Add basic library code to manage projects, activities and times.

lib/projects.go

@@ -0,0 +1,142 @@
+package lib
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+)
+
+// Project entity. In addition to the JSON properties as defined by the specification, it holds activities of the
+// project organized by title and by ID in a map.
+type Project struct {
+	ID                string `json:"id"`
+	Title             string `json:"title"`
+	activitiesByTitle map[string]*Activity
+	activitiesByID    map[string]*Activity
+	activitiesLoaded  bool
+}
+
+// NewProject creates a new project instance.
+func NewProject() *Project {
+	return &Project{
+		activitiesByID:    make(map[string]*Activity),
+		activitiesByTitle: make(map[string]*Activity),
+	}
+}
+
+// GetProjects retrieves all stored project instances. It does not load related data like activities or times.
+func GetProjects() ([]*Project, error) {
+	folder, folderErr := getProjectFolder()
+	if folderErr != nil {
+		return nil, folderErr
+	}
+
+	dirErr := os.MkdirAll(folder, 0o750)
+	if dirErr != nil {
+		return nil, dirErr
+	}
+
+	files, filesErr := os.ReadDir(folder)
+	if filesErr != nil {
+		return nil, filesErr
+	}
+
+	projects := []*Project{}
+	for _, file := range files {
+		project, fileErr := readProject(filepath.Join(folder, file.Name()))
+		if fileErr != nil {
+			return nil, fileErr
+		}
+		projects = append(projects, project)
+	}
+
+	return projects, nil
+}
+
+// GetProject retrieves a single project by its ID. It does not load related data like activities or times.
+func GetProject(id string) (*Project, error) {
+	file, fileErr := getProjectFile(id)
+	if fileErr != nil {
+		return nil, fileErr
+	}
+	project, err := readProject(file)
+	if err != nil {
+		return nil, err
+	}
+
+	project.ID = id
+
+	return project, nil
+}
+
+// SetProject persists a project.
+func SetProject(project *Project) error {
+	uuid, uuidErr := newUUID()
+	if uuidErr != nil {
+		return uuidErr
+	}
+
+	project.ID = uuid
+
+	file, fileErr := getProjectFile(uuid)
+	if fileErr != nil {
+		return fileErr
+	}
+
+	return writeProject(file, project)
+}
+
+// readProject reads a project from a file and converts it into an entity instance.
+func readProject(filename string) (*Project, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	project := NewProject()
+	if err := json.NewDecoder(file).Decode(&project); err != nil {
+		return nil, err
+	}
+
+	return project, nil
+}
+
+// writeProject writes a project instance to a file.
+func writeProject(filename string, project *Project) error {
+	dirErr := os.MkdirAll(filepath.Dir(filename), 0o750)
+	if dirErr != nil {
+		return dirErr
+	}
+
+	file, fileErr := os.Create(filename)
+	if fileErr != nil {
+		return fileErr
+	}
+	defer file.Close()
+
+	encoder := json.NewEncoder(file)
+	encoder.SetIndent("", "    ")
+
+	jsonErr := encoder.Encode(project)
+	if jsonErr != nil {
+		return jsonErr
+	}
+
+	return nil
+}
+
+// getProjectFolder returns the folder to store project entity files in.
+func getProjectFolder() (string, error) {
+	return getDataDir("projects")
+}
+
+// getProjectFile returns the file name for a project entity instance.
+func getProjectFile(name string) (string, error) {
+	folder, err := getProjectFolder()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(folder, name+".json"), nil
+}