SOLID-laracast

SOLID laracast

<?php

namespace Acme\Reporting;

use Auth, DB, Exception;

class SalesReporter 
{
    public functon between($startDate, $endDate) {

        // Q: do we need a user for this class to work ??
        // auth is application login move to controller 
        if (!Auth::check()) throw new Exception('login required');

        $sales = $this->queryDBForSalesBetween($startDate, $endDate);
        return $this->format($sales);
    }

    // Q: if we change our db layer than ?   Too many consumers of this class
    protected function queryDBForSalesBetween($startDate, $endDate) {
        return DB::table('sales')->whereBetween('created_at', [$startDate, $endDate])->sum('change') / 100;
    }

    // Q: now we need json response ??
    // Q: is it consumers responsibility to format ?
    // Q: if we need some class based formating than ??? 
    protected function format($sales) {
        return "<h1>Saled: $sales</h1>";
    }
}

// router php

Route::get('sales-report', function() {
    $report = new Acme\Reporting\SalesReporter();
    $begin = Carbon::now()->subDays(10);
    $end = Carbon::now();
    return $report->between($begin, $end);
});

/**

Q: how many resons this class has to change ?
Q: what are it's responsibilities ?

Goal: A class should have single responsibility 

*/

// extract db responsibilities to separete class
class SalesRepository 
{
    // Q: if we change our db layer than ?   Too many consumers of this class
    // A: now we have extracted to a separate class no problem
    public function between($startDate, $endDate) {
        return DB::table('sales')->whereBetween('created_at', [$startDate, $endDate])->sum('change') / 100;
    }
}

// for extracting the format method
interface SalesOutputInterface {
    public function output($sales);
}

// extracted the format method 
class HtmlOutput implements SalesOutputInterface {
    public function output($sales) {
        return "<h1>Saled: $sales</h1>";
    }
}

class SalesReporter 
{

    // move query/saving operations to repository interface/class
    private $repo; 

    public function __constructor(SalesRepository $repo) {
        $this->repo = $repo;
    }

    public functon between($startDate, $endDate, SalesOutputInterface $formatter) {

        // db operation extracted
        $sales = $this->repo->between($startDate, $endDate);

        return $formatter->output($sales);
    }
}

Route::get('sales-report', function() {
    $report = new Acme\Reporting\SalesReporter(new SalesRepository);
    $begin = Carbon::now()->subDays(10);
    $end = Carbon::now();
    return $report->between($begin, $end, new HtmlOutput);
});