using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Text;
using Microsoft.SqlServer.Management.Common;
using Microsoft.SqlServer.Management.Smo;
using Rule=System.Data.Rule;

namespace XSD2SQL
{
public class XSD2SQL
{
    private readonly Server _server;
    private readonly SqlConnection _connection;
    private Database _db;
    private DataSet _source;
    private string _databaseName;

    public XSD2SQL(string connectionString, DataSet source)
    {
        _connection = new SqlConnection(connectionString);
        _server = new Server(new ServerConnection(_connection));
        _source = source;
    }

    public void CreateDatabase(string databaseName)
    {
        _databaseName = databaseName;
        _db = _server.Databases[databaseName];
        if (_db != null) _db.Drop();
        _db = new Database(_server, _databaseName);
        _db.Create();
    }

    public void PopulateDatabase()
    {
        CreateTables(_source.Tables);
        CreateRelationships();
    }

    private void CreateRelationships()
    {
        foreach (DataTable table in _source.Tables)
        {
            foreach (DataRelation rel in table.ChildRelations)
                CreateRelation(rel);
        }
    }

    private void CreateRelation(DataRelation relation)
    {
        Table primaryTable = _db.Tables[relation.ParentTable.TableName];
        Table childTable = _db.Tables[relation.ChildTable.TableName];

        ForeignKey fkey = new ForeignKey(childTable, relation.RelationName);
        fkey.ReferencedTable = primaryTable.Name;

        fkey.DeleteAction = SQLActionTypeToSMO(relation.ChildKeyConstraint.DeleteRule);
        fkey.UpdateAction = SQLActionTypeToSMO(relation.ChildKeyConstraint.UpdateRule);


        for (int i = 0; i < relation.ChildColumns.Length; i++)
        {
            DataColumn col = relation.ChildColumns[i];
            ForeignKeyColumn fkc = new ForeignKeyColumn(fkey, col.ColumnName, relation.ParentColumns[i].ColumnName);

            fkey.Columns.Add(fkc);
        }

        fkey.Create();

    }

    private void CreateTables(DataTableCollection tables)
    {
        foreach (DataTable table in tables)
        {                
            DropExistingTable(table.TableName);
            Table newTable = new Table(_db, table.TableName);

            PopulateTable(ref newTable, table);                
            SetPrimaryKeys(ref newTable, table);
            newTable.Create();

        }
    }

    private void PopulateTable(ref Table outputTable, DataTable inputTable)
    {
        foreach (DataColumn column in inputTable.Columns)
        {
            CreateColumns(ref outputTable, column, inputTable);
        }
    }

    private void CreateColumns(ref Table outputTable, DataColumn inputColumn, DataTable inputTable)
    {
        Column newColumn = new Column(outputTable, inputColumn.ColumnName);
        newColumn.DataType = CLRTypeToSQLType(inputColumn.DataType);
        newColumn.Identity = inputColumn.AutoIncrement;
        newColumn.IdentityIncrement = inputColumn.AutoIncrementStep;
        newColumn.IdentitySeed = inputColumn.AutoIncrementSeed;
        newColumn.Nullable = inputColumn.AllowDBNull;
        newColumn.UserData = inputColumn.DefaultValue;

        outputTable.Columns.Add(newColumn);
    }

    private void SetPrimaryKeys(ref Table outputTable, DataTable inputTable)
    {
        Index newIndex = new Index(outputTable, "PK_" + outputTable.Name);
        newIndex.IndexKeyType = IndexKeyType.DriPrimaryKey;
        newIndex.IsClustered = false;

        foreach (DataColumn keyColumn in inputTable.PrimaryKey)
        {                                
            newIndex.IndexedColumns.Add(new IndexedColumn(newIndex, keyColumn.ColumnName, true));                
        }
        if (newIndex.IndexedColumns.Count > 0)
            outputTable.Indexes.Add(newIndex);
    }



    private DataType CLRTypeToSQLType(Type type)
    {
        switch (type.Name)
        {
            case "String":
                return DataType.NVarCharMax;

            case "Int32":
                return DataType.Int;

            case "Boolean":
                return DataType.Bit;

            case "DateTime":
                return DataType.DateTime;

            case "Byte[]":
                return DataType.VarBinaryMax;


        }

        return DataType.NVarCharMax;
    }

    private ForeignKeyAction SQLActionTypeToSMO(Rule rule)
    {
        string ruleStr = rule.ToString();

        return (ForeignKeyAction)Enum.Parse(typeof (ForeignKeyAction), ruleStr);
    }

    private void DropExistingTable(string tableName)
    {
        Table table = _db.Tables[tableName];
        if (table != null) table.Drop();
    }

}
}