PluralKit/PluralKit.Core/Utils/QueryBuilder.cs

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#nullable enable
using System;
using System.Text;
namespace PluralKit.Core
{
public class QueryBuilder
{
private readonly string? _conflictField;
private readonly string? _condition;
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private readonly StringBuilder _insertFragment = new StringBuilder();
private readonly StringBuilder _valuesFragment = new StringBuilder();
private readonly StringBuilder _updateFragment = new StringBuilder();
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private bool _firstInsert = true;
private bool _firstUpdate = true;
public QueryType Type { get; }
public string Table { get; }
private QueryBuilder(QueryType type, string table, string? conflictField, string? condition)
{
Type = type;
Table = table;
_conflictField = conflictField;
_condition = condition;
}
public static QueryBuilder Insert(string table) => new QueryBuilder(QueryType.Insert, table, null, null);
public static QueryBuilder Update(string table, string condition) => new QueryBuilder(QueryType.Update, table, null, condition);
public static QueryBuilder Upsert(string table, string conflictField) => new QueryBuilder(QueryType.Upsert, table, conflictField, null);
public QueryBuilder Constant(string fieldName, string paramName)
{
if (_firstInsert) _firstInsert = false;
else
{
_insertFragment.Append(", ");
_valuesFragment.Append(", ");
}
_insertFragment.Append(fieldName);
_valuesFragment.Append(paramName);
return this;
}
public QueryBuilder Variable(string fieldName, string paramName)
{
Constant(fieldName, paramName);
if (_firstUpdate) _firstUpdate = false;
else _updateFragment.Append(", ");
_updateFragment.Append(fieldName);
_updateFragment.Append(" = ");
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_updateFragment.Append(paramName);
return this;
}
public string Build(string? suffix = null)
{
if (_firstInsert)
throw new ArgumentException("No fields have been added to the query.");
StringBuilder query = new StringBuilder(Type switch
{
QueryType.Insert => $"insert into {Table} ({_insertFragment}) values ({_valuesFragment})",
QueryType.Upsert => $"insert into {Table} ({_insertFragment}) values ({_valuesFragment}) on conflict ({_conflictField}) do update set {_updateFragment}",
QueryType.Update => $"update {Table} set {_updateFragment}",
_ => throw new ArgumentOutOfRangeException($"Unknown query type {Type}")
});
if (Type == QueryType.Update && _condition != null)
query.Append($" where {_condition}");
if (!string.IsNullOrEmpty(suffix))
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query.Append($" {suffix}");
query.Append(";");
return query.ToString();
}
public enum QueryType
{
Insert,
Update,
Upsert
}
}
}