IDs should always reflect position in file

projectlist.go

@@ -41,23 +41,27 @@ func (projectlist *ProjectList) Filter(predicate func(*Project) bool) *ProjectLi
 	return &newList
 }
 
+func (projectlist *ProjectList) GetNextId() int {
+	nextId := 0
+	for _, p := range projectlist.Projects {
+		if p.Id > nextId {
+			nextId = p.Id
+		}
+	}
+	return nextId + 1
+}
+
 // AddProject prepends a Project to the current ProjectList and takes care to set the ProjectId correctly
 func (projectlist *ProjectList) AddProject(project *Project) {
-	// The new project will be id 1
-	project.Id = 1
-	// All other projects get their id incremented
-	for _, p := range projectlist.Projects {
-		p.Id++
-	}
-	// Now prepend the project to the slice
-	projectlist.Projects = append(projectlist.Projects, &Project{})
-	copy(projectlist.Projects[1:], projectlist.Projects[0:])
-	projectlist.Projects[0] = project
+	project.Id = projectlist.GetNextId()
+	projectlist.Projects = append(projectlist.Projects, project)
 }
 
 // AddProjects adds all passed projects to the list
 func (projectlist *ProjectList) AddProjects(projects []*Project) {
-	projectlist.Projects = append(projectlist.Projects, projects...)
+	for _, v := range projects {
+		projectlist.AddProject(v)
+	}
 }
 func (projectlist *ProjectList) Combine(other *ProjectList) { projectlist.AddProjects(other.Projects) }
 
@@ -75,38 +79,38 @@ func (projectlist *ProjectList) GetProject(id int) (*Project, error) {
 // RemoveProjectById removes any Project with given Project 'id' from the ProjectList.
 // Returns an error if no Project was removed.
 func (projectlist *ProjectList) RemoveProjectById(id int) error {
-	var newList ProjectList
 	found := false
-	for _, p := range projectlist.Projects {
-		if p.Id != id {
-			newList.AddProject(p)
-		} else {
+	var remIdx int
+	var p *Project
+	for remIdx, p = range projectlist.Projects {
+		if p.Id == id {
 			found = true
+			break
 		}
 	}
 	if !found {
 		return errors.New("project not found")
 	}
-	*projectlist = newList
+	projectlist.Projects = append(projectlist.Projects[:remIdx], projectlist.Projects[remIdx+1:]...)
 	return nil
 }
 
 // RemoveProject removes any Project from the ProjectList with the same String representation as the given Project.
 // Returns an error if no Project was removed.
 func (projectlist *ProjectList) RemoveProject(project Project) error {
-	var newList ProjectList
 	found := false
-	for _, p := range projectlist.Projects {
-		if p.String() != project.String() {
-			newList.AddProject(p)
-		} else {
+	var remIdx int
+	var p *Project
+	for remIdx, p = range projectlist.Projects {
+		if p.String() == project.String() {
 			found = true
+			break
 		}
 	}
 	if !found {
 		return errors.New("project not found")
 	}
-	*projectlist = newList
+	projectlist.Projects = append(projectlist.Projects[:remIdx], projectlist.Projects[remIdx+1:]...)
 	return nil
 }
 
@@ -126,6 +130,14 @@ func (projectlist *ProjectList) ArchiveProjectToFile(project Project, filename s
 	return err
 }
 
+func (projectlist *ProjectList) ResetIds() {
+	projectId := 1
+	for _, v := range projectlist.Projects {
+		v.Id = projectId
+		projectId++
+	}
+}
+
 // LoadFromFile loads a ProjectList from *os.File.
 // Note: This will clear the current TimerList and overwrite it's contents with whatever is in *os.File.
 func (projectlist *ProjectList) LoadFromFile(file *os.File) error {
@@ -143,8 +155,8 @@ func (projectlist *ProjectList) LoadFromFile(file *os.File) error {
 			return err
 		}
 		project.Id = projectId
-		projectlist.AddProject(project)
 		projectId++
+		projectlist.Projects = append(projectlist.Projects, project)
 	}
 	if err := scanner.Err(); err != nil {
 		return err
@@ -157,8 +169,12 @@ func (projectlist *ProjectList) WriteToFile(file *os.File) error {
 	writer := bufio.NewWriter(file)
 	_, err := writer.WriteString(projectlist.String())
 	writer.Flush()
+	if err != nil {
 		return err
 	}
+	projectlist.ResetIds()
+	return nil
+}
 
 // LoadFromFilename loads a ProjectList from the filename.
 func (projectlist *ProjectList) LoadFromFilename(filename string) error {
@@ -172,7 +188,11 @@ func (projectlist *ProjectList) LoadFromFilename(filename string) error {
 
 // WriteToFilename writes a ProjectList to the specified file (most likely called "project.txt").
 func (projectlist *ProjectList) WriteToFilename(filename string) error {
-	return ioutil.WriteFile(filename, []byte(projectlist.String()), 0640)
+	if err := ioutil.WriteFile(filename, []byte(projectlist.String()), 0640); err != nil {
+		return err
+	}
+	projectlist.ResetIds()
+	return nil
 }
 
 // String returns a complete list of projects in project.txt format.