//
//  RadialSegmentedRingView.swift
//  medmap
//
//  Created by RSA on 15/09/2026.
//

import SwiftUI

/// A single colored arc segment of a `RadialSegmentedRingView`.
struct RadialRingSegment: Identifiable {
	let id = UUID()
	let percentage: Double
	let color: Color
}

/// Renders a ring made of proportional colored arc segments, with a small gap between each segment.
struct RadialSegmentedRingView: View {

	let segments: [RadialRingSegment]
	var lineWidth: CGFloat = 6
	var gapDegrees: Double = 6

	private var total: Double {
		max(segments.reduce(0) { $0 + $1.percentage }, 0.0001)
	}

	var body: some View {
		ZStack {
			ForEach(Array(segments.enumerated()), id: \.element.id) { index, segment in
				let (start, end) = arcRange(for: index)
				Circle()
					.trim(from: start, to: end)
					.stroke(segment.color, style: StrokeStyle(lineWidth: lineWidth, lineCap: .round))
					.rotationEffect(.degrees(-90))
			}
		}
	}

	/// Computes the normalized (0...1) start/end trim values for the segment at `index`, leaving a small gap between segments.
	private func arcRange(for index: Int) -> (CGFloat, CGFloat) {
		let gapFraction = gapDegrees / 360
		var start = 0.0
		for i in 0..<index {
			start += segments[i].percentage / total
		}
		let length = segments[index].percentage / total
		let clampedGap = min(gapFraction, length / 2)
		return (CGFloat(start + clampedGap), CGFloat(start + length - clampedGap))
	}
}

#Preview {
	RadialSegmentedRingView(
		segments: [
			RadialRingSegment(percentage: 60, color: .green),
			RadialRingSegment(percentage: 25, color: .orange),
			RadialRingSegment(percentage: 15, color: .red)
		],
		lineWidth: 6
	)
	.frame(width: 92, height: 92)
	.padding(40)
}