use std::borrow::Cow;
use std::fmt::{self, Display};
use std::num::ParseIntError;
use std::str::FromStr;

use serde::{Deserialize, Deserializer, de::Error};

use crate::device::FormattableDevice;

#[derive(Debug)]
pub struct TempState {
    pub name: String,
    pub id: RfDeviceId,
    pub temperature: f32,
    pub humidity: u8,
}

impl TempState {
    pub fn new(id: RfDeviceId, name: String) -> Self {
        TempState {
            name,
            id,
            temperature: 0.0,
            humidity: 0,
        }
    }
}

impl FormattableDevice for TempState {
    fn format_open_metrics(&self) -> impl Display + '_ {
        TempFormatter { device: self }
    }
}

struct TempFormatter<'a> {
    device: &'a TempState,
}

impl Display for TempFormatter<'_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        if self.device.temperature > 0.0 {
            writeln!(
                f,
                "sensor_temperature{{model=\"{}\", id=\"{}\", channel=\"{}\", name=\"{}\"}} {}",
                self.device.id.name,
                self.device.id.id,
                self.device.id.channel,
                self.device.name,
                self.device.temperature
            )?;
        }

        if self.device.humidity > 0 {
            writeln!(
                f,
                "sensor_humidity{{model=\"{}\", id=\"{}\", channel=\"{}\", name=\"{}\"}} {}",
                self.device.id.name,
                self.device.id.id,
                self.device.id.channel,
                self.device.name,
                self.device.humidity
            )?;
        }

        Ok(())
    }
}

#[derive(Debug, PartialEq)]
pub struct RfPayload<'a> {
    pub name: &'a str,
    pub id: u16,
    pub channel: u8,
    pub battery: bool,
    pub temperature: f32,
    pub humidity: u8,
}

impl<'a> RfPayload<'a> {
    pub fn device_id(&self) -> RfDeviceId {
        RfDeviceId {
            name: self.name.into(),
            id: self.id,
            channel: self.channel,
        }
    }
}

#[derive(Hash, PartialEq, Eq, Debug, Default, Clone)]
pub struct RfDeviceId {
    pub name: String,
    pub id: u16,
    pub channel: u8,
}

impl<'de> Deserialize<'de> for RfDeviceId {
    fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        let str = <Cow<'de, str>>::deserialize(deserializer)?;
        Self::from_str(&str).map_err(D::Error::custom)
    }
}

impl FromStr for RfDeviceId {
    type Err = ParseIntError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let mut parts = s.splitn(3, ':');
        let name = parts.next().unwrap_or_default();
        let id = parts.next().unwrap_or_default().parse()?;
        let channel = parts.next().unwrap_or_default().parse()?;
        Ok(RfDeviceId {
            name: name.into(),
            id,
            channel,
        })
    }
}

pub fn parse_rf_payload<'a>(payload: &'a str) -> Option<RfPayload<'a>> {
    let mut parts = payload.split(";").skip(2);
    let name = parts.next()?;
    let id = parts.next()?.strip_prefix("ID=")?.parse().ok()?;
    let channel = parts.next()?.strip_prefix("CHN=")?.parse().ok()?;
    let battery = parts.next()?.strip_prefix("BAT=")? == "OK";
    let temperature = parts.next()?.strip_prefix("TEMP=")?;
    let temperature = u32::from_str_radix(temperature, 16).ok()?;
    let humidity = parts.next()?.strip_prefix("HUM=")?.parse().ok()?;

    Some(RfPayload {
        name,
        id,
        channel,
        battery,
        temperature: temperature as f32 / 10.0,
        humidity,
    })
}

#[test]
fn test_rf_payload() {
    assert_eq!(
        RfPayload {
            name: "Bresser-3CH",
            id: 49,
            channel: 1,
            battery: true,
            temperature: 16.1,
            humidity: 58
        },
        parse_rf_payload("20;1E;Bresser-3CH;ID=49;CHN=0001;BAT=OK;TEMP=00a1;HUM=58;").unwrap()
    )
}