add more

context.go

@@ -1,12 +1,64 @@
 package rei
 
-import tgba "github.com/go-telegram-bot-api/telegram-bot-api/v5"
+import (
+	"fmt"
+	"reflect"
+	"sync"
+
+	tgba "github.com/go-telegram-bot-api/telegram-bot-api/v5"
+)
 
 type Ctx struct {
 	Event
 	State
-	Caller *TelegramClient
-	ma     *Matcher
+	Caller  *TelegramClient
+	Message *tgba.Message
+	ma      *Matcher
+}
+
+// decoder 反射获取的数据
+type decoder []dec
+
+type dec struct {
+	index int
+	key   string
+}
+
+// decoder 缓存
+var decoderCache = sync.Map{}
+
+// Parse 将 Ctx.State 映射到结构体
+func (ctx *Ctx) Parse(model interface{}) (err error) {
+	var (
+		rv       = reflect.ValueOf(model).Elem()
+		t        = rv.Type()
+		modelDec decoder
+	)
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("parse state error: %v", r)
+		}
+	}()
+	d, ok := decoderCache.Load(t)
+	if ok {
+		modelDec = d.(decoder)
+	} else {
+		modelDec = decoder{}
+		for i := 0; i < t.NumField(); i++ {
+			t1 := t.Field(i)
+			if key, ok := t1.Tag.Lookup("zero"); ok {
+				modelDec = append(modelDec, dec{
+					index: i,
+					key:   key,
+				})
+			}
+		}
+		decoderCache.Store(t, modelDec)
+	}
+	for _, d := range modelDec { // decoder类型非小内存，无法被编译器优化为快速拷贝
+		rv.Field(d.index).Set(reflect.ValueOf(ctx.State[d.key]))
+	}
+	return nil
 }
 
 // CheckSession 判断会话连续性