<?php
/**
 * php-sql-creator.php
 * 
 * A pure PHP SQL creator, which generates SQL from the output of PHPSQLParser.
 * 
 * Copyright (c) 2012, André Rothe <hide@address.com, hide@address.com>
 * 
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice, 
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice, 
 *     this list of conditions and the following disclaimer in the documentation 
 *     and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY 
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 
 * DAMAGE.
 */

if (!defined('HAVE_PHP_SQL_CREATOR')) {

    require_once(dirname(__FILE__) . '/classes/exceptions.php');

    class PHPSQLCreator {

        public function __construct($parsed = false) {
            if ($parsed) {
                $this->create($parsed);
            }
        }

        public function create($parsed) {
            $k = key($parsed);
            switch ($k) {

            case "UNION":
            case "UNION ALL":
                throw new UnsupportedFeatureException($k);
                break;
            case "SELECT":
                $this->created = $this->processSelectStatement($parsed);
                break;
            case "INSERT":
                $this->created = $this->processInsertStatement($parsed);
                break;
            case "DELETE":
                $this->created = $this->processDeleteStatement($parsed);
                break;
            case "UPDATE":
                $this->created = $this->processUpdateStatement($parsed);
                break;
            default:
                throw new UnsupportedFeatureException($k);
                break;
            }
            return $this->created;
        }

        protected function processSelectStatement($parsed) {
            $sql = $this->processSELECT($parsed['SELECT']) . " " . $this->processFROM($parsed['FROM']);
            if (isset($parsed['WHERE'])) {
                $sql .= " " . $this->processWHERE($parsed['WHERE']);
            }
            if (isset($parsed['GROUP'])) {
                $sql .= " " . $this->processGROUP($parsed['GROUP']);
            }
            if (isset($parsed['ORDER'])) {
                $sql .= " " . $this->processORDER($parsed['ORDER']);
            }
            if (isset($parsed['LIMIT'])) {
                $sql .= " " . $this->processLIMIT($parsed['LIMIT']);
            }
            return $sql;
        }

        protected function processInsertStatement($parsed) {
            return $this->processINSERT($parsed['INSERT']) . " " . $this->processVALUES($parsed['VALUES']);
            # TODO: subquery?
        }

        protected function processDeleteStatement($parsed) {
            return $this->processDELETE($parsed['DELETE']) . " " . $this->processFROM($parsed['FROM']) . " "
                    . $this->processWHERE($parsed['WHERE']);
        }

        protected function processUpdateStatement($parsed) {
            $sql = $this->processUPDATE($parsed['UPDATE']) . " " . $this->processSET($parsed['SET']);
            if (isset($parsed['WHERE'])) {
                $sql .= " " . $this->processWHERE($parsed['WHERE']);
            }
            return $sql;
        }

        protected function processDELETE($parsed) {
            $sql = "DELETE";
            foreach ($parsed['TABLES'] as $k => $v) {
                $sql .= $v . ",";
            }
            return substr($sql, 0, -1);
        }

        protected function processSELECT($parsed) {
            $sql = "";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processColRef($v);
                $sql .= $this->processSelectExpression($v);
                $sql .= $this->processFunction($v);
                $sql .= $this->processConstant($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('SELECT', $k, $v, 'expr_type');
                }

                $sql .= ",";
            }
            $sql = substr($sql, 0, -1);
            return "SELECT " . $sql;
        }

        protected function processFROM($parsed) {
            $sql = "";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processTable($v, $k);
                $sql .= $this->processTableExpression($v, $k);
                $sql .= $this->processSubquery($v, $k);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('FROM', $k, $v, 'expr_type');
                }

                $sql .= " ";
            }
            return "FROM " . substr($sql, 0, -1);
        }

        protected function processORDER($parsed) {
            $sql = "";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processOrderByAlias($v);
                $sql .= $this->processColRef($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('ORDER', $k, $v, 'expr_type');
                }

