using System.Globalization;
using System.Text.Json.Nodes;
using w4c_workflows.Models.Nodes;

namespace w4c_workflows.Services.Nodes.Executors;

/// <summary>
/// Wait node. Pauses for the configured duration (per item, since it runs in
/// each-item mode) and then passes the item through unchanged. The delay is
/// capped to protect the in-process run loop from a runaway configuration.
/// </summary>
public sealed class WaitNodeExecutor : INodeExecutor
{
    /// <summary>Upper bound on a single wait, so one node cannot stall the run loop indefinitely.</summary>
    public static readonly TimeSpan MaxDelay = TimeSpan.FromMinutes(5);

    public string Type => "core.wait";

    public async Task<NodeExecutionOutcome> RunAsync(NodeExecutionContext context, CancellationToken ct)
    {
        var delay = ResolveDelay(context);
        if (delay > TimeSpan.Zero)
            await Task.Delay(delay, ct);

        return NodeExecutionOutcome.Single(context.Input(0).ToList());
    }

    private static TimeSpan ResolveDelay(NodeExecutionContext context)
    {
        var amount = ReadDouble(context, "amount", 1);
        if (amount <= 0)
            return TimeSpan.Zero;

        var unit = context.Parameters["unit"] is JsonValue value && value.TryGetValue<string>(out var text)
            ? text
            : "seconds";

        var delay = unit switch
        {
            "milliseconds" => TimeSpan.FromMilliseconds(amount),
            "minutes" => TimeSpan.FromMinutes(amount),
            _ => TimeSpan.FromSeconds(amount),
        };

        return delay > MaxDelay ? MaxDelay : delay;
    }

    private static double ReadDouble(NodeExecutionContext context, string name, double defaultValue)
    {
        if (context.Parameters[name] is not JsonValue value)
            return defaultValue;

        if (value.TryGetValue<double>(out var doubleValue))
            return doubleValue;
        if (value.TryGetValue<decimal>(out var decimalValue))
            return (double)decimalValue;
        if (value.TryGetValue<long>(out var longValue))
            return longValue;
        if (value.TryGetValue<string>(out var text)
            && double.TryParse(text, NumberStyles.Float, CultureInfo.InvariantCulture, out var parsed))
            return parsed;

        return defaultValue;
    }
}