use std::collections::HashMap;
use std::sync::{Arc, RwLock};

use color_eyre::Result;
use futures_signals::signal::{Mutable, MutableSignalCloned};
use tracing::error;
use zbus::blocking::Connection;
use zbus::zvariant::ObjectPath;

use crate::clients::networkmanager::dbus::{
    ActiveConnectionDbusProxyBlocking, DbusProxyBlocking, DeviceDbusProxyBlocking,
};
use crate::clients::networkmanager::state::{
    determine_cellular_state, determine_vpn_state, determine_wifi_state, determine_wired_state,
    CellularState, State, VpnState, WifiState, WiredState,
};
use crate::{
    read_lock, register_fallible_client, spawn_blocking, spawn_blocking_result, write_lock,
};

mod dbus;
pub mod state;

type PathMap<'l, ValueType> = HashMap<ObjectPath<'l>, ValueType>;

#[derive(Debug)]
pub struct Client(Arc<ClientInner<'static>>);

#[derive(Debug)]
struct ClientInner<'l> {
    state: Mutable<State>,
    root_object: &'l DbusProxyBlocking<'l>,
    active_connections: RwLock<PathMap<'l, ActiveConnectionDbusProxyBlocking<'l>>>,
    devices: RwLock<PathMap<'l, DeviceDbusProxyBlocking<'l>>>,
    dbus_connection: Connection,
}

impl Client {
    fn new() -> Result<Client> {
        let state = Mutable::new(State {
            wired: WiredState::Unknown,
            wifi: WifiState::Unknown,
            cellular: CellularState::Unknown,
            vpn: VpnState::Unknown,
        });
        let dbus_connection = Connection::system()?;
        let root_object = {
            let root_object = DbusProxyBlocking::new(&dbus_connection)?;
            // Workaround for the fact that zbus (unnecessarily) requires a static lifetime here
            Box::leak(Box::new(root_object))
        };

        Ok(Client(Arc::new(ClientInner {
            state,
            root_object,
            active_connections: RwLock::new(HashMap::new()),
            devices: RwLock::new(HashMap::new()),
            dbus_connection,
        })))
    }

    fn run(&self) -> Result<()> {
        macro_rules! spawn_path_list_watcher {
            (
                $client:expr,
                $property:ident,
                $property_changes:ident,
                $proxy_type:ident,
                $(|$inner_client:ident, $new_path:ident| $property_watcher:expr,)*
            ) => {
                let client = $client.clone();
                spawn_blocking_result!({
                    let changes = client.root_object.$property_changes();
                    for _ in changes {
                        let mut new_pathmap = HashMap::new();
                        {
                            let new_paths = client.root_object.$property()?;
                            let pathmap = read_lock!(client.$property);
                            for new_path in new_paths {
                                if pathmap.contains_key(&new_path) {
                                    let proxy = pathmap
                                        .get(&new_path)
                                        .expect("Should contain the key, guarded by runtime check");
                                    new_pathmap.insert(new_path, proxy.to_owned());
                                } else {
                                    let new_proxy = $proxy_type::builder(&client.dbus_connection)
                                        .path(new_path.clone())?
                                        .build()?;
                                    new_pathmap.insert(new_path.clone(), new_proxy);
                                    $({
                                        let $inner_client = &client;
                                        let $new_path = &new_path;
                                        $property_watcher
                                    })*
                                }
                            }
                        }
                        *write_lock!(client.$property) = new_pathmap;
                        client.state.set(State {
                            // TODO: Investigate if there's a sane way to do only the relevant updates
                            wired: determine_wired_state(&read_lock!(client.devices))?,
                            wifi: determine_wifi_state(&read_lock!(client.devices))?,
                            cellular: determine_cellular_state(&read_lock!(client.devices))?,
                            vpn: determine_vpn_state(&read_lock!(client.active_connections))?,
                        });
                    }
                    Ok(())
                });
            }
        }

        macro_rules! spawn_property_watcher {
            (
                $client:expr,
                $path:expr,
                $property_changes:ident,
                $containing_list:ident
            ) => {
                let client = $client.clone();
                let path = $path.clone();
                spawn_blocking_result!({
                    let changes = read_lock!(client.$containing_list)
                        .get(&path)
                        .expect("Should contain the key upon watcher start")
                        .$property_changes();
                    for _ in changes {
                        if !read_lock!(client.$containing_list).contains_key(&path) {
                            break;
                        }
                        client.state.set(State {
                            // TODO: Investigate if there's a sane way to do only the relevant updates
                            wired: determine_wired_state(&read_lock!(client.devices))?,
                            wifi: determine_wifi_state(&read_lock!(client.devices))?,
                            cellular: determine_cellular_state(&read_lock!(client.devices))?,
                            vpn: determine_vpn_state(&read_lock!(client.active_connections))?,
                        });
                    }
                    Ok(())
                });
            };
        }

        // Initialisation
        {
            // Initial active connections path list
            {
                let new_paths = self.0.root_object.active_connections()?;
                let mut pathmap = write_lock!(self.0.active_connections);
                for new_path in new_paths {
                    let new_proxy =
                        ActiveConnectionDbusProxyBlocking::builder(&self.0.dbus_connection)
                            .path(new_path.clone())?
                            .build()?;
                    pathmap.insert(new_path, new_proxy);
                }
            }

            // Initial devices path list
            {
                let new_paths = self.0.root_object.devices()?;
                let mut pathmap = write_lock!(self.0.devices);
                for new_path in new_paths {
                    let new_proxy = DeviceDbusProxyBlocking::builder(&self.0.dbus_connection)
                        .path(new_path.clone())?
                        .build()?;
                    pathmap.insert(new_path.clone(), new_proxy);
                    spawn_property_watcher!(self.0, new_path, receive_state_changed, devices);
                }
            }

            self.0.state.set(State {
                wired: determine_wired_state(&read_lock!(self.0.devices))?,
                wifi: determine_wifi_state(&read_lock!(self.0.devices))?,
                cellular: determine_cellular_state(&read_lock!(self.0.devices))?,
                vpn: determine_vpn_state(&read_lock!(self.0.active_connections))?,
            });
        }

        spawn_path_list_watcher!(
            self.0,
            active_connections,
            receive_active_connections_changed,
            ActiveConnectionDbusProxyBlocking,
        );

        spawn_path_list_watcher!(
            self.0,
            devices,
            receive_devices_changed,
            DeviceDbusProxyBlocking,
            |client, path| {
                spawn_property_watcher!(client, path, receive_state_changed, devices);
            },
        );

        Ok(())
    }

    pub fn subscribe(&self) -> MutableSignalCloned<State> {
        self.0.state.signal_cloned()
    }
}

pub fn create_client() -> Result<Arc<Client>> {
    let client = Arc::new(Client::new()?);
    {
        let client = client.clone();
        spawn_blocking_result!({
            client.run()?;
            Ok(())
        });
    }
    Ok(client)
}

register_fallible_client!(Client, networkmanager);