Managing Product Reviews and Data Aggregation in PHP

Introduction

Hello, and welcome to today's lesson! Today, we are going to dive into the world of managing product reviews and applying data aggregation in practice. We will start with a relatively simple Starter Task to set up our base and then gradually build up to a more complex solution involving data aggregation. Let's jump in!

Starter Task: Methods and Their Definitions

For our starter task, we will lay the foundation by implementing basic operations for managing product reviews. We will be using classes to encapsulate the details of a product review. Our Review class will consist of the following properties: $text — The textual content of the review. $rating — The rating score of the review, ranging from 1 to 5. $flagged — A boolean indicating whether the review is flagged as inappropriate. These are the methods we will implement in a ReviewManager class: addReview($productId, $reviewId, $reviewText, $rating) — Adds a review to the product specified by $productId . If a review with $reviewId already exists, it updates the existing review. Returns true if the review was added or updated successfully, false otherwise. For newly added items, the $flagged attribute is set to false initially. getReview($productId, $reviewId) — Returns the review details ($text, $rating, and $flagged fields) for the review specified by $reviewId under the given $productId . If the review or product does not exist, returns null . deleteReview($productId, $reviewId) — Deletes the review specified by $reviewId under the given $productId . Returns true if the review was deleted, false otherwise.

Starter Task Implementation

Let's look at the code that implements these functionalities in PHP: <?php class Review { public $text; public $rating; public $flagged; public function __construct($text, $rating, $flagged = false) { $this->text = $text; $this->rating = $rating; $this->flagged = $flagged; } } class ReviewManager { private $products = []; public function addReview($productId, $reviewId, $reviewText, $rating) { if ($rating < 1 || $rating > 5) { return false; // Invalid rating } $this->products[$productId][$reviewId] = new Review($reviewText, $rating); return true; } public function getReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { return $this->products[$productId][$reviewId]; } return null; } public function deleteReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { unset($this->products[$productId][$reviewId]); if (empty($this->products[$productId])) { unset($this->products[$productId]); // Remove product if no reviews left } return true; } return false; } } // Example usage $reviewManager = new ReviewManager(); // Adding some reviews $reviewManager->addReview("p1", "r1", "Great product!", 5); $reviewManager->addReview("p1", "r2", "Not bad", 3); // Testing getReview method $reviewR1 = $reviewManager->getReview("p1", "r1"); if ($reviewR1 !== null) { echo "Review r1 for p1: {"; echo "text: " . $reviewR1->text . ", "; echo "rating: " . $reviewR1->rating . ", "; echo "flagged: " . ($reviewR1->flagged ? "true" : "false") . "}\n"; } else { echo "Review r1 for p1 not found.\n"; } $reviewR3 = $reviewManager->getReview("p1", "r3"); if ($reviewR3 !== null) { echo "Review r3 for p1 found.\n"; } else { echo "Review r3 for p1 not found.\n"; } // Testing deleteReview method if ($reviewManager->deleteReview("p1", "r2")) { echo "Review r2 for p1 deleted successfully.\n"; } else { echo "Failed to delete review r2 for p1.\n"; } $reviewR2 = $reviewManager->getReview("p1", "r2"); if ($reviewR2 !== null) { echo "Review r2 for p1 found.\n"; } else { echo "Review r2 for p1 not found.\n"; } This code establishes the foundational methods needed for managing product reviews within a ReviewManager class. The addReview method allows for adding a new review or updating an existing one, ensuring each review contains valid rating values between 1 and 5. The getReview method retrieves the review details for a specific product, including the review text and rating, returning null if the product or review doesn't exist. The deleteReview method facilitates the removal of a specific review, and if no reviews are left for a product, the product itself is removed from the product list. Together, these methods form the basic operations required to manage a collection of product reviews efficiently. Now, let's extend this with new features.

