use std::{
    collections::{hash_map::Entry, HashMap},
    env,
    fs::File,
    io::{prelude::*, BufReader},
    net::{TcpListener, TcpStream},
};

use maud::html;
use percent_encoding::percent_decode_str;
use pukram2html::{convert, convert_extended, convert_subheader, Settings};

mod request;
use request::Request;

fn main() {
    let mut context = Context::default();
    let mut args = env::args();
    args.next();
    let address = args.next().unwrap_or("127.0.0.1:8080".to_string());
    let listener = TcpListener::bind(address).expect("Invalid bind address!");
    eprintln!("Strated server!");

    for stream in listener.incoming() {
        eprintln!("New connection!");

        let Ok(stream) = stream else {
            eprintln!("Connection failed!");
            continue;
        };

        context.handle_connection(stream);
    }
}

fn fail(mut stream: TcpStream) {
    let _ = write!(stream, "HTTP/1.1 404 Not Found\r\n\r\n");
    let _ = writeln!(stream, "Page not found!");
}

struct Comment {
    name: Box<str>,
    text: Box<str>,
}

#[derive(Default)]
struct SiteInfo {
    comments: Vec<Comment>,
    visits: usize,
}

#[derive(Default)]
struct Context {
    infos: HashMap<Box<str>, SiteInfo>,
}

impl Context {
    fn handle_connection(&mut self, mut stream: TcpStream) {
        let Some(request) = Request::from(&stream) else {
            eprintln!("Invalid request!");
            return;
        };

        eprintln!();
        eprintln!("Request:");
        eprintln!("- Method: {}", request.method);
        eprintln!("- Path: {}", request.path);
        eprintln!("- Version: {}", request.version);
        eprintln!("- Headers:");
        for header in request.headers {
            eprintln!("  - {header}");
        }
        eprintln!("- Body: {}", request.body);
        eprintln!();

        let Ok(current_dir) = env::current_dir() else {
            fail(stream);
            return;
        };

        let mut path = current_dir;

        let (relative_path, _) = request
            .path
            .split_once('?')
            .unwrap_or((&request.path, Default::default()));

        if relative_path.contains("//") {
            fail(stream);
            return;
        }

        let relative_path = if relative_path.is_empty() {
            String::new()
        } else {
            let path = percent_decode_str(&relative_path[1..]).decode_utf8_lossy();
            if path.contains('_') {
                let path = path.replace('_', " ");
                let _ = write!(stream, "HTTP/1.1 308 Permanent Redirect\r\n");
                let _ = write!(stream, "Location: /{path}\r\n\r\n");
                return;
            }
            path.to_string()
        };

        let (pk_file, pki_file, start_level) = if !relative_path.is_empty() {
            path.push(&relative_path);
            let (pk_extension, pki_extension) = if let Some(extension) = path.extension() {
                (format!("{extension:?}.pk"), format!("{extension:?}.pki"))
            } else {
                ("pk".to_string(), "pki".to_string())
            };
            let pk_path = path.with_extension(pk_extension);
            let pki_path = path.with_extension(pki_extension);

            let (Ok(pk_file), Ok(pki_file)) = (File::open(pk_path), File::open(pki_path)) else {
                fail(stream);
                return;
            };

            (pk_file, Some(pki_file), 1)
        } else {
            let mut pk_path = path.clone();
            pk_path.push("index.pk");

            let Ok(pk_file) = File::open(pk_path) else {
                fail(stream);
                return;
            };

