using System.Collections.Concurrent;
using System.CommandLine;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.Json;
using ZB.MOM.WW.ScadaBridge.CLI;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;

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

/// <summary>
/// Drives the production command tree against a loopback recorder. Every public
/// management contract must actually cross HTTP from a CLI action. A constructor
/// reference, an unregistered group, or a help-only leaf cannot satisfy this gate.
/// Server replies are deliberate errors so no local success handlers write exports.
/// </summary>
[Collection("Console")]
public class ManagementSurfaceParityTests
{
    /// <summary>Verifies that every HTTP management contract is sent by the production CLI.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task EveryHttpManagementContract_IsSentByTheProductionCli()
    {
        var sent = await ProbeProductionTree();
        var registered = typeof(ManagementEnvelope).Assembly.GetTypes()
            .Where(t => t.Namespace == typeof(ManagementEnvelope).Namespace && !t.IsAbstract
                && t.Name.EndsWith("Command", StringComparison.Ordinal))
            .Where(t => ManagementCommandRegistry.Resolve(t.Name[..^7]) == t)
            .Select(ManagementCommandRegistry.GetCommandName).ToHashSet();
        var missing = registered.Except(sent.Keys).Order().ToArray();
        Assert.True(missing.Length == 0, "No CLI dispatch for: " + string.Join(", ", missing));
        Assert.Empty(sent.Keys.Except(registered));
    }

    /// <summary>Verifies that removing a production schema group is detected by the parity probe.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task RemovingProductionSchemaGroup_IsDetectedByParityProbe()
    {
        var sent = await ProbeProductionTree(omitGroup: "shared-schema");
        Assert.DoesNotContain("ListSharedSchemas", sent.Keys);
        Assert.Contains("ListSharedScripts", sent.Keys);
    }

    private static async Task<ConcurrentDictionary<string, string>> ProbeProductionTree(string? omitGroup = null)
    {
        var root = CliApplication.BuildRoot();
        var recorded = new ConcurrentDictionary<string, string>();
        var directory = Directory.CreateTempSubdirectory("cli-parity-");
        var file = Path.Combine(directory.FullName, "input.json");
        await File.WriteAllTextAsync(file, "{}");
        var csv = Path.Combine(directory.FullName, "native.csv");
        await File.WriteAllTextAsync(csv, "SourceName,Connection,SourceReference,Filter\nSource,Connection,Path,\n");
        using var stop = new CancellationTokenSource(TimeSpan.FromSeconds(30));
        var listener = new TcpListener(IPAddress.Loopback, 0);
        listener.Start();
        var url = $"http://127.0.0.1:{((IPEndPoint)listener.LocalEndpoint).Port}";
        var currentPath = "";
        var server = Task.Run(async () =>
        {
            try
            {
                while (!stop.IsCancellationRequested)
                {
                    using var client = await listener.AcceptTcpClientAsync(stop.Token);
                    await using var stream = client.GetStream();
                    using var reader = new StreamReader(stream, Encoding.UTF8, leaveOpen: true);
                    var length = 0;
                    while (await reader.ReadLineAsync(stop.Token) is { Length: > 0 } line)
                        if (line.StartsWith("Content-Length:", StringComparison.OrdinalIgnoreCase))
                            length = int.Parse(line[15..].Trim());
                    var buffer = new char[length];
                    var read = 0;
                    while (read < length)
                    {
                        var count = await reader.ReadAsync(buffer.AsMemory(read), stop.Token);
                        if (count == 0) throw new EndOfStreamException();
                        read += count;
                    }
                    using var body = JsonDocument.Parse(new string(buffer));
                    recorded[body.RootElement.GetProperty("command").GetString()!] = currentPath;
                    const string response = "{\"error\":\"parity probe\",\"code\":\"PROBE\"}";
                    var bytes = Encoding.UTF8.GetBytes($"HTTP/1.1 400 Bad Request\r\nContent-Type: application/json\r\nContent-Length: {response.Length}\r\nConnection: close\r\n\r\n{response}");
                    await stream.WriteAsync(bytes, stop.Token);
                }
            }
            catch (OperationCanceledException) when (stop.IsCancellationRequested) { }
        }, stop.Token);
        try
        {
            foreach (var (leaf, path) in Leaves(root, []))
            {
                // Separate REST and persistent SignalR surfaces, not management contracts.
                if (path.Length == 0 || path[0] == "audit" || path[0] == omitGroup
                    || string.Join(' ', path) == "debug stream") continue;
                currentPath = string.Join(' ', path);
                var args = new List<string>(path);
                foreach (var option in leaf.Options.Where(o => o.Required))
                {
                    args.Add(option.Name);
                    args.Add(ValueFor(option, currentPath, file, csv));
                }
                AddConditionalOptions(args, currentPath);
                args.AddRange(["--url", url, "--username", "probe", "--password", "probe", "--format", "json"]);
                var parse = root.Parse(args.ToArray());
                // Some convenience aliases require richer local files/preflight replies;
                // other leaves must still emit every contract. Missing coverage fails above.
                if (parse.Errors.Count > 0) continue;
                await parse.InvokeAsync().WaitAsync(stop.Token);
            }
        }
        finally
        {
            await stop.CancelAsync();
            listener.Stop();
            await server;
            directory.Delete(recursive: true);
        }
        return recorded;
    }

    private static IEnumerable<(Command Leaf, string[] Path)> Leaves(Command command, string[] path)
    {
        if (command.Subcommands.Count == 0) yield return (command, path);
        foreach (var child in command.Subcommands)
            foreach (var entry in Leaves(child, [.. path, child.Name])) yield return entry;
    }

    private static string ValueFor(Option option, string path, string file, string csv)
    {
        var type = option.GetType().GetGenericArguments().FirstOrDefault();
        type = Nullable.GetUnderlyingType(type ?? typeof(string)) ?? type;
        if (type == typeof(int) || type == typeof(long) || type == typeof(double)) return "1";
        if (type == typeof(Guid)) return "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa";
        if (type == typeof(bool)) return "true";
        if (type?.IsEnum == true) return Enum.GetNames(type)[0];
        return option.Name switch
        {
            "--schema-file" or "--input" or "--config-file" or "--der-file" => file,
            "--output" => file + ".out",
            "--file" => csv,
            "--bindings" => "[[\"Value\",1]]",
            "--direction" => "up",
            "--overrides" or "--config" => "{}",
            "--value-json" => "1",
            "--data-type" or "--value-type" => "Int32",
            "--trigger-type" => "Periodic",
            "--auth-type" or "--auth-mode" => "None",
            "--http-method" => "GET",
            "--type" => "OpcUa",
            "--endpoint-url" => "http://localhost",
            "--account-sid" => "AC" + new string('a', 32),
            "--from-address" => "sender@example.test",
            "--thumbprint" => new string('A', 40),
            "--role" => "Designer",
            "--code" or "--script" => "return null;",
            _ => "fixture"
        };
    }

    private static void AddConditionalOptions(List<string> args, string path)
    {
        if (path is "notification create" or "notification update")
            args.AddRange(["--emails", "recipient@example.test"]);
        if (path is "notification sms create" or "notification sms update")
            args.AddRange(["--from-number", "+15551234567"]);
        if (path == "notification sms create") args.AddRange(["--auth-token", "test-token"]);
        if (path == "notification recipient add") args.AddRange(["--email", "recipient@example.test"]);
    }
}