use std::{
    collections::HashMap,
    io::{Read, Write},
    net::TcpListener,
    str::from_utf8,
    sync::{Arc, Mutex},
    thread,
};

#[cfg(feature = "https")]
use rustls::{
    pki_types::{pem::PemObject, CertificateDer, PrivateKeyDer},
    ServerConfig, ServerConnection, StreamOwned,
};

use crate::{
    client,
    http::{request::RequestLine, Request, Response},
    Client,
};

pub struct Server {
    listener: TcpListener,

    on_request: Arc<Mutex<Option<Box<dyn Fn(Request) -> Response + Send + 'static>>>>,

    #[cfg(feature = "https")]
    tls_config: Option<Arc<ServerConfig>>,
}

impl Server {
    pub fn new(ip: &str, port: i32) -> Self {
        let addr = format!("{}:{}", ip, port);
        let listener = TcpListener::bind(addr).unwrap();

        Server {
            listener,

            on_request: Arc::new(Mutex::new(None)),

            #[cfg(feature = "https")]
            tls_config: None,
        }
    }

    pub fn run(&mut self) {
        for stream in self.listener.incoming() {
            let stream = stream.unwrap();

            let on_request = Arc::clone(&self.on_request);

            #[cfg(feature = "https")]
            let tls_config = self.tls_config.clone();

            thread::spawn(move || {
                #[cfg(feature = "https")]
                let stream = if let Some(tls_config) = tls_config {
                    let connection = ServerConnection::new(tls_config).unwrap();
                    client::Stream::Tls(StreamOwned::new(connection, stream))
                } else {
                    client::Stream::Tcp(stream)
                };

                #[cfg(not(feature = "https"))]
                let stream = client::Stream::Tcp(stream);

                let mut client = Client::new(stream);

                let mut buffer = vec![0; 1024];
                let bytes_read = client.read(&mut buffer).unwrap();

                if bytes_read > 0 {
                    if let Ok(request_str) = from_utf8(&buffer[..bytes_read]) {
                        // TODO: support proper error handling
                        if let Some(on_request) =
                            &*on_request.lock().unwrap_or_else(|e| e.into_inner())
                        {
                            let request;
                            {
                                let mut lines = request_str.lines();

                                let request_line = RequestLine::from_str(lines.next().unwrap());

                                let mut headers = HashMap::new();
                                for line in lines {
                                    if let Some((k, v)) = line.split_once(": ") {
                                        headers.insert(k, v);
                                    }
                                }

                                request = Request {
                                    request_line,
                                    headers,
                                };
                            }

                            let response = on_request(request);
                            {
                                let response_line = response.response_line.to_string();
                                client.write_string(response_line).unwrap();

                                if let Some(headers) = response.headers {
                                    for (k, v) in headers {
                                        client.write_string(format!("{}: {}", k, v)).unwrap();
                                    }
                                } else {
                                    client.write(b"\r\n").unwrap();
                                }

                                if let Some(content) = response.content {
                                    client.write_all(&content).unwrap();
                                } else {
                                    client.write(b"\r\n").unwrap();
                                }
                            }

                            client.flush().unwrap();
                        }
                    }
                }
            });
        }
    }

    #[cfg(feature = "https")]
    pub fn with_https(mut self, cert_file: &str, key_file: &str) -> Self {
        let certs = CertificateDer::pem_file_iter(cert_file)
            .unwrap()
            .map(|cert| cert.unwrap())
            .collect::<Vec<_>>();

        let key = PrivateKeyDer::from_pem_file(key_file).unwrap();

        let config = ServerConfig::builder()
            .with_no_client_auth()
            .with_single_cert(certs, key)
            .unwrap();

        self.tls_config = Some(Arc::new(config));

        self
    }

    pub fn on_request<F>(&mut self, f: F)
    where
        F: Fn(Request) -> Response + Send + 'static,
    {
        *self.on_request.lock().unwrap() = Some(Box::new(f))
    }
}