using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using System.Text.Json.Serialization;
using System.Text.Json;
using eprintServer.Enums;


namespace eprintServer.Entities;


[JsonConverter(typeof(QuantityPricingConfigConverter))]
public class QuantityPricingConfig
{
    public List<QuantityPricingTier> Tiers { get; set; } = new();
}

public class QuantityPricingConfigConverter : JsonConverter<QuantityPricingConfig?>
{
    public override QuantityPricingConfig? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        if (reader.TokenType == JsonTokenType.StartArray)
        {
            using var doc = JsonDocument.ParseValue(ref reader);
            var tiers = new List<QuantityPricingTier>();

            foreach (var element in doc.RootElement.EnumerateArray())
            {
                var tier = JsonSerializer.Deserialize<QuantityPricingTier>(element.GetRawText(), options);
                if (tier != null) tiers.Add(tier);
            }

            return tiers.Count == 0 ? null : new QuantityPricingConfig { Tiers = tiers };
        }

        if (reader.TokenType == JsonTokenType.Null)
            return null;

        if (reader.TokenType == JsonTokenType.StartObject)
        {
            using var doc = JsonDocument.ParseValue(ref reader);
            var tiers = new List<QuantityPricingTier>();

            if (doc.RootElement.TryGetProperty("tiers", out var tiersElement))
            {
                foreach (var element in tiersElement.EnumerateArray())
                {
                    var tier = JsonSerializer.Deserialize<QuantityPricingTier>(element.GetRawText(), options);
                    if (tier != null) tiers.Add(tier);
                }
            }

            return new QuantityPricingConfig { Tiers = tiers };
        }

        throw new JsonException($"Unexpected token {reader.TokenType} when parsing QuantityPricingConfig.");
    }

    public override void Write(Utf8JsonWriter writer, QuantityPricingConfig? value, JsonSerializerOptions options)
    {
        if (value == null)
        {
            writer.WriteNullValue();
            return;
        }

        writer.WriteStartObject();
        writer.WritePropertyName("tiers");
        JsonSerializer.Serialize(writer, value.Tiers, options);
        writer.WriteEndObject();
    }
}