<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db\oci;

use yii\base\InvalidArgumentException;
use yii\db\Connection;
use yii\db\Constraint;
use yii\db\Exception;
use yii\db\Expression;
use yii\db\Query;
use yii\helpers\StringHelper;
use yii\db\ExpressionInterface;

/**
 * QueryBuilder is the query builder for Oracle databases.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class QueryBuilder extends \yii\db\QueryBuilder
{
    /**
     * @var array mapping from abstract column types (keys) to physical column types (values).
     */
    public $typeMap = [
        Schema::TYPE_PK => 'NUMBER(10) NOT NULL PRIMARY KEY',
        Schema::TYPE_UPK => 'NUMBER(10) UNSIGNED NOT NULL PRIMARY KEY',
        Schema::TYPE_BIGPK => 'NUMBER(20) NOT NULL PRIMARY KEY',
        Schema::TYPE_UBIGPK => 'NUMBER(20) UNSIGNED NOT NULL PRIMARY KEY',
        Schema::TYPE_CHAR => 'CHAR(1)',
        Schema::TYPE_STRING => 'VARCHAR2(255)',
        Schema::TYPE_TEXT => 'CLOB',
        Schema::TYPE_TINYINT => 'NUMBER(3)',
        Schema::TYPE_SMALLINT => 'NUMBER(5)',
        Schema::TYPE_INTEGER => 'NUMBER(10)',
        Schema::TYPE_BIGINT => 'NUMBER(20)',
        Schema::TYPE_FLOAT => 'NUMBER',
        Schema::TYPE_DOUBLE => 'NUMBER',
        Schema::TYPE_DECIMAL => 'NUMBER',
        Schema::TYPE_DATETIME => 'TIMESTAMP',
        Schema::TYPE_TIMESTAMP => 'TIMESTAMP',
        Schema::TYPE_TIME => 'TIMESTAMP',
        Schema::TYPE_DATE => 'DATE',
        Schema::TYPE_BINARY => 'BLOB',
        Schema::TYPE_BOOLEAN => 'NUMBER(1)',
        Schema::TYPE_MONEY => 'NUMBER(19,4)',
    ];


    /**
     * {@inheritdoc}
     */
    protected function defaultExpressionBuilders()
    {
        return array_merge(parent::defaultExpressionBuilders(), [
            'yii\db\conditions\InCondition' => 'yii\db\oci\conditions\InConditionBuilder',
            'yii\db\conditions\LikeCondition' => 'yii\db\oci\conditions\LikeConditionBuilder',
        ]);
    }

    /**
     * {@inheritdoc}
     */
    public function buildOrderByAndLimit($sql, $orderBy, $limit, $offset)
    {
        $orderBy = $this->buildOrderBy($orderBy);
        if ($orderBy !== '') {
            $sql .= $this->separator . $orderBy;
        }

        $filters = [];
        if ($this->hasOffset($offset)) {
            $filters[] = 'rowNumId > ' . $offset;
        }
        if ($this->hasLimit($limit)) {
            $filters[] = 'rownum <= ' . $limit;
        }
        if (empty($filters)) {
            return $sql;
        }

        $filter = implode(' AND ', $filters);
        return <<<EOD
WITH USER_SQL AS ($sql),
    PAGINATION AS (SELECT USER_SQL.*, rownum as rowNumId FROM USER_SQL)
SELECT *
FROM PAGINATION
WHERE $filter
EOD;
    }

    /**
     * Builds a SQL statement for renaming a DB table.
     *
     * @param string $table the table to be renamed. The name will be properly quoted by the method.
     * @param string $newName the new table name. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB table.
     */
    public function renameTable($table, $newName)
    {
        return 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' RENAME TO ' . $this->db->quoteTableName($newName);
    }

    /**
     * Builds a SQL statement for changing the definition of a column.
     *
     * @param string $table the table whose column is to be changed. The table name will be properly quoted by the method.
     * @param string $column the name of the column to be changed. The name will be properly quoted by the method.
     * @param string $type the new column type. The [[getColumnType]] method will be invoked to convert abstract column type (if any)
     * into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
     * For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
     * @return string the SQL statement for changing the definition of a column.
     */
    public function alterColumn($table, $column, $type)
    {
        $type = $this->getColumnType($type);

        return 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' MODIFY ' . $this->db->quoteColumnName($column) . ' ' . $this->getColumnType($type);
    }

    /**
     * Builds a SQL statement for dropping an index.
     *
     * @param string $name the name of the index to be dropped. The name will be properly quoted by the method.
     * @param string $table the table whose index is to be dropped. The name will be properly quoted by the method.
     * @return string the SQL statement for dropping an index.
     */
    public function dropIndex($name, $table)
    {
        return 'DROP INDEX ' . $this->db->quoteTableName($name);
    }

