use crate::mime;
use crate::server::response;
use crate::server::ServerConfig;
use openssl::ssl::SslStream;
use std::fs::File;
use std::io::{copy, BufRead, BufReader, BufWriter, Error, Write};
use std::net::TcpStream;
use std::path::{Path, PathBuf};
use url::Url;

fn send_header(stream: &mut SslStream<TcpStream>, header: &response::Header) {
    match stream.ssl_write(&header.to_vec()) {
        Ok(_s) => {
            return;
        }
        Err(_e) => {
            return;
        }
    };
}

pub fn handle_request(config: &ServerConfig, mut stream: SslStream<TcpStream>) {
    let mut buffer = [0; 1024];
    match stream.ssl_read(&mut buffer) {
        Ok(s) => {
            if s == 0 || s > 1025 {
                send_header(&mut stream, &response::bad_request());
                return;
            }
        }
        Err(_) => {
            println!("received broken request");
            send_header(&mut stream, &response::bad_request());
            return;
        }
    };

    let request = match String::from_utf8(buffer.to_vec()) {
        Ok(request) => request,
        Err(_) => {
            println!("received empty request string");
            send_header(&mut stream, &response::bad_request());
            return;
        }
    };

    let location = match Url::parse(&request) {
        Ok(url) => url,
        Err(_) => {
            println!("received invalid request url");
            send_header(&mut stream, &response::bad_request());
            return;
        },
    };

    handle_response(config, location, &mut stream);
}

fn gen_path_index(path: &Path) -> PathBuf {
    match path.is_dir() {
        true => path.join("index.gmi"),
        false => PathBuf::from(path),
    }
}

fn write_line<T: Write>(line: &[u8], stream: &mut BufWriter<T>) -> Result<(), Error> {
    stream.write(line)?;
    stream.write(b"\r\n")?;
    Ok(())
}

fn handle_response(config: &ServerConfig, url: Url, mut stream: &mut SslStream<TcpStream>) {
    println!("responding for: {}", url);

    // url scheme must be either "gemini://" or "//" (empty)
    if url.scheme() != "gemini" && url.scheme() != "" {
        send_header(&mut stream, &response::proxy_request_refused());
        return;
    }

    // url request host must match
    if url.host() != config.default_host.host() {
        send_header(&mut stream, &response::proxy_request_refused());
        return;
    }

    // TODO: also drop on incorrect port in request

    let rel_path = match Path::new(url.path()).strip_prefix("/") {
        Ok(path) => path,
        Err(_) => {
            // empty path, gemini spec says to redirect client to root
            send_header(&mut stream, &response::redirect_permanent(
                config.default_host.as_str(),
            ));
            return;
        }
    };

    let path = gen_path_index(&config.gem_root.join(rel_path));

    // make sure we can't escape gem_root
    if !path.starts_with(&config.gem_root) {
        send_header(&mut stream, &response::bad_request());
        return;
    }

    let file = match File::open(&path) {
        Ok(file) => file,
        Err(_) => {
            println!("not found: {:?}", path);
            send_header(&mut stream, &response::not_found());
            return;
        }
    };
    println!("sending file: {:?}", path);

    let mime_type = match path.extension() {
        Some(ext) => mime::get_mime_type(ext),
        None => mime::default_mime_type(),
    };
    let header = response::Header::new(response::Status::Success, mime_type);
    send_header(&mut stream, &header);

    let mut buf_file = BufReader::new(file);
    let mut buf_stream = BufWriter::new(stream);

    if mime_type.starts_with("text/") {
        // We make sure to send all text/* files with correct CL/RF line endings
        for line in buf_file.lines() {
            match write_line(line.unwrap().as_bytes(), &mut buf_stream) {
                Ok(_) => {}
                Err(e) => {
                    println!("error while sending text file: {:?}\n  {}", path, e);
                    return;
                }
            }
        }
    } else {
        // Any other MIME type can just be copied as-is
        match copy(&mut buf_file, &mut buf_stream) {
            Ok(_) => {}
            Err(e) => {
                println!("error while sending file: {:?}\n  {}", path, e);
                return;
            }
        }
    }
}