refactored and added game save function (key: s)

grid.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type Grid struct {
+	Data          [][]int
+	Width, Height int
+}
+
+func GetFilename(generations int64) string {
+	now := time.Now()
+	return fmt.Sprintf("dump-%s-%d.gol", now.Format("20060102150405"), generations)
+}
+
+func (grid *Grid) SaveState(filename string) error {
+	file, err := os.Create(filename)
+	if err != nil {
+		return fmt.Errorf("failed to open state file: %w", err)
+	}
+	defer file.Close()
+
+	for y, _ := range grid.Data {
+		for _, cell := range grid.Data[y] {
+			_, err := file.WriteString(strconv.Itoa(cell))
+			if err != nil {
+				return fmt.Errorf("failed to write to state file: %w", err)
+			}
+		}
+		file.WriteString("\n")
+	}
+
+	return nil
+}
+
+func LoadState(filename string) (*Grid, error) {
+	fd, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	scanner := bufio.NewScanner(fd)
+
+	scanner.Split(bufio.ScanLines)
+
+	grid := &Grid{}
+
+	for scanner.Scan() {
+		items := strings.Split(scanner.Text(), "")
+		row := make([]int, len(items))
+
+		for idx, item := range items {
+			num, err := strconv.Atoi(item)
+			if err != nil {
+				return nil, err
+			}
+
+			if num > 1 {
+				return nil, errors.New("cells must be 0 or 1")
+			}
+
+			row[idx] = num
+		}
+
+		grid.Data = append(grid.Data, row)
+	}
+
+	// sanity check the grid
+	explen := 0
+	rows := 0
+	first := false
+	for _, row := range grid.Data {
+		length := len(row)
+
+		if first {
+			explen = length
+		}
+
+		if explen != length {
+			return nil, errors.New("all rows must be in the same length")
+		}
+
+		rows++
+	}
+
+	grid.Width = explen
+	grid.Height = rows
+
+	return grid, nil
+}