New Task: Advanced Functions and Data Aggregation

With our basic review management system in place, we will now introduce new methods to handle more complex operations, such as flagging inappropriate reviews and aggregating review data for a specific product. Here are the new methods we will add: flagReview($productId, $reviewId) — This method flags a specific review as inappropriate for a given product. Returns true if the review was successfully flagged, false otherwise. aggregateReviews($productId) — This method aggregates review data for a given product, providing statistics such as the total number of reviews, the number of flagged reviews, average rating, and review texts excluding flagged ones. If the product does not have any reviews or does not exist, returns null .

Implementation, Step 1: Adding the 'flag_review' Method

First, let's add functionality to flag a review: PHP<?php class Review { public $text; public $rating; public $flagged; public function __construct($text, $rating, $flagged = false) { $this->text = $text; $this->rating = $rating; $this->flagged = $flagged; } } class ReviewManager { private $products = []; public function addReview($productId, $reviewId, $reviewText, $rating) { if ($rating < 1 || $rating > 5) { return false; // Invalid rating } $this->products[$productId][$reviewId] = new Review($reviewText, $rating); return true; } public function getReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { return $this->products[$productId][$reviewId]; } return null; } public function deleteReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { unset($this->products[$productId][$reviewId]); if (empty($this->products[$productId])) { unset($this->products[$productId]); // Remove product if no reviews left } return true; } return false; } public function flagReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { $this->products[$productId][$reviewId]->flagged = true; return true; } return false; } } // Example usage $reviewManager = new ReviewManager(); // Adding some reviews $reviewManager->addReview("p1", "r1", "Great product!", 5); $reviewManager->addReview("p1", "r2", "Not bad", 3); $reviewManager->addReview("p1", "r3", "Terrible", 1); // Flagging a review $reviewManager->flagReview("p1", "r3"); // Testing flagReview method $reviewR3 = $reviewManager->getReview("p1", "r3"); if ($reviewR3 !== null) { echo "Review r3 for p1: {"; echo "text: " . $reviewR3->text . ", "; echo "rating: " . $reviewR3->rating . ", "; echo "flagged: " . ($reviewR3->flagged ? "true" : "false") . "}\n"; } else { echo "Review r3 for p1 not found.\n"; } In this step, we are adding the flagReview method to our ReviewManager class. This method enables users to mark a specific review as inappropriate. It checks whether the product and review exist in the dataset, and if they do, it sets the flagged attribute of the review to true. This flagging mechanism is crucial for maintaining the quality and appropriateness of the reviews in the system.

