death-notifier/src/main/php/TrackingManager.php

<?php

namespace php;

use Monolog\Logger;
use PDO;


/**
 * Manages interaction with the database in the context of trackings.
 */
class TrackingManager
{
    /**
     * The maximum length of a Wikipedia page title.
     */
    private const MAX_TITLE_LENGTH = 255;

    /**
     * @var Logger The logger to use for logging.
     */
    private Logger $logger;
    /**
     * @var string The filename of the database to interact with.
     */
    private string $db_filename;
    /**
     * @var Mediawiki The Mediawiki instance to use for interacting with Wikipedia.
     */
    private Mediawiki $mediawiki;


    /**
     * Constructs a new tracking manager.
     *
     * @param Logger $logger the logger to use for logging
     * @param string $db_filename the filename of the database to interact with
     */
    public function __construct(Logger $logger, Mediawiki $mediawiki, string $db_filename)
    {
        $this->logger = $logger;
        $this->mediawiki = $mediawiki;
        $this->db_filename = $db_filename;
    }


    /**
     * Populates the database with the necessary structures for users.
     *
     * @return void
     */
    public function install(): void
    {
        $conn = Database::connect($this->db_filename);
        $conn->exec("CREATE TABLE trackings(user_uuid text not null, person_name text not null, status text not null, PRIMARY KEY (user_uuid, person_name));");
    }

    /**
     * Adds a tracking to the database.
     *
     * @param string $user_uuid the user to whom the tracking belongs
     * @param string $person_name the name of the person to track
     * @return Response a response with no message, and a status indicating whether the insertion succeeded
     */
    public function add_tracking(string $user_uuid, string $person_name): Response
    {
        if (strlen($person_name) > self::MAX_TITLE_LENGTH)
            return new Response("Invalid page name: too long.", false);
        if (!$this->mediawiki->pages_exist([$person_name])[$person_name])
            return new Response("Page does not exist.", false);

        $status = $this->mediawiki->people_statuses([$person_name])[$person_name];
        if ($status === null)
            return new Response("Page does not refer to a person.", false);

        $conn = Database::connect($this->db_filename);
        $conn->beginTransaction();

        $stmt = $conn->prepare("SELECT COUNT(*) as count FROM trackings WHERE user_uuid=:user_uuid AND person_name=:person_name;");
        $stmt->bindValue(":user_uuid", $user_uuid);
        $stmt->bindValue(":person_name", $person_name);
        $stmt->execute();
        if ($stmt->fetch(PDO::FETCH_ASSOC)["count"] > 0) {
            $conn->rollBack();
            return new Response("Tracking already exists.", false);
        }

        $stmt = $conn->prepare("INSERT INTO trackings (user_uuid, person_name, status) VALUES (:user_uuid, :person_name, :status);");
        $stmt->bindValue(":user_uuid", $user_uuid);
        $stmt->bindValue(":person_name", $person_name);
        $stmt->bindValue(":status", $status);
        $stmt->execute();

        $conn->commit();
        return new Response(null, true);
    }

    /**
     * Removes a tracking from the database.
     *
     * @param string $user_uuid the user to whom the tracking belongs
     * @param string $person_name the name of the tracked person to remove
     * @return Response a response with no message, and a status indicating whether the removal succeeded
     */
    public function remove_tracking(string $user_uuid, string $person_name): Response
    {
        if (strlen($person_name) > self::MAX_TITLE_LENGTH)
            return new Response(null, false);

        $conn = Database::connect($this->db_filename);
        $stmt = $conn->prepare("DELETE FROM trackings WHERE user_uuid=:user_uuid AND person_name=:person_name;");
        $stmt->bindValue(":user_uuid", $user_uuid);
        $stmt->bindValue(":person_name", $person_name);
        $stmt->execute();

        return new Response(null, true);
    }

    /**
     * Lists all trackings of the indicated user.
     *
     * @param string $user_uuid the user to return the trackings of
     * @return Response a response with all trackings of the indicated user
     */
    public function list_trackings(string $user_uuid): Response
    {
        $conn = Database::connect($this->db_filename);
        $stmt = $conn->prepare("SELECT person_name, status FROM trackings WHERE user_uuid=:user_uuid;");
        $stmt->bindValue(":user_uuid", $user_uuid);
        $stmt->execute();
        $results = $stmt->fetchAll(PDO::FETCH_ASSOC);

        return new Response($results, true);
    }

    /**
     * Lists all unique names being tracked in the database.
     *
     * @return string[] the unique names in the database
     */
    public function list_all_trackings(): array
    {
        $conn = Database::connect($this->db_filename);
        $stmt = $conn->prepare("SELECT DISTINCT person_name FROM trackings;");
        $stmt->execute();
        return array_column($stmt->fetchAll(PDO::FETCH_ASSOC), "person_name");
    }

    /**
     * Updates trackings for the given names.
     *
     * @param string[] $people_names the names of the pages to update the tracking of
     * @return void
     */
    public function update_trackings(array $people_names): void
    {
        // TODO: Handle removed pages
        $people_statuses = $this->mediawiki->people_statuses($people_names);

        $conn = Database::connect($this->db_filename);
        $stmt = $conn->prepare("UPDATE trackings SET status=:status WHERE person_name=:person_name;");
        $stmt->bindParam(":status", $person_status);
        $stmt->bindParam(":person_name", $person_name);
        foreach ($people_statuses as $person_name => $person_status)
            $stmt->execute();
    }
}