<?php
/**
 * @class sqliteSchema
 *
 * @package Clearbricks
 * @subpackage DBSchema
 *
 * @copyright Olivier Meunier & Association Dotclear
 * @copyright GPL-2.0-only
 */

/** @cond ONCE */
if (class_exists('dbSchema')) {
/** @endcond */

    class sqliteSchema extends dbSchema implements i_dbSchema
    {
        private $table_hist = [];

        private $table_stack = []; // Stack for tables creation
        private $x_stack     = []; // Execution stack

        public function dbt2udt($type, &$len, &$default)
        {
            $type = parent::dbt2udt($type, $len, $default);

            switch ($type) {
                case 'float':
                    return 'real';
                case 'double':
                    return 'float';
                case 'timestamp':
                    # DATETIME real type is TIMESTAMP
                    if ($default == "'1970-01-01 00:00:00'") {
                        # Bad hack
                        $default = 'now()';
                    }
                    return 'timestamp';
                case 'integer':
                case 'mediumint':
                case 'bigint':
                case 'tinyint':
                case 'smallint':
                case 'numeric':
                    return 'integer';
                case 'tinytext':
                case 'longtext':
                    return 'text';
            }

            return $type;
        }

        public function udt2dbt($type, &$len, &$default)
        {
            $type = parent::udt2dbt($type, $len, $default);

            switch ($type) {
                case 'integer':
                case 'smallint':
                case 'bigint':
                    return 'integer';
                case 'real':
                case 'float:':
                    return 'real';
                case 'date':
                case 'time':
                    return 'timestamp';
                case 'timestamp':
                    if ($default == 'now()') {
                        # SQLite does not support now() default value...
                        $default = "'1970-01-01 00:00:00'";
                    }
                    return $type;
            }

            return $type;
        }

        public function flushStack()
        {
            foreach ($this->table_stack as $table => $def) {
                $sql = 'CREATE TABLE ' . $table . " (\n" . implode(",\n", $def) . "\n)\n ";
                $this->con->execute($sql);
            }

            foreach ($this->x_stack as $x) {
                $this->con->execute($x);
            }
        }

        public function db_get_tables()
        {
            $res = [];
            $sql = "SELECT * FROM sqlite_master WHERE type = 'table'";
            $rs  = $this->con->select($sql);

            $res = [];
            while ($rs->fetch()) {
                $res[] = $rs->tbl_name;
            }

            return $res;
        }

        public function db_get_columns($table)
        {
            $sql = 'PRAGMA table_info(' . $this->con->escapeSystem($table) . ')';
            $rs  = $this->con->select($sql);

            $res = [];
            while ($rs->fetch()) {
                $field   = trim($rs->name);
                $type    = trim($rs->type);
                $null    = trim($rs->notnull) == 0;
                $default = trim($rs->dflt_value);

                $len = null;
                if (preg_match('/^(.+?)\(([\d,]+)\)$/si', $type, $m)) {
                    $type = $m[1];
                    $len  = (integer) $m[2];
                }

                $res[$field] = [
                    'type'    => $type,
                    'len'     => $len,
                    'null'    => $null,
                    'default' => $default
                ];
            }
            return $res;
        }

        public function db_get_keys($table)
        {
            $t   = [];
            $res = [];

            # Get primary keys first
            $sql = "SELECT sql FROM sqlite_master WHERE type='table' AND name='" . $this->con->escape($table) . "'";
            $rs  = $this->con->select($sql);

            if ($rs->isEmpty()) {
                return [];
            }

            # Get primary keys
            $n = preg_match_all('/^\s*CONSTRAINT\s+([^,]+?)\s+PRIMARY\s+KEY\s+\((.+?)\)/msi', $rs->sql, $match);
            if ($n > 0) {
                foreach ($match[1] as $i => $name) {
                    $cols  = preg_split('/\s*,\s*/', $match[2][$i]);
                    $res[] = [
                        'name'    => $name,
                        'primary' => true,
                        'unique'  => false,
                        'cols'    => $cols
                    ];
                }
            }

