1 files changed, 71 insertions, 0 deletions

diff --git a/src/app/cursor.rs b/src/app/cursor.rs
new file mode 100644
index 0000000..f76d591
--- /dev/null
+++ b/src/app/cursor.rs
@@ -0,0 +1,71 @@
+use chrono::{Duration, Local, NaiveDate};
+use cursive::direction::Absolute;
+
+#[derive(Debug, Copy, Clone)]
+pub struct Cursor(pub NaiveDate);
+
+impl std::default::Default for Cursor {
+    fn default() -> Self {
+        Cursor::new()
+    }
+}
+
+impl Cursor {
+    pub fn new() -> Self {
+        Cursor {
+            0: Local::now().naive_local().date(),
+        }
+    }
+    pub fn small_seek(&mut self, d: Absolute) {
+        let today = Local::now().naive_local().date();
+        let cursor = self.0;
+        match d {
+            Absolute::Right => {
+                // forward by 1 day
+                let next = cursor.succ_opt().unwrap_or(cursor);
+                if next <= today {
+                    self.0 = next;
+                }
+            }
+            Absolute::Left => {
+                // backward by 1 day
+                // assumes an infinite past
+                self.0 = cursor.pred_opt().unwrap_or(cursor);
+            }
+            Absolute::Down => {
+                // forward by 1 week
+                let next = cursor.checked_add_signed(Duration::weeks(1)).unwrap();
+                if next <= today {
+                    self.0 = next;
+                }
+            }
+            Absolute::Up => {
+                // backward by 1 week
+                // assumes an infinite past
+                let next = cursor.checked_sub_signed(Duration::weeks(1)).unwrap();
+                self.0 = next;
+            }
+            Absolute::None => {}
+        }
+    }
+    fn long_seek(&mut self, offset: Duration) {
+        let cursor = self.0;
+        let today = Local::now().naive_local().date();
+        let next = cursor.checked_add_signed(offset).unwrap_or(cursor);
+
+        if next <= today {
+            self.0 = next;
+        } else {
+            self.0 = today;
+        }
+    }
+    pub fn month_forward(&mut self) {
+        self.long_seek(Duration::weeks(4));
+    }
+    pub fn month_backward(&mut self) {
+        self.long_seek(Duration::weeks(-4));
+    }
+    pub fn reset(&mut self) {
+        self.0 = Local::now().naive_local().date();
+    }
+}