use log::*; //{trace, debug, info, warn, error}
use esp32_nimble::{enums::*, uuid128, BLEAdvertisementData, BLEAdvertising, BLEDevice, BLEServer, NimbleProperties, OnWriteArgs};
use esp32_nimble::utilities::{mutex::Mutex, BleUuid};
use anyhow::Result;
use closure::closure;

use crate::dispatch::{Dispatch, RecvQ, SendQ};
use crate::commands::Commands;

// TODO HARDWARE: test these values to see if they are suitable
const BLE_MIN_INTERVAL: u16 = 24; // x 1.25ms
const BLE_MAX_INTERVAL: u16 = 48; // x 1.25ms
const BLE_LATENCY: u16 = 0; // Number of packets that can be missed, extending interval
const BLE_TIMEOUT: u16 = 500; // x10ms

const BUTTON_PRESSED: [u8; 1] = [0x1];
const BUTTON_RELEASED: [u8; 1] = [0x0];

const DEVICE_NAME: &str = "Gem Remotes";

const UUID_SERVICE_PAIR: BleUuid = uuid128!("9966ad5a-f13c-4b61-ba66-0861e08d09b4");
const UUID_SERVICE_LIFT: BleUuid = uuid128!("c1400000-8dda-45a3-959b-d23a0f8f53d7");

const UUID_BUTTON_UP: BleUuid = uuid128!("c1401121-8dda-45a3-959b-d23a0f8f53d7");
const UUID_BUTTON_DOWN: BleUuid = uuid128!("c1401122-8dda-45a3-959b-d23a0f8f53d7");
const UUID_BUTTON_STOP: BleUuid = uuid128!("c1401123-8dda-45a3-959b-d23a0f8f53d7");

pub struct BleServer {
    send_q: SendQ,
    recv_q: RecvQ,
}

impl BleServer {
    pub fn new(dp: &mut Dispatch) -> Self {
        let cmds = vec![
            // Switch to getting and updating notices; use the command version for sending commands only.
            //Commands::BluetoothUp { data: 0 },
            //Commands::BluetoothDown { data: 0 },
            //Commands::BluetoothStop { data: 0 },
            Commands::NotifyMotorDown,
            Commands::NotifyMotorStopping,
            Commands::NotifyMotorUp,
            Commands::NotifyMotorStopped,
        ];
        let r = dp.get_callback_channel(&cmds);
        let s = dp.get_cmd_channel();
        BleServer { 
            send_q: s.clone(), 
            recv_q: r.clone(),
        }
    }

    pub async fn run(&mut self) -> Result<()> {
        match self.do_run().await {
            Ok(_) => {error!("Exited bluetooth server wait loop with no error.");panic!();}
            Err(e) => {error!("Bluetooth task encountered error {}", e);panic!();}
        }
    }

    pub async fn do_run(&mut self) -> Result<()> {
        trace!("Entering BLE Run");
        let ble_device = BLEDevice::take();
        set_device_security(ble_device);
        let server = ble_device.get_server();
        set_server_callbacks(server);
        let _pairing_service = server.create_service(UUID_SERVICE_PAIR);
        let lift_service = server.create_service(UUID_SERVICE_LIFT);

        trace!("Setting up GATT");
        //TODO: require authentication (bonding counts?) for these!
        let sender = self.send_q.clone();
        //let mut cmd = Commands::BluetoothUp { data: 0 };
        let button_up = lift_service.lock().create_characteristic(
            UUID_BUTTON_UP,
            NimbleProperties::READ | NimbleProperties::WRITE_NO_RSP | NimbleProperties::NOTIFY,
        );
        button_up.lock().set_value(&[0])
        .on_write(closure!(clone sender, |args: &mut OnWriteArgs| {
            on_bluetooth_cmd(&sender, args, Commands::BluetoothUp {data: 0})
        }));

        let button_down = lift_service.lock().create_characteristic(
            UUID_BUTTON_DOWN,
            NimbleProperties::READ | NimbleProperties::WRITE_NO_RSP | NimbleProperties::NOTIFY,
        );
        button_down.lock().set_value(&[0])
        .on_write(closure!(clone sender, |args: &mut OnWriteArgs| {
            on_bluetooth_cmd(&sender, args, Commands::BluetoothDown {data: 0})
        }));

        let button_stop = lift_service.lock().create_characteristic(
            UUID_BUTTON_STOP,
            NimbleProperties::READ | NimbleProperties::WRITE_NO_RSP | NimbleProperties::NOTIFY,
        );
        button_stop.lock().set_value(&[1])
        .on_write(closure!(clone sender, |args: &mut OnWriteArgs| {
            on_bluetooth_cmd(&sender, args, Commands::BluetoothStop {_data: 0})
        }));


        let ble_advertiser = ble_device.get_advertising();
        
