Implemented the wrong way around

src/lib.rs

@@ -1,4 +1,4 @@
-use chrono::prelude::*;
+use chrono::{prelude::*, TimeDelta};
 use lazy_static::lazy_static;
 use rocket::serde::Serialize;
 use std::convert::Into;
@@ -71,6 +71,18 @@ pub fn time_to_blockheight(time: DateTime<Utc>, bi: BlockchainInfo) -> BlockHeig
     num_blocks + bi.latest_block_height
 }
 
+pub fn blockheight_specific_chain_to_time(height: BlockHeight, blockchain: BlockchainSupported) -> DateTime<Utc> {
+    let bi: BlockchainInfo = blockchain.into();
+    blockheight_to_time(height, bi)
+}
+
+#[deprecated = "The output of this function (Date & Time) will eventually be redundant, please look to change your own time keeping system to the superior blocktime as set out in this repository"]
+pub fn blockheight_to_time(height: BlockHeight, bi: BlockchainInfo) -> DateTime<Utc> {
+    // TODO check the + and - are the right way around
+    let diff_seconds = (height - bi.latest_block_height) * bi.block_period as i64;
+    bi.latest_block_time + TimeDelta::seconds(diff_seconds)
+}
+
 // I know there's code duplication... I _could_ abstract it out.
 // I think it's probably very YAGNI
 
@@ -170,8 +182,9 @@ pub fn update_all_blockheights() {
 
 #[cfg(test)]
 mod tests {
+    use chrono::TimeDelta;
+
     use super::*;
-    use chrono::Duration;
 
     #[test]
     #[ignore]
@@ -230,6 +243,22 @@ mod tests {
         assert_eq!(result, 1001);
     }
 
+    #[test]
+    fn back_and_forth() {
+        let latest_block_time = Utc.with_ymd_and_hms(2024, 10, 10, 10, 10, 0).unwrap();
+        let wanted_future_block_time = Utc.with_ymd_and_hms(2024, 10, 10, 10, 20, 1).unwrap();
+        let blockchain_info = BlockchainInfo {
+            block_period: 60 * 10, // 10 minutes
+            latest_block_height: 1000,
+            latest_block_time,
+        };
+        let result = time_to_blockheight(wanted_future_block_time, blockchain_info);
+        assert_eq!(result, 1001);
+        let future_time = blockheight_to_time(1001, blockchain_info);
+        assert_eq!(future_time, Utc.with_ymd_and_hms(2024, 10, 10, 10, 20, 0).unwrap());
+        // ignore the missing second... that second will not be needed in the future
+    }
+
     #[test]
     fn one_block_time_previous() {
         let latest_block_time = Utc.with_ymd_and_hms(2024, 10, 10, 10, 20, 1).unwrap();
@@ -261,23 +290,23 @@ mod tests {
         // Doesn't feel like an overly good test - but I can't think of anyother way that's "dynamic"
         // to me manually updating the times above
         let bi: BlockchainInfo = BlockchainSupported::BTC.into();
-        let wanted_time = bi.latest_block_time + Duration::seconds(bi.block_period as i64 + 1);
+        let wanted_time = bi.latest_block_time + TimeDelta::seconds(bi.block_period as i64 + 1);
         let bh = time_to_blockheight_specific_chain(wanted_time, BlockchainSupported::BTC);
         assert_eq!(bh, bi.latest_block_height + 1);
         let bi: BlockchainInfo = BlockchainSupported::BSV.into();
-        let wanted_time = bi.latest_block_time + Duration::seconds(bi.block_period as i64 + 2);
+        let wanted_time = bi.latest_block_time + TimeDelta::seconds(bi.block_period as i64 + 2);
         let bh = time_to_blockheight_specific_chain(wanted_time, BlockchainSupported::BSV);
         assert_eq!(bh, bi.latest_block_height + 1);
         let bi: BlockchainInfo = BlockchainSupported::XMR.into();
-        let wanted_time = bi.latest_block_time + Duration::seconds(bi.block_period as i64 + 3);
+        let wanted_time = bi.latest_block_time + TimeDelta::seconds(bi.block_period as i64 + 3);
         let bh = time_to_blockheight_specific_chain(wanted_time, BlockchainSupported::XMR);
         assert_eq!(bh, bi.latest_block_height + 1);
         let bi: BlockchainInfo = BlockchainSupported::ETH.into();
-        let wanted_time = bi.latest_block_time + Duration::seconds(bi.block_period as i64 + 4);
+        let wanted_time = bi.latest_block_time + TimeDelta::seconds(bi.block_period as i64 + 4);
         let bh = time_to_blockheight_specific_chain(wanted_time, BlockchainSupported::ETH);
         assert_eq!(bh, bi.latest_block_height + 1);
         let bi: BlockchainInfo = BlockchainSupported::ETH.into();
-        let wanted_time = bi.latest_block_time + Duration::seconds(bi.block_period as i64 + 5);
+        let wanted_time = bi.latest_block_time + TimeDelta::seconds(bi.block_period as i64 + 5);
         let bh = time_to_blockheight_specific_chain(wanted_time, BlockchainSupported::XMR);
         assert_ne!(bh, bi.latest_block_height + 1);
     }