Add custom type to allow to calculate Elapsed time of the day. (#2)

clock.go

@@ -11,6 +11,9 @@ func init() {
 	Restore()
 }
 
+// Day represents full day.
+const Day = 24 * time.Hour
+
 // Clock represents a global clock.
 var Clock clock.Clock
 

elapsed.go

@@ -0,0 +1,47 @@
+package clock
+
+import (
+	"math"
+	"time"
+)
+
+// DayElapsed elapsed time during a day
+type DayElapsed time.Duration
+
+// NewDayElapsed creates new DayElapsed from passed time.
+func NewDayElapsed(current time.Time, shift time.Duration) DayElapsed {
+	current = current.UTC()
+	midnight := current.Truncate(Day)
+	resetTimeForCurrentDay := midnight.Add(shift)
+
+	if current.Before(resetTimeForCurrentDay) {
+		resetTimeForCurrentDay = resetTimeForCurrentDay.Add(-Day) // if we are before reset time, it means reset time was yesterday
+	}
+
+	sub := current.Sub(resetTimeForCurrentDay)
+	return DayElapsed(sub)
+}
+
+// FullHours get full hours of current day
+func (e DayElapsed) FullHours() int {
+	return int(math.Floor(e.hours()))
+}
+
+// HourPart elapsed time of current hour (percentage)
+func (e DayElapsed) HourPart() float64 {
+	_, f := math.Modf(e.hours())
+	return f
+}
+
+// Remaining returns remaining time of the day
+func (e DayElapsed) Remaining() time.Duration {
+	remaining := Day - time.Duration(e)
+	if remaining < 0 {
+		remaining = 0
+	}
+	return remaining
+}
+
+func (e DayElapsed) hours() float64 {
+	return time.Duration(e).Hours()
+}

