using System.Collections.Concurrent;
using System.Reflection;
using Connected.Entities.Annotations;
using Connected.Entities.Storage;

namespace Connected.ServiceModel.Client.Data;
internal sealed class UpdateCommandBuilder : CommandBuilder
{
	private static readonly ConcurrentDictionary<string, StorageOperation> _cache;

	static UpdateCommandBuilder()
	{
		_cache = new();
	}

	private static ConcurrentDictionary<string, StorageOperation> Cache => _cache;
	private bool SupportsConcurrency { get; set; }
	protected override bool TryGetExisting(out StorageOperation? result)
	{
		return Cache.TryGetValue(Entity.GetType().FullName, out result);
	}

	protected override StorageOperation OnBuild()
	{
		WriteLine($"UPDATE [{Schema.Schema}].[{Schema.Name}] SET");

		WriteAssignments();
		WriteWhere();

		Trim();
		Write(';');

		var result = new StorageOperation { CommandText = CommandText, Concurrency = SupportsConcurrency ? DataConcurrencyMode.Enabled : DataConcurrencyMode.Disabled };

		foreach (var parameter in Parameters)
			result.AddParameter(parameter);

		Cache.TryAdd(Entity.GetType().FullName, result);

		return result;
	}

	private void WriteAssignments()
	{
		foreach (var property in Properties)
		{
			if (property.GetCustomAttribute<PrimaryKeyAttribute>() is not null)
			{
				WhereProperties.Add(property);

				continue;
			}

			var parameter = CreateParameter(property);

			WriteLine($"{ColumnName(property)} = {parameter.Name},");
		}

		Trim();
	}

	private void WriteWhere()
	{
		WriteLine(string.Empty);

		for (var i = 0; i < WhereProperties.Count; i++)
		{
			var property = WhereProperties[i];
			var parameter = CreateParameter(property);

			if (i == 0)
				WriteLine($" WHERE {ColumnName(property)} = {parameter.Name}");
			else
				WriteLine($" AND {ColumnName(property)} = {parameter.Name}");
		}
	}
}