<?php

class Task implements JsonSerializable
{
    private string $type; // task type
    private string $question; // the task title
    protected mixed $player_answer; // answer given by the player
    protected mixed $correct_answer;
    private float $max_mark; // maximum points that can be collected at this task
    private float $mark; // earned points
    private bool $is_template; // this task is a template
    private array $flags; // task flags
    private string $lua_script; // path to the corresponding Lua script
    private Game|Test|null $governor; // object that governs this task
    private LuaSandbox|null $lua_sandbox; // Lua sandbox, initially NULL
    private array $lua_params; // Lua script parameters

    // -------------

    protected function addLuaLibraries(): void {
        // register member methods
        $method_names = get_class_methods($this);
        $methods = [];
        foreach ($method_names as $method_name) {
            $methods[$method_name] = fn() => [ call_user_func(array(&$this, $method_name), ...func_get_args()) ];
        }
        $this->lua_sandbox->registerLibrary("task", $methods);

        // register generic functionality
        $this->lua_sandbox->registerLibrary("php", [
            "print" => function($str) {
                printf("%s\n", $str);
            },
            "replace" => "str_replace",
            "replace_field" => function($field, $replacement, $str) {
                return [ str_replace("{{" . $field . "}}", $replacement, $str) ];
            }
        ]);
    }
    private function createLuaSandbox(): void {
        if ($this->lua_sandbox === null) {
            $this->lua_sandbox = new LuaSandbox;
            $this->addLuaLibraries();
        }
    }
    private function luaCall(string $lua_function): void {
        $this->createLuaSandbox();
        $implementation = file_get_contents($this->getGameDir() . DIRECTORY_SEPARATOR . $this->lua_script);
        $function_call = "$lua_function()";
        $joined_code = $implementation . "\n\n" . $function_call;
        $fn = $this->lua_sandbox->loadString($joined_code);
        $fn->call();
    }

    function __construct(string $type, array &$a = null)
    {
        $this->type = $type;
        $this->is_template = $a["is_template"] ?? false;
        $this->max_mark = $a["max_mark"] ?? 1.0;
        $this->mark = $a["mark"] ?? -1;
        $this->question = $a["question"] ?? "";
        $this->flags = $a["flags"] ?? [];
        $this->player_answer = $a["player_answer"] ?? null;
        $this->correct_answer = $a["correct_answer"] ?? null;
        $this->lua_script = $a["lua_script"] ?? "";
        $this->lua_params = $a["lua_params"] ?? [];

        $this->governor = null;
        $this->lua_sandbox = null;
    }

    function setQuestion(string $question): void
    {
        $this->question = $question;
    }

    function getQuestion(): string
    {
        return $this->question;
    }

    // save answer
    function saveAnswer(mixed $ans): bool
    {
        $this->player_answer = $ans;
        return true;
    }

    // clear answer
    function clearAnswer(): void
    {
        $this->player_answer = "";
    }

    // set task type
    function setType(string $type): void {
        $this->type = $type;
    }

    // get task type
    function getType(): string
    {
        return $this->type;
    }

    function setMaxMark(float $max_mark): void
    {
        $this->max_mark = $max_mark;
    }

    function getMaxMark(): float
    {
        return $this->max_mark;
    }

    function setMark(float $mark): void {
        $this->mark = $mark;
    }

    function getMark(): float
    {
        return $this->mark;
    }

    private function luaCheck(): void {
        //$lua = new Lua($this->getGameDir() . DIRECTORY_SEPARATOR . $this->lua_script);
        return;
    }

    protected function staticCheck(): void {
        return;
    }

    function autoCheck(): void {
        if ($this->lua_script !== "") {
            $this->luaCheck();
        } else {
            $this->staticCheck();
        }
    }

    function toArray(string $mode = "all"): array
    {
        $a = [
            "type" => $this->type,
            "question" => $this->question,
            "max_mark" => $this->max_mark,
            "mark" => $this->mark,
            "correct_answer" => $this->correct_answer,
        ];

        if ($mode === "all") {
            $a["is_template"] = $this->is_template;
            $a["flags"] = $this->flags;
            $a["lua_script"] = $this->lua_script;
            $a["lua_params"] = $this->lua_params;
        }

        if (!$this->isTemplate()) {
            $a["player_answer"] = $this->player_answer;
        }

        return $a;
    }

    function jsonSerialize(): mixed
    {
        return $this->toArray();
    }

    function setTemplate(bool $is_template): void
    {
        $this->is_template = $is_template;
    }

    function isTemplate(): bool
    {
        return $this->is_template;
    }

    function getFlags(): array
    {
        return $this->flags;
    }

    function setFlags(array $flags): void
    {
        $this->flags = $flags;
    }

    function hasFlag(string $flag): bool
    {
        return in_array($flag, $this->flags);
    }

    function setLuaScript(string $lua_script): void
    {
        $this->lua_script = $lua_script;
    }

    public function getLuaScript(): string
    {
        return $this->lua_script;
    }

    public function getLuaParams(): array {
        return $this->lua_params;
    }

    public function setLuaParams(array $lua_params): void {
        $this->lua_params = $lua_params;
    }

    function getPlayerAnswer(): mixed {
        return $this->player_answer;
    }

//    /* FIXME: ez ugyanaz, mint a saveAnswer() */
//    function setPlayerAnswer(mixed $player_answer): void {
//        $this->player_answer = $player_answer;
//    }

    function setCorrectAnswer(mixed $correct_answer): void
    {
        $this->correct_answer = $correct_answer;
    }

    function getCorrectAnswer(): mixed
    {
        return $this->correct_answer;
    }

    private function luaRandomize(): void {
        $this->luaCall("randomize");
    }

    function randomize(): void
    {
        if ($this->lua_script !== "") {
            $this->luaRandomize();
        }
        return;
    }

    function setGovernor(Game|Test|null &$governor): void {
        $this->governor =  &$governor;
    }

    function &getGovernor(): Game|Test|null {
        return $this->governor;
    }

    function getGameDir(): string {
        $gov = $this->getGovernor();
        if ($gov == null) {
            return "";
        } else {
            return $gov->getGameDir();
        }
    }
}