Detect dock position on the screen for sandboxed macOS apps

DockPosition.swift

import AppKit

struct DockInfo {
    let position: DockPosition
    let frame: CGRect
}

enum DockPosition {
    case bottom
    case left
    case right
    case hiddenOrUnknown
}

func detectDockInfo() -> DockInfo? {
    for screen in NSScreen.screens {
        let full = screen.frame
        let visible = screen.visibleFrame

        let deltaLeft = visible.minX - full.minX
        let deltaBottom = visible.minY - full.minY
        let deltaRight = full.maxX - visible.maxX
        let deltaTop = full.maxY - visible.maxY // menu bar

        // Assume menu bar is always at top, subtract that first
        let menuBarHeight = deltaTop

        if deltaBottom > 0 {
            let height = deltaBottom
            let frame = CGRect(x: full.minX, y: full.minY, width: full.width, height: height)
            return DockInfo(position: .bottom, frame: frame)
        } else if deltaLeft > 0 {
            let width = deltaLeft
            let frame = CGRect(x: full.minX, y: full.minY, width: width, height: full.height - menuBarHeight)
            return DockInfo(position: .left, frame: frame)
        } else if deltaRight > 0 {
            let width = deltaRight
            let frame = CGRect(x: full.maxX - width, y: full.minY, width: width, height: full.height - menuBarHeight)
            return DockInfo(position: .right, frame: frame)
        }
    }

    return nil
}