chore: refactor into a RecordingDataManager, lay the ground work for a RenderManager

src/recording_data/hour.rs

@@ -0,0 +1,58 @@
+use futures::{TryStream, TryStreamExt as _};
+use snafu::{OptionExt as _, ResultExt as _, Snafu};
+use std::num::ParseIntError;
+
+use super::{CreateListerSnafu, Day, ListError, Month, RecordingDataManager, Year};
+
+pub type Hour = u8;
+
+#[derive(Debug, Snafu)]
+pub enum TakeError {
+    /// hours are supposed to be directories, but this wasn't (because it didn't end with `/`)
+    NotADirectory,
+
+    /// could not parse the hour as an integer
+    ParseIntegerError { source: ParseIntError },
+}
+
+pub fn take(s: &str) -> Result<(Hour, &str), TakeError> {
+    let (hour, rest) = s.split_once('/').context(NotADirectorySnafu)?;
+
+    let hour = hour.parse().context(ParseIntegerSnafu)?;
+
+    Ok((hour, rest))
+}
+
+#[derive(Debug, Snafu)]
+pub enum HourEntryError {
+    /// failed to get an entry from the storage operator's lister
+    ReceiveEntryError { source: opendal::Error },
+
+    /// failed to parse the entry as a hour
+    ParseError { source: TakeError },
+}
+
+impl RecordingDataManager {
+    pub async fn hours(
+        &self,
+        year: Year,
+        month: Month,
+        day: Day,
+    ) -> Result<impl TryStream<Ok = Hour, Error = HourEntryError> + Unpin, ListError> {
+        let lister = self
+            .operator
+            .lister(&format!("{year}/{month}/{day}/"))
+            .await
+            .context(CreateListerSnafu)?;
+
+        Ok(lister
+            .map_err(|error| HourEntryError::ReceiveEntryError { source: error })
+            .and_then(|entry| {
+                std::future::ready(
+                    take(entry.name())
+                        .map(|(hour, _rest)| hour)
+                        .context(ParseSnafu),
+                )
+            }))
+    }
+}