using System.Net.Http;
using Omika.App.Local.Abstractions;
using Omika.App.Local.Models;
using Omika.App.Navigation;
using Omika.App.ViewModels;
using Omika.Core.Observability;

namespace Omika.Tests.Mobile.Local;

/// <summary>
/// Tests du ViewModel de la liste des sites : chargement des options Type,
/// recherche serveur à la demande, restauration de la dernière recherche,
/// épinglage et navigation vers la fiche Site.
///
/// Couvre aussi la politique d'erreur de la recherche : la recherche à la demande
/// atteint l'API sans garde intermédiaire (<c>SiteLocalService.SearchSitesAsync</c>
/// → <c>_apiClient</c>), donc un échec réseau — ticket de production du 14/10,
/// « Connection failure » — remonte jusqu'ici et doit être journalisé en Warning/P2,
/// jamais en Error/P1.
/// </summary>
[Collection("TelemetrieStatique")]
public class SitesViewModelTests : LocalTestBase
{
    private readonly NavigationService _navigation = new();
    private readonly StubParametreMetierService _parametreMetier = new();

    private static SiteListItem Site(Guid id, string nom, string? type = null)
        => new()
        {
            SiteGuid = id,
            Nom = nom,
            Code = "S001",
            Type = type,
            Ville = "Lyon"
        };

    [Fact]
    public async Task Load_ChargeOptionsType_SansPeuplerLaListe()
    {
        _parametreMetier.SiteTypes = [new() { Label = "Entrepôt" }];
        var service = new FakeSiteService
        {
            Local = [Site(Guid.NewGuid(), "Alpha", "Entrepôt")]
        };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);

        await vm.LoadCommand.ExecuteAsync(null);

        Assert.False(vm.IsLoading);
        Assert.Contains("Tous", vm.TypeOptions);
        Assert.Contains("Entrepôt", vm.TypeOptions);
        Assert.False(vm.HasSites);
        Assert.True(vm.IsSearchNotStarted);
    }

    [Fact]
    public async Task Load_RestaureLaDerniereRecherche()
    {
        var site = Site(Guid.NewGuid(), "Alpha");
        var service = new FakeSiteService { LastSearch = [site] };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);

        await vm.LoadCommand.ExecuteAsync(null);

        Assert.True(vm.HasSites);
        Assert.Single(vm.Sites);
        Assert.Equal("Alpha", vm.Sites[0].Nom);
    }

    [Fact]
    public async Task Search_RetourneLesResultats()
    {
        var service = new FakeSiteService { SearchResults = [Site(Guid.NewGuid(), "Alpha")] };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);

        await vm.SearchCommand.ExecuteAsync(null);

        Assert.True(vm.HasSites);
        Assert.Single(vm.Sites);
        Assert.Equal("Alpha", vm.Sites[0].Nom);
    }

    [Fact]
    public async Task Search_SansResultat_ListeVide()
    {
        var service = new FakeSiteService { SearchResults = [] };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);

        await vm.SearchCommand.ExecuteAsync(null);

        Assert.False(vm.HasSites);
        Assert.True(vm.HasNoResults);
    }

    [Fact]
    public async Task Search_Erreur_Affichee()
    {
        var service = new FakeSiteService { ThrowOnSearch = true };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);

        await vm.SearchCommand.ExecuteAsync(null);

        Assert.NotNull(vm.ErrorMessage);
        Assert.False(vm.HasSites);
    }

    [Fact]
    public async Task Load_Erreur_Affichee()
    {
        var vm = new SitesViewModel(new ThrowingSiteService(), _parametreMetier, _navigation);

        await vm.LoadCommand.ExecuteAsync(null);

        Assert.NotNull(vm.ErrorMessage);
        Assert.False(vm.HasSites);
    }

    [Fact]
    public async Task ResetSearch_VideLaListe()
    {
        var service = new FakeSiteService { SearchResults = [Site(Guid.NewGuid(), "Alpha")] };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);
        await vm.SearchCommand.ExecuteAsync(null);
        Assert.True(vm.HasSites);

        await vm.ResetSearchCommand.ExecuteAsync(null);

        Assert.False(vm.HasSites);
        Assert.Empty(vm.Sites);
        Assert.False(vm.HasActiveFilters);
    }

