using FreeSql.Internal;
using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Linq;
using System.Text;

namespace FreeSql.MySql.Curd
{

    class MySqlInsertOrUpdate<T1> : Internal.CommonProvider.InsertOrUpdateProvider<T1> where T1 : class
    {
        public MySqlInsertOrUpdate(IFreeSql orm, CommonUtils commonUtils, CommonExpression commonExpression)
            : base(orm, commonUtils, commonExpression)
        {
        }

        public override string ToSql()
        {
            if (_source?.Any() != true) return null;

            var sqls = new string[2];
            var dbParams = new List<DbParameter>();
            var ds = SplitSourceByIdentityValueIsNull(_source);
            if (ds.Item1.Any()) sqls[0] = getInsertSql(ds.Item1, false);
            if (ds.Item2.Any()) sqls[1] = getInsertSql(ds.Item2, true);
            _params = dbParams.ToArray();
            if (ds.Item2.Any() == false) return sqls[0];
            if (ds.Item1.Any() == false) return sqls[1];
            return string.Join("\r\n\r\n;\r\n\r\n", sqls);

            string getInsertSql(List<T1> data, bool flagInsert)
            {
                var insert = _orm.Insert<T1>()
                    .AsTable(_tableRule).AsType(_table.Type)
                    .WithConnection(_connection)
                    .WithTransaction(_transaction)
                    .NoneParameter(true) as Internal.CommonProvider.InsertProvider<T1>;
                insert._source = data;
                insert._noneParameterFlag = flagInsert ? "cuc" : "cu";

                string sql = "";
                if (IdentityColumn != null && flagInsert) sql = insert.ToSql();
                else
                {
                    insert.InsertIdentity();
                    if (_doNothing == false)
                    {
                        var cols = _table.Columns.Values.Where(a => a.Attribute.IsPrimary == false && a.Attribute.CanUpdate == true && _updateIgnore.ContainsKey(a.Attribute.Name) == false);
                        sql = new OnDuplicateKeyUpdate<T1>(insert)
                            .UpdateColumns(cols.Select(a => a.Attribute.Name).ToArray())
                            .ToSql();
                    }
                    else
                    {
                        if (_table.Primarys.Any() == false) throw new Exception($"fsql.InsertOrUpdate + IfExistsDoNothing + MySql 要求实体类 {_table.CsName} 必须有主键");
                        sql = insert.ToSqlValuesOrSelectUnionAllExtension101(false, (rowd, idx, sb) =>
                            sb.Append(" \r\n FROM dual WHERE NOT EXISTS(").Append(
                                _orm.Select<T1>()
                                .AsTable((_, __) => _tableRule?.Invoke(__)).AsType(_table.Type)
                                .DisableGlobalFilter()
                                .WhereDynamic(rowd)
                                .Limit(1).ToSql("1").Replace(" \r\n", " \r\n    ")).Append(")"));
                    }
                }
                if (string.IsNullOrEmpty(sql)) return null;
                if (insert._params?.Any() == true) dbParams.AddRange(insert._params);
                return sql;
            }
        }
    }
}