Change how tasks are added and removed

1 files changed, 54 insertions, 41 deletions

diff --git a/main.go b/main.go
index bcfca7a..bf58df2 100644
--- a/main.go
+++ b/main.go
@@ -26,6 +26,8 @@ type InputLine struct {
 type TaskAddingJob struct {
 	Schedule cron.Schedule
 	Task     cron.Job
+	EntryID  cron.EntryID // this doesn't fit super well, but we'll figure that out soon I guess
+	Delete   bool
 }
 
 type Task struct {
@@ -39,7 +41,7 @@ func (t Task) Run() {
 	}
 }
 
-var lastSeenInput = map[InputLine]TaskAddingJob{}
+var jobsFromInput = map[InputLine]TaskAddingJob{}
 var todoistToken string
 var httpClient = http.Client{
 	Timeout: 10 * time.Second,
@@ -57,25 +59,36 @@ func main() {
 	log.Printf("Started watching '%s'", p)
 
 	c := cron.New()
+	c.Start()
 
 	for {
-		input, err := readInput(p)
+		err = readInput(p)
 		if err != nil {
 			log.Printf("Error reading input: %s", err)
 			continue
 		}
 
-		if inputChanged(lastSeenInput, input) {
-			log.Print("Updating task list")
-			lastSeenInput = input
-			c.Stop()
-			c := cron.New()
-			addJobs(c, input)
-			c.Start()
-			log.Print("Done updating task list")
+		for inputLine, taskAddingJob := range jobsFromInput {
+			if jobsFromInput[inputLine].EntryID == 0 {
+				taskAddingJob.EntryID = c.Schedule(
+					jobsFromInput[inputLine].Schedule,
+					jobsFromInput[inputLine].Task,
+				)
+				jobsFromInput[inputLine] = taskAddingJob
+
+				log.Printf(
+					"Added '%s' with recurrence '%s'",
+					inputLine.RawTask,
+					inputLine.RawSchedule,
+				)
+			} else if taskAddingJob.Delete {
+				c.Remove(taskAddingJob.EntryID)
+				delete(jobsFromInput, inputLine)
+				log.Printf("Removed '%s'", inputLine.RawTask)
+			}
 		}
 
-		time.Sleep(time.Minute) // re-read the input file every minute
+		time.Sleep(time.Minute)
 	}
 
 }
@@ -108,15 +121,19 @@ func inputFilePath() (string, error) {
 
 var inputFileRe = regexp.MustCompile(`([^\s]+\s+[^\s]+\s+[^\s]+\s+[^\s]+\s+[^\s]+)\s+(.*)`)
 
-func readInput(p string) (map[InputLine]TaskAddingJob, error) {
-	input := map[InputLine]TaskAddingJob{}
-
+func readInput(p string) error {
 	f, err := os.Open(p)
 	if err != nil {
-		return nil, fmt.Errorf("opening '%s': %w", p, err)
+		return fmt.Errorf("opening '%s': %w", p, err)
 	}
 	defer f.Close()
 
+	previousInput := map[InputLine]struct{}{}
+	for k := range jobsFromInput {
+		previousInput[k] = struct{}{}
+	}
+	currentInput := map[InputLine]struct{}{}
+
 	scanner := bufio.NewScanner(f)
 	for scanner.Scan() {
 		line := strings.TrimSpace(scanner.Text())
@@ -135,38 +152,41 @@ func readInput(p string) (map[InputLine]TaskAddingJob, error) {
 			RawTask:     matches[2],
 		}
 
+		currentInput[inputLine] = struct{}{}
+		if _, ok := previousInput[inputLine]; ok {
+			continue
+		}
+
 		schedule, err := cron.ParseStandard(inputLine.RawSchedule)
 		if err != nil {
-			log.Printf("Failed to add '%s' with recurrence '%s': %s", inputLine.RawTask, inputLine.RawSchedule, err)
+			log.Printf(
+				"Failed to add '%s' with recurrence '%s': %s",
+				inputLine.RawTask,
+				inputLine.RawSchedule,
+				err,
+			)
 			continue
 		}
-		job := Task{Name: inputLine.RawTask}
 
-		taskAddingJob := TaskAddingJob{
+		jobsFromInput[inputLine] = TaskAddingJob{
 			Schedule: schedule,
-			Task:     job,
+			Task:     Task{Name: inputLine.RawTask},
 		}
-
-		input[inputLine] = taskAddingJob
 	}
-
 	if err := scanner.Err(); err != nil {
-		return nil, fmt.Errorf("scanning: %w", err)
+		return fmt.Errorf("scanning: %w", err)
 	}
 
-	return input, nil
-}
-
-func inputChanged(old, new map[InputLine]TaskAddingJob) bool {
-	if len(new) != len(old) {
-		return true
-	}
-	for k := range old {
-		if _, ok := new[k]; !ok {
-			return true
+	// Mark stuff that we previously saw, but is now missing, for pruning.
+	for k := range previousInput {
+		if _, ok := currentInput[k]; !ok {
+			v := jobsFromInput[k]
+			v.Delete = true
+			jobsFromInput[k] = v
 		}
 	}
-	return false
+
+	return nil
 }
 
 func createTask(task string) error {
@@ -198,10 +218,3 @@ func createTask(task string) error {
 	log.Printf("Created task '%s'", task)
 	return nil
 }
-
-func addJobs(c *cron.Cron, tasks map[InputLine]TaskAddingJob) {
-	for _, task := range tasks {
-		_ = c.Schedule(task.Schedule, task.Task)
-	}
-	log.Printf("Added %d jobs", len(tasks))
-}