use std::cell::RefCell;
use std::time::Duration;
use std::{fmt::Display, string};
use std::error::Error;

use crate::GameState;

pub type Second = u64;

pub const MINUTE: Second = 60;
pub const HOUR: Second = MINUTE * 60;
pub const DAY: Second = HOUR * 24;
pub const YEAR: Second = DAY * 365;

pub const SYSTEM_TICK_INTERVAL: Second = 1 * DAY;

pub struct TimeMan
{
    time: Second,
    last_time: Second,
    pub auto_tick: Option<Second>
}

impl TimeMan
{
    pub fn new(time: Second)
    -> Self {
        Self {
            time,
            last_time: time,
            auto_tick: None
        }
    }

    pub fn seconds(&self)
    -> Second {
        self.time
    }

    pub fn advance(
        &mut self,
        by: Second)
    {
        self.time += by;
    }

    pub fn update(
        &mut self)
    -> Vec<Second>
    {
        match self.auto_tick {
            Some(advance) => { self.time += advance; },
            None => {}
        }

        let time_diff = self.time - self.last_time;
        
        let tick_diff = self.time / SYSTEM_TICK_INTERVAL -
                        self.last_time / SYSTEM_TICK_INTERVAL;

        if time_diff == 0 || tick_diff == 0 {
            self.last_time = self.time;
            return vec![];
        }

        let time_start = self.last_time - (self.last_time % SYSTEM_TICK_INTERVAL);
        let time_end = self.time - (self.time % SYSTEM_TICK_INTERVAL);

        let tick_start = time_start / SYSTEM_TICK_INTERVAL;
        let tick_end = time_end / SYSTEM_TICK_INTERVAL;

        self.last_time = self.time;
        (tick_start..tick_end).map(|v| {
            v * SYSTEM_TICK_INTERVAL
        }).collect::<Vec<_>>()
    }

    pub fn format_duration(time: Second) -> String
    {
        let seconds = time % 60;
        let minutes = (time / 60) % 60;
        let hours = (time / (60 * 60)) % 24;
        let days = (time / (60 * 60 * 24)) % 365;
        let years = time / (60 * 60 * 24 * 365);
        
        if time == 0 {
            return "0s".to_string();
        }

        format!("{}{}{}{}{}",
            if years > 0 { format!("{}y", years) } else { format!("") },
            if days > 0 { format!("{}d", days) } else { format!("") },
            if hours > 0 { format!("{}h", hours) } else { format!("") },
            if minutes > 0 { format!("{}m", minutes) } else { format!("") },
            if seconds > 0 { format!("{}s", seconds) } else { format!("") })
    }


} //impl TimeMan