Imports System.Text

Namespace Database.Sqlite
    Public Class DataParam
        Enum DataTypeEnum
            Varchar
            Nchar
            Blob
            Bit
            Datetime
            [Decimal]
            Real
            UniqueIdentifier
            Int
            [Integer]
            TinyInt
            [Single]
            Nvarchar
            SmallInt
            SmallUint
            Uint
            UnsignedInteger
        End Enum

        ''' <summary>
        ''' 列名
        ''' </summary>
        ''' <returns></returns>
        Public Property ColumnName() As String

        ''' <summary>
        ''' 当前值
        ''' </summary>
        ''' <returns></returns>
        Public Property Value() As String


        ''' <summary>
        ''' 默认值
        ''' </summary>
        ''' <returns></returns>
        Public Property DefaultValue() As String

        ''' <summary>
        ''' 数据类型
        ''' </summary>
        ''' <returns></returns>
        Public Property DataType() As DataTypeEnum

        ''' <summary>
        ''' 数据类型长度
        ''' </summary>
        ''' <returns></returns>
        Public Property DataTypeLength() As Integer


        ''' <summary>
        ''' 是否允许为空
        ''' </summary>
        ''' <returns></returns>
        Public Property IsNull() As Boolean = True

        ''' <summary>
        ''' 是否自动增长
        ''' </summary>
        ''' <returns></returns>
        Public Property IsAutoIncrement() As Boolean

        ''' <summary>
        ''' 是否为主键
        ''' </summary>
        ''' <returns></returns>
        Public Property IsPrimaryKey() As Boolean

        ''' <summary>
        ''' 是否为唯一值
        ''' </summary>
        ''' <returns></returns>
        Public Property IsUnique() As Boolean


        Public Function ToAddColString() As String
            Dim sb As New StringBuilder
            sb.Append($"`{ColumnName}`")

            Select Case DataType
                Case DataTypeEnum.Varchar, DataTypeEnum.Nchar, DataTypeEnum.Nvarchar
                    sb.Append($" {DataType}({DataTypeLength}) ")
                Case DataTypeEnum.Int,DataTypeEnum.Integer
                    sb.Append($" {DataType}")
                Case Else
                    sb.Append($" {DataType}")
            End Select

            If IsAutoIncrement Then sb.Append($" AUTOINCREMENT")

            sb.Append(IIf(IsNull, " Default Null", " Not Null"))

            If IsPrimaryKey Then
                sb.Append($" PRIMARY KEY")
            End If

            Return sb.ToString()
        End Function
    End Class
End Namespace