using ClawdDotNet.Core.Accounting;
using ClawdDotNet.Core.Engine;
using ClawdDotNet.Core.Mcp;
using ClawdDotNet.Core.Runtimes;
using ClawdDotNet.Core.Sandbox;
using ClawdDotNet.Core.Storage;
using ClawdDotNet.Core.Tests.Infrastructure;
using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;

namespace ClawdDotNet.Core.Tests.Runtimes;

/// <summary>
/// #712: A foreign agent in the engine — it goes to the runner instead of the model, and
/// everything around a run (usage, chat, the refusal without a runner) stays the same.
/// </summary>
public sealed class ForeignRunEngineTests : IDisposable
{
    private readonly string _root = Path.Combine(Path.GetTempPath(), "clawd-tests", "foreign-engine-" + Guid.NewGuid().ToString("N")[..8]);
    private readonly SqliteUsageRepository _usage;
    private readonly EngineFixture _fixture;

    public ForeignRunEngineTests()
    {
        _usage = new SqliteUsageRepository(new SqliteStorage(Path.Combine(_root, "state.db")));
        _fixture = new EngineFixture(usage: _usage);
    }

    public void Dispose()
    {
        SqliteStorage.ReleasePooledConnections(_root);
        try { Directory.Delete(_root, recursive: true); }
        catch { /* cleanup is secondary */ }
    }

    private sealed class ScriptedSandbox(string output) : ISandboxRunner
    {
        public SandboxRequest? Request { get; private set; }
        public bool IsAvailable => true;
        public string? UnavailableReason => null;

        public Task<SandboxResult> RunAsync(SandboxRequest request, CancellationToken ct)
        {
            Request = request;
            return Task.FromResult(new SandboxResult { ExitCode = 0, StandardOutput = output });
        }
    }

    private Core.Config.AgentConfig ForeignAgent(string kind = RuntimeKinds.Command)
    {
        var agent = _fixture.AddAgent("coder");
        agent.AgentDir = Path.Combine(_root, "Agents", "Agent-coder");
        agent.WorkspacePath = Path.Combine(agent.AgentDir, "Workspace");
        Directory.CreateDirectory(agent.WorkspacePath);
        agent.Runtime = new AgentRuntimeConfig { Kind = kind, Command = "/usr/bin/answer" };
        return agent;
    }

    private ScriptedSandbox UseSandbox(string output, ClaudeCodeSettings? claude = null)
    {
        var sandbox = new ScriptedSandbox(output);
        _fixture.Engine.ForeignRunner = new ForeignRunner(sandbox,
            [new CommandRuntime(), new ClaudeCodeRuntime(() => claude ?? new ClaudeCodeSettings())],
            new McpGrants(), null, null, NullLogger.Instance);
        return sandbox;
    }

    [Fact]
    public async Task A_foreign_agent_does_not_reach_the_model()
    {
        var agent = ForeignAgent();
        var sandbox = UseSandbox("answer from the command");

        var result = await _fixture.Engine.RunAsync(agent, "Do it.", "test-instance", CancellationToken.None);

        result.Status.ShouldBe(AgentRunStatus.Completed);
        result.FinalMessage.ShouldBe("answer from the command");
        _fixture.Client.ReceivedRequests.ShouldBeEmpty();
        sandbox.Request!.StandardInput!.ShouldContain("Do it.");
    }

    [Fact]
    public async Task The_briefing_is_the_one_a_native_run_gets()
    {
        var agent = ForeignAgent();
        var sandbox = UseSandbox("ok");

        await _fixture.Engine.RunAsync(agent, "Do it.", "test-instance", CancellationToken.None);

        // The runner removed the run's files; the briefing went to the sandbox through them.
        sandbox.Request!.Environment["CLAWD_BRIEFING_FILE"].ShouldBe("/run/agent/briefing.md");
    }

    [Fact]
    public async Task Without_a_runner_the_agent_does_not_fall_back_to_the_native_engine()
    {
        var agent = ForeignAgent();

        var result = await _fixture.Engine.RunAsync(agent, "Do it.", "test-instance", CancellationToken.None);

        result.Status.ShouldBe(AgentRunStatus.Failed);
        result.FinalMessage!.ShouldContain("not set up");
        _fixture.Client.ReceivedRequests.ShouldBeEmpty();
    }

    [Fact]
    public async Task A_subscription_run_is_recorded_with_its_tokens_and_marked()
    {
        var agent = ForeignAgent(RuntimeKinds.ClaudeCode);
        var claude = Path.Combine(_root, "claude");
        File.WriteAllText(claude, "");
        UseSandbox("""
            {"type":"system","subtype":"init","model":"claude-sonnet-5"}
            {"type":"result","subtype":"success","is_error":false,"num_turns":3,"result":"done","total_cost_usd":0.9,"usage":{"input_tokens":100,"cache_read_input_tokens":900,"output_tokens":50}}
            """, new ClaudeCodeSettings { Executable = claude, Auth = ClaudeCodeSettings.SubscriptionAuth, OAuthToken = "oat" });

        await _fixture.Engine.RunAsync(agent, "Do it.", "test-instance", CancellationToken.None);

        var usage = (await _usage.GetRecentAsync(5, CancellationToken.None)).Single();
        usage.Runtime.ShouldBe(RuntimeKinds.ClaudeCode);
        usage.OnSubscription.ShouldBeTrue();
        usage.CostUsd.ShouldBe(0m, "a subscription does not bill the run");
        usage.CostIsKnown.ShouldBeTrue();
        usage.PromptTokens.ShouldBe(1000);
        usage.CompletionTokens.ShouldBe(50);
        usage.Model.ShouldBe("claude-sonnet-5");
    }

    [Fact]
    public async Task In_a_chat_each_message_is_a_run_and_both_sides_are_shown()
    {
        var agent = ForeignAgent();
        UseSandbox("the answer");

        await _fixture.Engine.ChatAsync(agent, "a question", "test-instance", CancellationToken.None);

        _fixture.Engine.GetChatHistory("coder").Select(e => (e.Role, e.Content)).ShouldBe([
            ("user", "a question"),
            ("assistant", "the answer")
        ]);
    }
}