using System.Net;
using System.Text;
using System.Text.Json;
using Clawdforge;
using Clawdforge.Exceptions;
using Clawdforge.Models;
using Xunit;

namespace Clawdforge.Tests;

/// <summary>
/// Tests use a custom <see cref="HttpMessageHandler"/> mock — zero extra
/// dependencies, more idiomatic for an SDK than spinning up an ASP.NET
/// TestHost.
/// </summary>
public class ForgeClientTests
{
    [Fact]
    public async Task Healthz_ReturnsParsedBody()
    {
        var handler = new MockHandler((req, ct) =>
        {
            Assert.Equal(HttpMethod.Get, req.Method);
            Assert.Equal("/healthz", req.RequestUri!.AbsolutePath);
            return JsonResponse(new
            {
                ok = true,
                claude_present = true,
                claude_version = "1.2.3 (Claude Code)",
            });
        });

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var h = await client.HealthzAsync();

        Assert.True(h.Ok);
        Assert.True(h.ClaudePresent);
        Assert.Equal("1.2.3 (Claude Code)", h.ClaudeVersion);
    }

    [Fact]
    public async Task Run_SerializesSnakeCase_AndDeserializesResult()
    {
        string? capturedBody = null;
        string? capturedAuth = null;

        var handler = new MockHandler(async (req, ct) =>
        {
            Assert.Equal(HttpMethod.Post, req.Method);
            Assert.Equal("/run", req.RequestUri!.AbsolutePath);
            capturedAuth = req.Headers.Authorization?.ToString();
            capturedBody = await req.Content!.ReadAsStringAsync(ct);

            return JsonResponse(new
            {
                ok = true,
                result = new { hello = "world" },
                duration_ms = 4321,
                stop_reason = "end_turn",
            });
        });

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test/", Token = "cf_test" },
            http);

        var res = await client.RunAsync(new RunRequest
        {
            Prompt = "Reply with JSON: {\"hello\":\"world\"}",
            Model = "sonnet",
            TimeoutSecs = 60,
        });

        Assert.True(res.Ok);
        Assert.Equal(4321, res.DurationMs);
        Assert.Equal("end_turn", res.StopReason);
        Assert.Equal(JsonValueKind.Object, res.Result.ValueKind);
        Assert.Equal("world", res.Result.GetProperty("hello").GetString());

        Assert.Equal("Bearer cf_test", capturedAuth);
        Assert.NotNull(capturedBody);
        // Verify wire shape: snake_case + no nulls.
        using var doc = JsonDocument.Parse(capturedBody!);
        Assert.True(doc.RootElement.TryGetProperty("prompt", out _));
        Assert.True(doc.RootElement.TryGetProperty("model", out _));
        Assert.True(doc.RootElement.TryGetProperty("timeout_secs", out _));
        Assert.False(doc.RootElement.TryGetProperty("system", out _));
        Assert.False(doc.RootElement.TryGetProperty("files", out _));
    }

    [Fact]
    public async Task Run_PropagatesStringResult_AsJsonElementString()
    {
        var handler = new MockHandler((req, ct) => JsonResponse(new
        {
            ok = true,
            result = "plain text reply",
            duration_ms = 100,
            stop_reason = "end_turn",
        }));

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var res = await client.RunAsync(new RunRequest { Prompt = "x" });
        Assert.Equal(JsonValueKind.String, res.Result.ValueKind);
        Assert.Equal("plain text reply", res.AsText());
    }

    [Fact]
    public async Task Run_AsJsonGenericRoundtrips()
    {
        var handler = new MockHandler((req, ct) => JsonResponse(new
        {
            ok = true,
            result = new { qty = 2, unit = "cup", food = "rice" },
            duration_ms = 1,
            stop_reason = "end_turn",
        }));

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var res = await client.RunAsync(new RunRequest { Prompt = "x" });
        var ing = res.AsJson<Ingredient>();
        Assert.NotNull(ing);
        Assert.Equal(2, ing!.Qty);
        Assert.Equal("cup", ing.Unit);
        Assert.Equal("rice", ing.Food);
    }

    [Fact]
    public async Task Run_401_RaisesForgeAuthException()
    {
        var handler = new MockHandler((req, ct) =>
            JsonResponse(new { detail = "Not authenticated" }, HttpStatusCode.Unauthorized));

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_bad" },
            http);

        var ex = await Assert.ThrowsAsync<ForgeAuthException>(() =>
            client.RunAsync(new RunRequest { Prompt = "x" }));
        Assert.Equal(401, ex.StatusCode);
        Assert.Contains("Not authenticated", ex.Body);
    }

