Merge pull request #17 from StevanFreeborn/stevanfreeborn/refactor/use-grid-in-day-seven-part-one

refactor: use internal packages

cmd/07/main.go

@@ -2,7 +2,10 @@ package main
 
 import (
 	"github.com/StevanFreeborn/advent-of-code-2025/internal/file"
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/grid"
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/move"
 	"github.com/StevanFreeborn/advent-of-code-2025/internal/position"
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/queue"
 )
 
 const StartCharacter = "S"
@@ -10,66 +13,62 @@ const SplitterCharacter = "^"
 
 func SolvePartOne(filePath string) int {
 	input := file.ReadAllLines(filePath)
-	numOfRows := len(input)
-	numOfCols := len(input[0])
+	grid := grid.From(input)
 
-	startRow := -1
-	startCol := -1
+	var startPosition position.Position
 
-	for row := range numOfRows - 1 {
-		for col := range numOfCols - 1 {
-			v := string(input[row][col])
+	for row := range grid.NumberOfRows() - 1 {
+		for col := range grid.NumberOfColumns() - 1 {
+			current := position.From(row, col)
+			v := grid.GetValueAt(current)
 
 			if v == StartCharacter {
-				startRow = row
-				startCol = col
+				startPosition = current
 				break
 			}
 		}
 	}
 
-	if startRow < 0 || startCol < 0 {
+	if startPosition == nil {
 		panic("unable to find start location")
 	}
 
-	beamStart := position.From(startRow+1, startCol)
-	beamsQueue := []position.Position{
-		beamStart,
-	}
+	beamStart := startPosition.Move(move.Down)
+	beamsQueue := queue.New[position.Position]()
+	beamsQueue.Enqueue(beamStart)
+
 	visited := map[position.Position]bool{}
 
 	total := 0
 
-	for len(beamsQueue) > 0 {
-		currentBeam := beamsQueue[0]
-		beamsQueue = beamsQueue[1:]
+	for beamsQueue.IsEmpty() == false {
+		currentBeam, _ := beamsQueue.Dequeue()
 
 		if visited[currentBeam] {
 			continue
 		}
 
-		if currentBeam.Row() < 0 || currentBeam.Row() >= numOfRows {
-			continue
-		}
-
-		if currentBeam.Column() < 0 || currentBeam.Column() >= numOfCols {
+		if grid.InBounds(currentBeam) == false {
 			continue
 		}
 
 		visited[currentBeam] = true
 
-		value := string(input[currentBeam.Row()][currentBeam.Column()])
+		value := grid.GetValueAt(currentBeam)
 
 		if value == SplitterCharacter {
 			total++
-			rightBeam := position.From(currentBeam.Row(), currentBeam.Column()+1)
-			leftBeam := position.From(currentBeam.Row(), currentBeam.Column()-1)
-			beamsQueue = append(beamsQueue, rightBeam, leftBeam)
+
+			rightBeam := currentBeam.Move(move.Right)
+			leftBeam := currentBeam.Move(move.Left)
+
+			beamsQueue.Enqueue(rightBeam)
+			beamsQueue.Enqueue(leftBeam)
 			continue
 		}
 
-		nextBeam := position.From(currentBeam.Row()+1, currentBeam.Column())
-		beamsQueue = append(beamsQueue, nextBeam)
+		nextBeam := currentBeam.Move(move.Down)
+		beamsQueue.Enqueue(nextBeam)
 	}
 
 	return total

internal/position/position.go

@@ -1,9 +1,12 @@
 // Package position provides types and functions to represent and manipulate positions and moves on a 2D grid.
 package position
 
+import "github.com/StevanFreeborn/advent-of-code-2025/internal/move"
+
 type Position interface {
 	Row() int
 	Column() int
+	Move(move.Move) Position
 }
 
 type position struct {
@@ -25,3 +28,7 @@ func (p position) Row() int {
 func (p position) Column() int {
 	return p.column
 }
+
+func (p position) Move(move move.Move) Position {
+	return From(p.row+move.NumberOfRows(), p.column+move.NumberOfColumns())
+}

internal/position/position_test.go

@@ -3,6 +3,7 @@ package position_test
 import (
 	"testing"
 