            (pk_file, None, 0)
        };

        use Entry::*;
        let info = match self.infos.entry(relative_path.clone().into_boxed_str()) {
            Occupied(o) => o.into_mut(),
            Vacant(v) => v.insert(SiteInfo::default()),
        };

        let mut entries = request.body.split('&');
        if let (Some(name_entry), Some(text_entry), None) =
            (entries.next(), entries.next(), entries.next())
        {
            if let (Some(("name", input_name)), Some(("text", input_text))) =
                (name_entry.split_once('='), text_entry.split_once('='))
            {
                let name_value = input_name.replace('+', " ");
                let decoded_name = percent_decode_str(&name_value).decode_utf8_lossy();
                eprintln!("Received comment by \"{decoded_name}\":");
                let name = decoded_name
                    .replace('&', "&amp;")
                    .replace('<', "&lt;")
                    .replace('>', "&gt;")
                    .into();

                let text_value = input_text.replace('+', " ");
                let decoded_text = percent_decode_str(&text_value).decode_utf8_lossy();
                for line in decoded_text.lines() {
                    eprintln!("  {line}");
                }
                eprintln!();
                let mut text_buf = Vec::new();
                convert(decoded_text.lines(), &mut text_buf);
                let text = std::str::from_utf8(text_buf.as_slice())
                    .unwrap_or_default()
                    .into();

                info.comments.push(Comment { name, text });
            }
        }

        info.visits += 1;

        let _ = write!(stream, "HTTP/1.1 200 OK\r\n\r\n");

        let _ = writeln!(stream, "<meta charset=\"utf-8\">");

        let _ = writeln!(stream, "<p>👁️{}</p>", info.visits);

        let title = relative_path
            .rsplit_once('/')
            .map(|(_, title)| title)
            .unwrap_or(&relative_path);
        if !title.is_empty() {
            let _ = writeln!(stream, "<h1>{title}</h1>");
        }

        let path_ref = &path;

        let handle_entry = |entry: &str, output: &mut TcpStream, level: usize| {
            let level = level + 1;
            let mut path = path_ref.clone();
            let entry = if let Some((entry, _)) = entry.split_once(':') {
                entry
            } else {
                entry
            };
            path.push(entry);
            let extension = if let Some(extension) = path.extension() {
                format!("{extension:?}.pki")
            } else {
                "pki".to_string()
            };
            path.set_extension(extension);
            let Ok(file) = File::open(path) else {
                return;
            };
            let _ = writeln!(
                output,
                "<h{level}><a href=\"{relative_path}/{entry}\">{entry}</a></h{level}>"
            );
            convert_subheader(
                BufReader::new(file)
                    .lines()
                    .map(|line| line.unwrap_or_default()),
                output,
                level,
            );
        };

        convert_extended(
            BufReader::new(pk_file)
                .lines()
                .map(|line| line.unwrap_or_default()),
            &mut stream,
            Settings::default()
                .with_handler(handle_entry)
                .with_start_level(start_level)
                .with_use_textboxes(true),
        );

        let parent_path = relative_path
            .rsplit_once('/')
            .map(|(path, _)| path)
            .unwrap_or_default();

        let _ = writeln!(stream, "<hr>");
        let _ = writeln!(stream, "<a href=\"/{parent_path}\">&lt;&lt; Back</a>");

        if let Some(pki_file) = pki_file {
            let _ = writeln!(stream, "<h1>Description</h1>");

            convert_subheader(
                BufReader::new(pki_file)
                    .lines()
                    .map(|line| line.unwrap_or_default()),
                &mut stream,
                1,
            );

            let _ = writeln!(stream, "<hr>");
            let _ = writeln!(stream, "<a href=\"/{parent_path}\">&lt;&lt; Back</a>");
        }

        let html = html! {
            h1 { "Comments" }
            form method="POST" {
                input type="text" name="name" value="anon" placeholder="Name";
                br;
                textarea rows="5" cols="60" name="text" placeholder="Enter comment..." {}
                br;
                input type="submit" value="Send!";
            }
        };
        let _ = stream.write_all(html.into_string().as_bytes());

        for Comment { name, text } in &info.comments {
            let _ = writeln!(stream, "<fieldset><legend>{name}</legend>{text}</fieldset>");
        }

        let _ = writeln!(stream, "<hr>");
        let _ = writeln!(stream, "<a href=\"/{parent_path}\">&lt;&lt; Back</a>");
    }
}