elapsed_test.go

@@ -0,0 +1,171 @@
+package clock_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/msales/go-clock"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDayElapsed_FullHours_and_HourPart(t *testing.T) {
+	tests := []struct {
+		name          string
+		dayElapsed    clock.DayElapsed
+		wantFullHour  int
+		wantHourPart  float64
+		wantRemaining time.Duration
+	}{
+		{
+			name:          "midnight",
+			dayElapsed:    clock.DayElapsed(time.Duration(0)),
+			wantFullHour:  0,
+			wantHourPart:  0.0,
+			wantRemaining: clock.Day,
+		},
+		{
+			name:          "00:30",
+			dayElapsed:    clock.DayElapsed(30 * time.Minute),
+			wantFullHour:  0,
+			wantHourPart:  0.5,
+			wantRemaining: 23*time.Hour + 30*time.Minute,
+		},
+		{
+			name:          "01:00",
+			dayElapsed:    clock.DayElapsed(60 * time.Minute),
+			wantFullHour:  1,
+			wantHourPart:  0.0,
+			wantRemaining: 23 * time.Hour,
+		},
+		{
+			name:          "01:30",
+			dayElapsed:    clock.DayElapsed(90 * time.Minute),
+			wantFullHour:  1,
+			wantHourPart:  0.5,
+			wantRemaining: 22*time.Hour + 30*time.Minute,
+		},
+		{
+			name:          "22:59",
+			dayElapsed:    clock.DayElapsed(1379 * time.Minute),
+			wantFullHour:  22,
+			wantHourPart:  0.9833333333,
+			wantRemaining: 1*time.Hour + 1*time.Minute,
+		},
+		{
+			name:          "23:59",
+			dayElapsed:    clock.DayElapsed(1439 * time.Minute),
+			wantFullHour:  23,
+			wantHourPart:  0.9833333333,
+			wantRemaining: 1 * time.Minute,
+		},
+		{
+			name:          "16:37",
+			dayElapsed:    clock.DayElapsed(997 * time.Minute),
+			wantFullHour:  16,
+			wantHourPart:  0.6166666667,
+			wantRemaining: 7*time.Hour + 23*time.Minute,
+		},
+		{
+			name:          "25:30 overdue",
+			dayElapsed:    clock.DayElapsed(25*time.Hour + 30*time.Minute),
+			wantFullHour:  25,
+			wantHourPart:  0.5,
+			wantRemaining: 0,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotFullHours := tt.dayElapsed.FullHours()
+			gotHourPart := tt.dayElapsed.HourPart()
+			gotRemaining := tt.dayElapsed.Remaining()
+			assert.Equal(t, tt.wantFullHour, gotFullHours)
+			assert.InDelta(t, tt.wantHourPart, gotHourPart, 0.00001)
+			assert.Equal(t, tt.wantRemaining, gotRemaining)
+		})
+	}
+}
+
+func TestNewDayElapsed(t *testing.T) {
+	tests := []struct {
+		name          string
+		current       time.Time
+		shift         time.Duration
+		wantElapsed   clock.DayElapsed
+		wantRemaining time.Duration
+		wantFullHours int
+		wantHourPart  float64
+	}{
+		{
+			name:          "Reset time on midnight",
+			current:       time.Date(2021, 3, 15, 15, 59, 30, 0, time.UTC),
+			shift:         0, // UTC midnight
+			wantElapsed:   clock.DayElapsed(15*time.Hour + 59*time.Minute + 30*time.Second),
+			wantRemaining: 8*time.Hour + 30*time.Second,
+			wantFullHours: 15,
+			wantHourPart:  0.9916666667,
+		},
+		{
+			name:          "Reset time on midnight at midnight",
+			current:       time.Date(2021, 3, 15, 0, 0, 0, 0, time.UTC),
+			shift:         0, // UTC midnight
+			wantElapsed:   clock.DayElapsed(0),
+			wantRemaining: clock.Day,
+			wantFullHours: 0,
+			wantHourPart:  0,
+		},
+		{
+			name:          "Reset time at 13:20, current time at 13:20",
+			current:       time.Date(2021, 3, 15, 13, 20, 0, 0, time.UTC),
+			shift:         13*time.Hour + 20*time.Minute,
+			wantElapsed:   clock.DayElapsed(0),
+			wantRemaining: clock.Day,
+			wantFullHours: 0,
+			wantHourPart:  0,
+		},
+		{
+			name:          "Reset time at 16:00 UTC, current at 15:59:30",
+			current:       time.Date(2021, 3, 15, 15, 59, 30, 0, time.UTC),
+			shift:         16 * time.Hour,
+			wantElapsed:   clock.DayElapsed(23*time.Hour + 59*time.Minute + 30*time.Second),
+			wantRemaining: 30 * time.Second,
+			wantFullHours: 23,
+			wantHourPart:  0.9916666667,
+		},
+		{
+			name:          "Reset time at 15:00 UTC, current at 15:59:30",
+			current:       time.Date(2021, 3, 15, 15, 59, 30, 0, time.UTC),
+			shift:         15 * time.Hour,
+			wantElapsed:   clock.DayElapsed(59*time.Minute + 30*time.Second),
+			wantRemaining: 23*time.Hour + 30*time.Second,
+			wantFullHours: 0,
+			wantHourPart:  0.9916666667,
+		},
+		{
+			name:          "Reset time at 16:00 UTC, current at 15:59:30 UTC+1",
+			current:       time.Date(2021, 3, 15, 15, 59, 30, 0, time.FixedZone("UTC1", 3600)),
+			shift:         16 * time.Hour,
+			wantElapsed:   clock.DayElapsed(22*time.Hour + 59*time.Minute + 30*time.Second),
+			wantRemaining: 1*time.Hour + 30*time.Second,
+			wantFullHours: 22,
+			wantHourPart:  0.9916666667,
+		},
+		{
+			name:          "Reset time at 23:00 UTC, current at 00:00:00 UTC+1",
+			current:       time.Date(2021, 3, 15, 0, 0, 0, 0, time.FixedZone("UTC1", 3600)),
+			shift:         23 * time.Hour,
+			wantElapsed:   clock.DayElapsed(0),
+			wantRemaining: clock.Day,
+			wantFullHours: 0,
+			wantHourPart:  0,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			elapsed := clock.NewDayElapsed(tt.current, tt.shift)
+			assert.Equal(t, tt.wantElapsed, elapsed)
+			assert.Equal(t, tt.wantRemaining, elapsed.Remaining())
+			assert.Equal(t, tt.wantFullHours, elapsed.FullHours())
+			assert.InDelta(t, tt.wantHourPart, elapsed.HourPart(), 0.0001)
+		})
+	}
+}