                $sql .= ",";
            }
            $sql = substr($sql, 0, -1);
            return "ORDER BY " . $sql;
        }

        protected function processLIMIT($parsed) {
            $sql = ($parsed['offset'] ? $parsed['offset'] . ", " : "") . $parsed['rowcount'];
            if ($sql === "") {
                throw new UnableToCreateSQLException('LIMIT', 'rowcount', $parsed, 'rowcount');
            }
            return "LIMIT " . $sql;
        }

        protected function processGROUP($parsed) {
            $sql = "";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processColRef($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('GROUP', $k, $v, 'expr_type');
                }

                $sql .= ",";
            }
            $sql = substr($sql, 0, -1);
            return "GROUP BY " . $sql;
        }

        protected function processRecord($parsed) {
            if ($parsed['expr_type'] !== 'record') {
                return "";
            }
            $sql = "";
            foreach ($parsed['data'] as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processConstant($v);
                $sql .= $this->processFunction($v);
                $sql .= $this->processOperator($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('record', $k, $v, 'expr_type');
                }

                $sql .= ",";
            }
            $sql = substr($sql, 0, -1);
            return "(" . $sql . ")";

        }

        protected function processVALUES($parsed) {
            $sql = "";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processRecord($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('VALUES', $k, $v, 'expr_type');
                }

                $sql .= ",";
            }
            $sql = substr($sql, 0, -1);
            return "VALUES " . $sql;
        }

        protected function processINSERT($parsed) {
            $sql = "INSERT INTO " . $parsed['table'];

            if ($parsed['columns'] === false) {
                return $sql;
            }

            $columns = "";
            foreach ($parsed['columns'] as $k => $v) {
                $len = strlen($columns);
                $columns .= $this->processColRef($v);

                if ($len == strlen($columns)) {
                    throw new UnableToCreateSQLException('INSERT[columns]', $k, $v, 'expr_type');
                }

                $columns .= ",";
            }

            if ($columns !== "") {
                $columns = " (" . substr($columns, 0, -1) . ")";
            }

            $sql .= $columns;
            return $sql;
        }

        protected function processUPDATE($parsed) {
            return "UPDATE " . $parsed[0]['table'];
        }

        protected function processSetExpression($parsed) {
            if ($parsed['expr_type'] !== 'expression') {
                return "";
            }
            $sql = "";
            foreach ($parsed['sub_tree'] as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processColRef($v);
                $sql .= $this->processConstant($v);
                $sql .= $this->processOperator($v);
                $sql .= $this->processFunction($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('SET expression subtree', $k, $v, 'expr_type');
                }

                $sql .= " ";
            }

            $sql = substr($sql, 0, -1);
            return $sql;
        }

        protected function processSET($parsed) {
            $sql = "";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processSetExpression($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('SET', $k, $v, 'expr_type');
                }

                $sql .= ",";
            }
            return "SET " . substr($sql, 0, -1);
        }

        protected function processWHERE($parsed) {
            $sql = "WHERE ";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);

                $sql .= $this->processOperator($v);
                $sql .= $this->processConstant($v);
                $sql .= $this->processColRef($v);
                $sql .= $this->processSubquery($v);
                $sql .= $this->processInList($v);
                $sql .= $this->processFunction($v);
                $sql .= $this->processWhereExpression($v);
                $sql .= $this->processWhereBracketExpression($v);

                if (strlen($sql) == $len) {
                    throw new UnableToCreateSQLException('WHERE', $k, $v, 'expr_type');
                }

                $sql .= " ";
            }
            return substr($sql, 0, -1);
        }

        protected function processWhereExpression($parsed) {
            if ($parsed['expr_type'] !== 'expression') {
                return "";
            }
            $sql = "";
            foreach ($parsed['sub_tree'] as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processColRef($v);
                $sql .= $this->processConstant($v);
                $sql .= $this->processOperator($v);
                $sql .= $this->processInList($v);
                $sql .= $this->processFunction($v);
                $sql .= $this->processWhereExpression($v);
                $sql .= $this->processWhereBracketExpression($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('WHERE expression subtree', $k, $v, 'expr_type');
                }

