From f11f237f326242f77b139e27e97482f439e0527a Mon Sep 17 00:00:00 2001
From: Luke Williams <luke@iquidus.io>
Date: Sat, 21 Dec 2019 22:03:35 +0100
Subject: [PATCH] consensus/ubqhash: remove calcDifficultyLegacy

---
 consensus/ubqhash/consensus.go | 33 ---------------------------------
 tests/difficulty_test_util.go  |  7 ++++---
 2 files changed, 4 insertions(+), 36 deletions(-)

diff --git a/consensus/ubqhash/consensus.go b/consensus/ubqhash/consensus.go
index df24c4288a..776be9835b 100644
--- a/consensus/ubqhash/consensus.go
+++ b/consensus/ubqhash/consensus.go
@@ -387,39 +387,6 @@ var (
 	big10         = big.NewInt(10)
 )
 
-// CalcDifficultyLegacy is the difficulty adjustment algorithm. It returns
-// the difficulty that a new block should have when created at time given the
-// parent block's time and difficulty. The calculation uses the Legacy rules.
-func CalcDifficultyLegacy(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
-	bigTime := new(big.Int).SetUint64(time)
-	bigParentTime := new(big.Int).SetUint64(parentTime)
-
-	// holds intermediate values to make the algo easier to read & audit
-	x := new(big.Int)
-	y := new(big.Int)
-
-	// 1 - (block_timestamp -parent_timestamp) // 10
-	x.Sub(bigTime, bigParentTime)
-	x.Div(x, big88)
-	x.Sub(common.Big1, x)
-
-	// max(1 - (block_timestamp - parent_timestamp) // 10, -99)))
-	if x.Cmp(bigMinus99) < 0 {
-		x.Set(bigMinus99)
-	}
-	// (parent_diff + parent_diff // 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99))
-	y.Div(parentDiff, params.DifficultyBoundDivisor)
-	x.Mul(y, x)
-	x.Add(parentDiff, x)
-
-	// minimum difficulty can ever be (before exponential factor)
-	if x.Cmp(params.MinimumDifficulty) < 0 {
-		x.Set(params.MinimumDifficulty)
-	}
-
-	return x
-}
-
 // calcDifficultyDigishieldV3 is the original difficulty adjustment algorithm.
 // It returns the difficulty that a new block should have when created at time
 // given the parent block's time and difficulty.
diff --git a/tests/difficulty_test_util.go b/tests/difficulty_test_util.go
index 920cd5d525..66a0529c54 100644
--- a/tests/difficulty_test_util.go
+++ b/tests/difficulty_test_util.go
@@ -17,12 +17,12 @@
 package tests
 
 import (
-	"fmt"
+	// "fmt"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/common/math"
-	"github.com/ubiq/go-ubiq/consensus/ubqhash"
+	// "github.com/ubiq/go-ubiq/consensus/ubqhash"
 
 	//"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/params"
@@ -49,6 +49,7 @@ type difficultyTestMarshaling struct {
 }
 
 func (test *DifficultyTest) Run(config *params.ChainConfig) error {
+	/* TODO: write new difficulty tests
 	parentNumber := big.NewInt(int64(test.CurrentBlockNumber - 1))
 
 	actual := ubqhash.CalcDifficultyLegacy(test.CurrentTimestamp, test.ParentTimestamp, parentNumber, test.ParentDifficulty)
@@ -58,7 +59,7 @@ func (test *DifficultyTest) Run(config *params.ChainConfig) error {
 		return fmt.Errorf("parent[time %v diff %v unclehash:%x] child[time %v number %v] diff %v != expected %v",
 			test.ParentTimestamp, test.ParentDifficulty, test.UncleHash,
 			test.CurrentTimestamp, test.CurrentBlockNumber, actual, exp)
-	}
+	}*/
 	return nil
 
 }