using System.CommandLine;
using System.Net;
using System.Text;
using System.Text.Json;
using ZB.MOM.WW.ScadaBridge.CLI;
using ZB.MOM.WW.ScadaBridge.CLI.Commands;

namespace ZB.MOM.WW.ScadaBridge.CLI.Tests.Commands;

/// <summary>
/// Tests for the <c>scadabridge audit backfill-source-node</c> subcommand
/// (Audit Log #23 M5.6 T5): argument parsing, request-body construction,
/// HTTP wiring, and CLI scaffold.
/// </summary>
[Collection("Console")]
public class AuditBackfillCommandTests
{
    // ─────────────────────────────────────────────────────────────────────
    // BuildRequestBody
    // ─────────────────────────────────────────────────────────────────────

    [Fact]
    public void BuildRequestBody_DefaultArgs_ContainsExpectedFields()
    {
        var args = new AuditBackfillSourceNodeArgs
        {
            Sentinel = "unknown",
            Before = "2026-01-01T00:00:00Z",
            BatchSize = 5000,
        };

        var body = AuditBackfillHelpers.BuildRequestBody(args);
        using var doc = JsonDocument.Parse(body);
        var root = doc.RootElement;

        Assert.Equal("unknown", root.GetProperty("sentinel").GetString());
        Assert.Equal("2026-01-01T00:00:00Z", root.GetProperty("before").GetString());
        Assert.Equal(5000, root.GetProperty("batchSize").GetInt32());
    }

    [Fact]
    public void BuildRequestBody_CustomSentinelAndBatch_ReflectedInJson()
    {
        var args = new AuditBackfillSourceNodeArgs
        {
            Sentinel = "pre-feature",
            Before = "2026-06-01T00:00:00Z",
            BatchSize = 1000,
        };

        var body = AuditBackfillHelpers.BuildRequestBody(args);
        using var doc = JsonDocument.Parse(body);
        var root = doc.RootElement;

        Assert.Equal("pre-feature", root.GetProperty("sentinel").GetString());
        Assert.Equal("2026-06-01T00:00:00Z", root.GetProperty("before").GetString());
        Assert.Equal(1000, root.GetProperty("batchSize").GetInt32());
    }

    // ─────────────────────────────────────────────────────────────────────
    // RunBackfillAsync — HTTP execution
    // ─────────────────────────────────────────────────────────────────────

    private sealed class CapturingHandler : HttpMessageHandler
    {
        private readonly HttpStatusCode _status;
        private readonly string _responseBody;

        public CapturingHandler(HttpStatusCode status, string responseBody)
        {
            _status = status;
            _responseBody = responseBody;
        }

        public string? LastRequestUri { get; private set; }
        public string? LastRequestBody { get; private set; }
        public string? LastMethod { get; private set; }

        protected override async Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request, CancellationToken cancellationToken)
        {
            LastRequestUri = request.RequestUri!.PathAndQuery;
            LastMethod = request.Method.Method;
            if (request.Content != null)
            {
                LastRequestBody = await request.Content.ReadAsStringAsync(cancellationToken);
            }
            return new HttpResponseMessage(_status)
            {
                Content = new StringContent(_responseBody, Encoding.UTF8, "application/json"),
            };
        }
    }

    private static string SuccessBody(long rowsUpdated = 42, string sentinel = "unknown", string before = "2026-01-01T00:00:00.0000000Z")
        => JsonSerializer.Serialize(new { rowsUpdated, sentinel, before });

    [Fact]
    public async Task RunBackfill_Success_ReturnsZeroAndWritesOutput()
    {
        var handler = new CapturingHandler(HttpStatusCode.OK, SuccessBody(rowsUpdated: 42));
        var client = new ManagementHttpClient(new HttpClient(handler), "http://localhost:9001", "u", "p");
        var output = new StringWriter();

        var args = new AuditBackfillSourceNodeArgs
        {
            Sentinel = "unknown",
            Before = "2026-01-01T00:00:00Z",
            BatchSize = 5000,
        };

        var exit = await AuditBackfillHelpers.RunBackfillAsync(client, args, output);

        Assert.Equal(0, exit);
        var text = output.ToString();
        Assert.Contains("42", text);
        Assert.Contains("backfill complete", text, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public async Task RunBackfill_RequestUri_ContainsBackfillPath()
    {
        var handler = new CapturingHandler(HttpStatusCode.OK, SuccessBody());
        var client = new ManagementHttpClient(new HttpClient(handler), "http://localhost:9001", "u", "p");
        var output = new StringWriter();

        await AuditBackfillHelpers.RunBackfillAsync(
            client,
            new AuditBackfillSourceNodeArgs { Sentinel = "unknown", Before = "2026-01-01T00:00:00Z" },
            output);