Step 2: Adding the 'aggregate_reviews' Method

Next, we will implement the method to aggregate reviews: <?php class Review { public $text; public $rating; public $flagged; public function __construct($text, $rating, $flagged = false) { $this->text = $text; $this->rating = $rating; $this->flagged = $flagged; } } class AggregatedData { public $totalReviews; public $flaggedReviews; public $averageRating; public $reviewTexts; public function __construct($totalReviews, $flaggedReviews, $averageRating, $reviewTexts) { $this->totalReviews = $totalReviews; $this->flaggedReviews = $flaggedReviews; $this->averageRating = $averageRating; $this->reviewTexts = $reviewTexts; } } class ReviewManager { private $products = []; public function addReview($productId, $reviewId, $reviewText, $rating) { if ($rating < 1 || $rating > 5) { return false; // Invalid rating } $this->products[$productId][$reviewId] = new Review($reviewText, $rating); return true; } public function getReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { return $this->products[$productId][$reviewId]; } return null; } public function deleteReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { unset($this->products[$productId][$reviewId]); if (empty($this->products[$productId])) { unset($this->products[$productId]); // Remove product if no reviews left } return true; } return false; } public function flagReview($productId, $reviewId) { if (isset($this->products[$productId][$reviewId])) { $this->products[$productId][$reviewId]->flagged = true; return true; } return false; } public function aggregateReviews($productId) { if (!isset($this->products[$productId]) || empty($this->products[$productId])) { return null; // No reviews or product doesn't exist } $totalReviews = count($this->products[$productId]); $flaggedReviews = 0; $totalRating = 0; $reviewTexts = []; foreach ($this->products[$productId] as $review) { if ($review->flagged) { $flaggedReviews++; } else { $totalRating += $review->rating; $reviewTexts[] = $review->text; } } $averageRating = ($totalReviews == $flaggedReviews) ? 0.0 : $totalRating / ($totalReviews - $flaggedReviews); return new AggregatedData($totalReviews, $flaggedReviews, $averageRating, $reviewTexts); } } // Example usage $reviewManager = new ReviewManager(); // Adding some reviews $reviewManager->addReview("p1", "r1", "Great product!", 5); $reviewManager->addReview("p1", "r2", "Not bad", 3); $reviewManager->addReview("p1", "r3", "Terrible", 1); // Flagging a review $reviewManager->flagReview("p1", "r3"); // Testing the aggregation method $aggregatedData = $reviewManager->aggregateReviews("p1"); if ($aggregatedData !== null) { echo "Aggregated data for p1: {\n"; echo "total_reviews: " . $aggregatedData->totalReviews . ",\n"; echo "flagged_reviews: " . $aggregatedData->flaggedReviews . ",\n"; echo "average_rating: " . $aggregatedData->averageRating . ",\n"; echo "review_texts: ["; foreach ($aggregatedData->reviewTexts as $text) { echo "\"$text\", "; } echo "]\n}\n"; } else { echo "No aggregated data for p1.\n"; } In this step, the aggregateReviews method is added to the ReviewManager class, along with the definition of an AggregatedData class. The method aggregates review data for a given product by calculating various statistics, such as the total number of reviews, the number of flagged reviews, the average rating excluding flagged reviews, and a list of review texts that are not flagged. The method first ensures the product exists and contains reviews. It then iterates through the reviews to collect the necessary data, considering only non-flagged reviews for the average rating and review texts. If all reviews are flagged, the average rating defaults to zero. This aggregation provides a comprehensive overview of a product’s review status, useful for both users and administrators.

Conclusion

Great job! Today, you have learned how to manage product reviews and apply data aggregation in practice using PHP. We started with basic operations for adding, retrieving, and deleting reviews. Then, we extended our functionality to include flagging reviews and aggregating review data. This gradual build-up demonstrates how to enhance features incrementally and handle more complex data aggregation tasks. Feel free to practice solving similar challenges to strengthen your skills further. Keep coding, and see you in the next lesson!

Next Lesson: Applying Data Filtering and Aggregation in a User Management System Using PHP

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PHP

<?php

class Review {
    public $text;
    public $rating;
    public $flagged;

    public function __construct($text, $rating, $flagged = false) {
        $this->text = $text;
        $this->rating = $rating;
        $this->flagged = $flagged;
    }
}

class ReviewManager {
    private $products = [];

    public function addReview($productId, $reviewId, $reviewText, $rating) {
        if ($rating < 1 || $rating > 5) {
            return false; // Invalid rating
        }
        $this->products[$productId][$reviewId] = new Review($reviewText, $rating);
        return true;
    }

    public function getReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            return $this->products[$productId][$reviewId];
        }
        return null;
    }

    public function deleteReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            unset($this->products[$productId][$reviewId]);
            if (empty($this->products[$productId])) {
                unset($this->products[$productId]); // Remove product if no reviews left
            }
            return true;
        }
        return false;
    }
}

// Example usage
$reviewManager = new ReviewManager();

// Adding some reviews
$reviewManager->addReview("p1", "r1", "Great product!", 5);
$reviewManager->addReview("p1", "r2", "Not bad", 3);

// Testing getReview method
$reviewR1 = $reviewManager->getReview("p1", "r1");
if ($reviewR1 !== null) {
    echo "Review r1 for p1: {";
    echo "text: " . $reviewR1->text . ", ";
    echo "rating: " . $reviewR1->rating . ", ";
    echo "flagged: " . ($reviewR1->flagged ? "true" : "false") . "}\n";
} else {
    echo "Review r1 for p1 not found.\n";
}

$reviewR3 = $reviewManager->getReview("p1", "r3");
if ($reviewR3 !== null) {
    echo "Review r3 for p1 found.\n";
} else {
    echo "Review r3 for p1 not found.\n";
}

