Sleep

A night reads as a shape before it reads as data: each stage is a solid block in its own lane (Awake, REM, Light, Deep), joined to the next by a hairline step, drawn in from the left whenever the night changes. Drag anywhere on the chart and a scrubber follows your finger with a chip reading the stage and time under it, a haptic as it crosses into another stage, and the stage totals below lighting up with it. Swipe the time asleep, or tap a night in the strip, to move through the week.

Notes

• Map your samples to [SleepSegment] per night, in order and without gaps, and pass them to SleepTimeline(segments:). HealthKit's sleep analysis samples map one to one.
• Bind scrub to read the time under the finger elsewhere. The array helpers sleepStageTotals, sleepAsleep, sleepInBed, sleepEfficiency and sleepSegment(at:) do the arithmetic the screen shows.
• Colours come in as fills and inks by stage, so the chart is painted in your theme's blocks. The example uses four scheme blocks and the family's numerals for every figure.
• VoiceOver reads the night as one summary and steps through the segments with swipe up and down ("REM, 3:42 AM to 4:10 AM"). At accessibility text sizes the lane labels give their width back to the chart.
• Reduce Motion swaps the left-to-right draw for a fade.
• The example ships loading, no ring data and error states as previews; each empty state has one action.
• SleepTimelineExample at the end of SleepTimeline.swift is the screen shown in the preview; copy it as a starting point.