extern crate getopts;
extern crate pencil;
extern crate modelthing;
extern crate env_logger;
extern crate pulldown_cmark;
extern crate regex;
#[macro_use] extern crate lazy_static;
#[macro_use] extern crate log;

use std::env;
use std::fs::{File, create_dir};
use std::io::Write;
use std::collections::BTreeMap;
use std::path::Path;
use getopts::Options;
use pencil::Pencil;
use pencil::{Request, PencilResult, Response, HTTPError, PencilError};
use pencil::{redirect, abort};
use pencil::method::{Get, Post};
use regex::Regex;
use modelthing::transpile_scheme::TranspileScheme;
use modelthing::transpile_js::TranspileJS;
use modelthing::repr_latex::ReprLaTeX;

/*
This command doesn't use error_chain (or raise errors in general) because the
web framework handles panics as 500 errors automatically.
*/


fn home(r: &mut Request) -> PencilResult {
    let context: BTreeMap<String,String> = BTreeMap::new();
    return r.app.render_template("home.html", &context);
}

fn readme(r: &mut Request) -> PencilResult {
    let mut context = BTreeMap::new();
    let raw_text = include_str!("../../README.txt");
    context.insert("raw_text".to_string(), raw_text.to_string());
    return r.app.render_template("raw.html", &context);
}

fn model_list(r: &mut Request) -> PencilResult {
    let namespace = r.view_args.get("namespace").unwrap();
    if !is_clean_name(namespace) {
        return abort(404);
    }
    if !(namespace == "examples" || namespace == "sandbox") {
        // TODO: check if namespace path exists, else 404
        return abort(404);
    }
    let paths = modelthing::search_models(Path::new(namespace));
    let l: Vec<Vec<String>> = paths.iter()
                              .map(|x| vec![namespace.to_string(),
                                            Path::new(x).strip_prefix(namespace)
                                                        .unwrap()
                                                        .to_string_lossy()
                                                        .to_string()
                                           ])
                              .collect();
    let mut context = BTreeMap::new();
    context.insert("model_slug_list".to_string(), l);
    context.insert("namespace".to_string(), vec![vec![namespace.to_string()]]);
    return r.app.render_template("model_list.html", &context);
}

fn model_view(r: &mut Request) -> PencilResult {
    let namespace = r.view_args.get("namespace").unwrap();
    let model_slug = r.view_args.get("model_slug").unwrap();
    let model_path = Path::new(namespace).join(model_slug);
    match modelthing::load_model_entry(model_path.as_path()) {
        Ok(me) => {
            let mut markdown_html = String::new();
            let p = pulldown_cmark::Parser::new_ext(
                &me.markdown,
                pulldown_cmark::Options::empty());
            pulldown_cmark::html::push_html(&mut markdown_html, p);
            let mut context = BTreeMap::new();
            context.insert("namespace".to_string(), namespace.to_string());
            context.insert("model_slug".to_string(), model_slug.to_string());
            context.insert("model_name".to_string(), me.ast.name.clone());
            context.insert("model_description".to_string(),
                me.ast.description.clone().unwrap_or("".to_string()));
            context.insert("markdown_html".to_string(), markdown_html);
            context.insert("markdown".to_string(), me.markdown.clone());
            context.insert("modelica".to_string(), format!("{:?}", me.ast));
            context.insert("latex".to_string(), me.ast.repr_latex().unwrap());
            context.insert("editable".to_string(),
                if namespace == "sandbox" { "true".to_string() } else { "".to_string() });
            r.app.render_template("model_view.html", &context)
        },
        Err(_) => Err(PencilError::PenHTTPError(pencil::HTTPError::NotFound)),
    }
}

fn model_repr(r: &mut Request) -> PencilResult {
    let namespace = r.view_args.get("namespace").unwrap();
    let model_slug = r.view_args.get("model_slug").unwrap();
    let model_path = Path::new(namespace).join(model_slug);
    let format = r.url
                  .query_pairs()
                  .filter(|x| x.0 == "format")
                  .map(|(_,v)| v.into_owned())
                  .nth(0)
                  .unwrap_or("".to_string());
    let format: &str = &format;
    match modelthing::load_model_entry(model_path.as_path()) {
        Ok(me) => {
            match format {
                "scheme" => Ok(Response::from(me.ast.transpile_scheme().unwrap())),
                "javascript" => Ok(Response::from(me.ast.transpile_js().unwrap())),
                "latex" => Ok(Response::from(me.ast.repr_latex().unwrap())),
                _ => abort(403),
            }
        },
        Err(_) => Err(PencilError::PenHTTPError(pencil::HTTPError::NotFound)),
    }
}

