using System.Globalization;

namespace w4c_workflows.Services.Execution;

/// <summary>
/// A <c>task.result</c> event as consumed by the run lifecycle engine. The
/// worker publishes these via <see cref="TaskResultMessage.ToFields"/>; this
/// record is the control-plane parse of the same flat field names.
/// </summary>
public sealed record TaskResult(
    string RunId,
    string TaskId,
    int Attempt,
    string TenantId,
    bool Success,
    int ExitCode,
    string? Output,
    string? Error,
    long DurationMs)
{
    /// <summary>Parses a stream message into a result, throwing if a required field is missing.</summary>
    public static TaskResult FromFields(IReadOnlyDictionary<string, string> fields)
    {
        static string Get(IReadOnlyDictionary<string, string> fields, string key) =>
            fields.TryGetValue(key, out var value) && !string.IsNullOrEmpty(value)
                ? value
                : throw new InvalidOperationException($"missing required result field '{key}'");

        static int GetInt(IReadOnlyDictionary<string, string> fields, string key, int fallback) =>
            fields.TryGetValue(key, out var raw) && int.TryParse(raw, out var n) ? n : fallback;

        static long GetLong(IReadOnlyDictionary<string, string> fields, string key, long fallback) =>
            fields.TryGetValue(key, out var raw) && long.TryParse(raw, NumberStyles.Integer, CultureInfo.InvariantCulture, out var n) ? n : fallback;

        var status = Get(fields, "status");
        return new TaskResult(
            Get(fields, "run_id"),
            Get(fields, "task_id"),
            GetInt(fields, "attempt", 1),
            Get(fields, "tenant_id"),
            string.Equals(status, "succeeded", StringComparison.Ordinal),
            GetInt(fields, "exit_code", -1),
            fields.GetValueOrDefault("output"),
            fields.GetValueOrDefault("error"),
            GetLong(fields, "duration_ms", 0));
    }
}