use std::io::{Read, Result, Write};
use std::net::TcpStream;
use std::net::ToSocketAddrs;
use std::os::unix::fs::OpenOptionsExt;
use std::time::Duration;
use termion::input::TermRead;

// Some Gopher servers can be kind of slow, we may want to up this or
// make it configurable eventually.
pub const TCP_TIMEOUT_IN_SECS: u64 = 8;
pub const TCP_TIMEOUT_DURATION: Duration = Duration::from_secs(TCP_TIMEOUT_IN_SECS);

#[derive(Copy, Clone, PartialEq, Debug)]
pub enum Type {
    Text,       // 0 | 96 | cyan
    Menu,       // 1 | 94 | blue
    CSOEntity,  // 2 |    | white background
    Error,      // 3 | 91 | red
    Binhex,     // 4 |  4 | white underline
    DOSFile,    // 5 |  4 | white underline
    UUEncoded,  // 6 |  4 | white underline
    Search,     // 7 |  0 | white
    Telnet,     // 8 | 90 | gray underline
    Binary,     // 9 |  4 | white underline
    Mirror,     // + |    | white background
    GIF,        // g |  4 | white underline
    Telnet3270, // T |    | white background
    HTML,       // h | 92 | green
    Image,      // I |  4 | white underline
    PNG,        // p |  4 | white underline
    Info,       // i | 93 | yellow
    Sound,      // s |  4 | white underline
    Document,   // d |  4 | white underline
}

impl Type {
    pub fn is_download(self) -> bool {
        match self {
            Type::Binhex
            | Type::DOSFile
            | Type::UUEncoded
            | Type::Binary
            | Type::GIF
            | Type::Image
            | Type::PNG
            | Type::Sound
            | Type::Document => true,
            _ => false,
        }
    }
}

impl Type {
    pub fn char(&self) -> Option<char> {
        Some(match self {
            Type::Text => '0',
            Type::Menu => '1',
            Type::CSOEntity => '2',
            Type::Error => '3',
            Type::Binhex => '4',
            Type::DOSFile => '5',
            Type::UUEncoded => '6',
            Type::Search => '7',
            Type::Telnet => '8',
            Type::Binary => '9',
            Type::Mirror => '+',
            Type::GIF => 'g',
            Type::Telnet3270 => 'T',
            Type::HTML => 'h',
            Type::Image => 'I',
            Type::PNG => 'p',
            Type::Info => 'i',
            Type::Sound => 's',
            Type::Document => 'd',
        })
    }

    pub fn from(c: char) -> Option<Type> {
        Some(match c {
            '0' => Type::Text,
            '1' => Type::Menu,
            '2' => Type::CSOEntity,
            '3' => Type::Error,
            '4' => Type::Binhex,
            '5' => Type::DOSFile,
            '6' => Type::UUEncoded,
            '7' => Type::Search,
            '8' => Type::Telnet,
            '9' => Type::Binary,
            '+' => Type::Mirror,
            'g' => Type::GIF,
            'T' => Type::Telnet3270,
            'h' => Type::HTML,
            'I' => Type::Image,
            'p' => Type::PNG,
            'i' => Type::Info,
            's' => Type::Sound,
            'd' => Type::Document,
            _ => return None,
        })
    }
}

// Fetches a gopher URL and returns a raw Gopher response.
pub fn fetch_url(url: &str) -> Result<String> {
    let (_, host, port, sel) = parse_url(url);
    fetch(host, port, sel)
}

// Fetches a gopher URL by its component parts and returns a raw Gopher response.
pub fn fetch(host: &str, port: &str, selector: &str) -> Result<String> {
    get(host, port, selector).and_then(|mut stream| {
        let mut body = String::new();
        stream.read_to_string(&mut body)?;
        Ok(body)
    })
}

// Downloads a binary to disk. Allows canceling with Ctrl-c.
// Returns the path it was saved to and the size in bytes.
pub fn download_url(url: &str) -> Result<(String, usize)> {
    let (_, host, port, sel) = parse_url(url);
    let filename = sel
        .split_terminator('/')
        .rev()
        .nth(0)
        .ok_or_else(|| error!("Bad download filename: {}", sel))?;
    let mut path = std::path::PathBuf::from(".");
    path.push(filename);
    let stdin = termion::async_stdin();
    let mut keys = stdin.keys();

    get(host, port, sel).and_then(|mut stream| {
        let mut file = std::fs::OpenOptions::new()
            .write(true)
            .create(true)
            .truncate(true)
            .mode(0o770)
            .open(path)?;

        let mut buf = [0; 1024];
        let mut bytes = 0;
        while let Ok(count) = stream.read(&mut buf) {
            if count == 0 {
                break;
            }
            bytes += count;
            file.write(&buf[..count]);
            if let Some(Ok(termion::event::Key::Ctrl('c'))) = keys.next() {
                return Err(error!("Download canceled"));
            }
        }
        Ok((filename.to_string(), bytes))
    })
}

// Make a Gopher request and return a TcpStream ready to be read()'d.
pub fn get(host: &str, port: &str, selector: &str) -> Result<TcpStream> {
    let selector = selector.replace('?', "\t"); // search queries
    format!("{}:{}", host, port)
        .to_socket_addrs()
        .and_then(|mut socks| socks.next().ok_or_else(|| error!("Can't create socket")))
        .and_then(|sock| TcpStream::connect_timeout(&sock, TCP_TIMEOUT_DURATION))
        .and_then(|mut stream| {
            stream.set_read_timeout(Some(TCP_TIMEOUT_DURATION))?;
            stream.write(format!("{}\r\n", selector).as_ref());
            Ok(stream)
        })
}

