pub mod files;
pub mod hagent;
pub mod metrics;
pub mod prcs;
pub mod services;

// TODO : saving current flags state

use crate::options::structs::CustomError;
use crate::options::structs::TrackingProcess;
use files::create_watcher;
use files::file_handler;
use inotify::Inotify;
use log::{error, warn};
use prcs::{
    freeze_process, is_active, is_frozen, restart_process, start_process, terminate_process,
    unfreeze_process,
};
use services::service_handler;
use std::process::Command;
use std::sync::Arc;
use tokio::join;
use tokio::sync::mpsc;
use tokio::time::Duration;

const GET_ID_CMD: &str = "hostname";

/// # Fn `run_daemons`
/// ## async func to run 3 main daemons: process, service and file monitors and manage process state according to given messages into channel 
/// 
/// *input*      : `Arc<TrackingProcess>`, `Arc<mpsc::Sender<u8>>`, `&mut mpsc::Receiver<u8>`,
///
/// *output*     : ()
///
/// *initiator*  : main thread
///
/// *managing*   : Arc to current process struct, Arc to managing channel writer, mut ref to managing channel reader
///
/// *depends on* : all module `prcs`'s functions, fn `running_handler`, fn `utils::files::create_watcher`
/// 
/// > *hint* : give mpsc with capacity 1 to jump over potential errors during running process
///
pub async fn run_daemons(
    proc: Arc<TrackingProcess>,
    tx: Arc<mpsc::Sender<u8>>,
    rx: &mut mpsc::Receiver<u8>,
) {
    // creating watchers + ---buffers---
    let mut watchers: Vec<Inotify> = vec![];
    for file in proc.dependencies.files.clone().into_iter() {
        if let Ok(watcher) = create_watcher(&file.filename, &file.src).await {
            watchers.push(watcher);
        } else {
            let _ = tx.send(121).await;
        }
        // watchers.push(create_watcher(&file.filename, &file.src).await.unwrap());
    }
    let watchers_clone: Arc<tokio::sync::Mutex<Vec<Inotify>>> =
        Arc::new(tokio::sync::Mutex::new(watchers));

    loop {
        let run_hand = running_handler(proc.clone(), tx.clone(), watchers_clone.clone());
        tokio::select! {
            _ = run_hand => continue,
            _val = rx.recv() => { 
                if process_protocol_symbol(proc.clone(), _val.unwrap()).await.is_err() {
                    return;
                } 
            },
        }
        tokio::task::yield_now().await;
    }
}

async fn process_protocol_symbol(proc: Arc<TrackingProcess>, val: u8) -> Result<(), CustomError>{
    match val {
        // 1 - File-dependency handling error -> terminating (after waiting)
        1 => {
            if is_active(&proc.name).await {
                error!("File-dependency handling error: Terminating {} process ..." , &proc.name);
                terminate_process(&proc.name).await;
                tokio::time::sleep(Duration::from_millis(500)).await;
            }
            // return;
        },
        // 2 - File-dependency handling error -> holding (after waiting)
        2 => {
            if !is_frozen(&proc.name).await {
                error!("File-dependency handling error: Freezing {} process ..." , &proc.name);
                freeze_process(&proc.name).await;
                tokio::time::sleep(Duration::from_millis(100)).await;
            }
        },
        // 3 - Running process error
        3 => {
            error!("Error due to starting {} process", &proc.name);
            return Err(CustomError::Fatal)
        },
        // 4 - Timeout of waiting service-dependency -> staying (after waiting)
        4 => {
            // warn!("Timeout of waiting service-dependency: Ignoring  on {} process ..." , &proc.name);
            tokio::time::sleep(Duration::from_millis(100)).await;
        },
        // 5 - Timeout of waiting service-dependency -> terminating (after waiting)
        5 => {
            if is_active(&proc.name).await {
                error!("Timeout of waiting service-dependency: Terminating {} process ..." , &proc.name);
                terminate_process(&proc.name).await;
                tokio::time::sleep(Duration::from_millis(500)).await;
            }
        },
        // 6 - Timeout of waiting service-dependency -> holding (after waiting)
        6 => {
            // println!("holding {}-{}", proc.name, is_active(&proc.name).await);
            if !is_frozen(&proc.name).await {
                error!("Timeout of waiting service-dependency: Freezing {} process ..." , &proc.name);
                freeze_process(&proc.name).await;
                tokio::time::sleep(Duration::from_secs(1)).await;
            }
        },
        // // 7 - File-dependency change -> terminating (after check)
        7 => {
            error!("File-dependency warning (file changed). Terminating {} process...", &proc.name);
            terminate_process(&proc.name).await;
            tokio::time::sleep(Duration::from_millis(100)).await;
            return Err(CustomError::Fatal)
        },
        // // 8 - File-dependency change -> restarting (after check)
        8 => {
            warn!("File-dependency warning (file changed). Restarting {} process...", &proc.name);
            let _ = restart_process(&proc.name, &proc.path).await;
            tokio::time::sleep(Duration::from_millis(100)).await;
        },
        // // 9 - File-dependency change -> staying (after check)
        9 => {
            // no need to trash logs
            warn!("File-dependency warning (file changed). Ignoring event on {} process...", &proc.name);
            tokio::time::sleep(Duration::from_millis(100)).await;
        },