// Testing deleteReview method
if ($reviewManager->deleteReview("p1", "r2")) {
    echo "Review r2 for p1 deleted successfully.\n";
} else {
    echo "Failed to delete review r2 for p1.\n";
}

$reviewR2 = $reviewManager->getReview("p1", "r2");
if ($reviewR2 !== null) {
    echo "Review r2 for p1 found.\n";
} else {
    echo "Review r2 for p1 not found.\n";
}

<?php

class Review {
    public $text;
    public $rating;
    public $flagged;

    public function __construct($text, $rating, $flagged = false) {
        $this->text = $text;
        $this->rating = $rating;
        $this->flagged = $flagged;
    }
}

class ReviewManager {
    private $products = [];

    public function addReview($productId, $reviewId, $reviewText, $rating) {
        if ($rating < 1 || $rating > 5) {
            return false; // Invalid rating
        }
        $this->products[$productId][$reviewId] = new Review($reviewText, $rating);
        return true;
    }

    public function getReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            return $this->products[$productId][$reviewId];
        }
        return null;
    }

    public function deleteReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            unset($this->products[$productId][$reviewId]);
            if (empty($this->products[$productId])) {
                unset($this->products[$productId]); // Remove product if no reviews left
            }
            return true;
        }
        return false;
    }
}

// Example usage
$reviewManager = new ReviewManager();

// Adding some reviews
$reviewManager->addReview("p1", "r1", "Great product!", 5);
$reviewManager->addReview("p1", "r2", "Not bad", 3);

// Testing getReview method
$reviewR1 = $reviewManager->getReview("p1", "r1");
if ($reviewR1 !== null) {
    echo "Review r1 for p1: {";
    echo "text: " . $reviewR1->text . ", ";
    echo "rating: " . $reviewR1->rating . ", ";
    echo "flagged: " . ($reviewR1->flagged ? "true" : "false") . "}\n";
} else {
    echo "Review r1 for p1 not found.\n";
}

$reviewR3 = $reviewManager->getReview("p1", "r3");
if ($reviewR3 !== null) {
    echo "Review r3 for p1 found.\n";
} else {
    echo "Review r3 for p1 not found.\n";
}

// Testing deleteReview method
if ($reviewManager->deleteReview("p1", "r2")) {
    echo "Review r2 for p1 deleted successfully.\n";
} else {
    echo "Failed to delete review r2 for p1.\n";
}

$reviewR2 = $reviewManager->getReview("p1", "r2");
if ($reviewR2 !== null) {
    echo "Review r2 for p1 found.\n";
} else {
    echo "Review r2 for p1 not found.\n";
}

PHP

<?php

class Review {
    public $text;
    public $rating;
    public $flagged;

    public function __construct($text, $rating, $flagged = false) {
        $this->text = $text;
        $this->rating = $rating;
        $this->flagged = $flagged;
    }
}

class ReviewManager {
    private $products = [];

    public function addReview($productId, $reviewId, $reviewText, $rating) {
        if ($rating < 1 || $rating > 5) {
            return false; // Invalid rating
        }
        $this->products[$productId][$reviewId] = new Review($reviewText, $rating);
        return true;
    }

    public function getReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            return $this->products[$productId][$reviewId];
        }
        return null;
    }

    public function deleteReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            unset($this->products[$productId][$reviewId]);
            if (empty($this->products[$productId])) {
                unset($this->products[$productId]); // Remove product if no reviews left
            }
            return true;
        }
        return false;
    }

    public function flagReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            $this->products[$productId][$reviewId]->flagged = true;
            return true;
        }
        return false;
    }
}

// Example usage
$reviewManager = new ReviewManager();

// Adding some reviews
$reviewManager->addReview("p1", "r1", "Great product!", 5);
$reviewManager->addReview("p1", "r2", "Not bad", 3);
$reviewManager->addReview("p1", "r3", "Terrible", 1);

// Flagging a review
$reviewManager->flagReview("p1", "r3");

