<?php

namespace com\fwdekker\deathnotifier\tracking;

use com\fwdekker\deathnotifier\Action;
use com\fwdekker\deathnotifier\Config;
use com\fwdekker\deathnotifier\LoggerUtil;
use com\fwdekker\deathnotifier\mailer\Email;
use com\fwdekker\deathnotifier\mailer\EmailQueue;
use com\fwdekker\deathnotifier\UnexpectedException;
use com\fwdekker\deathnotifier\validation\EqualsCliPasswordRule;
use com\fwdekker\deathnotifier\validation\InvalidTypeException;
use com\fwdekker\deathnotifier\validation\InvalidValueException;
use com\fwdekker\deathnotifier\validation\RuleSet;
use com\fwdekker\deathnotifier\wikipedia\PersonStatus;
use com\fwdekker\deathnotifier\wikipedia\Wikipedia;
use com\fwdekker\deathnotifier\wikipedia\WikipediaException;
use Monolog\Logger;


/**
 * Updates all trackings that users have added.
 *
 * @see NotifyStatusChangedEmail
 * @see NotifyArticleDeletedEmail
 * @see NotifyArticleUndeletedEmail
 */
class UpdateTrackingsAction extends Action
{
    /**
     * @var Logger the logger to log with
     */
    private readonly Logger $logger;
    /**
     * @var Logger the database logger to log with
     */
    private readonly Logger $db_logger;
    /**
     * @var TrackingList the list of trackings to update
     */
    private readonly TrackingList $tracking_list;
    /**
     * @var Wikipedia the API of Wikipedia
     */
    private readonly Wikipedia $wikipedia;
    /**
     * @var EmailQueue the queue to add notifications to
     */
    private readonly EmailQueue $mailer;


    /**
     * Constructs a new `UpdateTrackingsAction`.
     *
     * @param TrackingList $tracking_list the list of trackings to update
     * @param Wikipedia $wikipedia the API of Wikipedia
     * @param EmailQueue $mailer the queue to add notifications to
     */
    public function __construct(TrackingList $tracking_list, Wikipedia $wikipedia, EmailQueue $mailer)
    {
        $this->logger = LoggerUtil::with_name($this::class);
        $this->db_logger = LoggerUtil::db_with_name($this::class);
        $this->tracking_list = $tracking_list;
        $this->wikipedia = $wikipedia;
        $this->mailer = $mailer;
    }


    /**
     * Updates all trackings that users have added.
     *
     * @param array<int|string, mixed> $inputs `"password": string`: the CLI password
     * @return null
     * @throws InvalidTypeException if any of the inputs has the incorrect type
     * @throws InvalidValueException if the CLI password is wrong
     * @throws UnexpectedException if Wikipedia could not be reached
     * @noinspection PhpDocRedundantThrowsInspection can be thrown through {@see TrackingList::transaction()}
     */
    public function handle(array $inputs): mixed
    {
        (new RuleSet(["password" => [new EqualsCliPasswordRule()]]))->check($inputs);

        // Process changes
        $new_deletions = [];
        $new_undeletions = [];
        $new_status_changes = [];
        $this->tracking_list->transaction(function () use (&$new_deletions, &$new_undeletions, &$new_status_changes) {
            $names = $this->tracking_list->list_all_unique_person_names();
            if (empty($names))
                return;

            try {
                $people_statuses = $this->wikipedia->query_people_info($names, resolve_moves: true);
            } catch (WikipediaException $exception) {
                $this->logger->error("Failed to query page info.", ["cause" => $exception, "pages" => $names]);
                throw new UnexpectedException("Could not reach Wikipedia. Maybe the website is down?");
            }

            $this->tracking_list->rename_persons($people_statuses->redirects);
            $new_deletions = $this->tracking_list->delete_persons($people_statuses->missing);
            $new_undeletions = $this->tracking_list->undelete_persons(array_keys($people_statuses->results));
            $new_status_changes = $this->tracking_list->update_statuses(
                array_combine(
                    array_keys($people_statuses->results),
                    array_map(fn($it) => $it["status"], $people_statuses->results)
                )
            );
        });

        // Send mails, log events
        // TODO: Restrict number of notifications to 1 per hour (excluding "oops we're not sure" message)
        // TODO: Wait for some time after person has been marked as dead before sending the email
        $emails = [];

