Refactor Sudoku field and solver implementation

field/cell.go

@@ -1,123 +1,77 @@
 package field
 
-// ────────────────────────────────────────────────────────────────────────────── //
-// NOTES STRUCTURE                                                                //
-// ────────────────────────────────────────────────────────────────────────────── //
-
 import "slices"
 
 type Notes struct {
 	numbers []int
 }
 
-func (n *Notes) Add(field *Field, cell *Cell, note int, trigger string, marks []Mark) {
-	if slices.Contains(n.numbers, note) {
-		return // Note already exists
+func (n *Notes) Add(f *Field, cell *Cell, note int, trigger string, marks []Mark) error {
+	if n == nil || cell == nil || cell.notes != n {
+		return ErrInvalidCell
 	}
-	field.changes = append(field.changes, Change{
-		Cell:       cell,
-		marks:      marks,
-		action:     ActionSetNote,
-		value:      note,
-		from:       0,
-		triggerdBy: trigger,
-	})
-	n.numbers = append(n.numbers, note)
+	return f.AddChange(&ExternalChange{Cell: cell, Marks: marks, Action: ActionSetNote, Value: note, TriggerdBy: trigger})
 }
 
-func (n *Notes) Remove(field *Field, cell *Cell, note int, trigger string, marks []Mark) {
-	for i, existing := range n.numbers {
-		if existing == note {
-			field.changes = append(field.changes, Change{
-				Cell:       cell,
-				marks:      marks,
-				action:     ActionRemoveNote,
-				value:      0,
-				from:       note,
-				triggerdBy: trigger,
-			})
-
-			n.numbers = append(n.numbers[:i], n.numbers[i+1:]...)
-			return
-		}
+func (n *Notes) Remove(f *Field, cell *Cell, note int, trigger string, marks []Mark) error {
+	if n == nil || cell == nil || cell.notes != n {
+		return ErrInvalidCell
 	}
+	return f.AddChange(&ExternalChange{Cell: cell, Marks: marks, Action: ActionRemoveNote, From: note, TriggerdBy: trigger})
 }
 
 func (n *Notes) Get() []int {
-	copySlice := make([]int, len(n.numbers))
-	copy(copySlice, n.numbers)
-	return copySlice
+	if n == nil {
+		return nil
+	}
+	return slices.Clone(n.numbers)
 }
 
-func (n *Notes) Has(i int) bool {
-	return slices.Contains(n.numbers, i)
+func (n *Notes) Has(number int) bool {
+	return n != nil && slices.Contains(n.numbers, number)
 }
 
-// ────────────────────────────────────────────────────────────────────────────── //
-// CELL STRUCTURE                                                                 //
-// ────────────────────────────────────────────────────────────────────────────── //
-
 type Cell struct {
 	number int
-	Notes  *Notes
-	Pos    *Position
+	notes  *Notes
+	pos    *Position
 }
 
 func NewCell(number int, pos *Position) *Cell {
-	cell := Cell{
-		number: number,
-		Pos:    pos,
-		Notes:  &Notes{},
-	}
-	return &cell
+	return &Cell{number: number, notes: &Notes{}, pos: pos}
 }
 
-func (c *Cell) SetNumber(field *Field, n int, trigger string, marks []Mark) {
-	if c.number == n {
-		return
+func (c *Cell) SetNumber(f *Field, number int, trigger string, marks []Mark) error {
+	if c == nil {
+		return ErrInvalidCell
 	}
-
-	if field == nil {
-		return
-	}
-
-	if n <= 0 || n > field.props.Rows || n > field.props.Columns {
-		return
-	}
-
-	field.changes = append(field.changes, Change{
-		Cell:       c,
-		marks:      marks,
-		action:     ActionSetNumber,
-		value:      n,
-		from:       c.number,
-		triggerdBy: trigger,
-	})
-
-	c.number = n
+	return f.AddChange(&ExternalChange{Cell: c, Marks: marks, Action: ActionSetNumber, Value: number, From: c.number, TriggerdBy: trigger})
 }
 
-func (c *Cell) RemoveNumber(field *Field, trigger string, marks []Mark) {
-	if c.number == 0 {
-		return
+func (c *Cell) RemoveNumber(f *Field, trigger string, marks []Mark) error {
+	if c == nil {
+		return ErrInvalidCell
 	}
-
-	if field == nil {
-		return
-	}
-
-	field.changes = append(field.changes, Change{
-		action:     ActionSetNumber,
-		Cell:       c,
-		value:      0,
-		from:       c.number,
-		marks:      marks,
-		triggerdBy: trigger,
-	})
-
-	c.number = 0
+	return f.AddChange(&ExternalChange{Cell: c, Marks: marks, Action: ActionRemoveNumber, From: c.number, TriggerdBy: trigger})
 }
 
 func (c *Cell) GetNumber() int {
+	if c == nil {
+		return 0
+	}
 	return c.number
 }
+
+func (c *Cell) GetNotes() *Notes {
+	if c == nil {
+		return nil
+	}
+	return c.notes
+}
+
+func (c *Cell) GetPosition() *Position {
+	if c == nil {
+		return nil
+	}
+	return c.pos
+}