From af4c28e1b7e57b09d7680da6f42e87ec5731abba Mon Sep 17 00:00:00 2001
From: rhuairahrighairigh <ruaridh.odonnell@gmail.com>
Date: Wed, 11 Jul 2018 22:02:07 +0100
Subject: [PATCH] plan out validation

---
 internal/x/paychan/handler.go |  3 ++-
 internal/x/paychan/keeper.go  | 13 +++++++++++--
 internal/x/paychan/types.go   | 17 ++++++++++-------
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/internal/x/paychan/handler.go b/internal/x/paychan/handler.go
index cb89735d..47840412 100644
--- a/internal/x/paychan/handler.go
+++ b/internal/x/paychan/handler.go
@@ -21,9 +21,9 @@ func NewHandler(k Keeper) sdk.Handler {
 	}
 }
 
-// TODO does validation go here or in the keeper?
 
 // Handle CreateMsg.
+// Leaves validation to the keeper methods.
 func handleMsgCreate(ctx sdk.Context, k Keeper, msg MsgCreate) sdk.Result {
 	// TODO maybe remove tags for first version
 	tags, err := k.CreatePaychan(msg.sender, msg.receiver, msg.amount)
@@ -37,6 +37,7 @@ func handleMsgCreate(ctx sdk.Context, k Keeper, msg MsgCreate) sdk.Result {
 }
 
 // Handle CloseMsg.
+// Leaves validation to the keeper methods.
 func handleMsgClose(ctx sdk.Context, k Keeper, msg MsgClose) sdk.Result {
 	// TODO maybe remove tags for first version
 	tags, err := k.ClosePaychan(msg.sender, msg.receiver, msg.id, msg.receiverAmount)
diff --git a/internal/x/paychan/keeper.go b/internal/x/paychan/keeper.go
index 1a22136b..74aa0ddb 100644
--- a/internal/x/paychan/keeper.go
+++ b/internal/x/paychan/keeper.go
@@ -8,6 +8,8 @@ import (
 )
 
 // keeper of the paychan store
+// Handles validation internally. Does not rely on calling code to do validation.
+// Aim to keep public methids safe, private ones not necessaily.
 type Keeper struct {
 	storeKey sdk.StoreKey
 	cdc        *wire.Codec // needed to serialize objects before putting them in the store
@@ -63,7 +65,7 @@ func (keeper Keeper) setPaychan(pych Paychan) sdk.Error {
 // Create a new payment channel and lock up sender funds.
 func (keeer Keeper) CreatePaychan(sender sdk.Address, receiver sdkAddress, amt sdk.Coins) (sdk.Tags, sdk.Error) {
 	// Calculate next id (num existing paychans plus 1)
-	id := len(keeper.GetPaychans(sender, receiver)) + 1
+	id := len(keeper.GetPaychans(sender, receiver)) + 1 // TODO check for overflow?
 	// subtract coins from sender
 	k.coinKeeper.SubtractCoins(ctx, sender, amt)
 	// create new Paychan struct (create ID)
@@ -76,9 +78,13 @@ func (keeer Keeper) CreatePaychan(sender sdk.Address, receiver sdkAddress, amt s
 
 
 	// TODO validation
+	// coins valid and positive
+
 	// sender has enough coins - done in Subtract method
 	// receiver address exists?
 	// paychan doesn't exist already
+	// sender and receiver different?
+
 
 	tags := sdk.NewTags()
 	return tags, err
@@ -99,9 +105,12 @@ func (keeper Keeper) ClosePaychan(sender sdk.Address, receiver sdk.Address, id i
 
 
 	// TODO validation
+	// id ≥ 0
+	// coins valid and positive
 	// paychan exists
-	// output coins are less than paychan balance
+	// output coins are equal to paychan balance
 	// sender and receiver addresses exist?
+	// overflow in sender and receiver balances?
 
 	//sdk.NewTags(
 	//	"action", []byte("channel closure"),
diff --git a/internal/x/paychan/types.go b/internal/x/paychan/types.go
index 3dbb0549..5eb3bf10 100644
--- a/internal/x/paychan/types.go
+++ b/internal/x/paychan/types.go
@@ -79,13 +79,12 @@ func (msg MsgCreate) GetSignBytes() []byte {
 
 func (msg MsgCreate) ValidateBasic() sdk.Error {
 	// TODO implement
-	// verify msg as much as possible without using external information (such as account balance)
-	// are all fields present
-	// are all fields valid
-	// maybe check if sender and receiver is different
+	// Validate msg as an optimisation to avoid all validation going to keeper. It's run before the sigs are checked by the auth module.
+	// Validate without external information (such as account balance)
 
-	// maybe add custom errors
-	// learn how the errors work
+	// check if all fields present / not 0 valued
+	// do coin checks for amount
+	// check if Address valid?
 
 	// example from bank
 	// if len(in.Address) == 0 {
@@ -149,7 +148,11 @@ func (msg MsgClose) GetSignBytes() []byte {
 
 func (msg MsgClose) ValidateBasic() sdk.Error {
 	// TODO implement
-	//return msg.IBCPacket.ValidateBasic()
+	
+	// check if all fields present / not 0 valued
+	// check id ≥ 0
+	// do coin checks for amount
+	// check if Address valid?
 }
 
 func (msg MsgClose) GetSigners() []sdk.Address {