using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using ScadaLink.AuditLog.Configuration;

namespace ScadaLink.AuditLog.Tests.Configuration;

/// <summary>
/// Task 9 (Bundle E): <see cref="AuditLogOptions"/> binding + validator
/// behavior. The validator enforces invariants used by M2+ writers
/// (per <c>docs/plans/2026-05-20-auditlog-m1-foundation.md</c>):
/// <c>DefaultCapBytes &gt; 0</c>, <c>ErrorCapBytes &gt;= DefaultCapBytes</c>,
/// <c>RetentionDays in [30, 3650]</c>. Header-redact defaults match the
/// design doc (alog.md §6): Authorization, X-Api-Key, Cookie, Set-Cookie.
/// </summary>
public class AuditLogOptionsTests
{
    private static IOptions<AuditLogOptions> BuildOptions(Dictionary<string, string?> config)
    {
        var configuration = new ConfigurationBuilder()
            .AddInMemoryCollection(config)
            .Build();
        var services = new ServiceCollection();
        services.AddAuditLog(configuration);
        return services.BuildServiceProvider().GetRequiredService<IOptions<AuditLogOptions>>();
    }

    [Fact]
    public void ValidBinding_PopulatesAllScalarFields()
    {
        var opts = BuildOptions(new Dictionary<string, string?>
        {
            ["AuditLog:DefaultCapBytes"] = "4096",
            ["AuditLog:ErrorCapBytes"] = "32768",
            ["AuditLog:RetentionDays"] = "180",
        }).Value;

        Assert.Equal(4096, opts.DefaultCapBytes);
        Assert.Equal(32768, opts.ErrorCapBytes);
        Assert.Equal(180, opts.RetentionDays);
    }

    [Fact]
    public void DefaultsAreReasonable_WhenSectionEmpty()
    {
        var opts = BuildOptions(new Dictionary<string, string?>()).Value;

        Assert.Equal(8192, opts.DefaultCapBytes);
        Assert.Equal(65536, opts.ErrorCapBytes);
        Assert.Equal(365, opts.RetentionDays);
        Assert.Contains("Authorization", opts.HeaderRedactList);
        Assert.Contains("X-Api-Key", opts.HeaderRedactList);
        Assert.Contains("Cookie", opts.HeaderRedactList);
        Assert.Contains("Set-Cookie", opts.HeaderRedactList);
        Assert.Empty(opts.GlobalBodyRedactors);
        Assert.Empty(opts.PerTargetOverrides);
    }

    [Fact]
    public void HeaderRedactList_BindsFromConfig_AppendsToDefaults()
    {
        // Microsoft.Extensions.Configuration's collection binder appends to a
        // defaulted list (it does not replace it), so config-supplied entries
        // augment the built-in redact list rather than overriding it. The
        // built-in entries are the safety-net defaults documented on
        // AuditLogOptions; supplying additional headers is the supported
        // extension point.
        var opts = BuildOptions(new Dictionary<string, string?>
        {
            ["AuditLog:HeaderRedactList:0"] = "X-Custom-Auth",
            ["AuditLog:HeaderRedactList:1"] = "X-Tenant-Id",
        }).Value;

        Assert.Contains("X-Custom-Auth", opts.HeaderRedactList);
        Assert.Contains("X-Tenant-Id", opts.HeaderRedactList);
        Assert.Contains("Authorization", opts.HeaderRedactList);
        Assert.Contains("X-Api-Key", opts.HeaderRedactList);
    }

    [Fact]
    public void PerTargetOverrides_BindsFromConfig()
    {
        var opts = BuildOptions(new Dictionary<string, string?>
        {
            ["AuditLog:PerTargetOverrides:CRM:CapBytes"] = "16384",
            ["AuditLog:PerTargetOverrides:CRM:AdditionalBodyRedactors:0"] = @"\d{16}",
        }).Value;

        Assert.True(opts.PerTargetOverrides.ContainsKey("CRM"));
        var crm = opts.PerTargetOverrides["CRM"];
        Assert.Equal(16384, crm.CapBytes);
        Assert.NotNull(crm.AdditionalBodyRedactors);
        Assert.Contains(@"\d{16}", crm.AdditionalBodyRedactors!);
    }

    [Fact]
    public void InvalidDefaultCapBytes_FailsValidation()
    {
        var result = new AuditLogOptionsValidator().Validate(
            Options.DefaultName,
            new AuditLogOptions { DefaultCapBytes = 0 });

        Assert.True(result.Failed);
        Assert.Contains("DefaultCapBytes", result.FailureMessage);
    }

    [Fact]
    public void InvalidErrorCapBytes_FailsValidation()
    {
        var result = new AuditLogOptionsValidator().Validate(
            Options.DefaultName,
            new AuditLogOptions { DefaultCapBytes = 1000, ErrorCapBytes = 100 });

        Assert.True(result.Failed);
        Assert.Contains("ErrorCapBytes", result.FailureMessage);
    }

    [Fact]
    public void RetentionDaysBelowMinimum_FailsValidation()
    {
        var result = new AuditLogOptionsValidator().Validate(
            Options.DefaultName,
            new AuditLogOptions { RetentionDays = 0 });

        Assert.True(result.Failed);
        Assert.Contains("RetentionDays", result.FailureMessage);
    }

    [Fact]
    public void RetentionDaysAboveMaximum_FailsValidation()
    {
        var result = new AuditLogOptionsValidator().Validate(
            Options.DefaultName,
            new AuditLogOptions { RetentionDays = 3651 });

        Assert.True(result.Failed);
        Assert.Contains("RetentionDays", result.FailureMessage);
    }

    [Fact]
    public void DefaultOptions_PassValidation()
    {
        var result = new AuditLogOptionsValidator().Validate(
            Options.DefaultName,
            new AuditLogOptions());

        Assert.True(result.Succeeded, result.FailureMessage);
    }

    [Fact]
    public void InvalidRetention_BoundViaConfig_RejectedOnValueAccess()
    {
        var configuration = new ConfigurationBuilder()
            .AddInMemoryCollection(new Dictionary<string, string?>
            {
                ["AuditLog:RetentionDays"] = "0",
            })
            .Build();
        var services = new ServiceCollection();
        services.AddAuditLog(configuration);
        var provider = services.BuildServiceProvider();
        var opts = provider.GetRequiredService<IOptions<AuditLogOptions>>();

        var ex = Assert.Throws<OptionsValidationException>(() => _ = opts.Value);
        Assert.Contains("RetentionDays", ex.Message);
    }
}