FeedPage.cs

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using System.Text.Json;
using Fauna.Exceptions;
using Fauna.Mapping;
using Fauna.Types;
using static Fauna.Core.ResponseFields;
 
namespace Fauna.Core;
 
public class FeedPage<T> where T : notnull
{
    public List<Event<T>> Events { get; private init; } = [];
 
    public string Cursor { get; private init; } = null!;
 
    public bool HasNext { get; private init; }
 
    public QueryStats Stats { get; private init; }
 
    internal static FeedPage<T> From(string body, MappingContext ctx)
    {
        var json = JsonSerializer.Deserialize<JsonElement>(body);
 
        var err = GetError(json);
        if (err != null)
        {
            throw new FaunaException(err.Value);
        }
 
        return new FeedPage<T>
        {
            Cursor = GetCursor(json),
            Events = GetEvents(json, ctx),
            Stats = GetStats(json),
            HasNext = json.TryGetProperty(HasNextFieldName, out var elem) && elem.GetBoolean()
        };
    }
 
    private static List<Event<T>> GetEvents(JsonElement json, MappingContext ctx)
    {
        if (!json.TryGetProperty(EventsFieldName, out var elem))
        {
            return new List<Event<T>>();
        }
 
        var events = elem.EnumerateArray().Select(e => Event<T>.From(e, ctx)).ToList();
        return events;
    }
 
    private static QueryStats GetStats(JsonElement json)
    {
        return json.TryGetProperty(StatsFieldName, out var elem) ? elem.Deserialize<QueryStats>() : default;
    }
 
    private static string GetCursor(JsonElement json)
    {
        return json.TryGetProperty(CursorFieldName, out var elem) ? elem.GetString()! : null!;
    }
 
    private static ErrorInfo? GetError(JsonElement json)
    {
        return json.TryGetProperty(ErrorFieldName, out var elem) ? elem.Deserialize<ErrorInfo>() : null;
    }
}