using System;

using System.Collections.Generic;

using System.Text;



namespace Kwan.Data

{

    /// <summary>

    /// 条件表达式

    /// </summary>

    [Serializable]

    public partial class Expression

    {

        public Expression() 

        {

            

        }

        private List<Command.Parameter> mParameters = new List<Command.Parameter>();

        public List<Command.Parameter> Parameters

        {

            get

            {

                return mParameters;

            }

        }

        private StringBuilder mSqlText = new StringBuilder();

        public StringBuilder SqlText

        {

            get

            {

                return mSqlText;

            }

             

        }

        internal void Parse(Command cmd)

        {

            if (SqlText.Length > 0)

            {

                cmd.Text.Append(" where " + SqlText.ToString());

                foreach (Command.Parameter p in Parameters)

                {

                    cmd.AddParameter(p);

                }

            }

        }

        public static Expression operator &(Expression exp1, Expression exp2)

        {

            if (exp1 == null || exp1.SqlText.Length == 0)

                return exp2;

            if (exp2 == null || exp2.SqlText.Length == 0)

                return exp1;



            Expression exp = new Expression();

            exp.SqlText.Append("(");

            exp.SqlText.Append(exp1.ToString());



            exp.SqlText.Append(")");

            exp.Parameters.AddRange(exp1.Parameters);

            exp.SqlText.Append(" and (");

            exp.SqlText.Append(exp2.SqlText.ToString());

            exp.SqlText.Append(")");

            exp.Parameters.AddRange(exp2.Parameters);

            return exp;

        }

        public static Expression operator |(Expression exp1, Expression exp2)

        {

            if (exp1 == null || exp1.SqlText.Length == 0)

                return exp2;

            if (exp2 == null || exp2.SqlText.Length == 0)

                return exp1;

            Expression exp = new Expression();

            exp.SqlText.Append("(");

            exp.SqlText.Append(exp1.ToString());

           

            exp.SqlText.Append(")");

            exp.Parameters.AddRange(exp1.Parameters);

            exp.SqlText.Append(" or (");

            exp.SqlText.Append(exp2.SqlText.ToString());

            exp.SqlText.Append(")");

            exp.Parameters.AddRange(exp2.Parameters);

            return exp;



        }

        internal static string GetParamName()

        {

          



                ParamNameSeed pns = NameSeed;

                if (pns.Value > 200)

                    pns.Value = 0;

                else

                    pns.Value++;

                return "p" + pns.Value;

           

          

        }

        [ThreadStatic]

        static ParamNameSeed mNameSeed = new ParamNameSeed();

        internal static ParamNameSeed NameSeed

        {

            get

            {

                if (mNameSeed == null)

                    mNameSeed = new ParamNameSeed();

                return mNameSeed;

            }

        }

        internal class ParamNameSeed

        {

            public int Value

            {

                get;

                set;

            }

        }

        public override string ToString()

        {



            return SqlText.ToString();

        }

        

    }

    public class FieldInfo

    {

        public FieldInfo(string table, string name)

        {

            DBContext.Init();

            mTable = table;

            mName = name;

        }

        private string mTable;

        public string Table

        {

            get

            {

                return mTable;

            }

        }

        private string mName;

        public string Name

        {

            get

            {

                return mName;

            }

        }

        public Expression Eq(object value)

        {

            string p = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(string.Format(" {0}=@{1} ",Name,p));

            exp.Parameters.Add(new Command.Parameter{ Name=p, 

                Value=Mappings.PropertyCastAttribute.CastValue(Table,Name, value)});

            return exp;

        }

        public Expression LtEq(object value)

        {

            string p = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(string.Format(" {0}<=@{1} ", Name, p));

            exp.Parameters.Add(new Command.Parameter { Name = p,

                Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value)

            });

            return exp;

        }

        public Expression Lt(object value)

        {

            string p = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(string.Format(" {0}<@{1} ", Name, p));

            exp.Parameters.Add(new Command.Parameter { Name = p,

                Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value)

            });

            return exp;

        }

        public Expression Gt(object value)

        {

            string p = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(string.Format(" {0}>@{1} ", Name, p));

            exp.Parameters.Add(new Command.Parameter { Name = p,

                                                       Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value)

            });

            return exp;

        }

        public Expression GtEq(object value)

        {

            string p = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(string.Format(" {0}>=@{1} ", Name, p));

            exp.Parameters.Add(new Command.Parameter { Name = p, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value) });

            return exp;

        }

        public Expression NotEq(object value)

        {

            string p = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(string.Format(" {0}<>@{1} ", Name, p));

            exp.Parameters.Add(new Command.Parameter { Name = p, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value) });

            return exp;

        }

        public Expression In(System.Collections.IEnumerable values)

        {

            string p;

            int i = 0;

            Expression exp = new Expression();

            exp.SqlText.Append(" " + Name + " in (");

            foreach (object value in values)

            {

                p = Expression.GetParamName();

                if (i > 0)

                    exp.SqlText.Append(",");

                exp.SqlText.Append("@" + p);

                exp.Parameters.Add(new Command.Parameter { Name = p, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value) });



                i++;

            }

            exp.SqlText.Append(" )");

            return exp;

        }

        public Expression In(FieldInfo field, Expression expression)

        {

            Expression exp = new Expression();

            string astable = "T" + Expression.GetParamName();

            exp.SqlText.Append(" " + Name + " in (select "+astable+"."+ field.Name+" from "+ field.Table+" "+astable);

            if (expression != null && expression.SqlText.Length > 0)

            {

                exp.SqlText.Append(" where " + expression.SqlText.ToString());

                exp.Parameters.AddRange(expression.Parameters);

