import CoreGraphics
import XCTest
@testable import OrcaComputerUseMacOSCore

final class BackgroundInputTransportTests: XCTestCase {
    private let target = BackgroundInputTransport.Target(
        pid: 4242,
        windowID: 9001,
        windowFrame: CGRect(x: 300, y: 200, width: 520, height: 560)
    )

    func testMouseEventsNameTheWindowAndCarryAWindowLocalLocation() throws {
        try XCTSkipUnless(BackgroundInputTransport.isAvailable, "private symbols missing: \(BackgroundInputTransport.missingSymbols)")
        let point = CGPoint(x: 340, y: 275)
        for type in [CGEventType.leftMouseDown, .rightMouseUp, .otherMouseDown, .leftMouseDragged] {
            let event = try BackgroundInputTransport.mouseEvent(type, target: target, at: point, button: .left, clickState: 2, flags: .maskCommand)
            XCTAssertEqual(event.getIntegerValueField(CGEventField(rawValue: 51)!), 9001, "\(type)")
            XCTAssertEqual(try windowLocation(of: event), CGPoint(x: 40, y: 75), "\(type)")
            XCTAssertEqual(event.location, point)
            XCTAssertEqual(event.getIntegerValueField(.mouseEventClickState), 2)
            XCTAssertTrue(event.flags.contains(.maskCommand))
        }
    }



    func testTypedTextRidesTheKeyDownOnly() throws {
        let bareKeyUp = try XCTUnwrap(CGEvent(keyboardEventSource: nil, virtualKey: 0, keyDown: false))
        for (text, characters) in [("hé", ["h", "é"]), ("🚀e\u{301}👩‍💻", ["🚀", "e\u{301}", "👩‍💻"])] {
            let events = try BackgroundInputTransport.textEvents(text)
            XCTAssertEqual(events.map { $0.type }, characters.flatMap { _ in [CGEventType.keyDown, .keyUp] })
            XCTAssertEqual(events.filter { $0.type == .keyDown }.map(unicodeString), characters)
            // Why: an unset payload reads back as the keyboard layout's translation of key code 0.
            for event in events where event.type == .keyUp {
                XCTAssertEqual(unicodeString(event), unicodeString(bareKeyUp))
            }
        }
    }

    private func windowLocation(of event: CGEvent) throws -> CGPoint {
        let skyLight = dlopen("/System/Library/PrivateFrameworks/SkyLight.framework/SkyLight", RTLD_LAZY)
        let symbol = try XCTUnwrap(dlsym(skyLight, "CGEventGetWindowLocation"))
        typealias GetWindowLocation = @convention(c) (CGEvent) -> CGPoint
        // SAFETY: CGEventGetWindowLocation takes a CGEventRef and returns a CGPoint.
        return unsafeBitCast(symbol, to: GetWindowLocation.self)(event)
    }

    private func unicodeString(_ event: CGEvent) -> String {
        var length = 0
        var buffer = [UniChar](repeating: 0, count: 8)
        event.keyboardGetUnicodeString(maxStringLength: buffer.count, actualStringLength: &length, unicodeString: &buffer)
        return String(utf16CodeUnits: buffer, count: length)
    }
}