                $sql .= " ";
            }

            $sql = substr($sql, 0, -1);
            return $sql;
        }

        protected function processWhereBracketExpression($parsed) {
            if ($parsed['expr_type'] !== 'bracket_expression') {
                return "";
            }
            $sql = "";
            foreach ($parsed['sub_tree'] as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processColRef($v);
                $sql .= $this->processConstant($v);
                $sql .= $this->processOperator($v);
                $sql .= $this->processInList($v);
                $sql .= $this->processFunction($v);
                $sql .= $this->processWhereExpression($v);
                $sql .= $this->processWhereBracketExpression($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('WHERE expression subtree', $k, $v, 'expr_type');
                }

                $sql .= " ";
            }

            $sql = "(" . substr($sql, 0, -1) . ")";
            return $sql;
        }

        protected function processOrderByAlias($parsed) {
            if ($parsed['expr_type'] !== 'alias') {
                return "";
            }
            return $parsed['base_expr'] . $this->processDirection($parsed['direction']);
        }

        protected function processLimitRowCount($key, $value) {
            if ($key != 'rowcount') {
                return "";
            }
            return $value;
        }

        protected function processLimitOffset($key, $value) {
            if ($key !== 'offset') {
                return "";
            }
            return $value;
        }

        protected function processFunction($parsed) {
            if (($parsed['expr_type'] !== 'aggregate_function') && ($parsed['expr_type'] !== 'function')) {
                return "";
            }

            if ($parsed['sub_tree'] === false) {
                return $parsed['base_expr'] . "()";
            }

            $sql = "";
            foreach ($parsed['sub_tree'] as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processFunction($v);
                $sql .= $this->processConstant($v);
                $sql .= $this->processColRef($v);
                $sql .= $this->processReserved($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('function subtree', $k, $v, 'expr_type');
                }

                $sql .= ($this->isReserved($v) ? " " : ",");
            }
            return $parsed['base_expr'] . "(" . substr($sql, 0, -1) . ")";
        }

        protected function processSelectExpression($parsed) {
            if ($parsed['expr_type'] !== 'expression') {
                return "";
            }
            $sql = $this->processSubTree($parsed, " ");
            $sql .= $this->processAlias($parsed['alias']);
            return $sql;
        }

        protected function processSelectBracketExpression($parsed) {
            if ($parsed['expr_type'] !== 'bracket_expression') {
                return "";
            }
            $sql = $this->processSubTree($parsed, " ");
            $sql = "(" . $sql . ")";
            return $sql;
        }

        protected function processSubTree($parsed, $delim = " ") {
            if ($parsed['sub_tree'] === '') {
                return "";
            }
            $sql = "";
            foreach ($parsed['sub_tree'] as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processFunction($v);
                $sql .= $this->processOperator($v);
                $sql .= $this->processConstant($v);
                $sql .= $this->processSubQuery($v);
                $sql .= $this->processSelectBracketExpression($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('expression subtree', $k, $v, 'expr_type');
                }

                $sql .= $delim;
            }
            return substr($sql, 0, -1);
        }

        protected function processRefClause($parsed) {
            if ($parsed === false) {
                return "";
            }

            $sql = "";
            foreach ($parsed as $k => $v) {
                $len = strlen($sql);
                $sql .= $this->processColRef($v);
                $sql .= $this->processOperator($v);
                $sql .= $this->processConstant($v);

                if ($len == strlen($sql)) {
                    throw new UnableToCreateSQLException('expression ref_clause', $k, $v, 'expr_type');
                }

