using ClawdDotNet.Core.Engine;
using ClawdDotNet.Core.Sandbox;

namespace ClawdDotNet.Core.Runtimes;

/// <summary>
/// #712: A program as the runtime — for special cases, and the way to try the whole path
/// without a model. The message comes on stdin, the briefing in the file named by
/// <c>CLAWD_BRIEFING_FILE</c>; what the program prints is the result. A non-zero exit code
/// is a failure, with the end of stderr as its reason.
///
/// <para>The program can reach the MCP server itself: <c>$CLAWD_HELPER --mcp-bridge --socket
/// $CLAWD_MCP_SOCKET</c> with the token file in <c>CLAWD_MCP_TOKEN_FILE</c>.</para>
/// </summary>
public sealed class CommandRuntime : IForeignRuntime
{
    public string Kind => RuntimeKinds.Command;

    public SandboxRequest Prepare(ForeignRunContext context)
    {
        var runtime = context.Agent.Runtime;
        if (string.IsNullOrWhiteSpace(runtime.Command))
            throw new ForeignRunException("No command configured for this agent ('runtime.command').");

        File.WriteAllText(Path.Combine(context.PrivateDirectory, ForeignRunContext.BriefingFileName), context.Briefing);

        var command = runtime.Command.Trim();
        var readOnly = new List<string>(context.HelperPaths());
        if (Path.IsPathRooted(command))
        {
            var directory = Path.GetDirectoryName(command)!;
            if (!directory.StartsWith("/usr/", StringComparison.Ordinal) && directory != "/bin")
                readOnly.Add(directory);
        }
        else if (command.Contains('/'))
        {
            // Relative to the workspace — the run's copy of it.
            command = SandboxPaths.Work + "/" + command.TrimStart('.', '/');
        }

        return new SandboxRequest
        {
            Executable = command,
            Arguments = runtime.Arguments,
            WorkspacePath = context.WorkCopy,
            ProtectedPaths = [],
            ReadOnlyPaths = readOnly,
            Mounts = context.Mounts(),
            Environment = context.McpEnvironment(),
            Egress = runtime.Egress,
            StandardInput = context.Message,
            Limits = ForeignRunner.Limits(runtime)
        };
    }

    public ForeignRunOutcome Interpret(SandboxResult result, ForeignRunContext context, Action<string> note)
    {
        if (result.TimedOut)
            return new ForeignRunOutcome { Status = AgentRunStatus.Cancelled, Text = "[The command timed out]" + ClaudeCodeRuntime.Tail(result.StandardError) };
        if (result.OutputTruncated)
            return new ForeignRunOutcome { Status = AgentRunStatus.Failed, Text = "[The command produced more output than allowed]" };
        if (result.ExitCode != 0)
            return new ForeignRunOutcome
            {
                Status = AgentRunStatus.Failed,
                Text = $"[The command ended with exit code {result.ExitCode}]" + ClaudeCodeRuntime.Tail(result.StandardError)
            };
        return new ForeignRunOutcome { Status = AgentRunStatus.Completed, Text = result.StandardOutput.Trim(), Turns = 1 };
    }
}