package jef.mysql.migration;

import jef.model.migration.operation.AddFieldOperation;
import jef.model.migration.operation.AddForeignKeyOperation;
import jef.model.migration.operation.AddIndexOperation;
import jef.model.migration.operation.AddKeyOperation;
import jef.model.migration.operation.AddPrimaryKeyOperation;
import jef.model.migration.operation.AddTableOperation;
import jef.model.migration.operation.AddUniqueKeyOperation;
import jef.model.migration.operation.DropConstraintOperation;
import jef.model.migration.operation.DropFieldOperation;
import jef.model.migration.operation.DropTableOperation;
import jef.model.migration.operation.MigrationOperation;
import jef.model.migration.operation.RenameFieldOperation;
import jef.model.migration.operation.RenameTableOperation;
import jef.model.migration.operation.UpdateFieldOperation;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;

public class MysqlMigrationOperationTranslator {
    private static final Map<Class<? extends MigrationOperation>, Mapper<MigrationOperation>> translators;

    static {
        var map = new HashMap<Class<? extends MigrationOperation>, Mapper<MigrationOperation>>();
        map.put(AddFieldOperation.class, MysqlMigrationOperationTranslator::translateAddFieldOperation);
        map.put(AddForeignKeyOperation.class, MysqlMigrationOperationTranslator::translateAddForeignKeyOperation);
        map.put(AddIndexOperation.class, MysqlMigrationOperationTranslator::translateAddIndexOperation);
        map.put(AddKeyOperation.class, MysqlMigrationOperationTranslator::translateAddKeyOperation);
        map.put(AddPrimaryKeyOperation.class, MysqlMigrationOperationTranslator::translateAddPrimaryKeyOperation);
        map.put(AddTableOperation.class, MysqlMigrationOperationTranslator::translateAddTableOperation);
        map.put(AddUniqueKeyOperation.class, MysqlMigrationOperationTranslator::translateAddUniqueKeyOperation);
        map.put(DropConstraintOperation.class, MysqlMigrationOperationTranslator::translateDropConstraintOperation);
        map.put(DropFieldOperation.class, MysqlMigrationOperationTranslator::translateDropFieldOperation);
        map.put(DropTableOperation.class, MysqlMigrationOperationTranslator::translateDropTableOperation);
        map.put(RenameFieldOperation.class, MysqlMigrationOperationTranslator::translateRenameFieldOperation);
        map.put(RenameTableOperation.class, MysqlMigrationOperationTranslator::translateRenameTableOperation);
        map.put(UpdateFieldOperation.class, MysqlMigrationOperationTranslator::translateUpdateFieldOperation);
        translators = Collections.unmodifiableMap(map);
    }

    public static PreparedStatement translate(Connection connection, MigrationOperation operation) throws SQLException {
        return Optional.ofNullable(translators.get(operation.getClass())).orElseThrow().apply(connection, operation);
    }

    private static PreparedStatement translateAddFieldOperation(Connection connection, MigrationOperation operation) throws SQLException {
        AddFieldOperation op = (AddFieldOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " ADD COLUMN `" + op.getField() + "` "
                                           + op.getSqlType() + (op.isNotNull() ? " NOT NULL" : "") //TODO add after field specification
                                           + " LAST");
    }

    private static PreparedStatement translateAddForeignKeyOperation(Connection connection, MigrationOperation operation) throws SQLException {
        AddForeignKeyOperation op = (AddForeignKeyOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " ADD CONSTRAINT `" + op.getName() + "`"
                                           + " FOREIGN KEY (" + op.getFields().stream().map(e -> "`" + e + "`").collect(Collectors.joining(", ")) + ")"
                                           + " REFERENCES `" + op.getReferencedTable() + "`(" + op.getReferencedFields().stream()
                                                   .map(e -> "`" + e + "`")
                                                   .collect(Collectors.joining(", ")) + ")");
    }

    private static PreparedStatement translateAddIndexOperation(Connection connection, MigrationOperation operation) throws SQLException {
        AddIndexOperation op = (AddIndexOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " ADD CONSTRAINT `" + op.getName() + "`"
                                           + " INDEX (" + op.getFields().stream().map(e -> "`" + e + "`").collect(Collectors.joining(", ")) + ")");
    }