                $sql .= " ";
            }
            return "(" . substr($sql, 0, -1) . ")";
        }

        protected function processAlias($parsed) {
            if ($parsed === false) {
                return "";
            }
            $sql = "";
            if ($parsed['as']) {
                $sql .= " as";
            }
            $sql .= " " . $parsed['name'];
            return $sql;
        }

        protected function processJoin($parsed) {
            if ($parsed === 'CROSS') {
                return ",";
            }
            if ($parsed === 'JOIN') {
                return "INNER JOIN";
            }
            if ($parsed === 'LEFT') {
                return "LEFT JOIN";
            }
            if ($parsed === 'RIGHT') {
                return "RIGHT JOIN";
            }
            // TODO: add more
            throw new UnsupportedFeatureException($parsed);
        }

        protected function processRefType($parsed) {
            if ($parsed === false) {
                return "";
            }
            if ($parsed === 'ON') {
                return " ON ";
            }
            if ($parsed === 'USING') {
                return " USING ";
            }
            // TODO: add more
            throw new UnsupportedFeatureException($parsed);
        }

        protected function processTable($parsed, $index) {
            if ($parsed['expr_type'] !== 'table') {
                return "";
            }

            $sql = $parsed['table'];
            $sql .= $this->processAlias($parsed['alias']);

            if ($index !== 0) {
                $sql = $this->processJoin($parsed['join_type']) . " " . $sql;
                $sql .= $this->processRefType($parsed['ref_type']);
                $sql .= $this->processRefClause($parsed['ref_clause']);
            }
            return $sql;
        }

        protected function processTableExpression($parsed, $index) {
            if ($parsed['expr_type'] !== 'table_expression') {
                return "";
            }
            $sql = substr($this->processFROM($parsed['sub_tree']), 5); // remove FROM keyword
            $sql = "(" . $sql . ")";
            $sql .= $this->processAlias($parsed['alias']);

            if ($index !== 0) {
                $sql = $this->processJoin($parsed['join_type']) . " " . $sql;
                $sql .= $this->processRefType($parsed['ref_type']);
                $sql .= $this->processRefClause($parsed['ref_clause']);
            }
            return $sql;
        }

        protected function processSubQuery($parsed, $index = 0) {
            if ($parsed['expr_type'] !== 'subquery') {
                return "";
            }

            $sql = $this->processSelectStatement($parsed['sub_tree']);
            $sql = "(" . $sql . ")";

            if (isset($parsed['alias'])) {
                $sql .= $this->processAlias($parsed['alias']);
            }

            if ($index !== 0) {
                $sql = $this->processJoin($parsed['join_type']) . " " . $sql;
                $sql .= $this->processRefType($parsed['ref_type']);
                $sql .= $this->processRefClause($parsed['ref_clause']);
            }
            return $sql;
        }

        protected function processOperator($parsed) {
            if ($parsed['expr_type'] !== 'operator') {
                return "";
            }
            return $parsed['base_expr'];
        }

        protected function processColRef($parsed) {
            if ($parsed['expr_type'] !== 'colref') {
                return "";
            }
            $sql = $parsed['base_expr'];
            if (isset($parsed['alias'])) {
                $sql .= $this->processAlias($parsed['alias']);
            }
            if (isset($parsed['direction'])) {
                $sql .= $this->processDirection($parsed['direction']);
            }
            return $sql;
        }

        protected function processDirection($parsed) {
            $sql = ($parsed ? " " . $parsed : "");
            return $sql;
        }

        protected function processReserved($parsed) {
            if (!$this->isReserved($parsed)) {
                return "";
            }
            return $parsed['base_expr'];
        }

        protected function isReserved($parsed) {
            return ($parsed['expr_type'] === 'reserved');
        }

        protected function processConstant($parsed) {
            if ($parsed['expr_type'] !== 'const') {
                return "";
            }
            return $parsed['base_expr'];
        }

        protected function processInList($parsed) {
            if ($parsed['expr_type'] !== 'in-list') {
                return "";
            }
            $sql = $this->processSubTree($parsed, ",");
            return "(" . $sql . ")";
        }

    } // END CLASS

    define('HAVE_PHP_SQL_CREATOR', 1);
}