Initial Commit

src/lib.rs

@@ -0,0 +1,62 @@
+use chrono::prelude::*;
+
+// TODO review whether a genesis block has a block height of 1 or 0
+
+type BlockHeight = i64;
+
+pub struct BlockchainBlockInfo {
+    block_period: u64, // in seconds maybe?
+
+    latest_block_height: BlockHeight,
+    latest_block_time: DateTime<Utc>,
+}
+
+pub fn time_to_blockheight(time: DateTime<Utc>, blockchain: BlockchainBlockInfo) -> BlockHeight {
+    let time_difference = (time - blockchain.latest_block_time).num_seconds();
+    let num_blocks = time_difference / blockchain.block_period as i64;
+    num_blocks + blockchain.latest_block_height
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn one_block_time_away() {
+        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 = BlockchainBlockInfo {
+            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);
+    }
+
+    #[test]
+    fn one_block_time_previous() {
+        let latest_block_time = Utc.with_ymd_and_hms(2024, 10, 10, 10, 20, 1).unwrap();
+        let wanted_future_block_time = Utc.with_ymd_and_hms(2024, 10, 10, 10, 10, 0).unwrap();
+        let blockchain_info = BlockchainBlockInfo {
+            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, 999);
+    }
+
+    #[test]
+    fn negative_block_time() {
+        let latest_block_time = Utc.with_ymd_and_hms(2024, 10, 10, 10, 30, 0).unwrap();
+        let wanted_negative_block_time = Utc.with_ymd_and_hms(2024, 10, 10, 10, 10, 0).unwrap();
+        let blockchain_info = BlockchainBlockInfo {
+            block_period: 60 * 10, // 10 minutes
+            latest_block_height: 1,
+            latest_block_time,
+        };
+        let result = time_to_blockheight(wanted_negative_block_time, blockchain_info);
+        assert_eq!(result, -1);
+    }
+}