using System.ComponentModel;
using ClaudeDo.Data.Models;
using ClaudeDo.Data.Repositories;
using ModelContextProtocol.Server;

namespace ClaudeDo.Worker.External;

public sealed record RunDto(
    string Id, int RunNumber, string? SessionId, bool IsRetry,
    string? ResultMarkdown, string? StructuredOutputJson, string? ErrorMarkdown,
    int? ExitCode, int? TurnCount, int? TokensIn, int? TokensOut,
    DateTime? StartedAt, DateTime? FinishedAt);

[McpServerToolType]
public sealed class RunHistoryMcpTools
{
    private readonly TaskRunRepository _runs;

    public RunHistoryMcpTools(TaskRunRepository runs) => _runs = runs;

    [McpServerTool, Description("List all execution runs for a task (newest run metadata, tokens, turns, result, error).")]
    public async Task<IReadOnlyList<RunDto>> ListRuns(string taskId, CancellationToken cancellationToken)
    {
        var runs = await _runs.GetByTaskIdAsync(taskId, cancellationToken);
        return runs.Select(ToDto).ToList();
    }

    [McpServerTool, Description("Get a single execution run by its run id.")]
    public async Task<RunDto> GetRun(string runId, CancellationToken cancellationToken)
    {
        var run = await _runs.GetByIdAsync(runId, cancellationToken)
            ?? throw new InvalidOperationException($"Run {runId} not found.");
        return ToDto(run);
    }

    private const int MaxLogBytes = 256 * 1024;

    [McpServerTool, Description("Fetch the raw log output of a task's latest run. Throws if no log is available.")]
    public async Task<string> GetTaskLog(string taskId, CancellationToken cancellationToken)
    {
        var run = await _runs.GetLatestByTaskIdAsync(taskId, cancellationToken)
            ?? throw new InvalidOperationException($"No runs found for task {taskId}.");
        if (string.IsNullOrWhiteSpace(run.LogPath) || !File.Exists(run.LogPath))
            throw new InvalidOperationException("No log available for the latest run.");

        var totalBytes = new FileInfo(run.LogPath).Length;
        if (totalBytes <= MaxLogBytes)
            return await File.ReadAllTextAsync(run.LogPath, cancellationToken);

        var buffer = new byte[MaxLogBytes];
        await using var fs = new FileStream(run.LogPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
        fs.Seek(totalBytes - MaxLogBytes, SeekOrigin.Begin);
        var read = await fs.ReadAsync(buffer, cancellationToken);
        var tail = System.Text.Encoding.UTF8.GetString(buffer, 0, read);
        return $"[truncated: showing last {MaxLogBytes} of {totalBytes} bytes]\n{tail}";
    }

    private static RunDto ToDto(TaskRunEntity r) => new(
        r.Id, r.RunNumber, r.SessionId, r.IsRetry,
        r.ResultMarkdown, r.StructuredOutputJson, r.ErrorMarkdown,
        r.ExitCode, r.TurnCount, r.TokensIn, r.TokensOut,
        r.StartedAt, r.FinishedAt);
}