    [Fact]
    public async Task Run_502_RaisesForgeApiException_WithRunFailureBody()
    {
        var handler = new MockHandler((req, ct) =>
            JsonResponse(new
            {
                ok = false,
                error = "timeout after 30s",
                stderr = "...",
                duration_ms = 30001,
                stop_reason = "timeout",
            }, HttpStatusCode.BadGateway));

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var ex = await Assert.ThrowsAsync<ForgeApiException>(() =>
            client.RunAsync(new RunRequest { Prompt = "x" }));
        Assert.Equal(502, ex.StatusCode);
        // Auth exception type must NOT match — only ForgeApiException.
        Assert.IsNotType<ForgeAuthException>(ex);
        Assert.Contains("timeout", ex.Body);
    }

    [Fact]
    public async Task Run_TransportFailure_RaisesForgeTransportException()
    {
        var handler = new MockHandler((HttpRequestMessage req, CancellationToken ct) =>
            Task.FromException<HttpResponseMessage>(new HttpRequestException("connection refused")));

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var ex = await Assert.ThrowsAsync<ForgeTransportException>(() =>
            client.RunAsync(new RunRequest { Prompt = "x" }));
        Assert.IsType<HttpRequestException>(ex.InnerException);
    }

    [Fact]
    public async Task Run_HonorsCancellation()
    {
        var handler = new MockHandler(async (req, ct) =>
        {
            await Task.Delay(TimeSpan.FromSeconds(10), ct);
            return JsonResponse(new { ok = true, result = "x", duration_ms = 0, stop_reason = "end_turn" });
        });

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        using var cts = new CancellationTokenSource(TimeSpan.FromMilliseconds(50));
        await Assert.ThrowsAnyAsync<OperationCanceledException>(() =>
            client.RunAsync(new RunRequest { Prompt = "x" }, cts.Token));
    }

    [Fact]
    public async Task UploadFile_StreamsMultipart_AndReturnsToken()
    {
        var seenBoundary = false;
        var seenTtl = false;
        var seenFile = false;

        var fileName = $"forge-upload-{Guid.NewGuid():N}.txt";
        var tmp = Path.Combine(Path.GetTempPath(), fileName);

        var handler = new MockHandler(async (req, ct) =>
        {
            Assert.Equal(HttpMethod.Post, req.Method);
            Assert.Equal("/files", req.RequestUri!.AbsolutePath);
            var contentType = req.Content!.Headers.ContentType!;
            Assert.Equal("multipart/form-data", contentType.MediaType);
            Assert.NotNull(contentType.Parameters.SingleOrDefault(p => p.Name == "boundary"));
            seenBoundary = true;

            var body = await req.Content.ReadAsStringAsync(ct);
            // .NET's MultipartFormDataContent emits unquoted name= / filename= params.
            seenTtl = body.Contains("name=ttl_secs") && body.Contains("3600");
            seenFile = body.Contains("name=file")
                       && body.Contains($"filename={fileName}")
                       && body.Contains("hello forge");

            return JsonResponse(new { file_token = "ff_abc123", ttl_secs = 3600, size = 11 });
        });

        await File.WriteAllTextAsync(tmp, "hello forge");
        try
        {
            using var http = new HttpClient(handler);
            using var client = new ForgeClient(
                new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
                http);

            var ft = await client.UploadFileAsync(tmp, ttlSecs: 3600);
            Assert.Equal("ff_abc123", ft.Token);
            Assert.Equal(3600, ft.TtlSecs);
            Assert.Equal(11, ft.Size);
        }
        finally
        {
            File.Delete(tmp);
        }

        Assert.True(seenBoundary);
        Assert.True(seenTtl, "ttl_secs field not found in multipart body");
        Assert.True(seenFile, "file field/filename not found in multipart body");
    }

    [Fact]
    public async Task AdminTokens_FullCrudCycle()
    {
        var calls = new List<(HttpMethod method, string path, string? body)>();

        var handler = new MockHandler(async (req, ct) =>
        {
            string? body = null;
            if (req.Content is not null)
            {
                body = await req.Content.ReadAsStringAsync(ct);
            }
            calls.Add((req.Method, req.RequestUri!.AbsolutePath, body));

            return req.Method.Method switch
            {
                "POST" => JsonResponse(new
                {
                    name = "petalparse",
                    token = "cf_secret_xyz",
                    ip_cidrs = new[] { "172.24.0.0/16" },
                }),
                "GET" => JsonResponse(new
                {
                    tokens = new object[]
                    {
                        new { name = "petalparse", ip_cidrs = new[] { "172.24.0.0/16" }, created_at = 1714000000 },
                        new { name = "cauldron", ip_cidrs = Array.Empty<string>(), created_at = 1714000100 },
                    },
                }),
                "DELETE" => JsonResponse(new { ok = true }),
                _ => new HttpResponseMessage(HttpStatusCode.MethodNotAllowed),
            };
        });

