use std::{
    io::{Read, Write},
    net::TcpStream,
    sync::Mutex,
    thread,
    time::Duration,
};

use anyhow::{bail, Context, Error, Result};
use serde_json::to_string;

use crate::{
    command::{CommandQuerySubtype, CommandRequest, CommandSubtypeResponse, MessageType},
    devices::{e1::E1, DeviceBackend},
    hex,
    packet_builder::PacketBuilder,
    security::{MsgType, Security},
    DeviceInfo,
};

enum ParseMessage {
    Success,
    Padding,
}

pub struct Device {
    info: DeviceInfo,

    socket: Mutex<TcpStream>,
    security: Security,

    device_backend: Box<dyn DeviceBackend>,

    buffer: Vec<u8>,
    sub_type: u16,
    device_protocol_version: u8,

    updates: Vec<Box<dyn Fn(&[u8]) -> Result<()>>>,

    token: [u8; 64],
    key: [u8; 32],
}

impl Device {
    pub fn connect(info: DeviceInfo, token: &str, key: &str) -> Result<Self> {
        let mut socket = Err(Error::msg(""));

        for _ in 0..10 {
            socket = TcpStream::connect(info.addr).context(info.addr);

            if socket.is_ok() {
                break;
            }

            thread::sleep(Duration::from_millis(500));
        }

        let socket = socket?;
        socket.set_write_timeout(Some(Duration::from_secs(10)))?;
        socket.set_read_timeout(Some(Duration::from_secs(10)))?;

        let mut me = Self {
            device_backend: Box::new(match info.device_type {
                0xE1 => E1::new()?,

                _ => bail!("unsupported device type: {:02X}", info.device_type),
            }),

            info,
            socket: Mutex::new(socket),
            security: Security::default(),

            buffer: Vec::new(),
            sub_type: 0,
            device_protocol_version: 0,

            updates: Vec::new(),

            token: hex(token)?.try_into().unwrap(),
            key: hex(key)?.try_into().unwrap(),
        };

        if me.info.protocol == 3 {
            me.authenticate()?;
        }

        me.refresh_status()?;

        Ok(me)
    }

    fn authenticate(&mut self) -> Result<()> {
        let request = self
            .security
            .encode_8370(&self.token, MsgType::HANDSHAKE_REQUEST)?;

        let mut socket = self.socket.lock().unwrap();

        socket.write(&request)?;

        let mut buffer = [0; 512];
        let bytes_read = socket.read(&mut buffer)?;

        if bytes_read < 20 {
            bail!(
                "Authentication failed! (answer too short) {:?}",
                &buffer[..bytes_read]
            );
        }

        self.security.tcp_key(&buffer[8..72], &self.key)?;

        Ok(())
    }

    pub fn refresh_status(&mut self) -> Result<()> {
        let mut cmds = vec![self.device_backend.build_query()];

        if self.sub_type == 0 {
            cmds.insert(0, CommandQuerySubtype::new(self.info.device_type).request());
        }

        for cmd in cmds {
            self.build_send(cmd)?;

            loop {
                let mut buf = [0; 512];
                let bytes_read = self.socket.lock().unwrap().read(&mut buf)?;

                if bytes_read == 0 {
                    bail!("socket error");
                }

                match self.parse_message(&buf[..bytes_read])? {
                    ParseMessage::Success => break,
                    ParseMessage::Padding => continue,
                }
            }
        }

        Ok(())
    }

    pub fn register_update<F>(&mut self, f: F)
    where
        F: Fn(&[u8]) -> Result<()> + 'static,
    {
        self.updates.push(Box::new(f));
    }

    fn parse_message(&mut self, msg: &[u8]) -> Result<ParseMessage> {
        let (messages, buffer) = self.security.decode_8370(&self.buffer, msg)?;
        self.buffer = buffer;

        if messages.is_empty() {
            return Ok(ParseMessage::Padding);
        }

        for mut message in messages {
            if message == b"ERROR" {
                bail!("parse message error");
            }

            let payload_len = message[4] as u16 + ((message[5] as u16) << 8) - 56;
            let payload_type = message[2] as u16 + ((message[3] as u16) << 8);

            // heartbeat
            if payload_type == 0x1001 || payload_type == 0x0001 {
                continue;
            }

            if message.len() > 56 && payload_len % 16 == 0 {
                let len = message.len();
                let crypt = &mut message[40..len - 16];