            }

            exp.SqlText.Append(")");

            return exp;

        }

        public Expression NotIn(System.Collections.IEnumerable values)

        {

            string p;

            int i = 0;

            Expression exp = new Expression();

            exp.SqlText.Append(" " + Name + " not in (");

            foreach (object value in values)

            {

                p = Expression.GetParamName();

                if (i > 0)

                    exp.SqlText.Append(",");

                exp.SqlText.Append("@" + p);

                exp.Parameters.Add(new Command.Parameter { Name = p, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value) });



                i++;

            }

            exp.SqlText.Append(")");

            return exp;

        }

        public Expression NotIn(FieldInfo field, Expression expression)

        {

            Expression exp = new Expression();

            string astable = "T" + Expression.GetParamName();

            exp.SqlText.Append(" " + Name + " not in (select " + astable + "." + field.Name + " from " + field.Table + " " + astable);

            if (expression != null && expression.SqlText.Length > 0)

            {

                exp.SqlText.Append(" where " + expression.SqlText.ToString());

                exp.Parameters.AddRange(expression.Parameters);

            }

            exp.SqlText.Append(")");

            return exp;

        }

        public Expression Between(object fromvalue, object tovalue)

        {

            string p, p1;

            p = Expression.GetParamName();

            p1 = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append( string.Format(" {0} Between @{1} and @{2}", Name, p, p1));

            exp.Parameters.Add(new Command.Parameter { Name = p, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, fromvalue) });

            exp.Parameters.Add(new Command.Parameter { Name = p1, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, tovalue) });

            return exp;

        }

        public Expression NotBetween(object fromvalue, object tovalue)

        {

            string p, p1;

            p = Expression.GetParamName();

            p1 = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(string.Format(" {0} not Between @{1} and @{2}", Name, p, p1));

            exp.Parameters.Add(new Command.Parameter { Name = p, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, fromvalue) });

            exp.Parameters.Add(new Command.Parameter { Name = p1, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, tovalue) });

            return exp;

        }

        public Expression Like(object value)

        {

            if (value != null && value is System.Collections.IEnumerable && value.GetType() != typeof(string))

                return LikeMany((System.Collections.IEnumerable)value);

            string pn = Expression.GetParamName();

            Expression exp = new Expression();

            exp.SqlText.Append(

                string.Format("{0} like @{1}", Name, pn)

                );

            exp.Parameters.Add(new Command.Parameter { Name = pn, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value) });

            return exp;

        }

        private Expression LikeMany(System.Collections.IEnumerable value)

        {

            

            Expression exp = new Expression();

            int i = 0;

            string pn;

            exp.SqlText.Append("(");

            foreach (object item in value)

            {

                pn = Expression.GetParamName();

                if (i > 0)

                    exp.SqlText.Append(" or ");

                exp.SqlText.Append(Name +" like @"+pn);

                exp.Parameters.Add(new Command.Parameter { Name = pn, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, item) });

                i++;

            }

            exp.SqlText.Append(")");

            return exp;

        }

        public Expression Match(object value)

        {

            if (value != null && value is System.Collections.IEnumerable && value.GetType() !=typeof(string))

                return MatchMany((System.Collections.IEnumerable)value);

            return Like("%" + value + "%");

        }

        private Expression MatchMany(System.Collections.IEnumerable value)

        {

            Expression exp = new Expression();

            int i = 0;

            string pn;

            exp.SqlText.Append("(");

            foreach (object item in value)

            {

                pn = Expression.GetParamName();

                if (i > 0)

                    exp.SqlText.Append(" or ");

                exp.SqlText.Append(Name + " like @" + pn);

                exp.Parameters.Add(new Command.Parameter { Name = pn, Value = "%"+item+"%" });

                i++;

            }

            exp.SqlText.Append(")");

            return exp;

        }

        public Expression IsNull()

        {

            Expression exp = new Expression();

            exp.SqlText.Append(" "+Name+" is null");

            return exp;

        }

        public Expression IsNotNull()

        {

            Expression exp = new Expression();

            exp.SqlText.Append(" " + Name + " is not null");

            return exp;

        }

        public override string ToString()

        {

            return Name;

        }

        public static Expression operator ==(FieldInfo field, object value)

        {

            if (value == null)

                return field.IsNull();

            if (value is System.Collections.IEnumerable && value.GetType() !=typeof(string))

                return field.In((System.Collections.IEnumerable)value);

            return field.Eq(value);

        }

        public static Expression operator !=(FieldInfo field, object value)

        {

            if (value == null)

                return field.IsNotNull();

            if (value is System.Collections.IEnumerable && value.GetType() != typeof(string))

                return field.NotIn((System.Collections.IEnumerable)value);

            return field.NotEq(value);

        }

        public static Expression operator >(FieldInfo field, object value)

        {

            return field.Gt(value);

        }

        public static Expression operator >=(FieldInfo field, object value)

        {

            return field.GtEq(value);

        }

        public static Expression operator <(FieldInfo field, object value)

        {

            return field.Lt(value);

        }

        public static Expression operator <=(FieldInfo field, object value)

        {

            return field.LtEq(value);

        }

        public FieldInfo At()

        {

            return new FieldInfo(Table, Table + "." + Name);

        }

        public FieldInfo At(string table)

        {

            return new FieldInfo(table, table + "." + Name);

        }



        public string Desc

        {

            get

            {

                return Name + " desc ";

            }

        }

        public string Asc

        {

            get

            {

                return Name + " asc ";

            }

        }

        public Field NewValue(object value)

        {



            return new Field { Name = Name, Value = Mappings.PropertyCastAttribute.CastValue(Table, Name, value) };

        }



        

    }

}