import AppKit
import Foundation
import Testing

@testable import phbar

@MainActor
struct AppDelegateTests {

	// MARK: - ScreenSync.diff

	@Test func diffReportsAddedWhenNothingOccupied() throws {
		let screen = try #require(NSScreen.main)
		let plan = PHScreenSync.diff(current: [screen], occupied: [])
		#expect(plan.added == [screen])
		#expect(plan.removed.isEmpty)
		#expect(plan.kept.isEmpty)
	}

	@Test func diffReportsRemovedWhenScreenGone() throws {
		let screen = try #require(NSScreen.main)
		let plan = PHScreenSync.diff(current: [], occupied: [screen])
		#expect(plan.removed == [screen])
		#expect(plan.added.isEmpty)
		#expect(plan.kept.isEmpty)
	}

	@Test func diffKeepsScreenStillAttached() throws {
		let screen = try #require(NSScreen.main)
		let plan = PHScreenSync.diff(current: [screen], occupied: [screen])
		#expect(plan.kept == [screen])
		#expect(plan.added.isEmpty)
		#expect(plan.removed.isEmpty)
	}

	/// A disconnected monitor reappears as a *new* `NSScreen` instance, so the
	/// same physical display must be reported as remove + add, never a keep.
	@Test func diffTreatsDistinctInstancesAsRemoveThenAdd() throws {
		let main = try #require(NSScreen.main)
		guard let other = NSScreen.screens.first(where: { $0 !== main }) else {
			// Single-monitor environment: nothing to contrast against. Verify
			// identity semantics hold for the same object re-presented instead.
			let kept = PHScreenSync.diff(current: [main], occupied: [main])
			#expect(kept.kept == [main])
			return
		}

		let plan = PHScreenSync.diff(current: [other], occupied: [main])
		#expect(plan.removed == [main])
		#expect(plan.added == [other])
		#expect(plan.kept.isEmpty)
	}

	@Test func diffIgnoresOrdering() throws {
		let main = try #require(NSScreen.main)
		guard let other = NSScreen.screens.first(where: { $0 !== main }) else {
			// Single-monitor environment: ordering is trivially stable.
			return
		}
		let plan = PHScreenSync.diff(current: [other, main], occupied: [main, other])
		#expect(Set(plan.kept.map(ObjectIdentifier.init)) == Set([main, other].map(ObjectIdentifier.init)))
		#expect(plan.added.isEmpty)
		#expect(plan.removed.isEmpty)
	}

	// MARK: - BarControllerFactory

	@Test func factoryBuildsControllerForScreen() throws {
		let screen = try #require(NSScreen.main)
		let config = try PHConfig.load()
		let factory = PHBarFactory(config: config, environment: .process, debug: false)

		let controller = try factory.make(for: screen)

		#expect(controller.screen === screen)
		#expect(controller.blocks.isEmpty == false)
	}
}