Two year secondary pow ratio fix (#2037)

* Tweak (consensus breaking) secondary_pow_ratio
* Look at chain type for sec pow ratio calc (hardfork is t4 only)

core/src/consensus.rs

@@ -63,7 +63,17 @@ pub const COINBASE_MATURITY: u64 = DAY_HEIGHT;
 /// function of block height (time). Starts at 90% losing a percent
 /// approximately every week. Represented as an integer between 0 and 100.
 pub fn secondary_pow_ratio(height: u64) -> u64 {
-	90u64.saturating_sub(height / WEEK_HEIGHT)
+	// TODO - this should all be cleaned up and simplified before mainnet.
+	if global::is_mainnet() {
+		90u64.saturating_sub(height / (2 * YEAR_HEIGHT / 90))
+	} else {
+		if height < T4_CUCKAROO_HARDFORK {
+			// Maintaining pre hardfork testnet4 behavior
+			90u64.saturating_sub(height / WEEK_HEIGHT)
+		} else {
+			90u64.saturating_sub(height / (2 * YEAR_HEIGHT / 90))
+		}
+	}
 }
 
 /// Cuckoo-cycle proof size (cycle length)

core/src/global.rs

@@ -19,8 +19,8 @@
 use consensus::HeaderInfo;
 use consensus::{
 	graph_weight, BASE_EDGE_BITS, BLOCK_TIME_SEC, COINBASE_MATURITY, CUT_THROUGH_HORIZON,
-	DAY_HEIGHT, DIFFICULTY_ADJUST_WINDOW, INITIAL_DIFFICULTY, PROOFSIZE, SECOND_POW_EDGE_BITS,
-	STATE_SYNC_THRESHOLD, T4_CUCKAROO_HARDFORK, UNIT_DIFFICULTY, DEFAULT_MIN_EDGE_BITS,
+	DAY_HEIGHT, DEFAULT_MIN_EDGE_BITS, DIFFICULTY_ADJUST_WINDOW, INITIAL_DIFFICULTY, PROOFSIZE,
+	SECOND_POW_EDGE_BITS, STATE_SYNC_THRESHOLD, T4_CUCKAROO_HARDFORK, UNIT_DIFFICULTY,
 };
 use pow::{self, new_cuckaroo_ctx, new_cuckatoo_ctx, EdgeType, PoWContext};
 /// An enum collecting sets of parameters used throughout the
@@ -294,6 +294,12 @@ pub fn is_production_mode() -> bool {
 		|| ChainTypes::Mainnet == *param_ref
 }
 
+/// Are we in mainnet?
+pub fn is_mainnet() -> bool {
+	let param_ref = CHAIN_TYPE.read();
+	ChainTypes::Mainnet == *param_ref
+}
+
 /// Helper function to get a nonce known to create a valid POW on
 /// the genesis block, to prevent it taking ages. Should be fine for now
 /// as the genesis block POW solution turns out to be the same for every new