using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using StellaOps.Scanner.Surface.Env;

namespace StellaOps.Scanner.Surface.Env.Tests;

public sealed class SurfaceEnvironmentBuilderTests
{
    [Fact]
    public void Build_UsesDefaults_WhenVariablesMissing()
    {
        var services = CreateServices();
        var environment = SurfaceEnvironmentFactory.Create(services, options =>
        {
            options.RequireSurfaceEndpoint = false;
        });

        Assert.Equal("surface-cache", environment.Settings.SurfaceFsBucket);
        Assert.Equal(4096, environment.Settings.CacheQuotaMegabytes);
        Assert.False(environment.Settings.PrefetchEnabled);
        Assert.NotNull(environment.Settings.CacheRoot);
        Assert.True(environment.Settings.CacheRoot.Exists);
    }

    [Fact]
    public void Build_ReadsEnvironmentVariables_WithPrefixes()
    {
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_BUCKET", "custom-bucket");
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_CACHE_QUOTA_MB", "512");
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", "https://surface.example.test");

        try
        {
            var services = CreateServices();
            var environment = SurfaceEnvironmentFactory.Create(services);

            Assert.Equal("custom-bucket", environment.Settings.SurfaceFsBucket);
            Assert.Equal(512, environment.Settings.CacheQuotaMegabytes);
        }
        finally
        {
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_BUCKET", null);
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_CACHE_QUOTA_MB", null);
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", null);
        }
    }

    [Fact]
    public void Build_Throws_WhenIntegerOutOfRange()
    {
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_CACHE_QUOTA_MB", "1");
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", "https://surface.example.test");

        try
        {
            var services = CreateServices();
            var exception = Assert.Throws<SurfaceEnvironmentException>(() => SurfaceEnvironmentFactory.Create(services));
            Assert.Equal("SURFACE_CACHE_QUOTA_MB", exception.Variable);
        }
        finally
        {
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_CACHE_QUOTA_MB", null);
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", null);
        }
    }

    [Fact]
    public void Build_Throws_WhenEndpointMissing_AndRequired()
    {
        var services = CreateServices();
        var exception = Assert.Throws<SurfaceEnvironmentException>(() =>
            SurfaceEnvironmentFactory.Create(services, options => options.RequireSurfaceEndpoint = true));

        Assert.Equal("SURFACE_FS_ENDPOINT", exception.Variable);
    }

    [Fact]
    public void Build_Throws_WhenEndpointInvalid()
    {
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", "not-a-uri");
        try
        {
            var services = CreateServices();
            var ex = Assert.Throws<SurfaceEnvironmentException>(() => SurfaceEnvironmentFactory.Create(services));
            Assert.Equal("SURFACE_FS_ENDPOINT", ex.Variable);
        }
        finally
        {
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", null);
        }
    }

    [Fact]
    public void Build_Throws_WhenTlsCertificateMissing()
    {
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", "https://surface.example.test");
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_TLS_CERT_PATH", "/does/not/exist.pem");
        try
        {
            var services = CreateServices();
            var ex = Assert.Throws<SurfaceEnvironmentException>(() => SurfaceEnvironmentFactory.Create(services));
            Assert.Equal("SURFACE_TLS_CERT_PATH", ex.Variable);
        }
        finally
        {
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_TLS_CERT_PATH", null);
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", null);
        }
    }

    [Fact]
    public void Build_UsesTenantResolver_WhenNotProvided()
    {
        Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", "https://surface.example.test");
        try
        {
            var services = CreateServices();
            var environment = SurfaceEnvironmentFactory.Create(services, options =>
            {
                options.TenantResolver = _ => "resolved-tenant";
            });

            Assert.Equal("resolved-tenant", environment.Settings.Tenant);
        }
        finally
        {
            Environment.SetEnvironmentVariable("SCANNER_SURFACE_FS_ENDPOINT", null);
        }
    }

    private static IServiceProvider CreateServices(Action<IServiceCollection>? configure = null)
    {
        var services = new ServiceCollection();
        var configuration = new ConfigurationBuilder().Build();

        services.AddSingleton<IConfiguration>(configuration);
        services.AddLogging(builder => builder.ClearProviders());

        configure?.Invoke(services);

        return services.BuildServiceProvider();
    }
}