Handle image attachments, refactor more

src/range.rs

@@ -0,0 +1,43 @@
+use anyhow::{bail, format_err, Result};
+use chrono::{DateTime, Local, LocalResult, NaiveDate, TimeZone};
+
+#[derive(Debug)]
+pub(super) struct Range {
+    pub start: DateTime<Local>,
+    pub end: DateTime<Local>,
+}
+
+pub(super) fn try_create_range<S: AsRef<str>>(date: S) -> Result<Range> {
+    Ok(Range {
+        start: create_day_bound(&date, 0, 0, 0)?,
+        end: create_day_bound(date, 23, 59, 59)?,
+    })
+}
+
+fn create_day_bound<S: AsRef<str>>(
+    day: S,
+    hour: u32,
+    minute: u32,
+    second: u32,
+) -> Result<DateTime<Local>> {
+    let ts: Vec<&str> = day.as_ref().split("-").collect();
+    if ts.len() != 3 {
+        bail!("Invalid date format! {}", day.as_ref())
+    }
+    let (year, month, day) = if let [year, month, day, ..] = &ts[..] {
+        (year, month, day)
+    } else {
+        bail!("Invalid date format! {}", day.as_ref())
+    };
+    let b = Local.from_local_datetime(
+        &NaiveDate::from_ymd_opt(year.parse()?, month.parse()?, day.parse()?)
+            .ok_or_else(|| format_err!("Invalid date!"))?
+            .and_hms_opt(hour, minute, second)
+            .ok_or_else(|| format_err!("Invalid time!"))?,
+    );
+    if let LocalResult::Single(b) = b {
+        Ok(b)
+    } else {
+        bail!("Cannot construct day boundary!")
+    }
+}