    [Fact]
    public async Task TogglePinned_EpingleEtAfficheDansOnglet()
    {
        Guid siteId = Guid.NewGuid();
        var service = new FakeSiteService { SearchResults = [Site(siteId, "Alpha")] };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);
        await vm.SearchCommand.ExecuteAsync(null);

        await vm.TogglePinnedCommand.ExecuteAsync(vm.Sites[0]);

        await vm.ShowPinnedCommand.ExecuteAsync(null);
        Assert.True(vm.IsShowingPinned);
        Assert.Single(vm.Sites);
        Assert.Equal(siteId, vm.Sites[0].SiteGuid);
    }

    [Fact]
    public async Task TogglePinned_AppliqueImmediatement_SansRechargerLaListe()
    {
        var service = new FakeSiteService
        {
            SearchResults = [Site(Guid.NewGuid(), "Alpha"), Site(Guid.NewGuid(), "Beta")]
        };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);
        await vm.SearchCommand.ExecuteAsync(null);

        // La collection affichée sert de témoin : un rechargement la remplacerait.
        var collection = vm.Sites;
        var item = vm.Sites[0];

        await vm.TogglePinnedCommand.ExecuteAsync(item);

        Assert.True(item.IsPinned);
        Assert.Same(collection, vm.Sites);
        Assert.Equal(2, vm.Sites.Count);
    }

    [Fact]
    public async Task OpenSite_NavigueVersDetail()
    {
        Guid siteId = Guid.NewGuid();
        var service = new FakeSiteService { SearchResults = [Site(siteId, "Alpha")] };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);
        await vm.SearchCommand.ExecuteAsync(null);

        vm.OpenSiteCommand.Execute(vm.Sites[0]);

        Assert.Equal(AppPage.SiteDetail, _navigation.CurrentPage);
        Assert.Equal(siteId, _navigation.CurrentParameter);
    }

    [Fact]
    public async Task OpenSite_Null_NeNaviguePas()
    {
        var vm = new SitesViewModel(new FakeSiteService(), _parametreMetier, _navigation);

        vm.OpenSiteCommand.Execute(null);

        Assert.Equal(AppPage.Home, _navigation.CurrentPage);
    }

    /// <summary>Fake configurable du service local de sites.</summary>
    private sealed class FakeSiteService : ISiteLocalService
    {
        public IReadOnlyList<SiteListItem> Local { get; set; } = [];
        public IReadOnlyList<SiteListItem> SearchResults { get; set; } = [];
        public IReadOnlyList<SiteListItem> LastSearch { get; set; } = [];
        public bool ThrowOnSearch { get; set; }

        /// <summary>Exception levée par la recherche quand <see cref="ThrowOnSearch"/> est vrai.</summary>
        public Exception SearchException { get; set; } = new InvalidOperationException("Erreur simulée");

        private readonly List<SiteListItem> _pinned = [];

        public Task<IReadOnlyList<SiteListItem>> GetSitesAsync(CancellationToken ct = default)
            => Task.FromResult(Local);

        public Task<IReadOnlyList<SiteListItem>> SearchSitesAsync(
            string? nom, string? code, string? type, string? ville,
            string? codePostal, string? telephone, string? email,
            CancellationToken ct = default)
            => ThrowOnSearch
                ? throw SearchException
                : Task.FromResult(SearchResults);

        public Task<IReadOnlyList<SiteListItem>> GetLastSearchAsync(CancellationToken ct = default)
            => Task.FromResult(LastSearch);

        public Task ClearLastSearchAsync(CancellationToken ct = default)
        {
            LastSearch = [];
            return Task.CompletedTask;
        }

        public Task<IReadOnlyList<SiteListItem>> GetPinnedAsync(CancellationToken ct = default)
            => Task.FromResult<IReadOnlyList<SiteListItem>>(_pinned);

        public Task SetPinnedAsync(Guid siteId, bool isPinned, SiteListItem? item, CancellationToken ct = default)
        {
            if (isPinned && item is not null && !_pinned.Any(s => s.SiteGuid == siteId))
            {
                _pinned.Add(item);
            }
            else if (!isPinned)
            {
                _pinned.RemoveAll(s => s.SiteGuid == siteId);
            }

            return Task.CompletedTask;
        }

        public Task<SiteDetail?> GetSiteByIdAsync(Guid siteGuid, CancellationToken ct = default)
            => Task.FromResult<SiteDetail?>(null);
    }

