using System.Collections;
using System.Globalization;
using System.Text.Json.Nodes;

namespace w4c_workflows.Services.Nodes;

/// <summary>
/// Converts the loosely-typed values YamlDotNet produces (scalars, nested
/// <c>Dictionary&lt;object, object&gt;</c> mappings and <c>List&lt;object&gt;</c>
/// sequences) into <see cref="JsonNode"/>, so node parameters keep their YAML
/// types and can be interpolated by the shared engine.
/// </summary>
public static class NodeParameterReader
{
    /// <summary>Builds a JSON object from a YAML mapping (null-safe).</summary>
    public static JsonObject ToJsonObject(Dictionary<string, object?>? mapping)
    {
        var result = new JsonObject();
        if (mapping == null)
            return result;

        foreach (var (key, value) in mapping)
            result[key] = ToJsonNode(value);

        return result;
    }

    /// <summary>Converts a single YamlDotNet value into a JSON node.</summary>
    public static JsonNode? ToJsonNode(object? value) => value switch
    {
        null => null,
        JsonNode node => node.DeepClone(),
        string text => JsonValue.Create(text),
        bool flag => JsonValue.Create(flag),
        char ch => JsonValue.Create(ch.ToString()),
        sbyte or byte or short or ushort or int or uint or long
            => JsonValue.Create(Convert.ToInt64(value, CultureInfo.InvariantCulture)),
        ulong unsigned => JsonValue.Create(unsigned),
        float or double or decimal
            => JsonValue.Create(Convert.ToDecimal(value, CultureInfo.InvariantCulture)),
        DateTime dateTime => JsonValue.Create(dateTime.ToString("O", CultureInfo.InvariantCulture)),
        DateTimeOffset offset => JsonValue.Create(offset.ToString("O", CultureInfo.InvariantCulture)),
        IDictionary dictionary => FromDictionary(dictionary),
        IEnumerable sequence => FromSequence(sequence),
        _ => JsonValue.Create(value.ToString()),
    };

    private static JsonObject FromDictionary(IDictionary dictionary)
    {
        var result = new JsonObject();
        foreach (DictionaryEntry entry in dictionary)
        {
            var key = Convert.ToString(entry.Key, CultureInfo.InvariantCulture);
            if (string.IsNullOrEmpty(key))
                continue;
            result[key] = ToJsonNode(entry.Value);
        }
        return result;
    }

    private static JsonArray FromSequence(IEnumerable sequence)
    {
        var result = new JsonArray();
        foreach (var element in sequence)
            result.Add(ToJsonNode(element));
        return result;
    }
}