            # Get unique keys
            $n = preg_match_all('/^\s*CONSTRAINT\s+([^,]+?)\s+UNIQUE\s+\((.+?)\)/msi', $rs->sql, $match);
            if ($n > 0) {
                foreach ($match[1] as $i => $name) {
                    $cols  = preg_split('/\s*,\s*/', $match[2][$i]);
                    $res[] = [
                        'name'    => $name,
                        'primary' => false,
                        'unique'  => true,
                        'cols'    => $cols
                    ];
                }
            }

            return $res;
        }

        public function db_get_indexes($table)
        {
            $sql = 'PRAGMA index_list(' . $this->con->escapeSystem($table) . ')';
            $rs  = $this->con->select($sql);

            $res = [];
            while ($rs->fetch()) {
                if (preg_match('/^sqlite_/', $rs->name)) {
                    continue;
                }

                $idx  = $this->con->select('PRAGMA index_info(' . $this->con->escapeSystem($rs->name) . ')');
                $cols = [];
                while ($idx->fetch()) {
                    $cols[] = $idx->name;
                }

                $res[] = [
                    'name' => $rs->name,
                    'type' => 'btree',
                    'cols' => $cols
                ];
            }

            return $res;
        }

        public function db_get_references($table)
        {
            $sql = 'SELECT * FROM sqlite_master WHERE type=\'trigger\' AND tbl_name = \'%1$s\' AND name LIKE \'%2$s_%%\' ';
            $res = [];

            # Find constraints on table
            $bir = $this->con->select(sprintf($sql, $this->con->escape($table), 'bir'));
            $bur = $this->con->select(sprintf($sql, $this->con->escape($table), 'bur'));

            if ($bir->isEmpty() || $bur->isempty()) {
                return $res;
            }

            while ($bir->fetch()) {
                # Find child column and parent table and column
                if (!preg_match('/FROM\s+(.+?)\s+WHERE\s+(.+?)\s+=\s+NEW\.(.+?)\s*?\) IS\s+NULL/msi', $bir->sql, $m)) {
                    continue;
                }

                $c_col   = $m[3];
                $p_table = $m[1];
                $p_col   = $m[2];

                # Find on update
                $on_update = 'restrict';
                $aur       = $this->con->select(sprintf($sql, $this->con->escape($p_table), 'aur'));
                while ($aur->fetch()) {
                    if (!preg_match('/AFTER\s+UPDATE/msi', $aur->sql)) {
                        continue;
                    }

                    if (preg_match('/UPDATE\s+' . $table . '\s+SET\s+' . $c_col . '\s*=\s*NEW.' . $p_col .
                        '\s+WHERE\s+' . $c_col . '\s*=\s*OLD\.' . $p_col . '/msi', $aur->sql)) {
                        $on_update = 'cascade';
                        break;
                    }

                    if (preg_match('/UPDATE\s+' . $table . '\s+SET\s+' . $c_col . '\s*=\s*NULL' .
                        '\s+WHERE\s+' . $c_col . '\s*=\s*OLD\.' . $p_col . '/msi', $aur->sql)) {
                        $on_update = 'set null';
                        break;
                    }
                }

                # Find on delete
                $on_delete = 'restrict';
                $bdr       = $this->con->select(sprintf($sql, $this->con->escape($p_table), 'bdr'));
                while ($bdr->fetch()) {
                    if (!preg_match('/BEFORE\s+DELETE/msi', $bdr->sql)) {
                        continue;
                    }

                    if (preg_match('/DELETE\s+FROM\s+' . $table . '\s+WHERE\s+' . $c_col . '\s*=\s*OLD\.' . $p_col . '/msi', $bdr->sql)) {
                        $on_delete = 'cascade';
                        break;
                    }

                    if (preg_match('/UPDATE\s+' . $table . '\s+SET\s+' . $c_col . '\s*=\s*NULL' .
                        '\s+WHERE\s+' . $c_col . '\s*=\s*OLD\.' . $p_col . '/msi', $bdr->sql)) {
                        $on_update = 'set null';
                        break;
                    }
                }

                $res[] = [
                    'name'    => substr($bir->name, 4),
                    'c_cols'  => [$c_col],
                    'p_table' => $p_table,
                    'p_cols'  => [$p_col],
                    'update'  => $on_update,
                    'delete'  => $on_delete
                ];
            }

            return $res;
        }

        public function db_create_table($name, $fields)
        {
            $a = [];

            foreach ($fields as $n => $f) {
                $type    = $f['type'];
                $len     = (integer) $f['len'];
                $default = $f['default'];
                $null    = $f['null'];