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/move"
 	"github.com/StevanFreeborn/advent-of-code-2025/internal/position"
 )
 
@@ -20,3 +21,14 @@ func TestFrom(t *testing.T) {
 		t.Errorf("expected column to be %d, got %d", column, pos.Column())
 	}
 }
+
+func TestMove(t *testing.T) {
+	expectedPos := position.From(3, 4)
+	startPos := position.From(2, 4)
+
+	result := startPos.Move(move.Down)
+
+	if result != expectedPos {
+		t.Errorf("expected position to be %+v, got %+v", expectedPos, result)
+	}
+}

internal/queue/queue.go

@@ -0,0 +1,55 @@
+// Package queue provides a thread-safe FIFO queue implementation.
+package queue
+
+import "sync"
+
+type Queue[T any] interface {
+	Enqueue(item T)
+	Dequeue() (T, bool)
+	IsEmpty() bool
+	Size() int
+}
+
+type queue[T any] struct {
+	items []T
+	lock  sync.Mutex
+}
+
+func New[T any]() Queue[T] {
+	return &queue[T]{items: []T{}}
+}
+
+func (q *queue[T]) Enqueue(item T) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	q.items = append(q.items, item)
+}
+
+func (q *queue[T]) Dequeue() (T, bool) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	if len(q.items) == 0 {
+		var zero T
+		return zero, false
+	}
+
+	item := q.items[0]
+	q.items = q.items[1:]
+	return item, true
+}
+
+func (q *queue[T]) IsEmpty() bool {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	return len(q.items) == 0
+}
+
+func (q *queue[T]) Size() int {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	return len(q.items)
+}

internal/queue/queue_test.go

@@ -0,0 +1,87 @@
+package queue_test
+
+import (
+	"testing"
+
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/queue"
+)
+
+func TestQueue_EnqueueDequeue(t *testing.T) {
+	q := queue.New[int]()
+
+	q.Enqueue(1)
+	q.Enqueue(2)
+	q.Enqueue(3)
+
+	expectedValues := []int{1, 2, 3}
+
+	for _, expected := range expectedValues {
+		value, ok := q.Dequeue()
+
+		if !ok {
+			t.Errorf("expected dequeue to be successful, but it failed")
+		}
+
+		if value != expected {
+			t.Errorf("expected value to be %d, got %d", expected, value)
+		}
+
+	}
+
+	_, ok := q.Dequeue()
+
+	if ok {
+		t.Errorf("expected dequeue to fail on empty queue, but it succeeded")
+	}
+
+	if !q.IsEmpty() {
+		t.Errorf("expected queue to be empty, but it is not")
+	}
+}
+
+func TestQueue_Size(t *testing.T) {
+	q := queue.New[string]()
+
+	if q.Size() != 0 {
+		t.Errorf("expected size to be 0, got %d", q.Size())
+	}
+
+	q.Enqueue("a")
+	q.Enqueue("b")
+
+	if q.Size() != 2 {
+		t.Errorf("expected size to be 2, got %d", q.Size())
+	}
+
+	q.Dequeue()
+
+	if q.Size() != 1 {
+		t.Errorf("expected size to be 1, got %d", q.Size())
+	}
+}
+
+func TestQueue_ConcurrentAccess(t *testing.T) {
+	q := queue.New[int]()
+	done := make(chan bool)
+	numGoroutines := 100
+	numItemsPerGoroutine := 100
+
+	for i := range numGoroutines {
+		go func(start int) {
+			for j := range numItemsPerGoroutine {
+				q.Enqueue(start + j)
+			}
+			done <- true
+		}(i * numItemsPerGoroutine)
+	}
+
+	for range numGoroutines {
+		<-done
+	}
+
+	expectedSize := numGoroutines * numItemsPerGoroutine
+
+	if q.Size() != expectedSize {
+		t.Errorf("expected size to be %d, got %d", expectedSize, q.Size())
+	}
+}