using System;
using System.Text.Json;

namespace StellaOps.Provenance;

public static partial class ProvenanceJsonParser
{
    private static JsonElement GetRequiredProperty(JsonElement parent, string name)
    {
        if (!parent.TryGetProperty(name, out var property) || property.ValueKind == JsonValueKind.Null)
        {
            throw new InvalidOperationException($"Provenance metadata missing required property {name}.");
        }

        return property;
    }

    private static string GetRequiredString(JsonElement parent, string name)
    {
        var element = GetRequiredProperty(parent, name);
        if (element.ValueKind is JsonValueKind.String)
        {
            var value = element.GetString();
            if (!string.IsNullOrWhiteSpace(value))
            {
                return value;
            }
        }

        throw new InvalidOperationException($"Provenance metadata property {name} must be a non-empty string.");
    }

    private static string? GetOptionalString(JsonElement parent, string name)
    {
        if (!parent.TryGetProperty(name, out var element))
        {
            return null;
        }

        return element.ValueKind == JsonValueKind.String ? element.GetString() : null;
    }

    private static long GetInt64(JsonElement parent, string name)
    {
        if (!parent.TryGetProperty(name, out var element))
        {
            throw new InvalidOperationException($"Provenance metadata missing {name}.");
        }

        if (element.ValueKind == JsonValueKind.Number && element.TryGetInt64(out var value))
        {
            return value;
        }

        if (element.ValueKind == JsonValueKind.String && long.TryParse(element.GetString(), out var parsed))
        {
            return parsed;
        }

        throw new InvalidOperationException($"Provenance metadata property {name} must be an integer.");
    }

    private static long? GetOptionalInt64(JsonElement parent, string name)
    {
        if (!parent.TryGetProperty(name, out var element))
        {
            return null;
        }

        if (element.ValueKind == JsonValueKind.Number && element.TryGetInt64(out var value))
        {
            return value;
        }

        if (element.ValueKind == JsonValueKind.String && long.TryParse(element.GetString(), out var parsed))
        {
            return parsed;
        }

        return null;
    }
}