init

crates/application/src/entry/use_cases/get_calendar.rs

@@ -0,0 +1,68 @@
+use std::collections::BTreeMap;
+use std::sync::Arc;
+
+use chrono::NaiveDate;
+
+use domain::entry::{DateRange, Mood, MoodEntry};
+use domain::ports::MoodEntryQueryPort;
+use domain::user::UserId;
+
+use crate::errors::ApplicationError;
+
+pub struct CalendarDay {
+    pub date: NaiveDate,
+    pub entries: Vec<MoodEntry>,
+    pub dominant_mood: Option<Mood>,
+}
+
+pub struct Deps {
+    pub query: Arc<dyn MoodEntryQueryPort>,
+}
+
+#[tracing::instrument(skip(deps))]
+pub async fn execute(
+    user_id: UserId,
+    range: DateRange,
+    deps: &Deps,
+) -> Result<Vec<CalendarDay>, ApplicationError> {
+    let entries = deps.query.find_by_date_range(&user_id, &range).await?;
+
+    let mut by_date: BTreeMap<NaiveDate, Vec<MoodEntry>> = BTreeMap::new();
+    for entry in entries {
+        let date = entry.logged_at().date_naive();
+        by_date.entry(date).or_default().push(entry);
+    }
+
+    let days = by_date
+        .into_iter()
+        .map(|(date, entries)| {
+            let dominant_mood = find_dominant_mood(&entries);
+            CalendarDay {
+                date,
+                entries,
+                dominant_mood,
+            }
+        })
+        .collect();
+
+    Ok(days)
+}
+
+fn find_dominant_mood(entries: &[MoodEntry]) -> Option<Mood> {
+    if entries.is_empty() {
+        return None;
+    }
+
+    let mut counts = [0u32; 5];
+    for entry in entries {
+        counts[entry.mood().value() as usize - 1] += 1;
+    }
+
+    let max_index = counts
+        .iter()
+        .enumerate()
+        .max_by_key(|(_, count)| *count)
+        .map(|(i, _)| i)?;
+
+    Mood::try_from(max_index as u8 + 1).ok()
+}