//
// Copyright 2025 Element Creations Ltd.
// Copyright 2022-2025 New Vector Ltd.
//
// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
// Please see LICENSE files in the repository root for full details.
//

@testable import ElementX
import Testing

@MainActor
struct StartChatScreenViewModelTests {
    private var viewModel: StartChatScreenViewModelProtocol!
    private var clientProxy: ClientProxyMock!
    private var userDiscoveryService: UserDiscoveryServiceMock!
    
    private var context: StartChatScreenViewModel.Context {
        viewModel.context
    }
    
    init() {
        clientProxy = .init(.init(userID: ""))
        userDiscoveryService = UserDiscoveryServiceMock()
        userDiscoveryService.searchProfilesWithReturnValue = .success([])
        let userSession = UserSessionMock(.init(clientProxy: clientProxy))
        viewModel = StartChatScreenViewModel(userSession: userSession,
                                             analytics: ServiceLocator.shared.analytics,
                                             userIndicatorController: UserIndicatorControllerMock(),
                                             userDiscoveryService: userDiscoveryService,
                                             appSettings: ServiceLocator.shared.settings)
    }
    
    @Test
    mutating func queryShowingNoResults() async {
        await search(query: "A")
        #expect(context.viewState.usersSection.type == .suggestions)
        
        await search(query: "AA")
        #expect(context.viewState.usersSection.type == .suggestions)
        #expect(!userDiscoveryService.searchProfilesWithCalled)
        
        await search(query: "AAA")
        assertSearchResults(toBe: 0)
        
        #expect(userDiscoveryService.searchProfilesWithCalled)
    }
    
    @Test
    func joinRoomByAddress() async throws {
        clientProxy.resolveRoomAliasReturnValue = .success(.init(roomId: "id", servers: []))
        
        let deferredViewState = deferFulfillment(viewModel.context.$viewState) { viewState in
            viewState.joinByAddressState == .addressFound(address: "#room:example.com", roomID: "id")
        }
        viewModel.context.roomAddress = "#room:example.com"
        try await deferredViewState.fulfill()
        
        let deferredAction = deferFulfillment(viewModel.actions) { action in
            action == .showRoom(roomID: "id")
        }
        context.send(viewAction: .joinRoomByAddress)
        try await deferredAction.fulfill()
    }
    
    @Test
    func joinRoomByAddressFailsBecauseInvalid() async throws {
        let deferred = deferFulfillment(viewModel.context.$viewState) { viewState in
            viewState.joinByAddressState == .invalidAddress
        }
        viewModel.context.roomAddress = ":"
        context.send(viewAction: .joinRoomByAddress)
        try await deferred.fulfill()
    }
    
    @Test
    func joinRoomByAddressFailsBecauseNotFound() async throws {
        clientProxy.resolveRoomAliasReturnValue = .failure(.failedResolvingRoomAlias)
        
        let deferred = deferFulfillment(viewModel.context.$viewState) { viewState in
            viewState.joinByAddressState == .addressNotFound
        }
        viewModel.context.roomAddress = "#room:example.com"
        context.send(viewAction: .joinRoomByAddress)
        try await deferred.fulfill()
    }
    
    // MARK: - History Sharing
    
    @Test
    func inviteConfirmationFetchesIdentity() async throws {
        clientProxy.directRoomForUserIDReturnValue = .success(nil)
        clientProxy.userIdentityForFallBackToServerReturnValue = .success(UserIdentityProxyMock(configuration: .init(verificationState: .notVerified)))
        
        // User identity becomes known, i.e. not unknown
        let deferred = deferFulfillment(viewModel.context.$viewState.compactMap(\.bindings.selectedUserToInvite)) {
            !$0.isUnknown
        }
        context.send(viewAction: .selectUser(.mockBob))
        try await deferred.fulfill()
        
        #expect(clientProxy.userIdentityForFallBackToServerCalled)
    }
    
    @Test
    func inviteConfirmationFallsBackToUnknownIdentityOnFailure() async throws {
        clientProxy.directRoomForUserIDReturnValue = .success(nil)
        clientProxy.userIdentityForFallBackToServerReturnValue = .failure(.forbiddenAccess)
        
        // User identity never becomes known, i.e. is never not unknown
        let deferred = deferFailure(viewModel.context.$viewState.compactMap(\.bindings.selectedUserToInvite), timeout: .seconds(5)) {
            !$0.isUnknown
        }
        context.send(viewAction: .selectUser(.mockBob))
        try await deferred.fulfill()
        
        #expect(clientProxy.userIdentityForFallBackToServerCalled)
    }
    
    // MARK: - Private
    
    private func assertSearchResults(toBe count: Int) {
        #expect(count >= 0)
        #expect(context.viewState.usersSection.type == .searchResult)
        #expect(context.viewState.usersSection.users.count == count)
        #expect(context.viewState.hasEmptySearchResults == (count == 0))
    }
    
    @discardableResult
    private mutating func search(query: String) async -> StartChatScreenViewState? {
        viewModel.context.searchQuery = query
        return await context.$viewState.nextValue
    }
}