                Security::aes_decrypt(crypt);

                if self.pre_process_message(crypt) {
                    let status = self.device_backend.process_message(crypt)?;

                    if status.len() > 0 {
                        for update in self.updates.iter() {
                            update(&status)?;
                        }
                    }
                }
            }
        }

        Ok(ParseMessage::Success)
    }

    fn pre_process_message(&mut self, msg: &[u8]) -> bool {
        if msg[9] == MessageType::QuerySubtype as u8 {
            let message = CommandSubtypeResponse::new(msg);

            self.sub_type = message.sub_type;
            self.device_protocol_version = message.header().device_protocol_version();

            false
        } else {
            true
        }
    }

    fn send_message(&self, msg: &[u8]) -> Result<()> {
        let data = self.security.encode_8370(msg, MsgType::ENCRYPTED_REQUEST)?;
        self.socket.lock().unwrap().write(&data)?;

        Ok(())
    }

    fn send_heartbeat(&self) -> Result<()> {
        let msg = PacketBuilder::builder(self.info.id, &[0x00]).finalize(0);
        self.send_message(&msg)
    }

    fn build_send(&self, cmd: CommandRequest) -> Result<()> {
        let data = PacketBuilder::builder(self.info.id, to_string(&cmd.serialize())?.as_bytes())
            .finalize(1);
        self.send_message(&data)
    }
}

#[cfg(test)]
mod test {
    use anyhow::{Context, Result};
    use futures::future::try_join;
    use serial_test::serial;

    use crate::{device::Device, Cloud, Startup};

    #[tokio::test]
    async fn verify_hex() -> Result<()> {
        let devices = Startup::discover().await?;

        const PY_TOKEN: &str =  "06df24fc4e8e950c6d9783051b8e38d971e5fbc617da259459d30d5e7d7fc05b4ccb708fe3a085f6f0af0f8cc961fa39dabfd0746f7bbcfbf7404d9cc5c2b077";
        const PY_KEY: &str = "2a5b5200c2c04d4c811d0550e1dc5b31435436b95b774d2a88d7e46d61fd9669";

        let token_hex = b"\x06\xdf$\xfcN\x8e\x95\x0cm\x97\x83\x05\x1b\x8e8\xd9q\xe5\xfb\xc6\x17\xda%\x94Y\xd3\r^}\x7f\xc0[L\xcbp\x8f\xe3\xa0\x85\xf6\xf0\xaf\x0f\x8c\xc9a\xfa9\xda\xbf\xd0to{\xbc\xfb\xf7@M\x9c\xc5\xc2\xb0w";
        let key_hex = b"*[R\x00\xc2\xc0ML\x81\x1d\x05P\xe1\xdc[1CT6\xb9[wM*\x88\xd7\xe4ma\xfd\x96i";

        for device_info in devices {
            let device = Device::connect(device_info, PY_TOKEN, PY_KEY)?;

            assert_eq!(&device.token, token_hex);
            assert_eq!(&device.key, key_hex);
        }

        Ok(())
    }

    #[tokio::test]
    async fn connect_py_token() -> Result<()> {
        let devices = Startup::discover().await?;

        const PY_TOKEN: &str = "18a821cb88293c6552dc576f0672d8b9445205f74b636764929de5e8badfa48a24caa9d741f632a18e1a9fee67c40b0b40edc21ac7c4c40b6352181cd4000203";
        const PY_KEY: &str = "0fc0c56ea8124414a362e6449ee45ba92558a54f159d4937af697e405f2326b9";

        for device_info in devices {
            Device::connect(device_info, PY_TOKEN, PY_KEY)?;
        }

        Ok(())
    }

    #[tokio::test]
    #[serial]
    async fn full_flow() -> Result<()> {
        let mut cloud = Cloud::new("michaelh.95@t-online.de", "Hoda.semi1")?;

        let (_, devices) = try_join(cloud.login(), Startup::discover()).await?;

        for device_info in devices {
            let (token, key) = cloud.keys(device_info.id).await?;

            Device::connect(device_info, &token, &key)
                .context(format!("\ntoken: {token}\nkey: {key}"))?;
        }

        Ok(())
    }
}