import AppKit
import SwiftUI

@MainActor
final class OverlayPanelController {
  private let panel: NSPanel

  init(model: AppModel) {
    panel = NSPanel(
      contentRect: NSRect(x: 0, y: 0, width: 304, height: 82),
      styleMask: [.borderless, .nonactivatingPanel],
      backing: .buffered,
      defer: false
    )
    panel.level = .floating
    panel.isOpaque = false
    panel.backgroundColor = .clear
    panel.hasShadow = true
    panel.hidesOnDeactivate = false
    panel.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary, .stationary]
    panel.contentView = NSHostingView(rootView: RecordingOverlay(model: model))
  }

  func show() {
    positionPanel()
    panel.orderFrontRegardless()
  }

  func hide() {
    panel.orderOut(nil)
  }

  private func positionPanel() {
    let mouse = NSEvent.mouseLocation
    let screen = NSScreen.screens.first { NSMouseInRect(mouse, $0.frame, false) } ?? NSScreen.main
    guard let frame = screen?.visibleFrame else { return }
    let x = frame.midX - panel.frame.width / 2
    let y = frame.minY + 42
    panel.setFrameOrigin(NSPoint(x: x, y: y))
  }
}

private struct RecordingOverlay: View {
  @ObservedObject var model: AppModel
  private let teal = Color(red: 0.039, green: 0.624, blue: 0.604)

  var body: some View {
    HStack(spacing: 14) {
      signal
        .frame(width: 46, height: 34)
      VStack(alignment: .leading, spacing: 3) {
        Text(title)
          .font(.system(size: 13, weight: .semibold))
        Text(detail)
          .font(.system(size: 12, design: .monospaced))
          .foregroundStyle(.secondary)
          .lineLimit(1)
      }
      Spacer(minLength: 6)
      if model.isRecording {
        Button(action: model.toggleRecording) {
          Image(systemName: "stop.fill")
            .font(.system(size: 11, weight: .bold))
            .frame(width: 28, height: 28)
        }
        .buttonStyle(.borderedProminent)
        .tint(teal)
        .clipShape(Circle())
        .help("Stop and transcribe")
      }
    }
    .padding(.horizontal, 17)
    .frame(width: 304, height: 82)
    .background(.ultraThickMaterial, in: RoundedRectangle(cornerRadius: 19, style: .continuous))
    .overlay {
      RoundedRectangle(cornerRadius: 19, style: .continuous)
        .strokeBorder(.white.opacity(0.13))
    }
  }

  @ViewBuilder
  private var signal: some View {
    switch model.state {
    case .recording:
      HStack(alignment: .center, spacing: 3) {
        ForEach(0..<5, id: \.self) { index in
          Capsule()
            .fill(teal)
            .frame(width: 4, height: barHeight(index))
        }
      }
    case .preparing, .transcribing:
      ProgressView().controlSize(.small).tint(teal)
    case .success:
      Image(systemName: "checkmark.circle.fill").font(.title2).foregroundStyle(teal)
    case .failure:
      Image(systemName: "exclamationmark.triangle.fill").font(.title3).foregroundStyle(.red)
    case .idle:
      Image(systemName: "waveform").foregroundStyle(teal)
    }
  }

  private var title: String {
    switch model.state {
    case .preparing: "Starting microphone"
    case .recording: "Recording"
    case .transcribing: "Transcribing"
    case .success(let message), .failure(let message): message
    case .idle: "Ready"
    }
  }

  private var detail: String {
    switch model.state {
    case .recording: Self.duration(model.elapsed)
    case .preparing: "Waiting for permission"
    case .transcribing: "Sending audio"
    case .failure: "Open Transui settings to fix this"
    case .success: "Done"
    case .idle: model.settings.shortcut.displayName
    }
  }

  private func barHeight(_ index: Int) -> CGFloat {
    let shape = [0.55, 0.82, 1.0, 0.72, 0.45][index]
    return 7 + 24 * max(0.08, model.level * shape)
  }

  private static func duration(_ interval: TimeInterval) -> String {
    let seconds = Int(interval)
    return String(format: "%02d:%02d", seconds / 60, seconds % 60)
  }
}