/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.hydromatic.optiq.impl;

import net.hydromatic.linq4j.QueryProvider;
import net.hydromatic.linq4j.Queryable;

import net.hydromatic.optiq.*;
import net.hydromatic.optiq.impl.java.AbstractQueryableTable;
import net.hydromatic.optiq.impl.java.JavaTypeFactory;
import net.hydromatic.optiq.jdbc.*;

import org.eigenbase.rel.RelNode;
import org.eigenbase.relopt.RelOptTable;
import org.eigenbase.relopt.RelOptUtil;
import org.eigenbase.reltype.*;
import org.eigenbase.util.Util;

import com.google.common.collect.ImmutableList;

import java.lang.reflect.Type;
import java.util.Collections;
import java.util.List;

import static net.hydromatic.optiq.impl.MaterializedViewTable.MATERIALIZATION_CONNECTION;

/**
 * Table whose contents are defined using an SQL statement.
 *
 * <p>It is not evaluated; it is expanded during query planning.</p>
 */
public class ViewTable
    extends AbstractQueryableTable
    implements TranslatableTable {
  private final String viewSql;
  private final List<String> schemaPath;
  private final RelProtoDataType protoRowType;

  public ViewTable(Type elementType, RelProtoDataType rowType, String viewSql,
      List<String> schemaPath) {
    super(elementType);
    this.viewSql = viewSql;
    this.schemaPath = ImmutableList.copyOf(schemaPath);
    this.protoRowType = rowType;
  }

  /** Table macro that returns a view. */
  public static ViewTableMacro viewMacro(SchemaPlus schema,
      final String viewSql, final List<String> schemaPath) {
    return new ViewTableMacro(OptiqSchema.from(schema), viewSql, schemaPath);
  }

  @Override public Schema.TableType getJdbcTableType() {
    return Schema.TableType.VIEW;
  }

  public RelDataType getRowType(RelDataTypeFactory typeFactory) {
    return protoRowType.apply(typeFactory);
  }

  public <T> Queryable<T> asQueryable(QueryProvider queryProvider,
      SchemaPlus schema, String tableName) {
    return queryProvider.createQuery(
        getExpression(schema, tableName, Queryable.class),
        elementType);
  }

  public RelNode toRel(
      RelOptTable.ToRelContext context,
      RelOptTable relOptTable) {
    return expandView(context, relOptTable.getRowType(), viewSql);
  }

  private RelNode expandView(
      RelOptTable.ToRelContext preparingStmt,
      RelDataType rowType,
      String queryString) {
    try {
      RelNode rel = preparingStmt.expandView(rowType, queryString, schemaPath);

      rel = RelOptUtil.createCastRel(rel, rowType, true);
      //rel = viewExpander.flattenTypes(rel, false);
      return rel;
    } catch (Throwable e) {
      throw Util.newInternal(
          e, "Error while parsing view definition:  " + queryString);
    }
  }

  /** Table function that implements a view. It returns the operator
   * tree of the view's SQL query. */
  static class ViewTableMacro implements TableMacro {
    protected final String viewSql;
    protected final OptiqSchema schema;
    /** Typically null. If specified, overrides the path of the schema as the
     * context for validating {@code viewSql}. */
    protected final List<String> schemaPath;

    ViewTableMacro(OptiqSchema schema, String viewSql,
        List<String> schemaPath) {
      this.viewSql = viewSql;
      this.schema = schema;
      this.schemaPath =
          schemaPath == null ? null : ImmutableList.copyOf(schemaPath);
    }

    public List<FunctionParameter> getParameters() {
      return Collections.emptyList();
    }

    public TranslatableTable apply(List<Object> arguments) {
      OptiqPrepare.ParseResult parsed =
          Schemas.parse(MATERIALIZATION_CONNECTION, schema, schemaPath,
              viewSql);
      final List<String> schemaPath1 =
          schemaPath != null ? schemaPath : schema.path(null);
      final JavaTypeFactory typeFactory = (JavaTypeFactory) parsed.typeFactory;
      return new ViewTable(typeFactory.getJavaClass(parsed.rowType),
          RelDataTypeImpl.proto(parsed.rowType), viewSql, schemaPath1);
    }
  }

  /** Returns the view's SQL definition. */
  public String getViewSql() {
    return viewSql;
  }

  /** Returns the the schema path of the view. */
  public List<String> getSchemaPath() {
    return schemaPath;
  }
}

// End ViewTable.java