add missing tasks.go file

src/disposa.blue/margo/mg/tasks.go

@@ -0,0 +1,184 @@
+package mg
+
+import (
+	"bytes"
+	"fmt"
+	"sync"
+	"time"
+)
+
+type taskTick struct{ ActionType }
+
+type Task struct {
+	Title    string
+	Cancel   func()
+	CancelID string
+}
+
+type TaskTicket struct {
+	ID       string
+	Title    string
+	Start    time.Time
+	CancelID string
+
+	tracker *taskTracker
+	cancel  func()
+}
+
+func (ti *TaskTicket) Done() {
+	if ti.tracker != nil {
+		ti.tracker.done(ti.ID)
+	}
+}
+
+func (ti *TaskTicket) Cancel() {
+	if ti.cancel != nil {
+		ti.cancel()
+	}
+}
+
+func (ti *TaskTicket) Cancellable() bool {
+	return ti.cancel != nil
+}
+
+type taskTracker struct {
+	mu       sync.Mutex
+	id       uint64
+	tickets  []*TaskTicket
+	timer    *time.Timer
+	dispatch Dispatcher
+	buf      bytes.Buffer
+}
+
+func newTaskTracker(dispatch Dispatcher) *taskTracker {
+	return &taskTracker{
+		timer:    time.NewTimer(1 * time.Second),
+		dispatch: dispatch,
+	}
+}
+
+func (tr *taskTracker) Reduce(mx *Ctx) *State {
+	tr.mu.Lock()
+	defer tr.mu.Unlock()
+
+	switch mx.Action.(type) {
+	case Started:
+		tr.start()
+	case taskTick:
+		if len(tr.tickets) != 0 {
+			tr.resetTimer()
+		}
+	}
+	if s := tr.status(); s != "" {
+		return mx.AddStatus(s)
+	}
+	return mx.State
+}
+
+func (tr *taskTracker) status() string {
+	tr.buf.Reset()
+	now := time.Now()
+	tr.buf.WriteString("Tasks")
+	initLen := tr.buf.Len()
+	title := ""
+	for _, t := range tr.tickets {
+		age := now.Sub(t.Start) / time.Second
+		switch age {
+		case 0:
+		case 1:
+			tr.buf.WriteString(" ◔")
+		case 2:
+			tr.buf.WriteString(" ◑")
+		case 3:
+			tr.buf.WriteString(" ◕")
+		default:
+			tr.buf.WriteString(" ●")
+		}
+		if title == "" && t.Title != "" && age >= 1 && age <= 3 {
+			title = t.Title
+		}
+	}
+	if tr.buf.Len() == initLen {
+		return ""
+	}
+	if title != "" {
+		tr.buf.WriteByte(' ')
+		tr.buf.WriteString(title)
+	}
+	return tr.buf.String()
+}
+
+func (tr *taskTracker) titles() (stale []string, fresh []string) {
+	now := time.Now()
+	for _, t := range tr.tickets {
+		dur := now.Sub(t.Start)
+		switch {
+		case dur >= 5*time.Second:
+			stale = append(stale, t.Title)
+		case dur >= 1*time.Second:
+			fresh = append(fresh, t.Title)
+		}
+	}
+	for _, t := range tr.tickets {
+		dur := now.Sub(t.Start)
+		switch {
+		case dur >= 5*time.Second:
+			stale = append(stale, t.Title)
+		case dur >= 1*time.Second:
+			fresh = append(fresh, t.Title)
+		}
+	}
+	return stale, fresh
+}
+
+func (tr *taskTracker) start() {
+	go func() {
+		for range tr.timer.C {
+			tr.dispatch(taskTick{})
+		}
+	}()
+}
+
+func (tr *taskTracker) resetTimer() {
+	defer tr.timer.Reset(1 * time.Second)
+}
+
+func (tr *taskTracker) done(id string) {
+	tr.mu.Lock()
+	defer tr.mu.Unlock()
+	defer tr.resetTimer()
+
+	l := make([]*TaskTicket, 0, len(tr.tickets)-1)
+	for _, t := range tr.tickets {
+		if t.ID != id {
+			l = append(l, t)
+		}
+	}
+	tr.tickets = l
+}
+
+func (tr *taskTracker) Begin(o Task) *TaskTicket {
+	tr.mu.Lock()
+	defer tr.mu.Unlock()
+	defer tr.resetTimer()
+
+	if cid := o.CancelID; cid != "" {
+		for _, t := range tr.tickets {
+			if t.CancelID == cid {
+				t.Cancel()
+			}
+		}
+	}
+
+	tr.id++
+	t := &TaskTicket{
+		ID:       fmt.Sprintf("@%d", tr.id),
+		CancelID: o.CancelID,
+		Title:    o.Title,
+		Start:    time.Now(),
+		cancel:   o.Cancel,
+		tracker:  tr,
+	}
+	tr.tickets = append(tr.tickets, t)
+	return t
+}