use std::{collections::HashMap, sync::Mutex};
use strum_macros::IntoStaticStr; 

use esp_idf_svc::systime::EspSystemTime;
use once_cell::sync::Lazy;
use ringbuffer::{ConstGenericRingBuffer, RingBuffer};
use text_template::Template;

const TXT_SHORT_LENGTH:usize = 8;
const TXT_LONG_LENGTH:usize = 32;

const BUFFER_SIZE:usize = 210;

#[link_section = ".rtc.data"]
static mut BUFFER:ConstGenericRingBuffer::<LogEntry, BUFFER_SIZE> = ConstGenericRingBuffer::<LogEntry, BUFFER_SIZE>::new();

static BUFFER_ACCESS: Lazy<Mutex<&mut ConstGenericRingBuffer::<LogEntry, BUFFER_SIZE>>> = Lazy::new(|| unsafe { Mutex::new(&mut BUFFER) });


pub struct LogEntry {
    pub timestamp: u64,
    pub message_id: u32,
    pub a: u32,
    pub b: u32,
    pub txt_short: heapless::String<TXT_SHORT_LENGTH>,
    pub txt_long: heapless::String<TXT_LONG_LENGTH>
}

pub fn init(){
    unsafe { 
        BUFFER = ConstGenericRingBuffer::<LogEntry, BUFFER_SIZE>::new();
    };
    let mut access = BUFFER_ACCESS.lock().unwrap();
    access.drain().for_each(|_| {});
}

fn limit_length <const LIMIT:usize> (input: &str, target: &mut heapless::String<LIMIT>){
    for char in input.chars() {
        match target.push(char) {
            Ok(_) => {}, //continue adding chars
            Err(_) => {
                //clear space for two asci chars
                while target.len()+2 >= LIMIT {
                    target.pop().unwrap();
                }
                //add .. to shortened strings
                target.push('.').unwrap();
                target.push('.').unwrap();
                return;
            },
        }
    }
}

pub fn log(message_key: LogMessage, number_a: u32, number_b: u32, txt_short:&str, txt_long:&str){
    let mut txt_short_stack:heapless::String<TXT_SHORT_LENGTH> = heapless::String::new();
    let mut txt_long_stack:heapless::String<TXT_LONG_LENGTH> = heapless::String::new();
    
    limit_length(txt_short, &mut txt_short_stack);
    limit_length(txt_long, &mut txt_long_stack);
    
    let time = EspSystemTime {}.now().as_millis() as u64;

    let template_string:&str = message_key.into();


    let mut values: HashMap<&str, &str> = HashMap::new();
    let number_a_str = number_a.to_string();
    let number_b_str = number_b.to_string();

    values.insert("number_a", &number_a_str);
    values.insert("number_b", &number_b_str);
    values.insert("txt_short", txt_short);
    values.insert("txt_long", txt_long);

    let template = Template::from(template_string);
    let serial_entry = template.fill_in(&values);
   
    println!("{serial_entry}");


    let entry = LogEntry{
        timestamp: time,
        message_id: 1,
        a: number_a,
        b: number_b,
        txt_short: txt_short_stack,
        txt_long: txt_long_stack,
    };


    let mut buffer = BUFFER_ACCESS.lock().unwrap();    
    buffer.push(entry);
}


#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn within_limit() {
        let test = "12345678";
        
        let mut txt_short_stack:heapless::String<TXT_SHORT_LENGTH> = heapless::String::new();
        let mut txt_long_stack:heapless::String<TXT_LONG_LENGTH> = heapless::String::new();
        limit_length(test, &mut txt_short_stack);
        limit_length(test, &mut txt_long_stack);

        assert_eq!(txt_short_stack.as_str(), test);
        assert_eq!(txt_long_stack.as_str(), test);
    }
}



#[derive(IntoStaticStr)]
pub enum LogMessage {
    #[strum(serialize = "Reset due to {{txt_long}} requires rtc clear {{a}} and force config mode {{b}}")]   
    reset_reason,
    #[strum(serialize = "Current restart to conf mode {{a}}")]   
    restart_to_config,
    #[strum(serialize = "Current low voltage detection is {{a}}")]   
    low_voltage,
    #[strum(serialize = "Error communicating with battery!! {{txt_long}}")]   
    battery_communication_error,
    #[strum(serialize = "Tank sensor raw {{a}} percent {{b}}")]   
    sensor_tank_raw,
    #[strum(serialize = "raw measure unscaled {{a}} hz {{b}}, plant {{txt_short}} sensor {{txt_long}}")]   
    raw_measure,
    #[strum(serialize = "IP info: {{txt_long}}")]   
    wifi_info,
    #[strum(serialize = "Plant:{{txt_short}} a:{{a}} b:{{b}}")]   
    test_sensor,
    #[strum(serialize = "Stay alive topic is {{txt_long}}")]   
    stay_alive,
    #[strum(serialize = "Connecting mqtt {{txt_short}} with id {{txt_long}}")]   
    mqtt_info,
    #[strum(serialize = "Received stay alive with value {{txt_short}}")]   
    mqtt_stay_alive_rec,
    #[strum(serialize = "Unknown topic recieved {{txt_long}}")]   
    unknown_topic,
}