using System.Security.Claims;
using Microsoft.AspNetCore.Components.Authorization;
using ZB.MOM.WW.ScadaBridge.CentralUI.Auth;
using ZB.MOM.WW.ScadaBridge.Commons.Entities.Sites;
using ZB.MOM.WW.ScadaBridge.Security;

namespace ZB.MOM.WW.ScadaBridge.CentralUI.Tests.Auth;

/// <summary>
/// Regression tests for site-scoped permissions. Site-scoped Deployment permissions are
/// written as <c>SiteId</c> claims at login but were never read — Deployment
/// pages listed and acted on every site. <see cref="SiteScopeService"/> is the
/// shared helper that reads those claims; these tests pin its behaviour.
/// </summary>
public class SiteScopeServiceTests
{
    private sealed class StubAuthStateProvider : AuthenticationStateProvider
    {
        private readonly ClaimsPrincipal _user;
        /// <summary>Initializes a new instance of the <c>StubAuthStateProvider</c> class.</summary>
        /// <param name="user">The user.</param>
        public StubAuthStateProvider(ClaimsPrincipal user) => _user = user;
        /// <inheritdoc />
        public override Task<AuthenticationState> GetAuthenticationStateAsync()
            => Task.FromResult(new AuthenticationState(_user));
    }

    private static SiteScopeService ForUser(params Claim[] claims)
    {
        var identity = new ClaimsIdentity(claims, authenticationType: "TestCookie");
        return new SiteScopeService(new StubAuthStateProvider(new ClaimsPrincipal(identity)));
    }

    private static Claim Role(string role) => new(JwtTokenService.RoleClaimType, role);
    private static Claim SiteClaim(int id) => new(JwtTokenService.SiteIdClaimType, id.ToString());

    private static List<Site> Sites(params int[] ids)
        => ids.Select(id => new Site($"Site{id}", $"SITE-{id}") { Id = id }).ToList();

    /// <summary>Verifies that a deployer with no site claims is treated as system-wide.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task DeploymentUserWithNoSiteClaims_IsSystemWide()
    {
        var svc = ForUser(Role("Deployer"));

        Assert.True(await svc.IsSystemWideAsync());
        Assert.Empty(await svc.PermittedSiteIdsAsync());
    }

    /// <summary>Verifies that filtering sites for a system-wide user returns every site.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task SystemWideUser_FilterSites_ReturnsAllSites()
    {
        var svc = ForUser(Role("Deployer"));

        var filtered = await svc.FilterSitesAsync(Sites(1, 2, 3));

        Assert.Equal(new[] { 1, 2, 3 }, filtered.Select(s => s.Id));
    }

    /// <summary>Verifies that filtering sites for a scoped user returns only the permitted sites.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task ScopedUser_FilterSites_ReturnsOnlyPermittedSites()
    {
        // Regression: a Deployment user scoped to sites 1 and 3 must NOT see site 2.
        var svc = ForUser(Role("Deployer"), SiteClaim(1), SiteClaim(3));

        var filtered = await svc.FilterSitesAsync(Sites(1, 2, 3, 4));

        Assert.Equal(new[] { 1, 3 }, filtered.Select(s => s.Id).OrderBy(x => x));
    }

    /// <summary>Verifies that a scoped user is allowed access only to the sites they were granted.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task ScopedUser_IsSiteAllowed_OnlyForGrantedSites()
    {
        var svc = ForUser(Role("Deployer"), SiteClaim(5));

        Assert.True(await svc.IsSiteAllowedAsync(5));
        Assert.False(await svc.IsSiteAllowedAsync(6));
    }

    /// <summary>Verifies that a scoped user is not system-wide and reports its permitted site ids.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task ScopedUser_IsNotSystemWide_AndReportsItsPermittedIds()
    {
        var svc = ForUser(Role("Deployer"), SiteClaim(7), SiteClaim(9));

        Assert.False(await svc.IsSystemWideAsync());
        Assert.Equal(new[] { 7, 9 }, (await svc.PermittedSiteIdsAsync()).OrderBy(x => x));
    }

    /// <summary>Verifies that a system-wide user is allowed access to any site.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task SystemWideUser_IsSiteAllowed_ForAnySite()
    {
        var svc = ForUser(Role("Deployer"));

        Assert.True(await svc.IsSiteAllowedAsync(1));
        Assert.True(await svc.IsSiteAllowedAsync(999));
    }

    // ── Administrator is system-wide regardless of SiteId claims (register 86) ──
    //
    // ManagementActor has always exempted Administrator from site scoping
    // (EnforceSiteScope and every handler that calls it). This service was
    // claims-only, so an Administrator who ALSO carried a scoped Deployer grant
    // could act fleet-wide through the CLI/HTTP surface while the UI hid the same
    // sites. The UI was the side that disagreed with the documented rule.