    /**
     * {@inheritdoc}
     */
    public function executeResetSequence($table, $value = null)
    {
        $tableSchema = $this->db->getTableSchema($table);
        if ($tableSchema === null) {
            throw new InvalidArgumentException("Unknown table: $table");
        }
        if ($tableSchema->sequenceName === null) {
            throw new InvalidArgumentException("There is no sequence associated with table: $table");
        }

        if ($value !== null) {
            $value = (int) $value;
        } else {
            if (count($tableSchema->primaryKey)>1) {
                throw new InvalidArgumentException("Can't reset sequence for composite primary key in table: $table");
            }
            // use master connection to get the biggest PK value
            $value = $this->db->useMaster(function (Connection $db) use ($tableSchema) {
                return $db->createCommand(
                    'SELECT MAX("' . $tableSchema->primaryKey[0] . '") FROM "'. $tableSchema->name . '"'
                )->queryScalar();
            }) + 1;
        }

        //Oracle needs at least two queries to reset sequence (see adding transactions and/or use alter method to avoid grants' issue?)
        $this->db->createCommand('DROP SEQUENCE "' . $tableSchema->sequenceName . '"')->execute();
        $this->db->createCommand('CREATE SEQUENCE "' . $tableSchema->sequenceName . '" START WITH ' . $value
            . ' INCREMENT BY 1 NOMAXVALUE NOCACHE')->execute();
    }

    /**
     * {@inheritdoc}
     */
    public function addForeignKey($name, $table, $columns, $refTable, $refColumns, $delete = null, $update = null)
    {
        $sql = 'ALTER TABLE ' . $this->db->quoteTableName($table)
            . ' ADD CONSTRAINT ' . $this->db->quoteColumnName($name)
            . ' FOREIGN KEY (' . $this->buildColumns($columns) . ')'
            . ' REFERENCES ' . $this->db->quoteTableName($refTable)
            . ' (' . $this->buildColumns($refColumns) . ')';
        if ($delete !== null) {
            $sql .= ' ON DELETE ' . $delete;
        }
        if ($update !== null) {
            throw new Exception('Oracle does not support ON UPDATE clause.');
        }

        return $sql;
    }

    /**
     * {@inheritdoc}
     */
    protected function prepareInsertValues($table, $columns, $params = [])
    {
        list($names, $placeholders, $values, $params) = parent::prepareInsertValues($table, $columns, $params);
        if (!$columns instanceof Query && empty($names)) {
            $tableSchema = $this->db->getSchema()->getTableSchema($table);
            if ($tableSchema !== null) {
                $columns = !empty($tableSchema->primaryKey) ? $tableSchema->primaryKey : [reset($tableSchema->columns)->name];
                foreach ($columns as $name) {
                    $names[] = $this->db->quoteColumnName($name);
                    $placeholders[] = 'DEFAULT';
                }
            }
        }
        return [$names, $placeholders, $values, $params];
    }

    /**
     * {@inheritdoc}
     * @see https://docs.oracle.com/cd/B28359_01/server.111/b28286/statements_9016.htm#SQLRF01606
     */
    public function upsert($table, $insertColumns, $updateColumns, &$params)
    {
        /** @var Constraint[] $constraints */
        list($uniqueNames, $insertNames, $updateNames) = $this->prepareUpsertColumns($table, $insertColumns, $updateColumns, $constraints);
        if (empty($uniqueNames)) {
            return $this->insert($table, $insertColumns, $params);
        }
        if ($updateNames === []) {
            // there are no columns to update
            $updateColumns = false;
        }

