//
//  NetworkMonitorTests.swift
//  PlantGuideTests
//
//  Unit tests for NetworkMonitor - the network connectivity monitoring service
//  that tracks network status and connection type changes.
//

import XCTest
import Network
@testable import PlantGuide

// MARK: - NetworkMonitorTests

final class NetworkMonitorTests: XCTestCase {

    // MARK: - Properties

    private var sut: NetworkMonitor!

    // MARK: - Test Lifecycle

    override func setUp() {
        super.setUp()
        sut = NetworkMonitor()
    }

    override func tearDown() {
        sut?.stopMonitoring()
        sut = nil
        super.tearDown()
    }

    // MARK: - Initialization Tests

    func testInit_CreatesMonitor() {
        XCTAssertNotNil(sut)
    }

    func testInit_StartsMonitoringAutomatically() {
        // NetworkMonitor starts monitoring in init
        // Just verify it doesn't crash and is created
        XCTAssertNotNil(sut)
    }

    // MARK: - Connection Status Tests

    func testIsConnected_InitialValue_IsBool() {
        // Just verify the property is accessible and is a boolean
        let isConnected = sut.isConnected
        XCTAssertTrue(isConnected || !isConnected) // Always true - just checks type
    }

    func testConnectionType_InitialValue_IsConnectionType() {
        // Verify the property is accessible and has a valid value
        let connectionType = sut.connectionType
        let validTypes: [ConnectionType] = [.wifi, .cellular, .ethernet, .unknown]
        XCTAssertTrue(validTypes.contains(connectionType))
    }

    // MARK: - Start/Stop Monitoring Tests

    func testStartMonitoring_WhenAlreadyStarted_DoesNotCrash() {
        // Given - Already started in init

        // When - Start again
        sut.startMonitoring()

        // Then - Should not crash
        XCTAssertNotNil(sut)
    }

    func testStopMonitoring_WhenMonitoring_StopsSuccessfully() {
        // Given - Already started in init

        // When
        sut.stopMonitoring()

        // Then - Should not crash
        XCTAssertNotNil(sut)
    }

    func testStopMonitoring_WhenAlreadyStopped_DoesNotCrash() {
        // Given
        sut.stopMonitoring()

        // When - Stop again
        sut.stopMonitoring()

        // Then - Should not crash
        XCTAssertNotNil(sut)
    }

    func testStartMonitoring_AfterStop_RestartsSuccessfully() {
        // Given
        sut.stopMonitoring()

        // When
        sut.startMonitoring()

        // Then - Should not crash
        XCTAssertNotNil(sut)
    }

    // MARK: - ConnectionType Tests

    func testConnectionType_WiFi_HasCorrectRawValue() {
        XCTAssertEqual(ConnectionType.wifi.rawValue, "wifi")
    }

    func testConnectionType_Cellular_HasCorrectRawValue() {
        XCTAssertEqual(ConnectionType.cellular.rawValue, "cellular")
    }

    func testConnectionType_Ethernet_HasCorrectRawValue() {
        XCTAssertEqual(ConnectionType.ethernet.rawValue, "ethernet")
    }

    func testConnectionType_Unknown_HasCorrectRawValue() {
        XCTAssertEqual(ConnectionType.unknown.rawValue, "unknown")
    }

    // MARK: - Thread Safety Tests

    func testConcurrentAccess_DoesNotCrash() {
        // Given
        let expectation = XCTestExpectation(description: "Concurrent access completes")
        expectation.expectedFulfillmentCount = 100

        // When - Access from multiple threads
        for _ in 0..<100 {
            DispatchQueue.global().async {
                _ = self.sut.isConnected
                _ = self.sut.connectionType
                expectation.fulfill()
            }
        }

        // Then
        wait(for: [expectation], timeout: 5.0)
    }

    func testConcurrentStartStop_DoesNotCrash() {
        // Given
        let expectation = XCTestExpectation(description: "Concurrent start/stop completes")
        expectation.expectedFulfillmentCount = 20

        // When - Start and stop from multiple threads
        for i in 0..<20 {
            DispatchQueue.global().async {
                if i % 2 == 0 {
                    self.sut.startMonitoring()
                } else {
                    self.sut.stopMonitoring()
                }
                expectation.fulfill()
            }
        }

        // Then
        wait(for: [expectation], timeout: 5.0)
    }

    // MARK: - Lifecycle Tests

    func testDeinit_StopsMonitoring() {
        // Given
        var monitor: NetworkMonitor? = NetworkMonitor()
        XCTAssertNotNil(monitor)

        // When
        monitor = nil

        // Then - Should not crash (deinit calls stopMonitoring)
        XCTAssertNil(monitor)
    }

    func testMultipleInstances_DoNotInterfere() {
        // Given
        let monitor1 = NetworkMonitor()
        let monitor2 = NetworkMonitor()