// Parses gopher URL into parts.
// Return (Type, host, port, sel)
pub fn parse_url(url: &str) -> (Type, &str, &str, &str) {
    let url = url.trim_start_matches("gopher://");

    // simple URLs, ex: "dog.com"
    if !url.contains(':') && !url.contains('/') {
        return (Type::Menu, url, "70", "/");
    }

    // non-gopher URLs, stick everything in selector
    if url.contains("://") {
        return (Type::HTML, "", "", url);
    }

    let mut typ = Type::Menu;
    let mut host;
    let mut port = "70";
    let mut sel = "/";

    // check selector first
    if let Some(idx) = url.find('/') {
        host = &url[..idx];
        sel = &url[idx..];
    } else {
        host = &url;
    }

    // ipv6
    if let Some(idx) = host.find('[') {
        if let Some(end) = host[idx + 1..].find(']') {
            host = &host[idx + 1..end + 1];
            if host.len() > end {
                if let Some(idx) = host[end..].find(':') {
                    port = &host[idx + 1..];
                }
            }
        } else {
            return (Type::Error, "Unclosed ipv6 bracket", "", url);
        }
    } else if let Some(idx) = host.find(':') {
        // two :'s == probably ipv6
        if host.len() > idx + 1 && !host[idx + 1..].contains(':') {
            // regular hostname w/ port -- grab port
            port = &host[idx + 1..];
            host = &host[..idx];
        }
    }

    // ignore type prefix on selector
    let mut chars = sel.chars();
    if let (Some('/'), Some(c), Some('/')) = (chars.nth(0), chars.nth(0), chars.nth(0)) {
        if let Some(t) = Type::from(c) {
            typ = t;
            sel = &sel[2..];
        }
    }

    (typ, host, port, sel)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_simple_parse() {
        let urls = vec![
            "gopher://gopher.club/1/phlogs/",
            "gopher://sdf.org:7777/1/maps",
            "gopher.floodgap.org",
            "gopher.floodgap.com/0/gopher/relevance.txt",
            "gopher://gopherpedia.com/7/lookup?Gopher",
            "gopher://dead:beef:1234:5678:9012:3456:feed:deed",
            "gopher://[1234:2345:dead:4567:7890:1234:beef:1111]:7443/1/files",
            "gopher://2001:cdba:0000:0000:0000:0000:3257:9121",
            "[2001:cdba::3257:9652]",
            "gopher://9999:aaaa::abab:baba:aaaa:9999",
            "[2001:2099:dead:beef:0000",
            "::1",
            "ssh://kiosk@bitreich.org",
            "https://github.com/dvkt/phetch",
        ];

        let (typ, host, port, sel) = parse_url(urls[0]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "gopher.club");
        assert_eq!(port, "70");
        assert_eq!(sel, "/phlogs/");

        let (typ, host, port, sel) = parse_url(urls[1]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "sdf.org");
        assert_eq!(port, "7777");
        assert_eq!(sel, "/maps");

        let (typ, host, port, sel) = parse_url(urls[2]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "gopher.floodgap.org");
        assert_eq!(port, "70");
        assert_eq!(sel, "/");

        let (typ, host, port, sel) = parse_url(urls[3]);
        assert_eq!(typ, Type::Text);
        assert_eq!(host, "gopher.floodgap.com");
        assert_eq!(port, "70");
        assert_eq!(sel, "/gopher/relevance.txt");

        let (typ, host, port, sel) = parse_url(urls[4]);
        assert_eq!(typ, Type::Search);
        assert_eq!(host, "gopherpedia.com");
        assert_eq!(port, "70");
        assert_eq!(sel, "/lookup?Gopher");

        let (typ, host, port, sel) = parse_url(urls[5]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "dead:beef:1234:5678:9012:3456:feed:deed");
        assert_eq!(port, "70");
        assert_eq!(sel, "/");

        let (typ, host, port, sel) = parse_url(urls[6]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "1234:2345:dead:4567:7890:1234:beef:1111");
        assert_eq!(port, "70");
        assert_eq!(sel, "/files");

        let (typ, host, port, sel) = parse_url(urls[7]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "2001:cdba:0000:0000:0000:0000:3257:9121");
        assert_eq!(port, "70");
        assert_eq!(sel, "/");

        let (typ, host, port, sel) = parse_url(urls[8]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "2001:cdba::3257:9652");
        assert_eq!(port, "70");
        assert_eq!(sel, "/");

        let (typ, host, port, sel) = parse_url(urls[9]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "9999:aaaa::abab:baba:aaaa:9999");
        assert_eq!(port, "70");
        assert_eq!(sel, "/");

        let (typ, host, port, sel) = parse_url(urls[10]);
        assert_eq!(typ, Type::Error);
        assert_eq!(host, "Unclosed ipv6 bracket");
        assert_eq!(port, "");
        assert_eq!(sel, "[2001:2099:dead:beef:0000");

        let (typ, host, port, sel) = parse_url(urls[11]);
        assert_eq!(typ, Type::Menu);
        assert_eq!(host, "::1");
        assert_eq!(port, "70");
        assert_eq!(sel, "/");

        let (typ, host, port, sel) = parse_url(urls[12]);
        assert_eq!(typ, Type::HTML);
        assert_eq!(host, "");
        assert_eq!(port, "");
        assert_eq!(sel, "ssh://kiosk@bitreich.org");

        let (typ, host, port, sel) = parse_url(urls[13]);
        assert_eq!(typ, Type::HTML);
        assert_eq!(host, "");
        assert_eq!(port, "");
        assert_eq!(sel, "https://github.com/dvkt/phetch");
    }
}