        // 10 - Process unfreaze call via file handler (or service handler)
        10 | 11 => {
            if is_frozen(&proc.name).await {
                warn!("Unfreezing process {} call...", &proc.name);
                unfreeze_process(&proc.name).await;
            }
            tokio::time::sleep(Duration::from_millis(100)).await;
        },
        // 11 - Process unfreaze call via service handler
        // 11 => {
        //     if is_frozen(&proc.name).await {
        //         warn!("Unfreezing process {} call...", &proc.name);
        //         unfreeze_process(&proc.name).await;
        //     }
        //     tokio::time::sleep(Duration::from_millis(100)).await;
        // },
        // 101 - Impermissible trigger values in JSON
        101 => {
            error!("Impermissible trigger values in JSON in {}'s block. Killing thread...", &proc.name);
            if is_active(&proc.name).await {
                terminate_process(&proc.name).await;
            }
            return Err(CustomError::Fatal)
        },
        //
        // 121 - Cannot create valid watcher for file dependency
        // todo : think about valid situation 
        121 => {
            error!("Cannot create valid watcher for file dependency. Terminating {} process...", &proc.name);
            let _ = terminate_process(&proc.name).await;
            return Err(CustomError::Fatal)
        },
        // 111 - global thread termination with killing current child in a face
        // of a current process
        111 => {
            warn!("Terminating {}'s child processes...", &proc.name);
            match is_active(&proc.name).await {
                true => {
                    terminate_process(&proc.name).await;
                },
                false => {
                    log::info!("Process {} is already terminated!", proc.name);
                },
            }
        },
        _ => {},
    }
    Ok(())
}
// check process status daemon
/// # Fn `run_daemons`
/// ## func to async exec subjobs of checking process, services and files states
/// 
/// *input*      : `Arc<TrackingProcess>`, `Arc<mpsc::Sender<u8>>`, `Arc<tokio::sync::Mutex<Vec<Inotify>>>`
///
/// *output*     : ()
///
/// *initiator*  : fn `run_daemons`
///
/// *managing*   : Arc to current process struct, Arc to Mutex to list of file watchers
///
/// *depends on* : fn `utils::files::file_handler`, fn `utils::services::service_handler`, fn `utils::prcs::{is_active, is_frozen, start_process}`
/// 
pub async fn running_handler(
    prc: Arc<TrackingProcess>,
    tx: Arc<mpsc::Sender<u8>>,
    watchers: Arc<tokio::sync::Mutex<Vec<Inotify>>>,
) {
    // services and files check (once)
    let files_check = file_handler(
        &prc.name,
        &prc.dependencies.files,
        tx.clone(),
        watchers.clone(),
    );
    let services_check = service_handler(&prc.name, &prc.dependencies.services, tx.clone());

    let res = join!(files_check, services_check);
    // if inactive -> spawn checks -> active is true
    if !is_active(&prc.name).await && res.0.is_ok() && res.1.is_ok() {
        if start_process(&prc.name, &prc.path).await.is_err() {
            tx.send(3).await.unwrap();
            return;
        }
    }
    // if frozen  -> spawn checks -> unfreeze is true
    else if is_frozen(&prc.name).await && res.0.is_ok() && res.1.is_ok() {
        tx.send(10).await.unwrap();
        return;
    }
    // tokio::time::sleep(Duration::from_millis(100)).await;
    tokio::task::yield_now().await;
}

// todo: cmd across cat /proc/self/mountinfo | grep "/docker/containers/" | head -1 | awk -F '/' '{print $5}'
/// # Fn `get_container_id`
/// ## for getting container id used in logs
/// 
/// *input*      : -
///
/// *output*     : Some(String) if cont-id was grubbed | None - if not  
///
/// *initiator*  : fn `options::logger::setup_logger`
///
/// *managing*   : -
///
/// *depends on* : -
/// 
pub fn get_container_id() -> Option<String> {
    match Command::new(GET_ID_CMD).output() {
        Ok(output) => {
            if !output.status.success() {
                return None;
            }
            let id = String::from_utf8_lossy(&output.stdout).to_string();
            if id.is_empty() {
                return None;
            }
            Some(String::from_utf8_lossy(&output.stdout).to_string())
        }
        Err(_) => None,
    }
}

#[cfg(test)]
mod utils_unittests {
    use super::get_container_id;
    #[test]
    fn check_if_container_id_can_be_grabed() {
        assert!(get_container_id().is_some());
    }
}