// Sends the modelica file
fn model_raw(r: &mut Request) -> PencilResult {
    let namespace = r.view_args.get("namespace").unwrap();
    let model_slug = r.view_args.get("model_slug").unwrap();
    let model_path = Path::new(namespace).join(model_slug).to_string_lossy().to_string();
    pencil::helpers::send_from_directory(&model_path, "model.modelica", true)
}

// Sends the markdown
fn model_markdown(r: &mut Request) -> PencilResult {
    let namespace = r.view_args.get("namespace").unwrap();
    let model_slug = r.view_args.get("model_slug").unwrap();
    let model_path = Path::new(namespace).join(model_slug).to_string_lossy().to_string();
    pencil::helpers::send_from_directory(&model_path, "page.md", true)
}

fn model_edit(r: &mut Request) -> PencilResult {
    let namespace = r.view_args.get("namespace").unwrap().clone();
    let model_slug = r.view_args.get("model_slug").unwrap().clone();
    let model_path = Path::new(&namespace).join(&model_slug);
    let mut context = BTreeMap::new();
    if namespace != "sandbox" {
        warn!("Tried to write outside of sandbox: {}", namespace);
        return abort(403);
    }
    match modelthing::load_model_entry(model_path.as_path()) {
        Ok(me) => {
            context.insert("namespace".to_string(), namespace.to_string());
            context.insert("model_slug".to_string(), model_slug.to_string());
            context.insert("model_name".to_string(), me.ast.name.clone());
            context.insert("markdown".to_string(), me.markdown.clone());
            context.insert("modelica".to_string(), format!("{:?}", me.ast));
            match r.method {
                Get => {
                    r.app.render_template("model_edit.html", &context)
                },
                Post => {
                    let modelica = r.form().get("modelica").expect("missing form val: modelica").clone();
                    let markdown = r.form().get("markdown").expect("missing form val: markdown").clone();

                    // Check that modelica is valid
                    if let Err(e) = modelthing::modelica_parser::parse_model(&modelica) {
                        error!("Modelica code not valid: {:?}", e);
                        return abort(500);
                    };

                    {
                        // overwrite existing
                        let mut f = File::create(format!("{}/{}/page.md", namespace, model_slug))
                            .expect("unable to create wiki file");
                        f.write_all(markdown.as_bytes()).expect("unable to write wiki file");
                    }
                    {
                        // overwrite existing
                        let mut f = File::create( format!("{}/{}/model.modelica", namespace, model_slug))
                            .expect("unable to create modelicafile");
                        f.write_all(modelica.as_bytes()).expect("unable to write modelica file");
                    }
                    redirect(&format!("/m/{}/{}/", namespace, model_slug), 301)
                },
                _ => {
                    warn!("Invalid method attempted");
                    abort(404)
                },
            }
        },
        Err(_) => Err(PencilError::PenHTTPError(pencil::HTTPError::NotFound)),
    }
}

fn is_clean_name(s: &str) -> bool {
    lazy_static! {
        static ref RE: Regex = Regex::new(r"^[0-9A-Za-z_-]+$").unwrap();
    }
    RE.is_match(s)
}

#[test]
fn test_is_clean_name() {
    assert_eq!(is_clean_name("name"), true);
    assert_eq!(is_clean_name("name.two"), false);
    assert_eq!(is_clean_name("name/thing"), false);
    assert_eq!(is_clean_name("unicode_α"), false);
    assert_eq!(is_clean_name("name_thing"), true);
    assert_eq!(is_clean_name("name-thing"), true);
    assert_eq!(is_clean_name("1234"), true);
}

fn model_create(r: &mut Request) -> PencilResult {
    let context: BTreeMap<String,String> = BTreeMap::new();
    match r.method {
        Get => {
            r.app.render_template("model_create.html", &context)
        },
        Post => {
            let namespace = r.form().get("namespace").expect("missing form val: namespace").clone();
            let model_slug = r.form().get("model_slug").expect("missing form val: model_slug").clone();
            if namespace != "sandbox" {
                warn!("Tried to write outside of sandbox: {}", namespace);
                return abort(403);
            }
            if !(is_clean_name(&namespace) && is_clean_name(&model_slug)) {
                warn!("Unclean: {} or {}", namespace, model_slug);
                return abort(404);
            }

            let modelica = &format!(
                "model {}\n\n\"blank description, edit me\"\n\tReal a;\nequation\n\ta = 1;\nend {};\n",
                model_slug,
                model_slug);
            let wiki_text = "blank wikitext; edit me!";

