#[macro_use]
extern crate lazy_static;

extern crate native_tls;
extern crate regex;

use cursive::align::HAlign;
use cursive::theme::Effect;
use cursive::traits::*;
use cursive::utils::markup::StyledString;
use cursive::view::Scrollable;
use cursive::views::{Dialog, EditView, Panel, SelectView};
use cursive::Cursive;

use std::str::FromStr;
use url::Url;

mod status;
use status::Status;

mod link;
use link::Link;

mod content;
mod history;

const HELP: &str = "Welcome to Asuka Gemini browser!

Press g to visit an URL
Press h to show/hide history
Press q to exit
";

fn main() {
    history::init();

    let mut siv = Cursive::default();

    let mut select = SelectView::new();

    select.add_all_str(HELP.lines());
    select.set_on_submit(|s, link| {
        follow_link(s, link);
    });

    siv.add_fullscreen_layer(
        Dialog::around(Panel::new(
            select.with_id("main").scrollable().full_screen(),
        ))
        .title("Asuka Browser")
        .h_align(HAlign::Center)
        .button("Quit", |s| s.quit())
        .with_id("container"),
    );

    // We can quit by pressing q
    siv.add_global_callback('q', |s| s.quit());
    // pressing g prompt for an URL
    siv.add_global_callback('g', |s| prompt_for_url(s));
    // pressing h shows/hides history
    siv.add_global_callback('h', |s| show_history(s));

    siv.run();
}

fn prompt_for_url(s: &mut Cursive) {
    s.add_layer(
        Dialog::new()
            .title("Enter URL")
            // Padding is (left, right, top, bottom)
            .padding((1, 1, 1, 0))
            .content(EditView::new().on_submit(goto_url).fixed_width(20))
            .with_id("url_popup"),
    );
}

fn goto_url(s: &mut Cursive, url: &str) {
    // Prepend gemini scheme if needed
    if url.starts_with("gemini://") {
        visit_url(s, &Url::parse(url).unwrap())
    } else {
        let url = format!("gemini://{}", url);
        visit_url(s, &Url::parse(&url).unwrap())
    };
}

fn show_history(s: &mut Cursive) {
    // Hide popup when pressing h on an opened popup
    if s.find_id::<Dialog>("history_popup").is_some() {
        s.pop_layer();
        return;
    }

    let mut select = SelectView::new();

    for url in history::content() {
        let url_s = url.as_str();
        select.add_item_str(url_s);
    }

    select.set_on_submit(|s, link| {
        s.pop_layer();
        follow_link(s, link);
    });

    s.add_layer(
        Dialog::around(select.scrollable().fixed_size((50, 10)))
            .title("History")
            .with_id("history_popup"),
    );
}

fn visit_url(s: &mut Cursive, url: &Url) {
    // Close URL popup if any
    if s.find_id::<Dialog>("url_popup").is_some() {
        s.pop_layer();
    }

    match make_absolute(url.as_str()) {
        Ok(url) => match content::get_data(&url) {
            Ok(new_content) => {
                history::append(url.as_str());
                draw_content(s, url, new_content);
            }
            Err(msg) => {
                s.add_layer(Dialog::info(msg));
            }
        },
        Err(_) => {
            s.add_layer(Dialog::info(format!("Could not parse {}", url.as_str())));
        }
    }
}

fn draw_content(s: &mut Cursive, url: Url, content: String) {
    let mut main_view = s.find_id::<SelectView>("main").unwrap();
    let mut container = s.find_id::<Dialog>("container").unwrap();

    // handle response status
    if let Some(status_line) = content.lines().next() {
        if let Ok(status) = Status::from_str(status_line) {
            match status {
                Status::Success(_meta) => {}
                Status::Gone(_meta) => {
                    s.add_layer(Dialog::info("Sorry page is gone."));
                    return;
                }
                Status::RedirectTemporary(new_url) | Status::RedirectPermanent(new_url) => {
                    follow_link(s, &new_url)
                }
                Status::TransientCertificateRequired(_meta)
                | Status::AuthorisedCertificatedRequired(_meta) => {
                    s.add_layer(Dialog::info(
                        "You need a valid certificate to access this page.",
                    ));
                    return;
                }
                other_status => {
                    s.add_layer(Dialog::info(format!("ERROR: {:?}", other_status)));
                    return;
                }
            }
        }
    }

    // set title and clear old content
    container.set_title(url.as_str());
    main_view.clear();

    // draw new content lines
    for line in content.lines().skip(1) {
        match Link::from_str(line) {
            Ok(link) => match link {
                Link::Http(_url, label) => {
                    let mut formatted = StyledString::new();
                    let www_label = format!("[WWW] {}", label);
                    formatted.append(StyledString::styled(www_label, Effect::Italic));

                    main_view.add_item(formatted, String::from("0"))
                }
                Link::Gopher(_url, label) => {
                    let mut formatted = StyledString::new();
                    let gopher_label = format!("[Gopher] {}", label);
                    formatted.append(StyledString::styled(gopher_label, Effect::Italic));

                    main_view.add_item(formatted, String::from("0"))
                }
                Link::Gemini(url, label) => {
                    let mut formatted = StyledString::new();
                    formatted.append(StyledString::styled(label, Effect::Underline));

                    main_view.add_item(formatted, url.to_string())
                }
                Link::Relative(url, label) => {
                    let mut formatted = StyledString::new();
                    formatted.append(StyledString::styled(label, Effect::Underline));

                    main_view.add_item(formatted, url.to_string())
                }
                Link::Unknown(_, _) => (),
            },
            Err(_) => main_view.add_item(str::replace(line, "\t", "    "), String::from("0")),
        }
    }
}

fn is_gemini_link(line: &str) -> bool {
    line != "0"
}

fn follow_link(s: &mut Cursive, line: &str) {
    if is_gemini_link(line) {
        let next_url = make_absolute(line).expect("Not an URL");
        visit_url(s, &next_url)
    }
}

fn make_absolute(url: &str) -> Result<url::Url, url::ParseError> {
    // Creates an absolute link if needed
    match history::get_current_host() {
        Some(host) => {
            if url.starts_with("gemini://") {
                Url::parse(url)
            } else if url.starts_with('/') {
                Url::parse(&format!("gemini://{}{}", host, url))
            } else {
                Url::parse(&format!("gemini://{}/{}", host, url))
            }
        }
        None => {
            if url.starts_with("gemini://") {
                Url::parse(url)
            } else {
                Url::parse(&format!("gemini://{}", url))
            }
        }
    }
}