                $type = $this->udt2dbt($type, $len, $default);
                $len  = $len > 0 ? '(' . $len . ')' : '';
                $null = $null ? 'NULL' : 'NOT NULL';

                if ($default === null) {
                    $default = 'DEFAULT NULL';
                } elseif ($default !== false) {
                    $default = 'DEFAULT ' . $default . ' ';
                } else {
                    $default = '';
                }

                $a[] = $n . ' ' . $type . $len . ' ' . $null . ' ' . $default;
            }

            $this->table_stack[$name][] = implode(",\n", $a);
            $this->table_hist[$name]    = $fields;
        }

        public function db_create_field($table, $name, $type, $len, $null, $default)
        {
            $type = $this->udt2dbt($type, $len, $default);
            $len  = $len > 0 ? '(' . $len . ')' : '';
            $null = $null ? 'NULL' : 'NOT NULL';

            if ($default === null) {
                $default = 'DEFAULT NULL';
            } elseif ($default !== false) {
                $default = 'DEFAULT ' . $default . ' ';
            } else {
                $default = '';
            }

            $sql =
            'ALTER TABLE ' . $this->con->escapeSystem($table) . ' ' .
            'ADD COLUMN ' . $this->con->escapeSystem($name) . ' ' .
                $type . $len . ' ' . $null . ' ' . $default;

            $this->con->execute($sql);
        }

        public function db_create_primary($table, $name, $cols)
        {
            $this->table_stack[$table][] = 'CONSTRAINT ' . $name . ' PRIMARY KEY (' . implode(',', $cols) . ') ';
        }

        public function db_create_unique($table, $name, $cols)
        {
            $this->table_stack[$table][] = 'CONSTRAINT ' . $name . ' UNIQUE (' . implode(',', $cols) . ') ';
        }

        public function db_create_index($table, $name, $type, $cols)
        {
            $this->x_stack[] = 'CREATE INDEX ' . $name . ' ON ' . $table . ' (' . implode(',', $cols) . ') ';
        }

        public function db_create_reference($name, $c_table, $c_cols, $p_table, $p_cols, $update, $delete)
        {
            if (!isset($this->table_hist[$c_table])) {
                return;
            }

            if (count($c_cols) > 1 || count($p_cols) > 1) {
                throw new Exception('SQLite UDBS does not support multiple columns foreign keys');
            }

            $c_col = $c_cols[0];
            $p_col = $p_cols[0];

            $update = strtolower($update);
            $delete = strtolower($delete);

            $cnull = $this->table_hist[$c_table][$c_col]['null'];

            # Create constraint
            $this->x_stack[] =
                'CREATE TRIGGER bir_' . $name . "\n" .
                'BEFORE INSERT ON ' . $c_table . "\n" .
                "FOR EACH ROW BEGIN\n" .
                '  SELECT RAISE(ROLLBACK,\'insert on table "' . $c_table . '" violates foreign key constraint "' . $name . '"\')' . "\n" .
                '  WHERE ' .
                ($cnull ? 'NEW.' . $c_col . " IS NOT NULL\n  AND " : '') .
                '(SELECT ' . $p_col . ' FROM ' . $p_table . ' WHERE ' . $p_col . ' = NEW.' . $c_col . ") IS NULL;\n" .
                "END;\n";

            # Update constraint
            $this->x_stack[] =
                'CREATE TRIGGER bur_' . $name . "\n" .
                'BEFORE UPDATE ON ' . $c_table . "\n" .
                "FOR EACH ROW BEGIN\n" .
                '  SELECT RAISE(ROLLBACK,\'update on table "' . $c_table . '" violates foreign key constraint "' . $name . '"\')' . "\n" .
                '  WHERE ' .
                ($cnull ? 'NEW.' . $c_col . " IS NOT NULL\n  AND " : '') .
                '(SELECT ' . $p_col . ' FROM ' . $p_table . ' WHERE ' . $p_col . ' = NEW.' . $c_col . ") IS NULL;\n" .
                "END;\n";