            // Check that modelica is valid
            if let Err(e) = modelthing::modelica_parser::parse_model(modelica) {
                error!("Modelica code not valid: {:?}", e);
                return abort(500);
            };

            // Ensure that namespace directory exists
            if let Err(e) = create_dir(format!("{}", namespace)) {
                error!("Couldn't create namespace diectory: {:?}", e);
                return abort(500);
            };

            if let Err(e) = create_dir(format!("{}/{}", namespace, model_slug)) {
                error!("Couldn't create model diectory: {:?}", e);
                return abort(500);
            };

            {
                let mut f = File::create(format!("{}/{}/page.md", namespace, model_slug))
                    .expect("unable to create wiki file");
                f.write_all(wiki_text.as_bytes()).expect("unable to write wiki file");
            }
            {
                let mut f = File::create( format!("{}/{}/model.modelica", namespace, model_slug))
                    .expect("unable to create modelicafile");
                f.write_all(modelica.as_bytes()).expect("unable to write modelica file");
            }
            redirect(&format!("/m/{}/{}/", namespace, model_slug), 301)
        },
        _ => {
            warn!("Invalid method attempted");
            abort(404)
        },
    }
}

fn page_not_found(_: HTTPError) -> PencilResult {
    let mut response = Response::from("404: Not Found");
    response.status_code = 404;
    Ok(response)
}

fn server_error(_: HTTPError) -> PencilResult {
    let mut response = Response::from("500: Server Error");
    response.status_code = 500;
    Ok(response)
}

fn print_usage(opts: Options) {
    let brief = "usage:\tmt-webface [options]";
    println!("");
    print!("{}", opts.usage(&brief));
}

fn main() {

    let args: Vec<String> = env::args().collect();

    let mut opts = Options::new();
    opts.optflag("h", "help", "print this help menu");
    opts.optflag("b", "bind", "local IP:port to bind to");
    opts.optflag("", "version", "print the version");

    let matches = match opts.parse(&args[1..]) {
        Ok(m) => m,
        Err(f) => {
            println!("{}\n", f.to_string());
            print_usage(opts);
            ::std::process::exit(-1);
        }
    };

    if matches.opt_present("help") {
        print_usage(opts);
        return;
    }

    if matches.opt_present("version") {
        println!("modelthing {}", env!("CARGO_PKG_VERSION"));
        return;
    }

    env_logger::init().unwrap();

    let mut app = Pencil::new("webface");
    app.name = "modelthing-webface".to_string();
    app.set_debug(true);
    app.set_log_level();
    app.httperrorhandler(404, page_not_found);
    app.httperrorhandler(500, server_error);
    app.enable_static_file_handling();
    debug!("root_path: {}", app.root_path);

    app.register_template("base.html");
    app.register_template("home.html");
    app.register_template("raw.html");
    app.get("/", "home", home);
    app.get("/readme/", "readme", readme);
    app.register_template("model_list.html");
    app.get("/m/<namespace:string>/", "model_list", model_list);
    app.register_template("model_view.html");
    app.get("/m/<namespace:string>/<model_slug:string>/", "model_view", model_view);
    app.get("/m/<namespace:string>/<model_slug:string>/raw/", "model_raw", model_raw);
    app.get("/m/<namespace:string>/<model_slug:string>/repr/", "model_repr", model_repr);
    app.get("/m/<namespace:string>/<model_slug:string>/markdown/", "model_markdown", model_markdown);
    app.register_template("model_create.html");
    app.route("/create/", &[Get, Post], "model_create", model_create);
    app.register_template("model_edit.html");
    app.route("/m/<namespace:string>/<model_slug:string>/edit/", &[Get, Post], "model_edit", model_edit);

    let bind = matches.opt_str("bind").unwrap_or("127.0.0.1:5000".to_string());
    let bind_str: &str = &bind;
    info!("Running on {}", bind);
    app.run(bind_str);
}