1 files changed, 65 insertions, 0 deletions
diff --git a/internal/timer/timer.go b/internal/timer/timer.go
new file mode 100644
index 0000000..3f2e3f5
--- /dev/null
+++ b/internal/timer/timer.go
@@ -0,0 +1,65 @@
+package timer
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+const (
+	stateFile = ".timr_state"
+)
+
+// stateFilePathOverride is used by tests to override the state file path.
+var stateFilePathOverride string
+
+type State struct {
+	StartTime    time.Time
+	ElapsedTime  time.Duration
+	Running      bool
+}
+
+func GetStateFile() (string, error) {
+	if stateFilePathOverride != "" {
+		return stateFilePathOverride, nil
+	}
+	configDir, err := os.UserConfigDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(configDir, "timr", stateFile), nil
+}
+
+func LoadState() (State, error) {
+	var state State
+	stateFilePath, err := GetStateFile()
+	if err != nil {
+		return state, err
+	}
+
+	data, err := os.ReadFile(stateFilePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return State{}, nil
+		}
+		return state, err
+	}
+
+	err = json.Unmarshal(data, &state)
+	return state, err
+}
+
+func (s *State) Save() error {
+	data, err := json.Marshal(s)
+	if err != nil {
+		return err
+	}
+
+	stateFilePath, err := GetStateFile()
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(stateFilePath, data, 0644)
+}