import XCTest
@testable import RouterOSAssistant

private final class MockTransport: RouterOSTransport {
    let kind: RouterOSTransportKind
    var connectError: Error?
    var deviceInfo = RouterDeviceInfo(boardName: "Mock", routerOSVersion: "7.0", architecture: "arm64", uptime: "1h")
    /// Canned `fetchMenuItems` responses, keyed by menu path — lets a test simulate whatever the
    /// router currently reports for `/interface bridge port`, `/ip address`, etc. without a real
    /// connection. Menu paths not present here return an empty list, same as a genuinely empty
    /// menu on the router.
    var menuItemsByPath: [String: [RouterOSMenuItem]] = [:]

    init(kind: RouterOSTransportKind, connectError: Error? = nil) {
        self.kind = kind
        self.connectError = connectError
    }

    func connect() async throws {
        if let connectError { throw connectError }
    }

    func fetchDeviceInfo() async throws -> RouterDeviceInfo { deviceInfo }
    func fetchInterfaces() async throws -> [NetworkInterface] { [] }
    func fetchFirewallRuleCounts() async throws -> FirewallRuleCounts { FirewallRuleCounts(filterRuleCount: 0, natRuleCount: 0) }
    func fetchMenuItems(menuPath: String, restPath: String) async throws -> [RouterOSMenuItem] { menuItemsByPath[menuPath] ?? [] }
    func fetchFieldValues(menuPath: String, restPath: String, whereField: String, whereValue: String, returnField: String) async throws -> Set<String> { [] }
    func apply(_ command: RouterOSCommand) async throws {}
    func disconnect() async {}
}

@MainActor
final class ConnectionServiceTests: XCTestCase {
    private let credentials = RouterOSCredentials(host: "192.168.88.1", username: "admin", password: "")

    func testFallsBackToSSHWhenRestFails() async {
        let service = ConnectionService()
        let sshTransport = MockTransport(kind: .ssh)

        await service.connect(
            with: credentials,
            makeRestTransport: { MockTransport(kind: .rest, connectError: RouterOSError.transportUnavailable("kein REST")) },
            makeSSHTransport: { sshTransport }
        )

        XCTAssertEqual(service.state, .connected(kind: .ssh))
    }

    func testUsesRestWhenAvailable() async {
        let service = ConnectionService()

        await service.connect(
            with: credentials,
            makeRestTransport: { MockTransport(kind: .rest) },
            makeSSHTransport: { MockTransport(kind: .ssh) }
        )

        XCTAssertEqual(service.state, .connected(kind: .rest))
    }

    func testUntrustedCertificateAsksForConfirmationInsteadOfFallingBackToSSH() async {
        let service = ConnectionService()

        await service.connect(
            with: credentials,
            makeRestTransport: { MockTransport(kind: .rest, connectError: RouterOSError.untrustedCertificate(fingerprint: "AA:BB")) },
            makeSSHTransport: { MockTransport(kind: .ssh) }
        )

        XCTAssertEqual(service.state, .needsCertificateConfirmation(fingerprint: "AA:BB"))
    }

    func testFailsWhenBothTransportsFail() async {
        let service = ConnectionService()

        await service.connect(
            with: credentials,
            makeRestTransport: { MockTransport(kind: .rest, connectError: RouterOSError.transportUnavailable("kein REST")) },
            makeSSHTransport: { MockTransport(kind: .ssh, connectError: RouterOSError.transportUnavailable("kein SSH")) }
        )

        guard case .failed = service.state else {
            XCTFail("Erwarteter Zustand .failed, war \(service.state)")
            return
        }
    }

    // MARK: - checkPortConflict (Setup wizard LAN step pre-check)

    private func connectedService(menuItemsByPath: [String: [RouterOSMenuItem]]) async -> ConnectionService {
        let service = ConnectionService()
        let transport = MockTransport(kind: .rest)
        transport.menuItemsByPath = menuItemsByPath
        await service.connect(with: credentials, makeRestTransport: { transport }, makeSSHTransport: { transport })
        return service
    }

    func testCheckPortConflictReturnsNilWhenPortIsFree() async throws {
        let service = await connectedService(menuItemsByPath: [:])
        let conflict = try await service.checkPortConflict(interfaceName: "ether4")
        XCTAssertNil(conflict)
    }

    func testCheckPortConflictNeverFlagsTheSharedBridgeItself() async throws {
        // "bridge" is this app's own shared-LAN interface, not "someone else's" configuration —
        // even if it happens to already carry addresses (the normal case), it must never be
        // reported as a conflict.
        let service = await connectedService(menuItemsByPath: [
            "/ip address": [RouterOSMenuItem(id: "*1", fields: ["interface": "bridge", "address": "192.168.88.1/24"])]
        ])
        let conflict = try await service.checkPortConflict(interfaceName: "bridge")
        XCTAssertNil(conflict)
    }

    func testCheckPortConflictDetectsBridgeMembership() async throws {
        let service = await connectedService(menuItemsByPath: [
            "/interface bridge port": [RouterOSMenuItem(id: "*1", fields: ["interface": "ether4", "bridge": "bridge"])]
        ])
        let conflict = try await service.checkPortConflict(interfaceName: "ether4")
        XCTAssertEqual(conflict, PortConflict(interfaceName: "ether4", reasons: [.bridgeMember(bridgeName: "bridge")]))
    }

    func testCheckPortConflictDetectsExistingAddressDhcpClientAndPppoeClientTogether() async throws {
        let service = await connectedService(menuItemsByPath: [
            "/ip address": [RouterOSMenuItem(id: "*1", fields: ["interface": "ether1", "address": "10.0.0.1/24"])],
            "/ip dhcp-client": [RouterOSMenuItem(id: "*2", fields: ["interface": "ether1"])],
            "/interface pppoe-client": [RouterOSMenuItem(id: "*3", fields: ["interface": "ether1"])]
        ])
        let conflict = try await service.checkPortConflict(interfaceName: "ether1")
        XCTAssertEqual(conflict, PortConflict(
            interfaceName: "ether1",
            reasons: [.hasAddresses(["10.0.0.1/24"]), .dhcpClient, .pppoeClient]
        ))
    }

    func testCheckPortConflictIgnoresEntriesForOtherInterfaces() async throws {
        let service = await connectedService(menuItemsByPath: [
            "/interface bridge port": [RouterOSMenuItem(id: "*1", fields: ["interface": "ether2", "bridge": "bridge"])],
            "/ip address": [RouterOSMenuItem(id: "*2", fields: ["interface": "ether2", "address": "192.168.88.1/24"])]
        ])
        let conflict = try await service.checkPortConflict(interfaceName: "ether5")
        XCTAssertNil(conflict)
    }
}