import SwiftUI

struct ActivityLogView: View {
    @Bindable var session: SessionState

    private static let timeFormatter: DateFormatter = {
        let fmt = DateFormatter()
        fmt.dateStyle = .none
        fmt.timeStyle = .medium
        return fmt
    }()

    var body: some View {
        ScrollViewReader { proxy in
            List(session.activityLog) { entry in
                HStack(alignment: .top, spacing: 8) {
                    Text(Self.timeFormatter.string(from: entry.timestamp))
                        .font(.caption2)
                        .foregroundStyle(.secondary)
                        .monospacedDigit()
                        .frame(width: 64, alignment: .leading)
                    Text(entry.text)
                        .font(.caption)
                }
                .id(entry.id)
                .listRowSeparator(.hidden)
                .accessibilityElement(children: .combine)
                .accessibilityLabel("\(Self.timeFormatter.string(from: entry.timestamp)): \(entry.text)")
            }
            .listStyle(.plain)
            .onChange(of: session.activityLog.count) { _, _ in
                if let last = session.activityLog.last {
                    proxy.scrollTo(last.id, anchor: .bottom)
                }
            }
        }
        .navigationTitle("Activity")
        .navigationBarTitleDisplayMode(.inline)
        .overlay {
            if session.activityLog.isEmpty {
                ContentUnavailableView(
                    "No Activity",
                    systemImage: "bell.slash",
                    description: Text("Events will appear here as they happen.")
                )
            }
        }
    }
}