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "admin-token" },
            http);

        var created = await client.CreateTokenAsync(new CreateTokenRequest
        {
            Name = "petalparse",
            IpCidrs = new[] { "172.24.0.0/16" },
        });
        Assert.Equal("petalparse", created.Name);
        Assert.Equal("cf_secret_xyz", created.Token);

        var list = await client.ListTokensAsync();
        Assert.Equal(2, list.Count);
        Assert.Contains(list, t => t.Name == "cauldron");

        await client.RevokeTokenAsync("petalparse");

        Assert.Equal(3, calls.Count);
        Assert.Equal("/admin/tokens", calls[0].path);
        Assert.Equal("/admin/tokens", calls[1].path);
        Assert.Equal("/admin/tokens/petalparse", calls[2].path);
    }

    [Fact]
    public async Task RunRequest_WithoutPrompt_ThrowsArgumentException()
    {
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" });

        await Assert.ThrowsAsync<ArgumentException>(() =>
            client.RunAsync(new RunRequest { Prompt = "" }));
    }

    [Fact]
    public async Task RunRequest_PromptWithOnlyWhitespace_Rejected()
    {
        // Audit L4: required-string args use IsNullOrWhiteSpace consistently —
        // a prompt of " \t\n " is not a meaningful request.
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" });

        await Assert.ThrowsAsync<ArgumentException>(() =>
            client.RunAsync(new RunRequest { Prompt = " \t\n " }));
    }

    [Fact]
    public async Task CreateToken_NameWithOnlyWhitespace_Rejected()
    {
        // Audit L4: required-string args use IsNullOrWhiteSpace consistently.
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "admin-token" });

        await Assert.ThrowsAsync<ArgumentException>(() =>
            client.CreateTokenAsync(new CreateTokenRequest { Name = "   " }));
    }

    [Fact]
    public void BaseUrl_IsTrimmedAtConstruction()
    {
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test/", Token = "cf_test" });

        Assert.Equal("http://forge.test", client.BaseUrl);
    }

    [Fact]
    public void BaseUrl_Cached_ReusesString()
    {
        // Audit nit: BaseUrl getter shouldn't rebuild the string on every
        // access. Identity check confirms a single cached instance.
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test/", Token = "cf_test" });

        var first = client.BaseUrl;
        var second = client.BaseUrl;
        Assert.Same(first, second);
    }

    [Fact]
    public async Task JsonOpts_MaxDepth_RejectsDeeplyNested()
    {
        // Audit M1: ForgeClient JsonOpts must cap deserialization depth so
        // the server's `result` field can't stack-walk the runtime via
        // pathological nesting. We synthesize a 200-deep object and verify
        // the SDK surfaces a transport exception (JsonException-wrapped),
        // NOT a stack-overflow / process termination.
        var deepResult = new string('[', 200) + new string(']', 200);
        var body = "{\"ok\":true,\"result\":" + deepResult
                 + ",\"duration_ms\":1,\"stop_reason\":\"end_turn\"}";

        var handler = new MockHandler((req, ct) => new HttpResponseMessage(HttpStatusCode.OK)
        {
            Content = new StringContent(body, Encoding.UTF8, "application/json"),
        });

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var ex = await Assert.ThrowsAsync<ForgeTransportException>(() =>
            client.RunAsync(new RunRequest { Prompt = "x" }));
        Assert.IsType<JsonException>(ex.InnerException);
    }

    [Fact]
    public async Task SummarizeBody_DeeplyNestedHandled()
    {
        // Audit M2: SummarizeBody parses the error body to extract a
        // `detail`/`error`/`message` string. A hostile error body with
        // pathological nesting must not crash the summarize path — the
        // JsonDocumentOptions.MaxDepth=32 cap means JsonDocument.Parse
        // throws JsonException, which SummarizeBody swallows. Verify the
        // 401 still surfaces as ForgeAuthException with body intact.
        var deeplyNestedBody = "{\"detail\":" + new string('[', 200) + new string(']', 200) + "}";

        var handler = new MockHandler((req, ct) => new HttpResponseMessage(HttpStatusCode.Unauthorized)
        {
            Content = new StringContent(deeplyNestedBody, Encoding.UTF8, "application/json"),
        });