    /// <summary>Service qui lève une exception pour tester l'état d'erreur.</summary>
    private sealed class ThrowingSiteService : ISiteLocalService
    {
        public Task<IReadOnlyList<SiteListItem>> GetSitesAsync(CancellationToken ct = default)
            => throw new InvalidOperationException("Erreur SQLite simulée");

        public Task<SiteDetail?> GetSiteByIdAsync(Guid siteGuid, CancellationToken ct = default)
            => throw new InvalidOperationException("Erreur SQLite simulée");
    }

    /// <summary>
    /// Ticket de production du 14/10 (« Connection failure ») : l'échec réseau de la
    /// recherche n'est pas un incident. L'événement part en Warning/P2, l'écran n'entre
    /// dans aucun groupe d'erreurs du Diagnostic Center, et l'utilisateur reçoit le
    /// libellé français stable plutôt qu'un message technique anglais.
    /// </summary>
    [Fact]
    public async Task Search_EchecReseau_SignaleEnWarningSansIncident()
    {
        var service = new FakeSiteService
        {
            ThrowOnSearch = true,
            SearchException = new HttpRequestException("Connection failure")
        };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);

        var telemetry = new CapturingTelemetry();
        ExceptionTelemetry.Initialize(telemetry, null);
        try
        {
            await vm.SearchCommand.ExecuteAsync(null);
        }
        finally
        {
            ExceptionTelemetry.Initialize(null, null);
        }

        Assert.Equal("Hors ligne — impossible de contacter le serveur.", vm.ErrorMessage);

        DiagnosticEvent evt = EvenementSites(telemetry);
        Assert.Equal(TelemetryLevel.Warning, evt.Level);
        Assert.Equal("HttpRequestException", evt.ErrorCode);
        AssertAucunIncident(telemetry);
    }

    /// <summary>
    /// Contre-épreuve : une erreur métier (hors réseau) reste un incident Error/P1.
    /// Le classement ne dégrade pas les vraies erreurs.
    /// </summary>
    [Fact]
    public async Task Search_ErreurMetier_ResteUnIncident()
    {
        var service = new FakeSiteService
        {
            ThrowOnSearch = true,
            SearchException = new InvalidOperationException("échec de recherche")
        };
        var vm = new SitesViewModel(service, _parametreMetier, _navigation);

        var telemetry = new CapturingTelemetry();
        ExceptionTelemetry.Initialize(telemetry, null);
        try
        {
            await vm.SearchCommand.ExecuteAsync(null);
        }
        finally
        {
            ExceptionTelemetry.Initialize(null, null);
        }

        DiagnosticEvent evt = EvenementSites(telemetry);
        Assert.Equal(TelemetryLevel.Error, evt.Level);
        Assert.Equal("InvalidOperationException", evt.ErrorCode);
    }

    /// <summary>
    /// Seul événement de diagnostic attribué au ViewModel : la télémétrie d'usage
    /// (fonctionnalités) est un <see cref="TelemetryEvent"/>, pas un
    /// <see cref="DiagnosticEvent"/>. Le filtre porte sur le composant, la télémétrie
    /// statique globale étant partagée avec les classes exécutées en parallèle.
    /// </summary>
    private static DiagnosticEvent EvenementSites(CapturingTelemetry telemetry) =>
        Assert.Single(
            telemetry.Events.OfType<DiagnosticEvent>(),
            e => e.Component == nameof(SitesViewModel));

    /// <summary>Aucun événement de diagnostic de cet écran en Error/Critical.</summary>
    private static void AssertAucunIncident(CapturingTelemetry telemetry) =>
        Assert.DoesNotContain(
            telemetry.Events.OfType<DiagnosticEvent>(),
            e => e.Component == nameof(SitesViewModel) && e.Level == TelemetryLevel.Error);

    /// <summary>Capture des événements de la télémétrie statique globale.</summary>
    private sealed class CapturingTelemetry : IOmikaTelemetry
    {
        public List<OmikaEvent> Events { get; } = [];

        public void Track(TelemetryEvent telemetryEvent) => Events.Add(telemetryEvent);

        public void Log(DiagnosticEvent diagnosticEvent) => Events.Add(diagnosticEvent);
    }
}