    private static PreparedStatement translateAddKeyOperation(Connection connection, MigrationOperation operation) throws SQLException {
        AddKeyOperation op = (AddKeyOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " ADD CONSTRAINT `" + op.getName() + "`"
                                           + " KEY (" + op.getFields().stream().map(e -> "`" + e + "`").collect(Collectors.joining(", ")) + ")");
    }

    private static PreparedStatement translateAddPrimaryKeyOperation(Connection connection, MigrationOperation operation) throws SQLException {
        AddPrimaryKeyOperation op = (AddPrimaryKeyOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " ADD " + (!op.getName().equals("PRIMARY") ? "CONSTRAINT `" + op.getName() + "`" : "")
                                           + " PRIMARY KEY (" + op.getFields().stream().map(e -> "`" + e + "`").collect(Collectors.joining(", ")) + ")");
//                                           + " ADD CONSTRAINT `" + op.getName() + "`"
//                                           + " PRIMARY KEY (" + op.getFields().stream().map(e -> "`" + e + "`").collect(Collectors.joining(", ")) + ")");
    }

    private static PreparedStatement translateAddTableOperation(Connection connection, MigrationOperation operation) throws SQLException {
        AddTableOperation op = (AddTableOperation) operation;
        return connection.prepareStatement("CREATE TABLE `" + op.getTable() + "` ("
                                           + op.getFields().stream().map(e -> {
            var f = e.build();
            return "`" + f.getField() + "` " + f.getSqlType() + (f.isNotNull() ? " NOT NULL" : "");
        }).collect(Collectors.joining(", "))
                                           + ")"); //TODO default collocation from database config or operation, field collation, primary key, constraints
    }

    private static PreparedStatement translateAddUniqueKeyOperation(Connection connection, MigrationOperation operation) throws SQLException {
        AddUniqueKeyOperation op = (AddUniqueKeyOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " ADD CONSTRAINT `" + op.getName() + "`"
                                           + " UNIQUE (" + op.getFields().stream().map(e -> "`" + e + "`").collect(Collectors.joining(", ")) + ")");
    }

    private static PreparedStatement translateDropConstraintOperation(Connection connection, MigrationOperation operation) throws SQLException {
        DropConstraintOperation op = (DropConstraintOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " DROP CONSTRAINT `" + op.getName() + "`");
    }

    private static PreparedStatement translateDropFieldOperation(Connection connection, MigrationOperation operation) throws SQLException {
        DropFieldOperation op = (DropFieldOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " DROP COLUMN `" + op.getField() + "`");
    }

    private static PreparedStatement translateDropTableOperation(Connection connection, MigrationOperation operation) throws SQLException {
        DropTableOperation op = (DropTableOperation) operation;
        return connection.prepareStatement("DROP TABLE `" + op.getTable() + "`");
    }

    private static PreparedStatement translateRenameFieldOperation(Connection connection, MigrationOperation operation) throws SQLException {
        RenameFieldOperation op = (RenameFieldOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " RENAME COLUMN `" + op.getOldName() + "` `" + op.getNewName() + "`");
    }

    private static PreparedStatement translateRenameTableOperation(Connection connection, MigrationOperation operation) throws SQLException {
        RenameTableOperation op = (RenameTableOperation) operation;
        return connection.prepareStatement("RENAME TABLE `" + op.getOldName() + "` `" + op.getNewName() + "`");
    }

    private static PreparedStatement translateUpdateFieldOperation(Connection connection, MigrationOperation operation) throws SQLException {
        UpdateFieldOperation op = (UpdateFieldOperation) operation;
        return connection.prepareStatement("ALTER TABLE `" + op.getTable() + "`"
                                           + " ALTER COLUMN `" + op.getField() + "` `" + op.getNewName() + "`"
                                           + op.getSqlType() + (op.isNotNull() ? " NOT NULL" : ""));
    }

    @FunctionalInterface
    private interface Mapper<T extends MigrationOperation> {
        PreparedStatement apply(Connection connection, T operation) throws SQLException;
    }
}