use crate::cfg::config::Config;  

use tokio;
use emissary_core::runtime::{
    AsyncRead, 
    AsyncWrite, 
};

use std::{io, 
          fs::File, 
          path::Path,
          io::Write}; 
// use emissary_core::Profile; 
// use emissary_core::i2np::Message;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use yosemite::SessionOptions;
use yosemite::{Session, style::Stream}; 
/* 
use i2p_client::ClientType;
use i2p_client::I2PClient; 
use i2p_client::SessionStyle::Stream;
use i2p_client::Session;  

struct I2PStatus {
    Connected: bool,
}

impl I2PStatus {
       pub fn connect(&self) -> Result<bool, std::io::Error> {

        let config: Config = Config::parse().unwrap();
        let client= I2PClient::new(true, "MeskPKG-manager".to_string(), "2.0", "2.58.0", 10);
        // let destination = Session::r#gen(&mut self, SigType::EdDsaSha512Ed25519)
        let session = Session::create(config.repo.repo_url, 
            &config.repo.destination.0,
            "MeskPKG-manager", 
            Stream, 
            "2.0", 
            "2.58");

        Ok(true)
    }
}
*/

struct I2P<S> {
    session: Option<Session<S>>,
    connected: bool, 
    config: Config,

}

impl<S> I2P<S> {
    /// Creates a new I2P object with the given configuration.
    ///
    /// # Returns
    ///
    /// A new I2P object with the given configuration. The session is initially set to None and the connected status is set to false.
    pub fn new(config: Config) -> Self {
        I2P {
            session: None,
            connected: false,
            config: config,
        }
    }

    /// Fetches the list of packages from the repository specified in the configuration.
    ///
    /// This function connects to the repository specified in the configuration, sends a GET request for the repository list and returns true if the request is successful, false otherwise.
    /// 
    /// # Errors
    ///
    /// Returns an error if the repository URL is invalid or if the request fails.
    ///
    pub async fn fetch_index(&mut self) -> Result<bool, std::io::Error> {
        let repo_url_str = &self.config.repo.repo_url;
        let cache_dir = &self.config.paths.cache_dir;

        let repo_pos = repo_url_str.find("/repo").ok_or_else(|| {
            io::Error::new(io::ErrorKind::InvalidData, "URL does not contain '/repo'")
        })?;
        // BaseURL 
        let base_url = &repo_url_str[..repo_pos];
        // Url after /repo
        let path_suffix = &repo_url_str[repo_pos + "/repo".len()..];
        // HTTP path 
        let request_path = format!("/repo{}{}", path_suffix, if path_suffix.ends_with(".tar.gz") { "" } else { "/INDEX.tar.gz" });

        let mut opts = SessionOptions::default();
        // FIXME: Make sure, opts setted to I2P
        // opts.set_host("127.0.0.1");
        // opts.set_port(7656);
        let mut session = Session::<Stream>::new(opts).await.map_err(|e| {
            io::Error::new(io::ErrorKind::Other, format!("Failed to create session: {}", e))
        })?;

        let mut stream = session.connect(base_url).await.map_err(|e| {
            io::Error::new(io::ErrorKind::ConnectionAborted, format!("Failed to connect: {}", e))
        })?;

        let request = format!("GET {} HTTP/1.1\r\nHost: {}\r\n\r\n", request_path, base_url);
        stream.write_all(request.as_bytes()).await.map_err(|e| {
            io::Error::new(io::ErrorKind::Other, format!("Failed to write request: {}", e))
        })?;

        let mut response_buffer = Vec::new();
        let mut chunk = [0u8; 1024]; 

        loop {
            // FIXME: Check docs and make suro stream allows to AsyncReadExt
            let bytes_read = stream.read(&mut chunk).await.map_err(|e| {
                io::Error::new(io::ErrorKind::Other, format!("Failed to read response: {}", e))
            })?;

            if bytes_read == 0 {
                break;
            }

            response_buffer.extend_from_slice(&chunk[..bytes_read]);

            if let Some(headers_end) = Self::find_double_crlf(&response_buffer) {
                let body_start = headers_end + 4;
                let headers_str = std::str::from_utf8(&response_buffer[..headers_end])
                    .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "Invalid header encoding"))?;

                if !headers_str.starts_with("HTTP/1.1 200") && !headers_str.starts_with("HTTP/1.0 200") {
                    return Err(io::Error::new(io::ErrorKind::Other, format!("HTTP Error: {}", headers_str.lines().next().unwrap_or("Unknown"))));
                }

                let file_path = Path::new(cache_dir).join("INDEX.tar.gz");
                let mut file = File::create(&file_path)?;
                file.write_all(&response_buffer[body_start..])?;
                while let Ok(bytes_read) = stream.read(&mut chunk).await {
                    if bytes_read == 0 {
                        break; 
                    }
                    file.write_all(&chunk[..bytes_read])?;
                }

                file.flush()?;
                break; 
            }
        }

        Ok(true)
    }

    fn find_double_crlf(buf: &[u8]) -> Option<usize> {
        for i in 0..buf.len().saturating_sub(3) {
            if buf[i] == b'\r' && buf[i+1] == b'\n' && buf[i+2] == b'\r' && buf[i+3] == b'\n' {
                return Some(i);
            }
        }
        None
    }
}