use anyhow::Context;
use serde::{Deserialize, Serialize};
use tracing::level_filters::LevelFilter;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt, EnvFilter, Layer};

use crate::{
    common::{config::ConfigLoader, get_logger_timer_rfc3339},
    rpc::cli::{NatType, PeerInfo, Route},
};

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PeerRoutePair {
    pub route: Route,
    pub peer: Option<PeerInfo>,
}

impl PeerRoutePair {
    pub fn get_latency_ms(&self) -> Option<f64> {
        let mut ret = u64::MAX;
        let p = self.peer.as_ref()?;
        for conn in p.conns.iter() {
            let Some(stats) = &conn.stats else {
                continue;
            };
            ret = ret.min(stats.latency_us);
        }

        if ret == u64::MAX {
            None
        } else {
            Some(f64::from(ret as u32) / 1000.0)
        }
    }

    pub fn get_rx_bytes(&self) -> Option<u64> {
        let mut ret = 0;
        let p = self.peer.as_ref()?;
        for conn in p.conns.iter() {
            let Some(stats) = &conn.stats else {
                continue;
            };
            ret += stats.rx_bytes;
        }

        if ret == 0 {
            None
        } else {
            Some(ret)
        }
    }

    pub fn get_tx_bytes(&self) -> Option<u64> {
        let mut ret = 0;
        let p = self.peer.as_ref()?;
        for conn in p.conns.iter() {
            let Some(stats) = &conn.stats else {
                continue;
            };
            ret += stats.tx_bytes;
        }

        if ret == 0 {
            None
        } else {
            Some(ret)
        }
    }

    pub fn get_loss_rate(&self) -> Option<f64> {
        let mut ret = 0.0;
        let p = self.peer.as_ref()?;
        for conn in p.conns.iter() {
            ret += conn.loss_rate;
        }

        if ret == 0.0 {
            None
        } else {
            Some(ret as f64)
        }
    }

    pub fn get_conn_protos(&self) -> Option<Vec<String>> {
        let mut ret = vec![];
        let p = self.peer.as_ref()?;
        for conn in p.conns.iter() {
            let Some(tunnel_info) = &conn.tunnel else {
                continue;
            };
            // insert if not exists
            if !ret.contains(&tunnel_info.tunnel_type) {
                ret.push(tunnel_info.tunnel_type.clone());
            }
        }

        if ret.is_empty() {
            None
        } else {
            Some(ret)
        }
    }

    pub fn get_udp_nat_type(self: &Self) -> String {
        let mut ret = NatType::Unknown;
        if let Some(r) = &self.route.stun_info {
            ret = NatType::try_from(r.udp_nat_type).unwrap();
        }
        format!("{:?}", ret)
    }
}

pub fn list_peer_route_pair(peers: Vec<PeerInfo>, routes: Vec<Route>) -> Vec<PeerRoutePair> {
    let mut pairs: Vec<PeerRoutePair> = vec![];

    for route in routes.iter() {
        let peer = peers.iter().find(|peer| peer.peer_id == route.peer_id);
        let has_tunnel = peer.map(|p| !p.conns.is_empty()).unwrap_or(false);
        let mut pair = PeerRoutePair {
            route: route.clone(),
            peer: peer.cloned(),
        };

        // it is relayed by public server, adjust the cost
        if !has_tunnel && pair.route.cost == 1 {
            pair.route.cost = 2;
        }

        pairs.push(pair);
    }

    pairs
}

pub fn cost_to_str(cost: i32) -> String {
    if cost == 1 {
        "p2p".to_string()
    } else {
        format!("relay({})", cost)
    }
}

pub fn float_to_str(f: f64, precision: usize) -> String {
    format!("{:.1$}", f, precision)
}

pub type NewFilterSender = std::sync::mpsc::Sender<String>;

pub fn init_logger(
    config: impl ConfigLoader,
    need_reload: bool,
) -> Result<Option<NewFilterSender>, anyhow::Error> {
    let file_config = config.get_file_logger_config();
    let file_level = file_config
        .level
        .map(|s| s.parse().unwrap())
        .unwrap_or(LevelFilter::OFF);

    let mut ret_sender: Option<NewFilterSender> = None;

