using System.Text.Json;
using Agent.Core.Ollama;
using Agent.Core.Runtime;
using Agent.Core.Tools;

namespace Agent.App.Logging;

public sealed class JsonLinesRuntimeObserver : IAgentRuntimeObserver, IDisposable
{
    private readonly RollingFileWriter _writer;

    public JsonLinesRuntimeObserver(string logDirectory, long maxBytes = 10 * 1024 * 1024, int retainedFiles = 5) =>
        _writer = new RollingFileWriter(Path.Combine(logDirectory, "llm.jsonl"), maxBytes, retainedFiles);

    public void LlmRequest(AgentLlmCallContext context, IReadOnlyList<OllamaMessage> messages) => Write(new
    {
        timestamp = DateTimeOffset.UtcNow, event_name = "llm.request", call_id = context.CallId,
        session_id = context.SessionId, task_id = context.TaskId, planner_task_id = context.PlannerTaskId,
        phase = context.Phase, iteration = context.Iteration, replan = context.Replan, model = context.Model,
        messages = messages.Select(static message => new { role = message.Role, content = message.Content, image_count = message.Images?.Count ?? 0, tool_name = message.ToolName })
    });

    public void LlmResponse(AgentLlmCallContext context, OllamaResult result) => Write(new
    {
        timestamp = DateTimeOffset.UtcNow, event_name = "llm.response", call_id = context.CallId,
        session_id = context.SessionId, task_id = context.TaskId, planner_task_id = context.PlannerTaskId,
        phase = context.Phase, iteration = context.Iteration, replan = context.Replan, model = context.Model,
        content = result.Content, input_tokens = result.InputTokens, output_tokens = result.OutputTokens,
        tool_calls = result.ToolCalls?.Select(static call => call.Function.Name).ToArray() ?? []
    });

    public void LlmFailure(AgentLlmCallContext context, string errorCode, string message) => Write(new
    {
        timestamp = DateTimeOffset.UtcNow, event_name = "llm.failure", call_id = context.CallId,
        session_id = context.SessionId, task_id = context.TaskId, planner_task_id = context.PlannerTaskId,
        phase = context.Phase, iteration = context.Iteration, replan = context.Replan, model = context.Model,
        error_code = errorCode, message
    });

    public void ToolResult(AgentLlmCallContext context, string toolName, ToolExecutionResult result) => Write(new
    {
        timestamp = DateTimeOffset.UtcNow, event_name = "llm.tool_result", call_id = context.CallId,
        session_id = context.SessionId, task_id = context.TaskId, planner_task_id = context.PlannerTaskId,
        phase = context.Phase, iteration = context.Iteration, replan = context.Replan, model = context.Model, tool_name = toolName,
        success = result.Success, external_effect = result.ExternalEffect, retry_allowed = result.RetryAllowed,
        output = result.Output, failure_fingerprint = result.FailureFingerprint
    });

    private void Write(object value)
    {
        _writer.WriteLine(JsonSerializer.Serialize(value));
    }

    public void Dispose() => _writer.Dispose();
}