use std::{net::TcpListener, process, rc::Rc};

use ctrlc;
use http::responses::{Body, Response};

use resvg::{
    tiny_skia::{Color, Pixmap, Transform},
    usvg,
};

mod handlers;
mod http;
mod icons;

fn main() {
    println!("luciders starting...");

    let listener =
        TcpListener::bind("[::]:7878").unwrap_or_else(|_| fatal("Failed to bind to address"));

    ctrlc::set_handler(move || {
        println!("Shutting down...");
        process::exit(0);
    })
    .unwrap_or_else(|_| fatal("Failed to set termination signal handler"));

    let icons_rc = Rc::new(match icons::Icons::build() {
        Ok(icons) => icons,
        Err(e) => fatal(e),
    });

    let mut handlers = handlers::Handlers::new();

    handlers.add_handler("/", |req| {
        if req.method != "GET" {
            return Response::new(req, 405, Body::Static("Method Not Allowed"));
        }

        Response::new(req, 200, Body::Static("OK - luciders is running"))
    });

    handlers.add_handler("/icons/[icon].svg", {
        let icons = Rc::clone(&icons_rc);
        move |req| {
            if req.method != "GET" {
                return Response::new(req, 405, Body::Static("Method Not Allowed"));
            }

            let icon_filename = match req.url.get_path_segment(1) {
                Some(icon) => icon,
                None => return Response::new(req, 404, Body::Static("Icon Segment Not Found")),
            };

            let icon_name = &icon_filename[..icon_filename.len() - icons::ICON_FILE_EXTENSION_LEN];

            if !icons.has_iconname(icon_name) {
                return Response::new(req, 404, Body::Static("Icon Not Found"));
            }

            let icon = match icons.get_icon(icon_name) {
                Some(icon) => icon,
                None => return Response::new(req, 500, Body::Static("Failed to read icon")),
            };

            return Response::new(req, 200, Body::Bytes(icon, "image/svg+xml"));
        }
    });

    handlers.add_handler("/icons/[icon].png", {
        let icons = Rc::clone(&icons_rc);
        move |req| {
            if req.method != "GET" {
                return Response::new(req, 405, Body::Static("Method Not Allowed"));
            }

            let icon_filename = match req.url.get_path_segment(1) {
                Some(icon) => icon,
                None => return Response::new(req, 404, Body::Static("Icon Segment Not Found")),
            };

            let icon_name = &icon_filename[..icon_filename.len() - icons::ICON_FILE_EXTENSION_LEN];

            if !icons.has_iconname(icon_name) {
                return Response::new(req, 404, Body::Static("Icon Not Found"));
            }

            let icon = match icons.get_icon(icon_name) {
                Some(icon) => icon,
                None => return Response::new(req, 500, Body::Static("Failed to read icon")),
            };

            let tree = match usvg::Tree::from_data(&icon, &usvg::Options::default()) {
                Ok(tree) => tree,
                Err(_) => {
                    return Response::new(req, 500, Body::Static("Failed to load icon into tree"))
                }
            };

            // Options handling
            let mut scale = 1;
            match req.url.query.get("scale") {
                Some(scale_str) => {
                    match scale_str.parse::<u32>() {
                        Ok(scale_val) => {
                            if scale_val <= 0 || scale_val > 100 {
                                return Response::new(req, 400, Body::Static("Invalid scale value. Scale value must be an integer > 0 and <= 100"));
                            }
                            scale = scale_val;
                        }
                        Err(_) => {
                            return Response::new(req, 400, Body::Static("Invalid scale value. Scale value must be an integer > 0 and <= 100"));
                        }
                    }
                }
                None => {}
            }

            let mut padding = 0;
            match req.url.query.get("padding") {
                Some(padding_str) => {
                    match padding_str.parse::<u32>() {
                        Ok(padding_val) => {
                            if padding_val > 100 {
                                return Response::new(req, 400, Body::Static("Invalid padding value. Padding value must be an integer >= 0 and <= 100"));
                            }

                            padding = padding_val;
                        }
                        Err(_) => {
                            return Response::new(req, 400, Body::Static("Invalid padding value. Padding value must be an integer >= 0 and <= 100"));
                        }
                    }
                }
                None => {}
            }

            let mut background = Color::TRANSPARENT;
            match req.url.query.get("background") {
                Some(background_str) => {
                    match u32::from_str_radix(&background_str, 16) {
                        Ok(background_val) => {
                            if background_val > 0xFFFFFF {
                                return Response::new(req, 400, Body::Static("Invalid background value. Background value must be a valid hex color 000000 - FFFFFF"));
                            }
                            let red = ((background_val >> 16) & 0xFF) as u8;
                            let green = ((background_val >> 8) & 0xFF) as u8;
                            let blue = (background_val & 0xFF) as u8;
                            background = Color::from_rgba8(red, green, blue, 255);
                        }
                        Err(_) => {
                            return Response::new(req, 400, Body::Static("Invalid background value. Background value must be a valid hex color"));
                        }
                    }
                }
                None => {}
            }

            let length = 24 * scale + padding;

            let mut pixmap = match Pixmap::new(length, length) {
                Some(pixmap) => pixmap,
                None => return Response::new(req, 500, Body::Static("Failed to create pixmap")),
            };

            let mut pixmap_mut = pixmap.as_mut();
            pixmap_mut.fill(background);

            resvg::render(
                &tree,
                    Transform::from_scale(scale as f32, scale as f32)
                    .post_concat(Transform::from_translate(length as f32 / 2.0 - 12.0 * scale as f32, length as f32 / 2.0 - 12.0 * scale as f32)),
                &mut pixmap_mut,
            );
            let png = match pixmap.encode_png() {
                Ok(png) => png,
                Err(_) => return Response::new(req, 500, Body::Static("Failed to encode PNG")),
            };

            return Response::new(req, 200, Body::Bytes(png, "image/png"));
        }
    });

    handlers.bind(listener);
}

fn fatal(msg: &'static str) -> ! {
    eprintln!("[FATAL] {}", msg);
    process::exit(1);
}

fn error(msg: &'static str) {
    eprintln!("[ERROR] {}", msg);
}