First attempt at DELETE

src/main.rs

@@ -188,14 +188,14 @@ fn interpret(table_name: TableName, operation: Operation, state: &mut State, con
         Insert(table_name, values) => {
             let table: &mut Table = todo!();
 
-            table.insert(values);
+            let _ = table.insert(values)?;
-            todo!()
+            Ok(Response::Inserted())
         },
         Delete(table_name, maybe_condition) => {
             let table: &mut Table = todo!();
 
-            table.delete_where(maybe_condition);
+            let rows_affected = table.delete_where(maybe_condition)?;
-            todo!()
+            Ok(Response::Deleted(rows_affected))
         },
         CreateTable(table_name, table_schema) => {
             let table = Table::new(table_schema);
@@ -353,6 +353,34 @@ impl Table {
             .collect()
     }
 
+    fn delete_row_by_id(&mut self, id: UUID) -> usize {
+        if let Some(row) = self.rows.remove(&id) {
+            for (column_position, column_index) in &mut self.indexes {
+                if let DbValue::Indexable(value) = &row[*column_position] {
+                    column_index.remove(value, id)
+                };
+            }
+            1
+        } else {
+            0
+        }
+    }
+
+    fn delete_rows_by_ids(&mut self, ids: HashSet<UUID>) -> usize {
+        let mut total_count = 0;
+        for id in ids {
+            total_count += self.delete_row_by_id(id)
+        }
+        total_count
+    }
+
+    fn delete_rows_by_value(&mut self, column_position: ColumnPosition, value: &DbValue) -> usize {
+        let matched_ids: HashSet<UUID> = self.rows.iter()
+            .filter_map(|(id, row)| if row.get(column_position) == Some(value) { Some(*id) } else { None })
+            .collect();
+        self.delete_rows_by_ids(matched_ids)
+    }
+
     fn select_where(&self, column_selection: ColumnSelection, maybe_condition: Option<Condition>) -> DbResult<Vec<Row>> {
         let selected_column_positions = self.schema.column_positions_from_column_selection(&column_selection)?;
         match maybe_condition {
@@ -414,10 +442,47 @@ impl Table {
         Ok(())
     }
 
-    fn delete_where(&mut self, maybe_condition: Option<Condition>) {
+    fn delete_where(&mut self, maybe_condition: Option<Condition>) -> DbResult<usize> {
         // kinda similar to select with respect to the conditions
         // update index
-        todo!()
+        match maybe_condition {
+            None => {
+                // delete all
+                let number_of_rows = self.rows.len();
+                self.rows = BTreeMap::new();
+                self.indexes = HashMap::new();
+                Ok(number_of_rows)
+            },
+
+            Some(Condition::Eq(eq_column_name, value)) => {
+                let (type_, eq_column_position) = self.schema.get_column(&eq_column_name)?;
+                if self.schema.is_primary(eq_column_position) {
+                    match value {
+                        DbValue::Indexable(IndexableDbValue::UUID(uuid)) => {
+                            Ok(self.delete_row_by_id(uuid))
+                        },
+                        _ =>
+                            return Err(Error::ValueDoesNotMatchExpectedType(self.schema.table_name.clone(), eq_column_name.clone(), type_, value.clone()))
+                    }
+
+                } else {
+                    match value {
+                        DbValue::Indexable(value) => {
+                            match self.indexes.get(&eq_column_position) {
+                                Some(column_index) => {
+                                    let ids = column_index.get(value);
+                                    Ok(self.delete_rows_by_ids(ids))
+                                },
+                                None =>
+                                    Ok(self.delete_rows_by_value(eq_column_position, &DbValue::Indexable(value)))
+                            }
+                        },
+                        _ =>
+                            Ok(self.delete_rows_by_value(eq_column_position, &value))
+                    }
+                }
+            }
+        }
     }
 }
 
@@ -440,7 +505,7 @@ impl ColumnIndex {
         }
     }
 
-    fn remove(&mut self, id: UUID) {
+    fn remove(&mut self, value: &IndexableDbValue, id: UUID) {
         todo!()
     }
 }