// Testing flagReview method
$reviewR3 = $reviewManager->getReview("p1", "r3");
if ($reviewR3 !== null) {
    echo "Review r3 for p1: {";
    echo "text: " . $reviewR3->text . ", ";
    echo "rating: " . $reviewR3->rating . ", ";
    echo "flagged: " . ($reviewR3->flagged ? "true" : "false") . "}\n";
} else {
    echo "Review r3 for p1 not found.\n";
}

PHP

<?php

class Review {
    public $text;
    public $rating;
    public $flagged;

    public function __construct($text, $rating, $flagged = false) {
        $this->text = $text;
        $this->rating = $rating;
        $this->flagged = $flagged;
    }
}

class AggregatedData {
    public $totalReviews;
    public $flaggedReviews;
    public $averageRating;
    public $reviewTexts;

    public function __construct($totalReviews, $flaggedReviews, $averageRating, $reviewTexts) {
        $this->totalReviews = $totalReviews;
        $this->flaggedReviews = $flaggedReviews;
        $this->averageRating = $averageRating;
        $this->reviewTexts = $reviewTexts;
    }
}

class ReviewManager {
    private $products = [];

    public function addReview($productId, $reviewId, $reviewText, $rating) {
        if ($rating < 1 || $rating > 5) {
            return false; // Invalid rating
        }
        $this->products[$productId][$reviewId] = new Review($reviewText, $rating);
        return true;
    }

    public function getReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            return $this->products[$productId][$reviewId];
        }
        return null;
    }

    public function deleteReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            unset($this->products[$productId][$reviewId]);
            if (empty($this->products[$productId])) {
                unset($this->products[$productId]); // Remove product if no reviews left
            }
            return true;
        }
        return false;
    }

    public function flagReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            $this->products[$productId][$reviewId]->flagged = true;
            return true;
        }
        return false;
    }

    public function aggregateReviews($productId) {
        if (!isset($this->products[$productId]) || empty($this->products[$productId])) {
            return null; // No reviews or product doesn't exist
        }

        $totalReviews = count($this->products[$productId]);
        $flaggedReviews = 0;
        $totalRating = 0;
        $reviewTexts = [];

        foreach ($this->products[$productId] as $review) {
            if ($review->flagged) {
                $flaggedReviews++;
            } else {
                $totalRating += $review->rating;
                $reviewTexts[] = $review->text;
            }
        }

        $averageRating = ($totalReviews == $flaggedReviews) ? 0.0 : $totalRating / ($totalReviews - $flaggedReviews);
        return new AggregatedData($totalReviews, $flaggedReviews, $averageRating, $reviewTexts);
    }
}

// Example usage
$reviewManager = new ReviewManager();

// Adding some reviews
$reviewManager->addReview("p1", "r1", "Great product!", 5);
$reviewManager->addReview("p1", "r2", "Not bad", 3);
$reviewManager->addReview("p1", "r3", "Terrible", 1);

// Flagging a review
$reviewManager->flagReview("p1", "r3");

// Testing the aggregation method
$aggregatedData = $reviewManager->aggregateReviews("p1");
if ($aggregatedData !== null) {
    echo "Aggregated data for p1: {\n";
    echo "total_reviews: " . $aggregatedData->totalReviews . ",\n";
    echo "flagged_reviews: " . $aggregatedData->flaggedReviews . ",\n";
    echo "average_rating: " . $aggregatedData->averageRating . ",\n";
    echo "review_texts: [";
    foreach ($aggregatedData->reviewTexts as $text) {
        echo "\"$text\", ";
    }
    echo "]\n}\n";
} else {
    echo "No aggregated data for p1.\n";
}