        $onCondition = ['or'];
        $quotedTableName = $this->db->quoteTableName($table);
        foreach ($constraints as $constraint) {
            $constraintCondition = ['and'];
            foreach ($constraint->columnNames as $name) {
                $quotedName = $this->db->quoteColumnName($name);
                $constraintCondition[] = "$quotedTableName.$quotedName=\"EXCLUDED\".$quotedName";
            }
            $onCondition[] = $constraintCondition;
        }
        $on = $this->buildCondition($onCondition, $params);
        list(, $placeholders, $values, $params) = $this->prepareInsertValues($table, $insertColumns, $params);
        if (!empty($placeholders)) {
            $usingSelectValues = [];
            foreach ($insertNames as $index => $name) {
                $usingSelectValues[$name] = new Expression($placeholders[$index]);
            }
            $usingSubQuery = (new Query())
                ->select($usingSelectValues)
                ->from('DUAL');
            list($usingValues, $params) = $this->build($usingSubQuery, $params);
        }
        $mergeSql = 'MERGE INTO ' . $this->db->quoteTableName($table) . ' '
            . 'USING (' . (isset($usingValues) ? $usingValues : ltrim($values, ' ')) . ') "EXCLUDED" '
            . "ON ($on)";
        $insertValues = [];
        foreach ($insertNames as $name) {
            $quotedName = $this->db->quoteColumnName($name);
            if (strrpos($quotedName, '.') === false) {
                $quotedName = '"EXCLUDED".' . $quotedName;
            }
            $insertValues[] = $quotedName;
        }
        $insertSql = 'INSERT (' . implode(', ', $insertNames) . ')'
            . ' VALUES (' . implode(', ', $insertValues) . ')';
        if ($updateColumns === false) {
            return "$mergeSql WHEN NOT MATCHED THEN $insertSql";
        }

        if ($updateColumns === true) {
            $updateColumns = [];
            foreach ($updateNames as $name) {
                $quotedName = $this->db->quoteColumnName($name);
                if (strrpos($quotedName, '.') === false) {
                    $quotedName = '"EXCLUDED".' . $quotedName;
                }
                $updateColumns[$name] = new Expression($quotedName);
            }
        }
        list($updates, $params) = $this->prepareUpdateSets($table, $updateColumns, $params);
        $updateSql = 'UPDATE SET ' . implode(', ', $updates);
        return "$mergeSql WHEN MATCHED THEN $updateSql WHEN NOT MATCHED THEN $insertSql";
    }

    /**
     * Generates a batch INSERT SQL statement.
     *
     * For example,
     *
     * ```php
     * $sql = $queryBuilder->batchInsert('user', ['name', 'age'], [
     *     ['Tom', 30],
     *     ['Jane', 20],
     *     ['Linda', 25],
     * ]);
     * ```
     *
     * Note that the values in each row must match the corresponding column names.
     *
     * @param string $table the table that new rows will be inserted into.
     * @param array $columns the column names
     * @param array|\Generator $rows the rows to be batch inserted into the table
     * @return string the batch INSERT SQL statement
     */
    public function batchInsert($table, $columns, $rows, &$params = [])
    {
        if (empty($rows)) {
            return '';
        }

        $schema = $this->db->getSchema();
        if (($tableSchema = $schema->getTableSchema($table)) !== null) {
            $columnSchemas = $tableSchema->columns;
        } else {
            $columnSchemas = [];
        }

        $values = [];
        foreach ($rows as $row) {
            $vs = [];
            foreach ($row as $i => $value) {
                if (isset($columns[$i], $columnSchemas[$columns[$i]])) {
                    $value = $columnSchemas[$columns[$i]]->dbTypecast($value);
                }
                if (is_string($value)) {
                    $value = $schema->quoteValue($value);
                } elseif (is_float($value)) {
                    // ensure type cast always has . as decimal separator in all locales
                    $value = StringHelper::floatToString($value);
                } elseif ($value === false) {
                    $value = 0;
                } elseif ($value === null) {
                    $value = 'NULL';
                } elseif ($value instanceof ExpressionInterface) {
                    $value = $this->buildExpression($value, $params);
                }
                $vs[] = $value;
            }
            $values[] = '(' . implode(', ', $vs) . ')';
        }
        if (empty($values)) {
            return '';
        }

        foreach ($columns as $i => $name) {
            $columns[$i] = $schema->quoteColumnName($name);
        }

        $tableAndColumns = ' INTO ' . $schema->quoteTableName($table)
        . ' (' . implode(', ', $columns) . ') VALUES ';

        return 'INSERT ALL ' . $tableAndColumns . implode($tableAndColumns, $values) . ' SELECT 1 FROM SYS.DUAL';
    }

    /**
     * {@inheritdoc}
     * @since 2.0.8
     */
    public function selectExists($rawSql)
    {
        return 'SELECT CASE WHEN EXISTS(' . $rawSql . ') THEN 1 ELSE 0 END FROM DUAL';
    }

    /**
     * {@inheritdoc}
     * @since 2.0.8
     */
    public function dropCommentFromColumn($table, $column)
    {
        return 'COMMENT ON COLUMN ' . $this->db->quoteTableName($table) . '.' . $this->db->quoteColumnName($column) . " IS ''";
    }

    /**
     * {@inheritdoc}
     * @since 2.0.8
     */
    public function dropCommentFromTable($table)
    {
        return 'COMMENT ON TABLE ' . $this->db->quoteTableName($table) . " IS ''";
    }
}
