/**
 * Relational pipes
 * Copyright © 2019 František Kučera (Frantovo.cz, GlobalCode.info)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
#pragma once

#include <relpipe/writer/AttributeMetadata.h>
#include <relpipe/writer/typedefs.h>

namespace relpipe {
namespace tr {
namespace sql {

class Parameter {
public:

	relpipe::writer::string_t value;
	// TODO: relpipe::writer::TypeId type;
};

class TypeCast {
public:

	relpipe::writer::string_t name;
	relpipe::writer::string_t type;
};

class Statement {
public:

	virtual ~Statement() {
	}

	/**
	 * output relation name;
	 * if empty, the SQL code (DML, DDL) will be executed, but no relational output will be generated
	 */
	relpipe::writer::string_t relation;
	/**
	 * SQL code, usually some SELECT;
	 * might be also DML or DDL
	 */
	relpipe::writer::string_t sql;
	/**
	 * Explicitly defined types of particular attributes.
	 * SQLite uses dynamic typing, so it is often impossible to obtain the proper types from the result set.
	 */
	std::vector<TypeCast> typeCasts;
	/**
	 * Query parameters
	 */
	std::vector<Parameter> parameters;
};

enum class KeepFile {
	/** The file will be kept even if it was created during this transformation, so all the input data will stay on the disk. */
	Always,
	/** The file will be deleted at the end of this transformation – even if the file already existed. This is potentially dangerous, because we can unintentionally delete a database file. */
	Never,
	/** The file will be kept only if it was already present before the transformation. */
	Automatic
};

/**
 * Allows copying relations from the input stream to the output stream.
 * Such relations are specified by a regular expression.
 * We can also specify the regex replacement string and rename such relations. 
 */
class CopyRelations {
public:

	CopyRelations(const relpipe::writer::string_t pattern, const relpipe::writer::string_t replacement, const relpipe::writer::boolean_t replace) : pattern(pattern), replacement(replacement), replace(replace) {
	}

	virtual ~CopyRelations() {
	}

	const relpipe::writer::string_t pattern;
	const relpipe::writer::string_t replacement;
	const relpipe::writer::boolean_t replace;
};

class Configuration {
public:


	/**
	 * By default, this transformation runs in-memory.
	 * If 'file' is not empty, this transformation will operate on an .sqlite file.
	 * The file will be created if it does not exist.
	 */
	relpipe::writer::string_t file;

	/**
	 * see KeepFile documentation
	 */
	KeepFile keepFile = KeepFile::Automatic;

	std::vector<Statement> statements;

	/**
	 * SQL script to be executed before the relational input.
	 */
	std::wistream* sqlBeforeRelational = nullptr;

	/**
	 * SQL script to be executed after the relational input.
	 */
	std::wistream* sqlAfterRelational = nullptr;

	std::vector<CopyRelations> copyRelations;

	virtual ~Configuration() {
	}
};

}
}
}