From 3dde62d629e231257f75f5146297e1ad9002776b Mon Sep 17 00:00:00 2001
From: Patrick Peng Sun <patrick@lawipac.com>
Date: Sun, 28 May 2017 21:48:29 +1000
Subject: [PATCH] state machine redesign state saving is controlled by main
 routine,

serveProc procude state transit,

its input is old state, output is new state.
---
 chatState.go |  9 +++++++--
 procedure.go |  2 +-
 server.go    | 20 +++++++++++++-------
 3 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/chatState.go b/chatState.go
index 4f1261c..66e3fd3 100644
--- a/chatState.go
+++ b/chatState.go
@@ -96,6 +96,11 @@ type ValidationResult struct {
 //Validator function type for validating all wechat inputs
 type Validator func(s chatState) ValidationResult
 
-func saveChatState(state chatState) {
-
+func saveChatState(openID, procedure string, state chatState) (err error) {
+	if isExpired(state.Expire) {
+		//skip saving sate
+		return
+	}
+	_, err = setCurrentState(openID, procedure, state)
+	return
 }
diff --git a/procedure.go b/procedure.go
index a57a940..61f2889 100644
--- a/procedure.go
+++ b/procedure.go
@@ -99,6 +99,6 @@ func isInProc(openID string) (result bool, state chatState) {
 }
 
 //follow procedure, if there is any
-func serveProc(openID string, input InWechatMsg) (next chatState) {
+func serveProc(state chatState, input InWechatMsg) (next chatState) {
 	return
 }
diff --git a/server.go b/server.go
index 38bd15c..cf374a5 100644
--- a/server.go
+++ b/server.go
@@ -72,23 +72,29 @@ func answerWechatPost(w http.ResponseWriter, r *http.Request) {
 
 	//are we in an existing procedure
 	openID := in.header.FromUserName
-	yes, state := isInProc(openID)
-	if yes {
-		state := serveProc(openID, in)
-		reply = state.response
+	inProc, state := isInProc(openID) //if inside a procedure, resume last saved state
+	if inProc {
+		state = serveProc(state, in) //transit to new state
+		reply = state.response       //xml response
 	} else {
-		state, processed := serveCommand(openID, in) //search or other command
+		state, processed := serveCommand(openID, in) //menu or txt command e.g. search
 		if !processed {                              // transfer to Customer Service (kf)
 			reply = buildKfForwardMsg(openID, "")
+			kfSendTxt(openID, "未识别的命令，已转接校友会理事会，稍后答复您")
 		} else {
 			reply = state.response
 		}
 	}
-	log.Println(reply)
+	log.Println(reply) //instant reply, answering user's request
 	w.Header().Set("Content-Type", "text/xml; charset=utf-8")
 	fmt.Fprint(w, reply)
 
-	saveChatState(state)
+	err := saveChatState(openID, state.Procedure, state)
+	if err != nil {
+		log.Println("Error Cannot Save chat sate")
+		log.Println(err)
+		log.Println(state)
+	}
 	return
 }