Date & Time: components 051-058 (wip)

time_range_picker.go

@@ -0,0 +1,102 @@
+package mujica
+
+import (
+	"fmt"
+	"log/slog"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/theme"
+)
+
+// TimeRange is a start and an end time of day. End before Start means it ends the next day.
+type TimeRange struct {
+	Start, End TimeOfDay
+}
+
+// Overnight reports whether r crosses midnight.
+func (r TimeRange) Overnight() bool { return r.End.Compare(r.Start) < 0 }
+
+// TimeRangePickerOptions configure a TimeRangePicker.
+type TimeRangePickerOptions struct {
+	Seconds bool
+	Hour12  bool
+	// MinuteStep and SecondStep must divide 60; zero means 1.
+	MinuteStep, SecondStep int
+	// Min and Max bound both ends; a zero Max means 23:59:59.
+	Min, Max TimeOfDay
+	// AllowOvernight accepts an end before the start, meaning the next day.
+	AllowOvernight bool
+	Disabled       bool
+	// Label names the pair for assistive technology.
+	Label string
+}
+
+// TimeRangePicker edits a start and an end time. It writes *value only when both ends are valid
+// and the end follows the start, or crosses midnight with AllowOvernight.
+func TimeRangePicker(c *ui.Context, value *TimeRange, opts TimeRangePickerOptions) DateTimeResult {
+	cfg := timePickerConfig("TimeRangePicker", TimePickerOptions{Seconds: opts.Seconds, Hour12: opts.Hour12,
+		MinuteStep: opts.MinuteStep, SecondStep: opts.SecondStep, Min: opts.Min, Max: opts.Max})
+	if !value.Start.Valid() || !value.End.Valid() {
+		panic(fmt.Sprintf("mujica: TimeRangePicker value %v is not a pair of times", *value))
+	}
+	if value.Overnight() && !opts.AllowOvernight {
+		panic(fmt.Sprintf("mujica: TimeRangePicker value %v crosses midnight without AllowOvernight", *value))
+	}
+	k := Tokens(c)
+	d := Density(c)
+	col := ui.Column(c).Gap(d.Unit()).AlignItems(ui.Start).Disabled(opts.Disabled).Role(ui.RoleGroup)
+	if opts.Label != "" {
+		col.Label(opts.Label)
+	}
+	draft := ui.Local(col, "time-range-draft", func() TimeRange { return *value })
+	seen := ui.Local(col, "time-range-seen", func() TimeRange { return *value })
+	problem := ui.Local(col, "time-range-error", func() string { return "" })
+	if *seen != *value {
+		*draft, *seen, *problem = *value, *value, ""
+	}
+	changed := false
+	col.Children(func() {
+		edited := false
+		ui.Row(c).Gap(d.Unit() * 2).AlignItems(ui.Center).Children(func() {
+			start, end := cfg, cfg
+			start.label, end.label = msg(c, "time_range_picker.start"), msg(c, "time_range_picker.end")
+			start.invalid, end.invalid = *problem != "", *problem != ""
+			if _, e := timeEditor(c, &draft.Start, start); e {
+				edited = true
+			}
+			ui.Text(c, "–").TextColor(k.TextMuted).Role(ui.RoleNone)
+			if _, e := timeEditor(c, &draft.End, end); e {
+				edited = true
+			}
+			if draft.Overnight() && opts.AllowOvernight {
+				ui.Text(c, msg(c, "time_range_picker.next_day")).FontSize(theme.CaptionSize).TextColor(k.AccentText)
+			}
+		})
+		if edited {
+			*problem = timeRangeProblem(c, *draft, cfg, opts.AllowOvernight)
+			if *problem == "" && *draft != *value {
+				slog.Debug("mujica: time_range_picker change", "from", *value, "to", *draft)
+				*value, *seen, changed = *draft, *draft, true
+			}
+		}
+		datetimeError(c, *problem)
+	})
+	return DateTimeResult{Element: col, changed: changed}
+}
+
+// timeRangeProblem explains why r cannot be written, or returns "".
+func timeRangeProblem(c *ui.Context, r TimeRange, cfg timeConfig, overnight bool) string {
+	for _, t := range []TimeOfDay{r.Start, r.End} {
+		if p := timePickerProblem(c, t, cfg); p != "" {
+			return p
+		}
+	}
+	switch {
+	case r.Start == r.End:
+		return msg(c, "time_range_picker.same")
+	case r.Overnight() && !overnight:
+		return msg(c, "time_range_picker.order")
+	}
+	return ""
+}