using System.Text.Json;

namespace Zcbot.WindowsNode;

internal enum JobRecoveryAction
{
    ResumeExecution,
    ResumeOutputUpload,
    ReplayTerminal,
    None,
}

internal sealed record JobRecoveryDecision(
    RecoverableJob Job,
    JobRecoveryAction Action);

internal sealed class JobRecoveryService(JobRepository repository)
{
    internal IReadOnlyList<JobRecoveryDecision> Scan() =>
        repository.ReadRecoverableJobs()
            .Select(job => new JobRecoveryDecision(job, Decide(job)))
            .ToArray();

    internal static JobRecoveryAction Decide(RecoverableJob job)
    {
        if (job.Terminal is not JsonElement terminal)
        {
            return JobRecoveryAction.ResumeExecution;
        }
        if (terminal.GetProperty("status").GetString() != JobStateMachine.Succeeded)
        {
            return JobRecoveryAction.ReplayTerminal;
        }
        return job.UploadComplete || job.CloudTerminal
            ? JobRecoveryAction.None
            : JobRecoveryAction.ResumeOutputUpload;
    }
}