import AppIntents
import Commanding
import Recording
import SwiftUI
import WidgetKit

/// The buttons controlling the recording flow through the App Intents the app executes, matching the current state: a pause
/// button while recording; discard, resume, and send buttons while paused; and only a discard button while the recorded input
/// is being processed.
struct RecordingControls: View {

    // MARK: Properties

    /// The dynamic content of the Live Activity to render.
    let state: RecordingActivityAttributes.ContentState

    // MARK: Body

    var body: some View {
        HStack(
            spacing: Constant.Spacing.stack
        ) {
            switch state.state {
            case .recording:
                pauseButton

            case .paused:
                discardButton
                recordButton
                processButton

            case .processing:
                discardButton
            }
        }
    }

}

// MARK: - Subviews

private extension RecordingControls {

    // MARK: Computed

    /// The discard button, shown while the recording is paused or being processed, that throws the recording away.
    var discardButton: some View {
        Button(intent: DiscardRecordingIntent()) {
            Image.Symbol.discard
                .resizable()
        }
        .buttonStyle(.action(
            type: .destructive
        ))
        .accessibilityLabel(Text("view.recording-controls.button.discard"))
    }

    /// The pause button, shown while recording, that pauses the ongoing recording.
    var pauseButton: some View {
        Button(intent: ToggleRecordingIntent()) {
            Image.Symbol.pause
                .resizable()
        }
        .buttonStyle(.action(
            type: .default
        ))
        .accessibilityLabel(Text("view.recording-controls.button.pause"))
    }

    /// The send button, shown while the recording is paused, that sends it for processing.
    var processButton: some View {
        Button(intent: ProcessRecordingIntent()) {
            Image.Symbol.send
                .resizable()
        }
        .buttonStyle(.action(
            type: .confirmative
        ))
        .accessibilityLabel(Text("view.recording-controls.button.send"))
    }

    /// The resume button, shown while the recording is paused, that resumes it.
    var recordButton: some View {
        Button(intent: ToggleRecordingIntent()) {
            Image.Symbol.microphone
                .resizable()
        }
        .buttonStyle(.action(
            type: .default
        ))
        .accessibilityLabel(Text("view.recording-controls.button.resume"))
    }

}

// MARK: - Constants

/// The constant values used across the recording Live Activity.
private enum Constant {
    /// The spacing constants.
    enum Spacing {
        /// The spacing between the elements of a stack.
        static let stack: CGFloat = 16
    }
}

// MARK: - Previews

#Preview(
    "Recording Controls view",
    as: .content,
    using: RecordingActivityAttributes()
) {
    RecordingLiveActivity()
} contentStates: {
    RecordingActivityAttributes.ContentState(
        state: .recording,
        anchor: .now,
        elapsed: 0
    )
    RecordingActivityAttributes.ContentState(
        state: .paused,
        anchor: nil,
        elapsed: 42
    )
    RecordingActivityAttributes.ContentState(
        state: .processing,
        anchor: nil,
        elapsed: 42
    )
}