import ActivityKit
import WidgetKit
import SwiftUI

@available(iOS 16.1, *)
struct TaskLiveActivity: Widget {
    private let accent = WidgetTheme.accent // brand orange

    var body: some WidgetConfiguration {
        ActivityConfiguration(for: TaskActivityAttributes.self) { context in
            // ── Lock screen / banner ──
            HStack(spacing: 12) {
                Image(systemName: context.state.isComplete ? "checkmark.circle.fill" : "hourglass")
                    .font(.system(size: 20))
                    .foregroundColor(context.state.isComplete ? .green : accent)
                    .frame(width: 24)
                VStack(alignment: .leading, spacing: 2) {
                    Text(context.attributes.title)
                        .font(.system(.body, design: .monospaced))
                        .foregroundColor(.white)
                        .lineLimit(1)
                        .minimumScaleFactor(0.8)
                        .strikethrough(context.state.isComplete)
                    if let due = context.state.dueDate {
                        Text(due, style: context.state.isComplete ? .date : .relative)
                            .font(.system(.caption, design: .monospaced))
                            .foregroundColor(.white.opacity(0.6))
                            .lineLimit(1)
                    }
                }
                .layoutPriority(1)

                if let due = context.state.dueDate, !context.state.isComplete {
                    Text(due, style: .timer)
                        .font(.system(.callout, design: .monospaced))
                        .monospacedDigit()
                        .foregroundColor(accent)
                        .lineLimit(1)
                        .minimumScaleFactor(0.72)
                        .frame(width: 92, alignment: .trailing)
                        .fixedSize(horizontal: false, vertical: true)
                }

                // Explicit stop control — a Live Activity can't be prevented
                // from being swiped away by the system, so this gives an
                // intentional, in-card way to end tracking instead.
                if #available(iOS 17.0, *), !context.state.isComplete {
                    Button(intent: StopCountdownIntent(taskID: context.attributes.taskID)) {
                        Image(systemName: "xmark.circle.fill")
                            .font(.system(size: 18))
                            .foregroundColor(.white.opacity(0.5))
                    }
                    .buttonStyle(.plain)
                }
            }
            .padding(.leading, 14)
            .padding(.trailing, 10)
            .padding(.vertical, 12)
            .activityBackgroundTint(WidgetTheme.background.opacity(0.9))
            .activitySystemActionForegroundColor(.white)

        } dynamicIsland: { context in
            DynamicIsland {
                DynamicIslandExpandedRegion(.leading) {
                    Image(systemName: "checklist")
                        .foregroundColor(accent)
                }
                DynamicIslandExpandedRegion(.trailing) {
                    if let due = context.state.dueDate, !context.state.isComplete {
                        Text(due, style: .timer)
                            .font(.system(.callout, design: .monospaced))
                            .monospacedDigit()
                            .foregroundColor(accent)
                            .lineLimit(1)
                            .minimumScaleFactor(0.75)
                            .frame(width: 86, alignment: .trailing)
                    }
                }
                DynamicIslandExpandedRegion(.center) {
                    Text(context.attributes.title)
                        .font(.system(.callout, design: .monospaced))
                        .lineLimit(1)
                }
                DynamicIslandExpandedRegion(.bottom) {
                    if #available(iOS 17.0, *), !context.state.isComplete {
                        Button(intent: StopCountdownIntent(taskID: context.attributes.taskID)) {
                            Label("Stop Countdown", systemImage: "xmark.circle")
                                .font(.system(.caption, design: .monospaced))
                        }
                        .buttonStyle(.plain)
                        .tint(accent)
                    }
                }
            } compactLeading: {
                Image(systemName: "checklist").foregroundColor(accent)
            } compactTrailing: {
                if let due = context.state.dueDate, !context.state.isComplete {
                    Text(due, style: .timer)
                        .font(.system(.caption2, design: .monospaced))
                        .monospacedDigit()
                        .foregroundColor(accent)
                        .lineLimit(1)
                        .minimumScaleFactor(0.7)
                        .frame(width: 48, alignment: .trailing)
                }
            } minimal: {
                Image(systemName: "checklist").foregroundColor(accent)
            }
        }
    }
}