    /// <summary>Verifies that an administrator carrying site claims is still system-wide.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task AdministratorWithSiteClaims_IsSystemWide()
    {
        var svc = ForUser(Role("Administrator"), Role("Deployer"), SiteClaim(1), SiteClaim(3));

        Assert.True(await svc.IsSystemWideAsync());
    }

    /// <summary>Verifies that filtering sites for an administrator with site claims returns every site.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task AdministratorWithSiteClaims_FilterSites_ReturnsAllSites()
    {
        var svc = ForUser(Role("Administrator"), Role("Deployer"), SiteClaim(1));

        var filtered = await svc.FilterSitesAsync(Sites(1, 2, 3));

        Assert.Equal(new[] { 1, 2, 3 }, filtered.Select(s => s.Id));
    }

    /// <summary>Verifies that an administrator with site claims is allowed access to sites outside those claims.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task AdministratorWithSiteClaims_IsSiteAllowed_ForSitesOutsideTheClaims()
    {
        var svc = ForUser(Role("Administrator"), SiteClaim(1));

        Assert.True(await svc.IsSiteAllowedAsync(2));
    }

    /// <summary>Verifies that an administrator with site claims reports no permitted site ids.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task AdministratorWithSiteClaims_ReportsNoPermittedIds()
    {
        // The invariant "system-wide => empty id set" must hold for every caller, so
        // a consumer that reads the ids without consulting IsSystemWide cannot
        // silently narrow an Administrator to a subset of sites.
        var svc = ForUser(Role("Administrator"), SiteClaim(1), SiteClaim(3));

        Assert.Empty(await svc.PermittedSiteIdsAsync());
    }

    /// <summary>Verifies that the administrator role match ignores case.</summary>
    /// <param name="role">The role.</param>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Theory]
    [InlineData("administrator")]
    [InlineData("ADMINISTRATOR")]
    public async Task AdministratorRoleMatch_IsCaseInsensitive(string role)
    {
        // ManagementActor compares roles with OrdinalIgnoreCase. ClaimsPrincipal
        // .IsInRole compares claim VALUES ordinally, so matching the actor requires
        // reading the role claims explicitly — otherwise the two sides would
        // disagree on a differently-cased role name.
        var svc = ForUser(Role(role), SiteClaim(1));

        Assert.True(await svc.IsSystemWideAsync());
    }

    /// <summary>Verifies that a designer with site claims remains scoped to those sites.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task DesignerWithSiteClaims_IsStillScoped()
    {
        // The class doc used to claim "any Admin/Design user" is system-wide. Only
        // Administrator is — on either side of the rule — and the doc was corrected
        // rather than the bypass widened.
        var svc = ForUser(Role("Designer"), SiteClaim(1));

        Assert.False(await svc.IsSystemWideAsync());
        Assert.False(await svc.IsSiteAllowedAsync(2));
    }

    // ── Resolve(ClaimsPrincipal): the same rule as a pure function ───────────
    // Display-gating callers (the rail pending-updates indicator) hold a principal
    // already and must NOT pay for the instance methods' authoritative, fail-closed
    // state refresh — which for a polling component would be a forced session
    // revalidation per tick per circuit. These pin that the pure overload answers
    // identically to the async path.

    private static ClaimsPrincipal Principal(params Claim[] claims)
        => new(new ClaimsIdentity(claims, authenticationType: "TestCookie"));

    /// <summary>Verifies that resolving an administrator yields a system-wide scope with an empty site set.</summary>
    /// <returns>The result.</returns>
    [Fact]
    public void Resolve_Administrator_IsSystemWideWithAnEmptySet()
    {
        // Even carrying SiteId claims: an Administrator's ids are not collected at
        // all, so "system-wide => empty set" holds for every caller.
        var (isSystemWide, sites) = SiteScopeService.Resolve(
            Principal(Role("Administrator"), SiteClaim(1), SiteClaim(2)));

        Assert.True(isSystemWide);
        Assert.Empty(sites);
    }

    /// <summary>Verifies that resolving a principal with site claims yields the scoped site set.</summary>
    /// <returns>The result.</returns>
    [Fact]
    public void Resolve_SiteClaims_YieldTheScopedSet()
    {
        var (isSystemWide, sites) = SiteScopeService.Resolve(
            Principal(Role("Deployer"), SiteClaim(1), SiteClaim(3)));

        Assert.False(isSystemWide);
        Assert.Equal([1, 3], sites.OrderBy(id => id));
    }

    /// <summary>Verifies that resolving a principal with no site claims yields a system-wide scope.</summary>
    /// <returns>The result.</returns>
    [Fact]
    public void Resolve_NoSiteClaims_IsSystemWide()
    {
        var (isSystemWide, sites) = SiteScopeService.Resolve(Principal(Role("Deployer")));

        Assert.True(isSystemWide);
        Assert.Empty(sites);
    }

    /// <summary>Verifies that resolving an unauthenticated principal yields a scope with no permitted sites.</summary>
    /// <returns>The result.</returns>
    [Fact]
    public void Resolve_UnauthenticatedPrincipal_IsScopedToNothing()
    {
        // Fail closed: not system-wide AND no permitted sites.
        var (isSystemWide, sites) = SiteScopeService.Resolve(new ClaimsPrincipal(new ClaimsIdentity()));

        Assert.False(isSystemWide);
        Assert.Empty(sites);
    }

    /// <summary>Verifies that the synchronous resolve produces the same result as the async path.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task Resolve_AgreesWithTheAsyncPath()
    {
        var claims = new[] { Role("Deployer"), SiteClaim(2), SiteClaim(5) };
        var svc = ForUser(claims);

        var (isSystemWide, sites) = SiteScopeService.Resolve(Principal(claims));

        Assert.Equal(await svc.IsSystemWideAsync(), isSystemWide);
        Assert.Equal((await svc.PermittedSiteIdsAsync()).OrderBy(id => id), sites.OrderBy(id => id));
    }
}