<?php

require_once __DIR__ . "/../core.php";
require_once __DIR__ . "/../lib/pairing.php";
require_once __DIR__ . "/../lib/rating.php";
require_once __DIR__ . "/../lib/favicon.php";

ensureSession();

function renderChoice(): void {
    [$left, $right] = [$_SESSION["left"], $_SESSION["right"]];

    $csrfToken = $_SESSION["csrfToken"];

    $ajax = isset($_GET["ajax"]);

    $favicon = getFaviconUrl($left, $right);

    if ($ajax) {
        include __DIR__ . "/../view/fragments/mobSelection.php";
    } else {
        $title = "MobMash - Vote";
        $description = "Which Minecraft mob is the best? Vote for your favorite mob. MobMash uses a chess rating algorithm to calculate a definitive ranking.";

        $content = function() use ($left, $right, $csrfToken, $favicon) {
            include __DIR__ . "/../view/pages/mobSelection.php";
        };

        include __DIR__ . "/../view/layout.php";
    }
}

function reload(): void {
    if (isset($_GET["ajax"])) {
        header("LOCATION: ?ajax", true, 303);
    } else {
        header("LOCATION: /", true, 303);
    }
}

function newPairing(): array {
    if (isset($_SESSION["csrfToken"]) && ($_REQUEST["csrfToken"] != $_SESSION["csrfToken"])) {
        return [$_SESSION["left"], $_SESSION["right"]];
    }

    return makeInitialPairing(session_id());
}

const LEFT = 1;
const RIGHT = 2;

function voteAndNextPairing(int $winner): array {
    if ($_POST["csrfToken"] != $_SESSION["csrfToken"]) {
        return [$_SESSION["left"], $_SESSION["right"]];
    }

    addMatch($_SESSION["left"]["id"], $_SESSION["right"]["id"], $winner, session_id());

    $winnerMob = ($winner == LEFT) ? $_SESSION["left"] : $_SESSION["right"];

    [$left, $right] = makeFollowUpPairing(session_id(), $winnerMob["id"]);
    if (($winner == LEFT && $left["id"] != $winnerMob["id"]) ||
        ($winner == RIGHT && $right["id"] != $winnerMob["id"])
    ) {
        [$left, $right] = [$right, $left];
    }

    return [$left, $right];
}

[$_SESSION["left"], $_SESSION["right"], $render] = match (true) {
    isset($_GET["new"]), !isset($_SESSION["left"]) => [...newPairing(), false],
    isset($_GET["left"]) => [...voteAndNextPairing(LEFT), false],
    isset($_GET["right"]) => [...voteAndNextPairing(RIGHT), false],
    default => [$_SESSION["left"], $_SESSION["right"], true],
};

if ($render) {
    renderChoice();
} else {
    $_SESSION["csrfToken"] = makeCcrfToken();
    reload();
}