        // TODO: we will need to enable / disable the ability to pair!
        advertise_pairing(ble_advertiser)?;
        
        loop {
            debug!("Waiting for updates that should be notified via bluetooth");
            let cmd =self.recv_q.recv().await.expect("Bluetooth notification queue unexpectedly closed");
            trace!("Received update to bluetooth variable {:?}", cmd);
            match cmd {
                // TODO DISCUSS: This logic (if one button is pressed others are released) could be done in app instead.
                Commands::NotifyMotorUp => {
                    button_up.lock().set_value(&BUTTON_PRESSED).notify();
                    button_down.lock().set_value(&BUTTON_RELEASED).notify();
                    button_stop.lock().set_value(&BUTTON_RELEASED).notify();
                }
                Commands::NotifyMotorDown => {
                    button_up.lock().set_value(&BUTTON_RELEASED).notify();
                    button_down.lock().set_value(&BUTTON_PRESSED).notify();
                    button_stop.lock().set_value(&BUTTON_RELEASED).notify();
                }
                Commands::NotifyMotorStopping => {
                    button_up.lock().set_value(&BUTTON_RELEASED).notify();
                    button_down.lock().set_value(&BUTTON_RELEASED).notify();
                    button_stop.lock().set_value(&BUTTON_PRESSED).notify();
                }
                Commands::NotifyMotorStopped => {
                    button_up.lock().set_value(&BUTTON_RELEASED).notify();
                    button_down.lock().set_value(&BUTTON_RELEASED).notify();
                    button_stop.lock().set_value(&BUTTON_RELEASED).notify();
                }
                _ => {
                    error!("Invalid command received by bluetooth handler {:?}", cmd);
                    // No need to reboot as state is recoverable.
                }
            }
        }
    }

}

fn on_bluetooth_cmd(sender: &SendQ, args: &mut OnWriteArgs, cmd: Commands) {
    let v = args.recv_data();
    // receiving incorrect data isn't fatal, but being unable to send events is.
    let attempt = match cmd {
        Commands::BluetoothUp { data: _ } => {
            if v.len() > 0 {
                sender.send_blocking(Commands::BluetoothUp {data: v[0]} )
            } else {error!("Received zero-byte bluetooth characteristic update {:?}", cmd); Ok(())}
        }
        Commands::BluetoothDown { data: _ } => {
            if v.len() > 0 {
                sender.send_blocking(Commands::BluetoothDown {data: v[0]} )
            } else {error!("Received zero-byte bluetooth characteristic update {:?}", cmd); Ok(())}
        }
        Commands::BluetoothStop { _data: _ } => {
            if v.len() > 0 {
                sender.send_blocking(Commands::BluetoothStop {_data: v[0]} )
            } else {error!("Received zero-byte bluetooth characteristic update {:?}", cmd); Ok(())}
        }
        _ => {error!("Tried to handle an unknown bluetooth command: {:?}",cmd);Ok(())}
    };
    match attempt {
        Ok(_) => {}
        Err(_) => {panic!("Unable to send notifications of bluetooth events")}
    }
}

fn set_device_security(dev: &mut BLEDevice) {
    dev.security()
        // Enable all security protections
        .set_auth(AuthReq::all())
        // Options we support for putting in pairing info.  
        // "NoInputOutput" means that we will have "just works" pairing
        .set_io_cap(SecurityIOCap::NoInputNoOutput)
        //Handle IOS's bluetooth address randomization
        .resolve_rpa();
}

fn set_server_callbacks(server: &mut BLEServer) {
    server.on_connect(|server, clntdesc| {
        // Print connected client data
        info!("client connected: {:?}", clntdesc);
        // Update connection parameters
        server
            .update_conn_params(
                clntdesc.conn_handle(),
                BLE_MIN_INTERVAL,
                BLE_MAX_INTERVAL,
                BLE_LATENCY,
                BLE_TIMEOUT,
            ).unwrap();
    });
    server.on_disconnect(|_desc, _reason| {
        info!("Disconnected, back to advertising");
    });
}

fn advertise_pairing(advertiser: &Mutex<BLEAdvertising>) -> Result<()> {
    trace!("Setting up advertiser");
    advertiser
        .lock()
        .set_data(
            BLEAdvertisementData::new()
                .name(DEVICE_NAME)
                .add_service_uuid(UUID_SERVICE_PAIR)
        )?;
    // TODO: this appears to run in its own thread; verify.
    // TODO: isn't there a  restart?  We'll need to switch between pairing and not.
    info!("Staring Bluetooth Server");
    advertiser.lock().start()?;
    Ok(())
}