Fitness Tracking Application

Example Code

<?php

interface iFitnessTracker {
    public function addUser(string $username, string $email, array $profile = []): bool;
    public function logWorkout(string $email, array $workoutDetails): bool;
    public function getUserWorkouts(string $email): array;
    public function getUserProfile(string $email): ?array;
    public function calculateOverallProgress(string $email): array;
}

class FitnessTracker implements iFitnessTracker {
    private array $users = [];
    private array $workouts = [];

    public function __construct() {
        // Simulate some initial data for demonstration
        $this->addUser('JohnDoe', 'john.doe@example.com', ['weight' => 75, 'height' => 175, 'goal' => 'Gain Muscle']);
        $this->addUser('JaneSmith', 'jane.smith@example.com', ['weight' => 60, 'height' => 165, 'goal' => 'Lose Weight']);

        $this->logWorkout('john.doe@example.com', ['date' => '2023-10-26', 'type' => 'Weightlifting', 'duration' => 60, 'calories_burned' => 400, 'details' => ['squats' => ['sets' => 3, 'reps' => 8, 'weight' => 80]]]);
        $this->logWorkout('john.doe@example.com', ['date' => '2023-10-28', 'type' => 'Cardio', 'duration' => 45, 'calories_burned' => 350, 'details' => ['run' => ['distance_km' => 5, 'speed_km_h' => 10]]]);

        $this->logWorkout('jane.smith@example.com', ['date' => '2023-10-27', 'type' => 'Yoga', 'duration' => 75, 'calories_burned' => 200, 'details' => ['session_type' => 'Vinyasa']]);
    }

    /
     * Adds a new user to the system.
     * @param string $username The user's chosen username.
     * @param string $email The user's email address (unique identifier).
     * @param array $profile An associative array containing profile details (e.g., weight, height, goal).
     * @return bool True if the user was added successfully, false if email already exists.
     */
    public function addUser(string $username, string $email, array $profile = []): bool {
        if (isset($this->users[$email])) {
            echo "User with email {$email} already exists.\n";
            return false;
        }
        $this->users[$email] = ['username' => $username, 'email' => $email, 'profile' => $profile];
        $this->workouts[$email] = []; // Initialize workouts array for the new user
        echo "User {$username} added successfully.\n";
        return true;
    }

    /
     * Logs a workout for a specific user.
     * @param string $email The email of the user logging the workout.
     * @param array $workoutDetails An associative array with workout details (e.g., date, type, duration, calories_burned, details).
     * @return bool True if the workout was logged successfully, false if the user does not exist.
     */
    public function logWorkout(string $email, array $workoutDetails): bool {
        if (!isset($this->users[$email])) {
            echo "User with email {$email} not found. Cannot log workout.\n";
            return false;
        }
        $this->workouts[$email][] = $workoutDetails;
        echo "Workout logged for {$this->users[$email]['username']}.\n";
        return true;
    }

    /
     * Retrieves all workouts for a specific user.
     * @param string $email The email of the user.
     * @return array An array of workout details for the user, or an empty array if no workouts or user not found.
     */
    public function getUserWorkouts(string $email): array {
        return $this->workouts[$email] ?? [];
    }

    /
     * Retrieves the profile details for a specific user.
     * @param string $email The email of the user.
     * @return array|null An array of profile details, or null if the user is not found.
     */
    public function getUserProfile(string $email): ?array {
        return $this->users[$email]['profile'] ?? null;
    }

    /
     * Calculates and returns a simple overall progress summary for a user.
     * This is a basic example; real applications would have more complex calculations.
     * @param string $email The email of the user.
     * @return array An associative array with summary statistics, or an empty array if user not found.
     */
    public function calculateOverallProgress(string $email): array {
        if (!isset($this->users[$email])) {
            return [];
        }

        $userWorkouts = $this->getUserWorkouts($email);
        $totalWorkouts = count($userWorkouts);
        $totalDuration = 0;
        $totalCaloriesBurned = 0;

        foreach ($userWorkouts as $workout) {
            $totalDuration += $workout['duration'] ?? 0;
            $totalCaloriesBurned += $workout['calories_burned'] ?? 0;
        }

        return [
            'total_workouts' => $totalWorkouts,
            'total_duration_minutes' => $totalDuration,
            'total_calories_burned' => $totalCaloriesBurned,
            'average_duration_per_workout' => $totalWorkouts > 0 ? round($totalDuration / $totalWorkouts, 2) : 0,
            'average_calories_per_workout' => $totalWorkouts > 0 ? round($totalCaloriesBurned / $totalWorkouts, 2) : 0
        ];
    }
}

// --- Demonstration --- 

echo "\n--- Initializing Fitness Tracker ---\n";
$tracker = new FitnessTracker();

echo "\n--- Getting User Workouts (John Doe) ---\n";
$johnWorkouts = $tracker->getUserWorkouts('john.doe@example.com');
echo "John Doe's Workouts: " . json_encode($johnWorkouts, JSON_PRETTY_PRINT) . "\n";

echo "\n--- Getting User Profile (Jane Smith) ---\n";
$janeProfile = $tracker->getUserProfile('jane.smith@example.com');
echo "Jane Smith's Profile: " . json_encode($janeProfile, JSON_PRETTY_PRINT) . "\n";

echo "\n--- Logging another workout for John Doe ---\n";
$tracker->logWorkout('john.doe@example.com', ['date' => '2023-10-29', 'type' => 'HIIT', 'duration' => 30, 'calories_burned' => 300]);

echo "\n--- Calculating Overall Progress (John Doe) ---\n";
$johnProgress = $tracker->calculateOverallProgress('john.doe@example.com');
echo "John Doe's Progress: " . json_encode($johnProgress, JSON_PRETTY_PRINT) . "\n";

echo "\n--- Trying to add an existing user ---\n";
$tracker->addUser('JohnathanDoe', 'john.doe@example.com');

echo "\n--- Trying to log workout for non-existent user ---\n";
$tracker->logWorkout('non.existent@example.com', ['date' => '2023-10-30', 'type' => 'Running', 'duration' => 60]);

?>