using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Serilog;
using Serilog.Core;
using Serilog.Events;
using Serilog.Sinks.InMemory;
using ZB.MOM.WW.Telemetry;
using ZB.MOM.WW.Telemetry.Serilog;

namespace ZB.MOM.WW.Telemetry.Serilog.Tests;

public sealed class RedactionTests
{
    private const string Masked = "***";

    private sealed class FakeRedactor : ILogRedactor
    {
        public void Redact(IDictionary<string, object?> properties)
        {
            if (properties.ContainsKey("apiKey"))
            {
                properties["apiKey"] = Masked;
            }
        }
    }

    private static string? ScalarOrNull(LogEvent logEvent, string propertyName) =>
        logEvent.Properties.TryGetValue(propertyName, out var value) && value is ScalarValue scalar
            ? scalar.Value?.ToString()
            : null;

    [Fact]
    public void Registered_redactor_masks_sensitive_property()
    {
        var serviceProvider = new ServiceCollection()
            .AddSingleton<ILogRedactor>(new FakeRedactor())
            .BuildServiceProvider();

        var sink = new InMemorySink();
        var options = new ZbTelemetryOptions { ServiceName = "mxgateway" };

        var loggerConfig = new LoggerConfiguration();
        ZbSerilogConfig.Apply(loggerConfig, options, serviceProvider);
        using Logger logger = loggerConfig.WriteTo.Sink(sink).CreateLogger();

        logger.Information("authenticating {apiKey}", "mxgw_secret");

        var logEvent = Assert.Single(sink.LogEvents);
        Assert.Equal(Masked, ScalarOrNull(logEvent, "apiKey"));
    }

    [Fact]
    public void No_redactor_registered_is_a_no_op()
    {
        var serviceProvider = new ServiceCollection().BuildServiceProvider();

        var sink = new InMemorySink();
        var options = new ZbTelemetryOptions { ServiceName = "mxgateway" };

        var loggerConfig = new LoggerConfiguration();
        ZbSerilogConfig.Apply(loggerConfig, options, serviceProvider);
        using Logger logger = loggerConfig.WriteTo.Sink(sink).CreateLogger();

        logger.Information("authenticating {apiKey}", "mxgw_secret");

        var logEvent = Assert.Single(sink.LogEvents);
        Assert.Equal("mxgw_secret", ScalarOrNull(logEvent, "apiKey"));
    }

    [Fact]
    public void AddZbSerilog_with_otlp_options_builds_without_error()
    {
        var builder = Host.CreateApplicationBuilder();

        builder.AddZbSerilog(o =>
        {
            o.ServiceName = "mxgateway";
            o.SiteId = "s1";
            o.NodeRole = "central";
            o.Exporter = ZbExporter.Otlp;
            o.OtlpEndpoint = "http://localhost:4317";
        });

        using var host = builder.Build();

        // Serilog.ILogger is registered by AddSerilog — not Microsoft.Extensions.Logging.ILogger.
        var logger = host.Services.GetRequiredService<ILogger>();
        logger.Information("otlp wiring smoke test");
    }

    [Fact]
    public void BuildResourceAttributes_contains_required_keys_and_optional_keys_when_set()
    {
        var options = new ZbTelemetryOptions
        {
            ServiceName = "mxgateway",
            ServiceNamespace = "ZB.MOM.WW",
            SiteId = "site-a",
            NodeRole = "central",
        };

        var attributes = ZbSerilogConfig.BuildResourceAttributes(options);

        // Required keys always present.
        Assert.True(attributes.ContainsKey("service.name"), "service.name must be present");
        Assert.True(attributes.ContainsKey("service.namespace"), "service.namespace must be present");
        Assert.True(attributes.ContainsKey("host.name"), "host.name must be present");

        // Optional keys present when options supply them.
        Assert.True(attributes.ContainsKey("site.id"), "site.id must be present when SiteId is set");
        Assert.True(attributes.ContainsKey("node.role"), "node.role must be present when NodeRole is set");

        Assert.Equal("mxgateway", attributes["service.name"]);
        Assert.Equal("ZB.MOM.WW", attributes["service.namespace"]);
        Assert.Equal(Environment.MachineName, attributes["host.name"]);
        Assert.Equal("site-a", attributes["site.id"]);
        Assert.Equal("central", attributes["node.role"]);
    }

    [Fact]
    public void BuildResourceAttributes_omits_optional_keys_when_not_set()
    {
        var options = new ZbTelemetryOptions
        {
            ServiceName = "mxgateway",
            SiteId = null,
            NodeRole = null,
        };

        var attributes = ZbSerilogConfig.BuildResourceAttributes(options);

        Assert.False(attributes.ContainsKey("site.id"), "site.id must be absent when SiteId is null");
        Assert.False(attributes.ContainsKey("node.role"), "node.role must be absent when NodeRole is null");
    }
}