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var ex = await Assert.ThrowsAsync<ForgeAuthException>(() =>
            client.RunAsync(new RunRequest { Prompt = "x" }));
        Assert.Equal(401, ex.StatusCode);
        // Raw body is preserved verbatim; only the summary parse is gated.
        Assert.Contains("detail", ex.Body);
    }

    [Fact]
    public async Task UploadStreamAsync_DisposesCallerStream()
    {
        // Audit M3: documented contract is that the caller's stream IS
        // disposed by the SDK once the request completes (matches
        // HttpClient/MultipartFormDataContent/StreamContent convention).
        var handler = new MockHandler((req, ct) =>
            JsonResponse(new { file_token = "ff_x", ttl_secs = 3600, size = 5 }));

        using var http = new HttpClient(handler);
        using var client = new ForgeClient(
            new ForgeOptions { BaseUrl = "http://forge.test", Token = "cf_test" },
            http);

        var observed = new DisposeObservingStream(new MemoryStream(Encoding.UTF8.GetBytes("hello")));
        var ft = await client.UploadStreamAsync(observed, "hello.txt", ttlSecs: 3600);

        Assert.Equal("ff_x", ft.Token);
        Assert.True(observed.WasDisposed,
            "UploadStreamAsync should dispose the caller's stream — see README contract.");
    }

    [Fact]
    public void AsJson_OnUndefinedResult_DefaultReturned()
    {
        // Audit L2: RunResult.AsJson<T>() previously threw InvalidOperationException
        // when Result.ValueKind == Undefined (default JsonElement). Guarded
        // to return default(T) instead.
        var rr = new RunResult { Ok = true, DurationMs = 0 };
        Assert.Equal(JsonValueKind.Undefined, rr.Result.ValueKind);

        // Reference type: returns null.
        Assert.Null(rr.AsJson<Ingredient>());
        // Value type: returns default(int) = 0.
        Assert.Equal(0, rr.AsJson<int>());
    }

    // ---- helpers -----------------------------------------------------------

    private static HttpResponseMessage JsonResponse(object payload, HttpStatusCode status = HttpStatusCode.OK)
    {
        var json = JsonSerializer.Serialize(payload);
        return new HttpResponseMessage(status)
        {
            Content = new StringContent(json, Encoding.UTF8, "application/json"),
        };
    }

    private sealed class Ingredient
    {
        public int Qty { get; init; }
        public string Unit { get; init; } = string.Empty;
        public string Food { get; init; } = string.Empty;
    }

    /// <summary>
    /// Wraps an inner stream and flips a flag the first time
    /// <see cref="Stream.Dispose(bool)"/> runs. Used by the
    /// UploadStreamAsync disposal-contract test.
    /// </summary>
    private sealed class DisposeObservingStream : Stream
    {
        private readonly Stream _inner;
        public bool WasDisposed { get; private set; }

        public DisposeObservingStream(Stream inner) { _inner = inner; }

        public override bool CanRead => _inner.CanRead;
        public override bool CanSeek => _inner.CanSeek;
        public override bool CanWrite => _inner.CanWrite;
        public override long Length => _inner.Length;
        public override long Position { get => _inner.Position; set => _inner.Position = value; }

        public override void Flush() => _inner.Flush();
        public override int Read(byte[] buffer, int offset, int count) => _inner.Read(buffer, offset, count);
        public override long Seek(long offset, SeekOrigin origin) => _inner.Seek(offset, origin);
        public override void SetLength(long value) => _inner.SetLength(value);
        public override void Write(byte[] buffer, int offset, int count) => _inner.Write(buffer, offset, count);

        protected override void Dispose(bool disposing)
        {
            WasDisposed = true;
            if (disposing) _inner.Dispose();
            base.Dispose(disposing);
        }
    }

    private sealed class MockHandler : HttpMessageHandler
    {
        private readonly Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> _handler;

        public MockHandler(Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> handler)
        {
            _handler = handler;
        }

        public MockHandler(Func<HttpRequestMessage, CancellationToken, HttpResponseMessage> handler)
            : this((req, ct) => Task.FromResult(handler(req, ct))) { }

        protected override Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request,
            CancellationToken cancellationToken)
        {
            return _handler(request, cancellationToken);
        }
    }
}