            # ON UPDATE
            if ($update == 'cascade') {
                $this->x_stack[] =
                    'CREATE TRIGGER aur_' . $name . "\n" .
                    'AFTER UPDATE ON ' . $p_table . "\n" .
                    "FOR EACH ROW BEGIN\n" .
                    '  UPDATE ' . $c_table . ' SET ' . $c_col . ' = NEW.' . $p_col . ' WHERE ' . $c_col . ' = OLD.' . $p_col . ";\n" .
                    "END;\n";
            } elseif ($update == 'set null') {
                $this->x_stack[] =
                    'CREATE TRIGGER aur_' . $name . "\n" .
                    'AFTER UPDATE ON ' . $p_table . "\n" .
                    "FOR EACH ROW BEGIN\n" .
                    '  UPDATE ' . $c_table . ' SET ' . $c_col . ' = NULL WHERE ' . $c_col . ' = OLD.' . $p_col . ";\n" .
                    "END;\n";
            } else # default on restrict
            {
                $this->x_stack[] =
                    'CREATE TRIGGER burp_' . $name . "\n" .
                    'BEFORE UPDATE ON ' . $p_table . "\n" .
                    "FOR EACH ROW BEGIN\n" .
                    '  SELECT RAISE (ROLLBACK,\'update on table "' . $p_table . '" violates foreign key constraint "' . $name . '"\')' . "\n" .
                    '  WHERE (SELECT ' . $c_col . ' FROM ' . $c_table . ' WHERE ' . $c_col . ' = OLD.' . $p_col . ") IS NOT NULL;\n" .
                    "END;\n";
            }

            # ON DELETE
            if ($delete == 'cascade') {
                $this->x_stack[] =
                    'CREATE TRIGGER bdr_' . $name . "\n" .
                    'BEFORE DELETE ON ' . $p_table . "\n" .
                    "FOR EACH ROW BEGIN\n" .
                    '  DELETE FROM ' . $c_table . ' WHERE ' . $c_col . ' = OLD.' . $p_col . ";\n" .
                    "END;\n";
            } elseif ($delete == 'set null') {
                $this->x_stack[] =
                    'CREATE TRIGGER bdr_' . $name . "\n" .
                    'BEFORE DELETE ON ' . $p_table . "\n" .
                    "FOR EACH ROW BEGIN\n" .
                    '  UPDATE ' . $c_table . ' SET ' . $c_col . ' = NULL WHERE ' . $c_col . ' = OLD.' . $p_col . ";\n" .
                    "END;\n";
            } else {
                $this->x_stack[] =
                    'CREATE TRIGGER bdr_' . $name . "\n" .
                    'BEFORE DELETE ON ' . $p_table . "\n" .
                    "FOR EACH ROW BEGIN\n" .
                    '  SELECT RAISE (ROLLBACK,\'delete on table "' . $p_table . '" violates foreign key constraint "' . $name . '"\')' . "\n" .
                    '  WHERE (SELECT ' . $c_col . ' FROM ' . $c_table . ' WHERE ' . $c_col . ' = OLD.' . $p_col . ") IS NOT NULL;\n" .
                    "END;\n";
            }
        }

        public function db_alter_field($table, $name, $type, $len, $null, $default)
        {
            $type = $this->udt2dbt($type, $len, $default);
            if ($type != 'integer' && $type != 'text' && $type != 'timestamp') {
                throw new Exception('SQLite fields cannot be changed.');
            }
        }

        public function db_alter_primary($table, $name, $newname, $cols)
        {
            throw new Exception('SQLite primary key cannot be changed.');
        }

        public function db_alter_unique($table, $name, $newname, $cols)
        {
            throw new Exception('SQLite unique index cannot be changed.');
        }

        public function db_alter_index($table, $name, $newname, $type, $cols)
        {
            $this->con->execute('DROP INDEX IF EXISTS ' . $name);
            $this->con->execute('CREATE INDEX ' . $newname . ' ON ' . $table . ' (' . implode(',', $cols) . ') ');
        }

        public function db_alter_reference($name, $newname, $c_table, $c_cols, $p_table, $p_cols, $update, $delete)
        {
            $this->con->execute('DROP TRIGGER IF EXISTS bur_' . $name);
            $this->con->execute('DROP TRIGGER IF EXISTS burp_' . $name);
            $this->con->execute('DROP TRIGGER IF EXISTS bir_' . $name);
            $this->con->execute('DROP TRIGGER IF EXISTS aur_' . $name);
            $this->con->execute('DROP TRIGGER IF EXISTS bdr_' . $name);

            $this->table_hist[$c_table] = $this->db_get_columns($c_table);
            $this->db_create_reference($newname, $c_table, $c_cols, $p_table, $p_cols, $update, $delete);
        }

        public function db_drop_unique($table, $name)
        {
            throw new Exception('SQLite unique index cannot be removed.');
        }
    }

/** @cond ONCE */
}
/** @endcond */