func WithHttpParamKey(key string) {
	paramKey = key
}

// WithHttpHeaderKey 设置头Key
func WithHttpHeaderKey(key string) {
	headerKey = key
}

// WithRequest 包装 http.Request, 接受客户端传递的lang并存入其 context 中
func WithRequest(r *http.Request) *http.Request {
	paramLang := r.FormValue(paramKey)
	headerLang := r.Header.Get(headerKey)

	acceptLanguage := r.Header.Get(KeyAcceptLanguage)
	ConfigLanguages(acceptLanguage, paramLang, headerLang)

	// 参数中的lang优先级大于header中
	lang := headerLang
	if len(paramLang) != 0 {
		lang = paramLang
	}

	ctx := r.Context()
	if len(lang) > 0 {
		ctx = context.WithValue(ctx, KeyLang, lang)
	}
	return r.WithContext(ctx)
}

// WithI18nMiddleware i18n中间件
func WithI18nMiddleware() func(next http.HandlerFunc) http.HandlerFunc {
	return func(next http.HandlerFunc) http.HandlerFunc {
		return func(writer http.ResponseWriter, request *http.Request) {
			req := WithRequest(request)
			next.ServeHTTP(writer, req)
		}
	}
}