import SwiftUI

/// A small horizontal audio level meter. `level` is a peak amplitude (0…1);
/// it's mapped to a dBFS scale (−60 dB … 0 dB) so normal speech is clearly visible.
struct LevelBar: View {
    let label: String
    let level: Float

    var body: some View {
        HStack(spacing: 8) {
            Text(label)
                .font(.caption2)
                .foregroundStyle(.secondary)
                .frame(width: 48, alignment: .leading)
            GeometryReader { geo in
                ZStack(alignment: .leading) {
                    RoundedRectangle(cornerRadius: 2).fill(Color.secondary.opacity(0.2))
                    RoundedRectangle(cornerRadius: 2)
                        .fill(color)
                        .frame(width: geo.size.width * fraction)
                }
            }
            .frame(height: 6)
        }
    }

    private var fraction: CGFloat {
        guard level > 0 else { return 0 }
        let db = 20 * log10(Double(level))          // −∞ … 0
        return CGFloat(min(1, max(0, (db + 60) / 60)))
    }

    private var color: Color {
        if fraction < 0.02 { return .gray }
        if fraction > 0.9 { return .red }
        return .green
    }
}