From 2a97045317dbd79d4f93f0e9a599869961679188 Mon Sep 17 00:00:00 2001
From: Jeromy <jeromyj@gmail.com>
Date: Wed, 22 Apr 2020 09:37:38 -0700
Subject: [PATCH] add an api for estimating gas prices

---
 api/api_full.go                  |  1 +
 api/apistruct/struct.go          | 15 ++++++++++-----
 chain/messagepool/messagepool.go | 14 ++++++++++++++
 node/impl/full/mpool.go          |  4 ++++
 4 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/api/api_full.go b/api/api_full.go
index 2e9a8d575..00da2f12a 100644
--- a/api/api_full.go
+++ b/api/api_full.go
@@ -66,6 +66,7 @@ type FullNode interface {
 	MpoolPushMessage(context.Context, *types.Message) (*types.SignedMessage, error) // get nonce, sign, push
 	MpoolGetNonce(context.Context, address.Address) (uint64, error)
 	MpoolSub(context.Context) (<-chan MpoolUpdate, error)
+	MpoolEstimateGasPrice(context.Context, uint64) (types.BigInt, error)
 
 	// FullNodeStruct
 
diff --git a/api/apistruct/struct.go b/api/apistruct/struct.go
index aff01078b..3383ec05c 100644
--- a/api/apistruct/struct.go
+++ b/api/apistruct/struct.go
@@ -81,11 +81,12 @@ type FullNodeStruct struct {
 		SyncMarkBad        func(ctx context.Context, bcid cid.Cid) error                `perm:"admin"`
 		SyncCheckBad       func(ctx context.Context, bcid cid.Cid) (string, error)      `perm:"read"`
 
-		MpoolPending     func(context.Context, types.TipSetKey) ([]*types.SignedMessage, error) `perm:"read"`
-		MpoolPush        func(context.Context, *types.SignedMessage) (cid.Cid, error)           `perm:"write"`
-		MpoolPushMessage func(context.Context, *types.Message) (*types.SignedMessage, error)    `perm:"sign"`
-		MpoolGetNonce    func(context.Context, address.Address) (uint64, error)                 `perm:"read"`
-		MpoolSub         func(context.Context) (<-chan api.MpoolUpdate, error)                  `perm:"read"`
+		MpoolPending          func(context.Context, types.TipSetKey) ([]*types.SignedMessage, error) `perm:"read"`
+		MpoolPush             func(context.Context, *types.SignedMessage) (cid.Cid, error)           `perm:"write"`
+		MpoolPushMessage      func(context.Context, *types.Message) (*types.SignedMessage, error)    `perm:"sign"`
+		MpoolGetNonce         func(context.Context, address.Address) (uint64, error)                 `perm:"read"`
+		MpoolSub              func(context.Context) (<-chan api.MpoolUpdate, error)                  `perm:"read"`
+		MpoolEstimateGasPrice func(context.Context, uint64) (types.BigInt, error)                    `perm:"read"`
 
 		MinerGetBaseInfo func(context.Context, address.Address, abi.ChainEpoch, types.TipSetKey) (*api.MiningBaseInfo, error) `perm:"read"`
 		MinerCreateBlock func(context.Context, *api.BlockTemplate) (*types.BlockMsg, error)                                   `perm:"write"`
@@ -332,6 +333,10 @@ func (c *FullNodeStruct) MpoolSub(ctx context.Context) (<-chan api.MpoolUpdate,
 	return c.Internal.MpoolSub(ctx)
 }
 
+func (c *FullNodeStruct) MpoolEstimateGasPrice(ctx context.Context, priority uint64) (types.BigInt, error) {
+	return c.Internal.MpoolEstimateGasPrice(ctx, priority)
+}
+
 func (c *FullNodeStruct) MinerGetBaseInfo(ctx context.Context, maddr address.Address, epoch abi.ChainEpoch, tsk types.TipSetKey) (*api.MiningBaseInfo, error) {
 	return c.Internal.MinerGetBaseInfo(ctx, maddr, epoch, tsk)
 }
diff --git a/chain/messagepool/messagepool.go b/chain/messagepool/messagepool.go
index 466a9ff8f..af4600541 100644
--- a/chain/messagepool/messagepool.go
+++ b/chain/messagepool/messagepool.go
@@ -822,3 +822,17 @@ func (mp *MessagePool) loadLocal() error {
 
 	return nil
 }
+
+const MinGasPrice = 0
+
+func (mp *MessagePool) EstimateGasPrice(ctx context.Context, priority uint64) (types.BigInt, error) {
+	// TODO: something smarter obviously
+	switch priority {
+	case 0:
+		return types.NewInt(MinGasPrice + 2), nil
+	case 1:
+		return types.NewInt(MinGasPrice + 1), nil
+	default:
+		return types.NewInt(MinGasPrice), nil
+	}
+}
diff --git a/node/impl/full/mpool.go b/node/impl/full/mpool.go
index 834d149ab..10895955b 100644
--- a/node/impl/full/mpool.go
+++ b/node/impl/full/mpool.go
@@ -118,3 +118,7 @@ func (a *MpoolAPI) MpoolGetNonce(ctx context.Context, addr address.Address) (uin
 func (a *MpoolAPI) MpoolSub(ctx context.Context) (<-chan api.MpoolUpdate, error) {
 	return a.Mpool.Updates(ctx)
 }
+
+func (a *MpoolAPI) MpoolEstimateGasPrice(ctx context.Context, priority uint64) (types.BigInt, error) {
+	return a.Mpool.EstimateGasPrice(ctx, priority)
+}