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

namespace FinalFactory.Rendezvous.Contracts;

public static class ContractJson
{
    private static readonly JsonSerializerOptions SharedOptions = CreateReadOnlyOptions();

    public static JsonSerializerOptions Options => SharedOptions;

    public static JsonSerializerOptions CreateOptions()
    {
        JsonSerializerOptions options = new(JsonSerializerDefaults.Web);
        Configure(options);
        return options;
    }

    public static void Configure(JsonSerializerOptions options)
    {
        if (options is null)
        {
            throw new ArgumentNullException(nameof(options));
        }

        options.AllowTrailingCommas = false;
        options.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
        // Nine is the minimum that lets ASP.NET generate the nullable fallback
        // OpenAPI schema; the 16 KiB HTTP body limit still bounds parser work.
        options.MaxDepth = 9;
        options.NumberHandling = JsonNumberHandling.Strict;
        options.PropertyNameCaseInsensitive = false;
        options.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
        options.ReadCommentHandling = JsonCommentHandling.Disallow;
        options.UnmappedMemberHandling = JsonUnmappedMemberHandling.Skip;
        options.WriteIndented = false;

        if (!options.Converters.OfType<JsonStringEnumConverter>().Any())
        {
            options.Converters.Add(
                new JsonStringEnumConverter(JsonNamingPolicy.CamelCase, allowIntegerValues: false));
        }
    }

    private static JsonSerializerOptions CreateReadOnlyOptions()
    {
        JsonSerializerOptions options = CreateOptions();
        options.MakeReadOnly(populateMissingResolver: true);
        return options;
    }
}