<?php

class Review {
    public $text;
    public $rating;
    public $flagged;

    public function __construct($text, $rating, $flagged = false) {
        $this->text = $text;
        $this->rating = $rating;
        $this->flagged = $flagged;
    }
}

class AggregatedData {
    public $totalReviews;
    public $flaggedReviews;
    public $averageRating;
    public $reviewTexts;

    public function __construct($totalReviews, $flaggedReviews, $averageRating, $reviewTexts) {
        $this->totalReviews = $totalReviews;
        $this->flaggedReviews = $flaggedReviews;
        $this->averageRating = $averageRating;
        $this->reviewTexts = $reviewTexts;
    }
}

class ReviewManager {
    private $products = [];

    public function addReview($productId, $reviewId, $reviewText, $rating) {
        if ($rating < 1 || $rating > 5) {
            return false; // Invalid rating
        }
        $this->products[$productId][$reviewId] = new Review($reviewText, $rating);
        return true;
    }

    public function getReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            return $this->products[$productId][$reviewId];
        }
        return null;
    }

    public function deleteReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            unset($this->products[$productId][$reviewId]);
            if (empty($this->products[$productId])) {
                unset($this->products[$productId]); // Remove product if no reviews left
            }
            return true;
        }
        return false;
    }

    public function flagReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            $this->products[$productId][$reviewId]->flagged = true;
            return true;
        }
        return false;
    }

    public function aggregateReviews($productId) {
        if (!isset($this->products[$productId]) || empty($this->products[$productId])) {
            return null; // No reviews or product doesn't exist
        }

        $totalReviews = count($this->products[$productId]);
        $flaggedReviews = 0;
        $totalRating = 0;
        $reviewTexts = [];

        foreach ($this->products[$productId] as $review) {
            if ($review->flagged) {
                $flaggedReviews++;
            } else {
                $totalRating += $review->rating;
                $reviewTexts[] = $review->text;
            }
        }

        $averageRating = ($totalReviews == $flaggedReviews) ? 0.0 : $totalRating / ($totalReviews - $flaggedReviews);
        return new AggregatedData($totalReviews, $flaggedReviews, $averageRating, $reviewTexts);
    }
}

// Example usage
$reviewManager = new ReviewManager();

// Adding some reviews
$reviewManager->addReview("p1", "r1", "Great product!", 5);
$reviewManager->addReview("p1", "r2", "Not bad", 3);
$reviewManager->addReview("p1", "r3", "Terrible", 1);

// Flagging a review
$reviewManager->flagReview("p1", "r3");

// Testing the aggregation method
$aggregatedData = $reviewManager->aggregateReviews("p1");
if ($aggregatedData !== null) {
    echo "Aggregated data for p1: {\n";
    echo "total_reviews: " . $aggregatedData->totalReviews . ",\n";
    echo "flagged_reviews: " . $aggregatedData->flaggedReviews . ",\n";
    echo "average_rating: " . $aggregatedData->averageRating . ",\n";
    echo "review_texts: [";
    foreach ($aggregatedData->reviewTexts as $text) {
        echo "\"$text\", ";
    }
    echo "]\n}\n";
} else {
    echo "No aggregated data for p1.\n";
}

PHP

<?php

class Review {
    public $text;
    public $rating;
    public $flagged;

    public function __construct($text, $rating, $flagged = false) {
        $this->text = $text;
        $this->rating = $rating;
        $this->flagged = $flagged;
    }
}

class ReviewManager {
    private $products = [];

    public function addReview($productId, $reviewId, $reviewText, $rating) {
        if ($rating < 1 || $rating > 5) {
            return false; // Invalid rating
        }
        $this->products[$productId][$reviewId] = new Review($reviewText, $rating);
        return true;
    }

    public function getReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            return $this->products[$productId][$reviewId];
        }
        return null;
    }

    public function deleteReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            unset($this->products[$productId][$reviewId]);
            if (empty($this->products[$productId])) {
                unset($this->products[$productId]); // Remove product if no reviews left
            }
            return true;
        }
        return false;
    }
}

// Example usage
$reviewManager = new ReviewManager();

// Adding some reviews
$reviewManager->addReview("p1", "r1", "Great product!", 5);
$reviewManager->addReview("p1", "r2", "Not bad", 3);

// Testing getReview method
$reviewR1 = $reviewManager->getReview("p1", "r1");
if ($reviewR1 !== null) {
    echo "Review r1 for p1: {";
    echo "text: " . $reviewR1->text . ", ";
    echo "rating: " . $reviewR1->rating . ", ";
    echo "flagged: " . ($reviewR1->flagged ? "true" : "false") . "}\n";
} else {
    echo "Review r1 for p1 not found.\n";
}

