Connected.Framework/Connected.Data/Update/InsertCommandBuilder.cs

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

namespace Connected.Data.Update;

internal class InsertCommandBuilder : CommandBuilder
{
    private static readonly ConcurrentDictionary<string, StorageOperation> _cache;

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

    private static ConcurrentDictionary<string, StorageOperation> Cache => _cache;
    private IStorageParameter PrimaryKeyParameter { get; set; }

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

        WriteColumns();
        WriteLine(")");
        Write("VALUES (");
        WriteValues();
        WriteLine(");");
        WriteOutput();

        var result = new StorageOperation { CommandText = CommandText };

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

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

        return result;
    }

    private void WriteOutput()
    {
        WriteLine($"SET {PrimaryKeyParameter.Name} = scope_identity();");
    }

    private void WriteColumns()
    {
        foreach (var property in Properties)
        {
            if (property.GetCustomAttribute<PrimaryKeyAttribute>() is not null || IsVersion(property))
            {
                if (IsVersion(property))
                    continue;

                PrimaryKeyParameter = CreateParameter(property, ParameterDirection.Output);

                continue;
            }

            CreateParameter(property);

            Write($"{ColumnName(property)}, ");
        }

        Trim();
    }

    private void WriteValues()
    {
        foreach (var property in Properties)
        {
            if (property.GetCustomAttribute<PrimaryKeyAttribute>() is not null || IsVersion(property))
                continue;

            Write($"@{ColumnName(property)}, ");
        }

        Trim();
    }

    protected override bool TryGetExisting(out StorageOperation? result)
    {
        return Cache.TryGetValue(Entity.GetType().FullName, out result);
    }
}