        Assert.Contains("backfill-source-node", handler.LastRequestUri);
        Assert.Equal("POST", handler.LastMethod);
    }

    [Fact]
    public async Task RunBackfill_RequestBody_ContainsSentinelAndBefore()
    {
        var handler = new CapturingHandler(HttpStatusCode.OK, SuccessBody());
        var client = new ManagementHttpClient(new HttpClient(handler), "http://localhost:9001", "u", "p");
        var output = new StringWriter();

        await AuditBackfillHelpers.RunBackfillAsync(
            client,
            new AuditBackfillSourceNodeArgs
            {
                Sentinel = "pre-feature",
                Before = "2026-01-01T00:00:00Z",
                BatchSize = 2000,
            },
            output);

        Assert.NotNull(handler.LastRequestBody);
        using var doc = JsonDocument.Parse(handler.LastRequestBody!);
        Assert.Equal("pre-feature", doc.RootElement.GetProperty("sentinel").GetString());
        Assert.Equal("2026-01-01T00:00:00Z", doc.RootElement.GetProperty("before").GetString());
        Assert.Equal(2000, doc.RootElement.GetProperty("batchSize").GetInt32());
    }

    [Fact]
    public async Task RunBackfill_Http403_ReturnsExitCode2()
    {
        var handler = new CapturingHandler(HttpStatusCode.Forbidden,
            "{\"error\":\"Permission required.\",\"code\":\"UNAUTHORIZED\"}");
        var client = new ManagementHttpClient(new HttpClient(handler), "http://localhost:9001", "u", "p");
        var output = new StringWriter();

        var exit = await AuditBackfillHelpers.RunBackfillAsync(
            client,
            new AuditBackfillSourceNodeArgs { Sentinel = "unknown", Before = "2026-01-01T00:00:00Z" },
            output);

        Assert.Equal(2, exit);
    }

    [Fact]
    public async Task RunBackfill_Http500_ReturnsExitCode1()
    {
        var handler = new CapturingHandler(HttpStatusCode.InternalServerError,
            "{\"error\":\"boom\",\"code\":\"INTERNAL\"}");
        var client = new ManagementHttpClient(new HttpClient(handler), "http://localhost:9001", "u", "p");
        var output = new StringWriter();

        var exit = await AuditBackfillHelpers.RunBackfillAsync(
            client,
            new AuditBackfillSourceNodeArgs { Sentinel = "unknown", Before = "2026-01-01T00:00:00Z" },
            output);

        Assert.Equal(1, exit);
    }

    // ─────────────────────────────────────────────────────────────────────
    // CLI parsing
    // ─────────────────────────────────────────────────────────────────────

    [Fact]
    public void BackfillSourceNode_Subcommand_ExistsInAuditCommandGroup()
    {
        var root = AuditCommandTestHarness.BuildRoot();
        var parse = root.Parse(new[] { "audit", "backfill-source-node", "--help" });
        Assert.Empty(parse.Errors);
    }

    [Fact]
    public void BackfillSourceNode_BeforeOption_IsRequired()
    {
        var root = AuditCommandTestHarness.BuildRoot();
        var (exit, _, err) = AuditCommandTestHarness.Invoke(root, "audit", "backfill-source-node");
        Assert.NotEqual(0, exit);
    }

    [Fact]
    public void BackfillSourceNode_HelpText_DescribesSentinelAndBefore()
    {
        var root = AuditCommandTestHarness.BuildRoot();
        var output = new StringWriter();
        var exit = root.Parse(new[] { "audit", "backfill-source-node", "--help" })
            .Invoke(new InvocationConfiguration { Output = output });

        Assert.Equal(0, exit);
        var text = output.ToString();
        Assert.Contains("sentinel", text, StringComparison.OrdinalIgnoreCase);
        Assert.Contains("before", text, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public void BackfillSourceNode_DefaultSentinel_IsUnknown()
    {
        // Verify the default sentinel value is "unknown" as documented.
        var url = new Option<string>("--url") { Recursive = true };
        var username = new Option<string>("--username") { Recursive = true };
        var password = new Option<string>("--password") { Recursive = true };
        var format = CliOptions.CreateFormatOption();

        var auditGroup = AuditCommands.Build(url, format, username, password);
        var backfillCmd = auditGroup.Subcommands
            .FirstOrDefault(c => c.Name == "backfill-source-node");

        Assert.NotNull(backfillCmd);

        // The subcommand exists and its description mentions maintenance/sentinel.
        Assert.False(string.IsNullOrWhiteSpace(backfillCmd!.Description));
    }
}