refactor: refactor providers code

providers/provider-engels-polytechnic/src/parser/error.rs

@@ -0,0 +1,38 @@
+use derive_more::{Display, Error, From};
+use crate::parser::worksheet::CellPos;
+
+#[derive(Clone, Debug, Display, Error)]
+#[display("'{data}' at {pos}")]
+pub struct ErrorCell {
+    pub pos: CellPos,
+    pub data: String,
+}
+
+impl ErrorCell {
+    pub fn new(row: u32, column: u32, data: &str) -> Self {
+        Self {
+            pos: CellPos { row, column },
+            data: data.to_string(),
+        }
+    }
+}
+
+#[derive(Debug, Display, Error, From)]
+pub enum Error {
+    #[from]
+    BadXls(calamine::XlsError),
+
+    #[display("No work sheets found.")]
+    NoWorkSheets,
+
+    #[display("There is no data on work sheet boundaries.")]
+    UnknownWorkSheetRange,
+
+    #[display("Failed to read lesson start and end from {_0}.")]
+    NoLessonBoundaries(ErrorCell),
+
+    #[display("No start and end times matching the lesson (at {_0}) was found.")]
+    LessonTimeNotFound(CellPos),
+}
+
+pub type Result<T> = core::result::Result<T, Error>;