<?php
/* vim: set expandtab sw=4 ts=4 sts=4: */
/**
 * Contains abstract class to hold relation preferences/statistics
 *
 * @package PhpMyAdmin
 */
if (! defined('PHPMYADMIN')) {
    exit;
}

/**
 * Relations preferences/statistics
 *
 * This class fetches the table master and foreign fields positions
 * and helps in generating the Table references and then connects
 * master table's master field to foreign table's foreign key.
 *
 * @package PhpMyAdmin
 * @abstract
 */
abstract class RelationStats
{
    protected $diagram;
    /**
     * Defines properties
     */
    public $xSrc, $ySrc;
    public $srcDir ;
    public $destDir;
    public $xDest, $yDest;
    public $wTick;

    /**
     * The constructor
     *
     * @param object $diagram       The diagram
     * @param string $master_table  The master table name
     * @param string $master_field  The relation field in the master table
     * @param string $foreign_table The foreign table name
     * @param string $foreign_field The relation field in the foreign table
     */
    public function __construct(
        $diagram, $master_table, $master_field, $foreign_table, $foreign_field
    ) {
        $this->diagram = $diagram;

        $src_pos  = $this->_getXy($master_table, $master_field);
        $dest_pos = $this->_getXy($foreign_table, $foreign_field);
        /*
         * [0] is x-left
        * [1] is x-right
        * [2] is y
        */
        $src_left   = $src_pos[0] - $this->wTick;
        $src_right  = $src_pos[1] + $this->wTick;
        $dest_left  = $dest_pos[0] - $this->wTick;
        $dest_right = $dest_pos[1] + $this->wTick;

        $d1 = abs($src_left - $dest_left);
        $d2 = abs($src_right - $dest_left);
        $d3 = abs($src_left - $dest_right);
        $d4 = abs($src_right - $dest_right);
        $d  = min($d1, $d2, $d3, $d4);

        if ($d == $d1) {
            $this->xSrc    = $src_pos[0];
            $this->srcDir  = -1;
            $this->xDest   = $dest_pos[0];
            $this->destDir = -1;
        } elseif ($d == $d2) {
            $this->xSrc    = $src_pos[1];
            $this->srcDir  = 1;
            $this->xDest   = $dest_pos[0];
            $this->destDir = -1;
        } elseif ($d == $d3) {
            $this->xSrc    = $src_pos[0];
            $this->srcDir  = -1;
            $this->xDest   = $dest_pos[1];
            $this->destDir = 1;
        } else {
            $this->xSrc    = $src_pos[1];
            $this->srcDir  = 1;
            $this->xDest   = $dest_pos[1];
            $this->destDir = 1;
        }
        $this->ySrc   = $src_pos[2];
        $this->yDest = $dest_pos[2];
    }

    /**
     * Gets arrows coordinates
     *
     * @param string $table  The current table name
     * @param string $column The relation column name
     *
     * @return array Arrows coordinates
     *
     * @access private
     */
    private function _getXy($table, $column)
    {
        $pos = array_search($column, $table->fields);
        // x_left, x_right, y
        return array(
            $table->x,
            $table->x + $table->width,
            $table->y + ($pos + 1.5) * $table->heightCell
        );
    }
}