namespace s8n_runtime;

using System.Text.Json;
using System.Text.Json.Serialization;

public class WorkflowRuntimeRunner
{
    private static readonly JsonSerializerOptions serializerOptions = new(JsonSerializerDefaults.Web)
    {
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
    };
    public static async Task<int> Main<TWorkflow>(string[] args, bool silent = false) where TWorkflow : WorkflowRuntime
    {
        if (!silent) Console.WriteLine("Starting workflow...");

        var cts = new CancellationTokenSource();
        Console.CancelKeyPress += (s, e) =>
        {
            if (!silent) Console.WriteLine("Canceling...");
            cts.Cancel();
            e.Cancel = true;
        };

        async Task<string?> FindWorkflowJsonFile()
        {
            if (args.FirstOrDefault(a => a.EndsWith("workflow.json")) is string jsonArg) return jsonArg;
            if (Environment.GetEnvironmentVariable("WORKFLOW_FILE") is string workflowFile) return workflowFile;

            var testPath = Path.GetFullPath("workflow.json");
            if (File.Exists(testPath))
            {
                return testPath;
            }
            return null;

        }

        var filePath = await FindWorkflowJsonFile();
        TWorkflow runtime;
        if (filePath == null)
        {
            runtime = Activator.CreateInstance<TWorkflow>();
        }
        else
        {
            runtime = JsonSerializer.Deserialize<TWorkflow>(File.OpenRead(filePath), serializerOptions)!;
        }
        runtime.Prepare();

        try
        {
            await runtime.RunAsync(cts.Token);
        }
        catch (TaskCanceledException)
        {
            if (!silent) Console.WriteLine("Canceled.");
        }
        finally
        {
            await runtime.OnStop();
        }


        if (runtime.StoreState == RuntimeStateStoreStrategy.WhenExit)
        {
            if (string.IsNullOrEmpty(filePath) is false)
            {
                JsonSerializer.Serialize(File.OpenWrite(filePath), runtime, serializerOptions);
            }
        }

        if (!silent) Console.WriteLine("Workflow stopped.");
        return 0;
    }
}