$reviewR3 = $reviewManager->getReview("p1", "r3");
if ($reviewR3 !== null) {
    echo "Review r3 for p1 found.\n";
} else {
    echo "Review r3 for p1 not found.\n";
}

// Testing deleteReview method
if ($reviewManager->deleteReview("p1", "r2")) {
    echo "Review r2 for p1 deleted successfully.\n";
} else {
    echo "Failed to delete review r2 for p1.\n";
}

$reviewR2 = $reviewManager->getReview("p1", "r2");
if ($reviewR2 !== null) {
    echo "Review r2 for p1 found.\n";
} else {
    echo "Review r2 for p1 not found.\n";
}

PHP

<?php

class Review {
    public $text;
    public $rating;
    public $flagged;

    public function __construct($text, $rating, $flagged = false) {
        $this->text = $text;
        $this->rating = $rating;
        $this->flagged = $flagged;
    }
}

class AggregatedData {
    public $totalReviews;
    public $flaggedReviews;
    public $averageRating;
    public $reviewTexts;

    public function __construct($totalReviews, $flaggedReviews, $averageRating, $reviewTexts) {
        $this->totalReviews = $totalReviews;
        $this->flaggedReviews = $flaggedReviews;
        $this->averageRating = $averageRating;
        $this->reviewTexts = $reviewTexts;
    }
}

class ReviewManager {
    private $products = [];

    public function addReview($productId, $reviewId, $reviewText, $rating) {
        if ($rating < 1 || $rating > 5) {
            return false; // Invalid rating
        }
        $this->products[$productId][$reviewId] = new Review($reviewText, $rating);
        return true;
    }

    public function getReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            return $this->products[$productId][$reviewId];
        }
        return null;
    }

    public function deleteReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            unset($this->products[$productId][$reviewId]);
            if (empty($this->products[$productId])) {
                unset($this->products[$productId]); // Remove product if no reviews left
            }
            return true;
        }
        return false;
    }

    public function flagReview($productId, $reviewId) {
        if (isset($this->products[$productId][$reviewId])) {
            $this->products[$productId][$reviewId]->flagged = true;
            return true;
        }
        return false;
    }

    public function aggregateReviews($productId) {
        if (!isset($this->products[$productId]) || empty($this->products[$productId])) {
            return null; // No reviews or product doesn't exist
        }

        $totalReviews = count($this->products[$productId]);
        $flaggedReviews = 0;
        $totalRating = 0;
        $reviewTexts = [];

        foreach ($this->products[$productId] as $review) {
            if ($review->flagged) {
                $flaggedReviews++;
            } else {
                $totalRating += $review->rating;
                $reviewTexts[] = $review->text;
            }
        }

        $averageRating = ($totalReviews == $flaggedReviews) ? 0.0 : $totalRating / ($totalReviews - $flaggedReviews);
        return new AggregatedData($totalReviews, $flaggedReviews, $averageRating, $reviewTexts);
    }
}

// Example usage
$reviewManager = new ReviewManager();

// Adding some reviews
$reviewManager->addReview("p1", "r1", "Great product!", 5);
$reviewManager->addReview("p1", "r2", "Not bad", 3);
$reviewManager->addReview("p1", "r3", "Terrible", 1);

// Flagging a review
$reviewManager->flagReview("p1", "r3");

// Testing the aggregation method
$aggregatedData = $reviewManager->aggregateReviews("p1");
if ($aggregatedData !== null) {
    echo "Aggregated data for p1: {\n";
    echo "total_reviews: " . $aggregatedData->totalReviews . ",\n";
    echo "flagged_reviews: " . $aggregatedData->flaggedReviews . ",\n";
    echo "average_rating: " . $aggregatedData->averageRating . ",\n";
    echo "review_texts: [";
    foreach ($aggregatedData->reviewTexts as $text) {
        echo "\"$text\", ";
    }
    echo "]\n}\n";
} else {
    echo "No aggregated data for p1.\n";
}