        $person_names = $new_deletions + $new_undeletions + array_keys($new_status_changes);
        $trackers = $this->tracking_list->list_trackers($person_names);

        foreach ($new_deletions as $new_deletion) {
            $this->db_logger->notice("Deleted article $new_deletion.");

            foreach ($trackers[$new_deletion] as $user_email)
                $emails[] = new NotifyArticleDeletedEmail($user_email, $new_deletion);
        }

        foreach ($new_undeletions as $new_undeletion) {
            $this->db_logger->notice("Undeleted article $new_undeletion.");

            foreach ($trackers[$new_undeletion] as $user_email)
                $emails[] = new NotifyArticleUndeletedEmail($user_email, $new_undeletion);
        }

        foreach ($new_status_changes as $person_name => $person_status) {
            if ($person_status === PersonStatus::Alive)
                $this->db_logger->notice("Person $person_name is now alive again.");

            foreach ($trackers[$person_name] as $user_email)
                $emails[] = new NotifyStatusChangedEmail($user_email, $person_name, $person_status->value);
        }

        $this->mailer->enqueue($emails);
        return null;
    }
}


/**
 * An email to inform a user a tracker person's status has changed.
 *
 * @see UpdateTrackingsAction
 */
class NotifyStatusChangedEmail extends Email
{
    /**
     * A string identifying the type of email.
     */
    public const TYPE = "notify-status-changed";

    /**
     * @var string the name of the person whose status has changed
     */
    public string $name;
    /**
     * @var string the new status of the person
     */
    public string $new_status;


    /**
     * Constructs a new `NotifyStatusChangedEmail`.
     *
     * @param string $recipient the intended recipient of this email
     * @param string $name the name of the person who died
     * @param string $new_status the new status of the person
     */
    public function __construct(string $recipient, string $name, string $new_status)
    {
        parent::__construct($this::TYPE . "/" . $name, $recipient);

        $this->name = $name;
        $this->new_status = $new_status;
    }


    public function get_subject(): string
    {
        return "$this->name may be $this->new_status";
    }

    public function get_body(): string
    {
        $base_path = Config::get("server.base_path");

        return
            "Someone has edited Wikipedia to state that $this->name is $this->new_status. " .
            "For more information, read their Wikipedia article at " .
            "https://en.wikipedia.org/wiki/" . rawurlencode($this->name) .
            "\n\n" .
            "You are receiving this message because of the preferences in your Death Notifier account. " .
            "To unsubscribe from these messages, go to the Death Notifier website, log in, and change your email " .
            "preferences." .
            "\n\n" .
            $base_path;
    }
}

/**
 * An email to inform a user that a tracked article has been deleted.
 *
 * @see UpdateTrackingsAction
 */
class NotifyArticleDeletedEmail extends Email
{
    /**
     * A string identifying the type of email.
     */
    public const TYPE = "notify-article-deleted";

    /**
     * @var string the name of the article that was deleted
     */
    public string $name;


    /**
     * Constructs a new `NotifyArticleDeletedEmail`.
     *
     * @param string $recipient the intended recipient of this email
     * @param string $name the name of the article that was deleted
     */
    public function __construct(string $recipient, string $name)
    {
        parent::__construct($this::TYPE . "/" . $name, $recipient);

        $this->name = $name;
    }


    public function get_subject(): string
    {
        return "$this->name article has been deleted";
    }

    public function get_body(): string
    {
        $base_path = Config::get("server.base_path");

        return
            "The Wikipedia article about $this->name has been deleted. " .
            "Death Notifier is now unable to send you a notification if $this->name dies. " .
            "If the Wikipedia article is ever re-created, Death Notifier will automatically resume tracking this " .
            "article, and you will receive another notification." .
            "\n\n" .
            "You are receiving this message because of the preferences in your Death Notifier account. " .
            "To unsubscribe from these messages, go to the Death Notifier website, log in, and change your email " .
            "preferences." .
            "\n\n" .
            $base_path;
    }
}

/**
 * An email to inform a user that a tracked article has been re-created.
 *
 * @see UpdateTrackingsAction
 */
class NotifyArticleUndeletedEmail extends Email
{
    /**
     * A string identifying the type of email.
     */
    public const TYPE = "notify-article-undeleted";

    /**
     * @var string the name of the article that was re-created
     */
    public string $name;


    /**
     * Constructs a new `NotifyArticleUndeletedEmail`.
     *
     * @param string $recipient the intended recipient of this email
     * @param string $name the name of the article that was re-created
     */
    public function __construct(string $recipient, string $name)
    {
        parent::__construct($this::TYPE . "/" . $name, $recipient);

        $this->name = $name;
    }


    public function get_subject(): string
    {
        return "$this->name article has been re-created";
    }

    public function get_body(): string
    {
        $base_path = Config::get("server.base_path");

        return
            "The Wikipedia article about $this->name has been re-created. " .
            "Death Notifier will once again track the article and notify you if $this->name dies." .
            "\n\n" .
            "You are receiving this message because of the preferences in your Death Notifier account. " .
            "To unsubscribe from these messages, go to the Death Notifier website, log in, and change your email " .
            "preferences." .
            "\n\n" .
            $base_path;
    }
}