type IRunner = {
    getVariable(key: string): unknown;
    setVariable(key: string, value: unknown): void;
    setSmartVariable(name: string, expression: string): void;
}
export function getTtrpgFunctions(runner: IRunner){
    /* time related */
    function ensure_time(){
        if(!runner.getVariable("time_day")){
            runner.setVariable("time_day", 1);
            runner.setVariable("time_hour", 0);
            runner.setVariable("time_minute", 0);
            runner.setSmartVariable("hour_total", "$time_day * 24 + $time_hour");
        }
    }
    // midnight - 6am is night time
    function is_night(){
        ensure_time();
        const hour = runner.getVariable("time_hour") as number;
        return hour < 6;
    }
    function add_minute(delta: number){
        ensure_time();
        const min = (runner.getVariable("time_minute") as number) + delta;
        runner.setVariable("time_minute", min % 60);
        if(min >= 60) add_hour(Math.floor(min / 60));
    }
    function add_hour(delta: number){
        ensure_time();
        const hour = (runner.getVariable("time_hour") as number) + delta;
        runner.setVariable("time_hour", hour % 24);
        if(hour >= 24) add_day(Math.floor(hour / 24));
    }
    function add_day(delta: number){
        ensure_time();
        const day = (runner.getVariable("time_day") as number) + delta;
        runner.setVariable("time_day", day);
    }
    /* stat related */
    function ensure_stat(stat: string){
        if(!runner.getVariable(stat)){
            const statBase = `${stat}_base`;
            const statMod = `${stat}_mod`;
            const statDamage = `${stat}_damage`;
            const statWound = `${stat}_wound`;
            runner.setVariable(statBase, 10);
            runner.setVariable(statMod, 0);
            runner.setVariable(statDamage, 0);
            runner.setVariable(statWound, false);
            runner.setSmartVariable(stat, `$${statBase} - $${statDamage} + $${statMod}`);
        }
    }
    function get_stat(stat: string){
        ensure_stat(stat);
        return runner.getVariable(stat) as number || 0;
    }
    function damage(stat: string, amount: number){
        const current = get_stat(stat);
        if(amount * 2 >= current)
            runner.setVariable(`${stat}_wound`, true);
        const damage = get_stat(`${stat}_damage`);
        runner.setVariable(`${stat}_damage`, damage + amount);
    }
    function heal(stat: string, amount = 0){
        ensure_stat(stat);
        runner.setVariable(`${stat}_wound`, false);
        const damage = get_stat(`${stat}_damage`);
        runner.setVariable(`${stat}_damage`, Math.max(0, damage - amount));
    }
    function check(id: string, stat: string): number {
        const statVal = get_stat(stat);
        const pass = Math.ceil(Math.random() * 20) <= statVal;
        const key = `${id}_${pass ? 'pass' : 'fail'}`;
        const progress = runner.getVariable(key) as number || 0;
        const newProgress = progress + Math.ceil(Math.random() * 4);
        runner.setVariable(key, newProgress);
        return pass ? newProgress : -newProgress;
    }
    function rollStat(){
        const index = Math.floor(Math.random() * 6);
        return ['str', 'dex', 'con', 'int', 'wis', 'cha'][index];
    }
    function fatigue(){
        damage(rollStat(), 1);
    }
    function regen(){
        let stat = rollStat();
        if(runner.getVariable(`${stat}_wound`) || get_stat(`${stat}_damage`) <= 0) {
            stat = rollStat();
        }
        if(runner.getVariable(`${stat}_wound`) || get_stat(`${stat}_damage`) <= 0) {
            return;
        }
        heal(stat, 1);
    }
    return {
        add_minutes: add_minute,
        add_hours: add_hour,
        add_days: add_day,

        damage,
        heal,
        check,

        fatigue,
        regen,
    };
}