        // When
        monitor1.stopMonitoring()

        // Then - monitor2 should still work
        XCTAssertNotNil(monitor2)
        let isConnected = monitor2.isConnected
        XCTAssertTrue(isConnected || !isConnected) // Just verify access works
    }

    // MARK: - Observable Property Tests

    func testIsConnected_CanBeObserved() {
        // Given
        let expectation = XCTestExpectation(description: "Property can be read")

        // When
        DispatchQueue.main.async {
            _ = self.sut.isConnected
            expectation.fulfill()
        }

        // Then
        wait(for: [expectation], timeout: 1.0)
    }

    func testConnectionType_CanBeObserved() {
        // Given
        let expectation = XCTestExpectation(description: "Property can be read")

        // When
        DispatchQueue.main.async {
            _ = self.sut.connectionType
            expectation.fulfill()
        }

        // Then
        wait(for: [expectation], timeout: 1.0)
    }

    // MARK: - Edge Cases

    func testRapidStartStop_DoesNotCrash() {
        // Rapidly toggle monitoring
        for _ in 0..<50 {
            sut.startMonitoring()
            sut.stopMonitoring()
        }

        // Should not crash
        XCTAssertNotNil(sut)
    }

    func testNewInstance_AfterOldOneDeallocated_Works() {
        // Given
        var monitor: NetworkMonitor? = NetworkMonitor()
        monitor?.stopMonitoring()
        monitor = nil

        // When
        let newMonitor = NetworkMonitor()

        // Then
        XCTAssertNotNil(newMonitor)
        let isConnected = newMonitor.isConnected
        XCTAssertTrue(isConnected || !isConnected)

        newMonitor.stopMonitoring()
    }

    // MARK: - Integration Tests

    func testNetworkMonitor_WorksWithActualNetwork() async throws {
        // This test verifies that the monitor works with the actual network
        // It's an integration test that depends on the device's network state

        // Wait a moment for the monitor to update
        try await Task.sleep(nanoseconds: 500_000_000) // 0.5 seconds

        // Just verify we can read the values without crashing
        let isConnected = sut.isConnected
        let connectionType = sut.connectionType

        // Log the actual values for debugging
        print("Network connected: \(isConnected)")
        print("Connection type: \(connectionType.rawValue)")

        // Verify we got valid values
        XCTAssertTrue(isConnected || !isConnected)
        let validTypes: [ConnectionType] = [.wifi, .cellular, .ethernet, .unknown]
        XCTAssertTrue(validTypes.contains(connectionType))
    }

    // MARK: - Memory Tests

    func testNoMemoryLeak_WhenCreatedAndDestroyed() {
        // Given
        weak var weakMonitor: NetworkMonitor?

        autoreleasepool {
            let monitor = NetworkMonitor()
            weakMonitor = monitor
            monitor.stopMonitoring()
        }

        // Note: Due to internal dispatch queues and NWPathMonitor,
        // the monitor may not be immediately deallocated.
        // This test primarily verifies no crash occurs.
        XCTAssertTrue(true)
    }
}

// MARK: - MockNetworkMonitor Tests

/// Tests for the MockNetworkMonitor used in other tests
final class MockNetworkMonitorTests: XCTestCase {

    // MARK: - Properties

    private var mockMonitor: MockNetworkMonitor!

    // MARK: - Test Lifecycle

    override func setUp() {
        super.setUp()
        mockMonitor = MockNetworkMonitor(isConnected: true)
    }

    override func tearDown() {
        mockMonitor = nil
        super.tearDown()
    }

    // MARK: - Mock Behavior Tests

    func testMockNetworkMonitor_WhenInitializedConnected_ReportsConnected() {
        // Given
        let monitor = MockNetworkMonitor(isConnected: true)

        // Then
        XCTAssertTrue(monitor.isConnected)
    }

    func testMockNetworkMonitor_WhenInitializedDisconnected_ReportsDisconnected() {
        // Given
        let monitor = MockNetworkMonitor(isConnected: false)

        // Then
        XCTAssertFalse(monitor.isConnected)
    }

    func testMockNetworkMonitor_CanChangeConnectionStatus() {
        // Given
        let monitor = MockNetworkMonitor(isConnected: true)
        XCTAssertTrue(monitor.isConnected)

        // When
        monitor.isConnected = false

        // Then
        XCTAssertFalse(monitor.isConnected)
    }

    func testMockNetworkMonitor_TrackStartMonitoringCalls() {
        // When
        mockMonitor.startMonitoring()

        // Then
        XCTAssertEqual(mockMonitor.startMonitoringCallCount, 1)
    }

    func testMockNetworkMonitor_TrackStopMonitoringCalls() {
        // When
        mockMonitor.stopMonitoring()

        // Then
        XCTAssertEqual(mockMonitor.stopMonitoringCallCount, 1)
    }
}