<?php


namespace Exodus4D\Pathfinder\Db\Sql\Mysql;


use DB\SQL;

class Constraint {

    // available actions
    const ACTIONS_DELETE = ['RESTRICT', 'CASCADE', 'SET NULL', 'NO ACTION'];
    const ACTIONS_UPDATE = ['RESTRICT', 'CASCADE', 'SET NULL', 'NO ACTION'];

    // default actions
    const ACTION_DELETE = 'RESTRICT';
    const ACTION_UPDATE = 'RESTRICT';

    const ERROR_ACTION_NOT_SUPPORTED = 'Constraint action `%s` is not supported.';

    protected $table;
    protected $keys = [];
    protected $referencedTable = '';
    protected $referencedCols = [];
    protected $onDelete = self::ACTION_DELETE;
    protected $onUpdate = self::ACTION_UPDATE;

    /**
     * Constraint constructor.
     * @param SQL\TableBuilder $table
     * @param array $keys
     * @param string $referencedTable
     * @param array $referencedCols
     */
    public function __construct(SQL\TableBuilder $table, $keys = [], $referencedTable = '', $referencedCols = ['id']){
        $this->table = &$table;
        $this->setKeys($keys);
        $this->setReferencedTable($referencedTable);
        $this->setReferencedCols($referencedCols);
    }

    /**
     * @param mixed $keys
     */
    public function setKeys($keys){
        $this->keys = (array)$keys;
    }

    /**
     * @param mixed $referencedTable
     */
    public function setReferencedTable($referencedTable){
        $this->referencedTable = $referencedTable;
    }

    /**
     * @param mixed $referencedCols
     */
    public function setReferencedCols($referencedCols){
        $this->referencedCols = (array)$referencedCols;
    }

    /**
     * @param string $onDelete
     */
    public function setOnDelete($onDelete){
        if( in_array($onDelete, self::ACTIONS_DELETE) ){
            $this->onDelete = $onDelete;
        }else{
            trigger_error(sprintf(self::ERROR_ACTION_NOT_SUPPORTED, $onDelete));
        }
    }

    /**
     * @param string $onUpdate
     */
    public function setOnUpdate($onUpdate){
        if( in_array($onUpdate, self::ACTIONS_UPDATE) ){
            $this->onUpdate = $onUpdate;
        }else{
            trigger_error(sprintf(self::ERROR_ACTION_NOT_SUPPORTED, $onUpdate));
        }
    }

    /**
     * @return array
     */
    public function getKeys(){
        return $this->keys;
    }

    /**
     * @return string
     */
    public function getReferencedTable(){
        return $this->referencedTable;
    }

    /**
     * @return array
     */
    public function getReferencedCols(){
        return $this->referencedCols;
    }

    /**
     * @return string
     */
    public function getOnDelete(){
        return $this->onDelete;
    }

    /**
     * @return string
     */
    public function getOnUpdate(){
        return $this->onUpdate;
    }

    /**
     * get a constraint name for this table.
     * This can either be used to generate unique constraint names for foreign keys in parent tables
     * or generate a "part" of a name. e.g. for db-Query all constraints of this table (ignore columns)
     * by "LIKE" selecting "information_schema"
     * -> To get a certain constraint or generate a unique constraint, ALL params are required!
     * @return string
     */
    public function getConstraintName(){
        $constraintName = 'fk_' . $this->table->name;

        if(!empty($this->getKeys())){
            $constraintName .= '___' . implode('__', $this->getKeys());
            if(!empty($this->getReferencedTable())){
                $constraintName .= '___' . $this->getReferencedTable();
                if(!empty($this->getReferencedCols())){
                    $constraintName .= '___' . implode('__', $this->getReferencedCols());
                }
            }
        }

        return $constraintName;
    }

    /**
     * checks if constraint is valid
     * -> all required members must be set!
     * @return bool
     */
    public function isValid(){
        $valid = false;

        if(
            !empty($this->getKeys()) &&
            !empty($this->getReferencedTable()) &&
            !empty($this->getReferencedCols())
        ){
            $valid = true;
        }

        return $valid;
    }
}