    // logger to rolling file
    let mut file_layer = None;
    if file_level != LevelFilter::OFF || need_reload {
        let mut l = tracing_subscriber::fmt::layer();
        l.set_ansi(false);
        let file_filter = EnvFilter::builder()
            .with_default_directive(file_level.into())
            .from_env()
            .with_context(|| "failed to create file filter")?;
        let (file_filter, file_filter_reloader) =
            tracing_subscriber::reload::Layer::new(file_filter);

        if need_reload {
            let (sender, recver) = std::sync::mpsc::channel();
            ret_sender = Some(sender);
            std::thread::spawn(move || {
                println!("Start log filter reloader");
                while let Ok(lf) = recver.recv() {
                    let e = file_filter_reloader.modify(|f| {
                        if let Ok(nf) = EnvFilter::builder()
                            .with_default_directive(lf.parse::<LevelFilter>().unwrap().into())
                            .from_env()
                            .with_context(|| "failed to create file filter")
                        {
                            println!("Reload log filter succeed, new filter level: {:?}", lf);
                            *f = nf;
                        }
                    });
                    if e.is_err() {
                        println!("Failed to reload log filter: {:?}", e);
                    }
                }
                println!("Stop log filter reloader");
            });
        }

        let file_appender = tracing_appender::rolling::Builder::new()
            .rotation(tracing_appender::rolling::Rotation::DAILY)
            .max_log_files(5)
            .filename_prefix(file_config.file.unwrap_or("easytier".to_string()))
            .build(file_config.dir.unwrap_or("./".to_string()))
            .with_context(|| "failed to initialize rolling file appender")?;
        file_layer = Some(
            l.with_writer(file_appender)
                .with_timer(get_logger_timer_rfc3339())
                .with_filter(file_filter),
        );
    }

    // logger to console
    let console_config = config.get_console_logger_config();
    let console_level = console_config
        .level
        .map(|s| s.parse().unwrap())
        .unwrap_or(LevelFilter::OFF);

    let console_filter = EnvFilter::builder()
        .with_default_directive(console_level.into())
        .from_env()
        .unwrap();

    let console_layer = tracing_subscriber::fmt::layer()
        .pretty()
        .with_timer(get_logger_timer_rfc3339())
        .with_writer(std::io::stderr)
        .with_filter(console_filter);

    tracing_subscriber::Registry::default()
        .with(console_layer)
        .with(file_layer)
        .init();

    Ok(ret_sender)
}

#[cfg(target_os = "windows")]
pub fn utf8_or_gbk_to_string(s: &[u8]) -> String {
    use encoding::{all::GBK, DecoderTrap, Encoding};
    if let Ok(utf8_str) = String::from_utf8(s.to_vec()) {
        utf8_str
    } else {
        // 如果解码失败，则尝试使用GBK解码
        if let Ok(gbk_str) = GBK.decode(&s, DecoderTrap::Strict) {
            gbk_str
        } else {
            String::from_utf8_lossy(s).to_string()
        }
    }
}

pub fn setup_panic_handler() {
    use std::backtrace;
    use std::io::Write;
    std::panic::set_hook(Box::new(|info| {
        let backtrace = backtrace::Backtrace::force_capture();
        println!("panic occurred: {:?}", info);
        let _ = std::fs::File::create("easytier-panic.log")
            .and_then(|mut f| f.write_all(format!("{:?}\n{:#?}", info, backtrace).as_bytes()));
        std::process::exit(1);
    }));
}

#[cfg(test)]
mod tests {
    use crate::common::config::{self};

    use super::*;

    async fn test_logger_reload() {
        println!("current working dir: {:?}", std::env::current_dir());
        let config = config::TomlConfigLoader::default();
        let s = init_logger(&config, true).unwrap();
        tracing::debug!("test not display debug");
        s.unwrap().send(LevelFilter::DEBUG.to_string()).unwrap();
        tokio::time::sleep(tokio::time::Duration::from_secs(1)).await;
        tracing::debug!("test display debug");
    }
}