use metrics::{describe_gauge, gauge, Gauge, Unit};
use serde::{Deserialize, Serialize};
use std::{
    path::PathBuf,
    sync::{Arc, RwLock},
    time::{Duration, Instant},
};
use teslatte::{
    auth::{AccessToken, RefreshToken},
    vehicles::{Endpoint, GetVehicleData},
    FleetApi, FleetVehicleApi,
};

use crate::{errors::*, types::CarState};

struct Metrics {
    battery_level: Gauge,
    charge_rate: Gauge,
    charge_request: Gauge,
    inside_temp: Gauge,
    outside_temp: Gauge,
    battery_heater: Gauge,
    climate_on: Gauge,
    preconditioning: Gauge,
    remote_heater_control_enabled: Gauge,
    tesla_online: Gauge,
}

impl Metrics {
    fn new() -> Self {
        describe_gauge!("tesla_battery_level", Unit::Percent, "Battery level");
        let battery_level = gauge!("tesla_battery_level");
        describe_gauge!("tesla_charge_rate", "Charge rate");
        let charge_rate = gauge!("tesla_charge_rate");
        describe_gauge!("tesla_charge_request", "Requested charge rate");
        let charge_request = gauge!("tesla_charge_request");
        describe_gauge!("tesla_inside_temp", "Inside temperature");
        let inside_temp = gauge!("tesla_inside_temp");
        describe_gauge!("tesla_outside_temp", "Outside temperature");
        let outside_temp = gauge!("tesla_outside_temp");
        describe_gauge!("tesla_battery_heater", "Battery heater");
        let battery_heater = gauge!("tesla_battery_heater");
        describe_gauge!("tesla_climate_on", "Climate control");
        let climate_on = gauge!("tesla_climate_on");
        describe_gauge!("tesla_preconditioning", "Preconditioning");
        let preconditioning = gauge!("tesla_preconditioning");
        describe_gauge!(
            "tesla_remote_heater_control_enabled",
            "Remote heater control enabled"
        );
        let remote_heater_control_enabled = gauge!("tesla_remote_heater_control_enabled");
        describe_gauge!("tesla_online", "Tesla online");
        let tesla_online = gauge!("tesla_online");

        Self {
            battery_level,
            charge_rate,
            charge_request,
            inside_temp,
            outside_temp,
            battery_heater,
            climate_on,
            preconditioning,
            remote_heater_control_enabled,
            tesla_online,
        }
    }
}

pub struct TeslaInterface {
    pub state: Arc<RwLock<CarState>>,
    api: FleetApi,
    vehicle: Box<teslatte::vehicles::VehicleData>,
    last_refresh: Instant,
    auth_path: PathBuf,
    metrics: Metrics,
    last_cop_state: String,
    last_climate_keeper: String,
    last_hvac_auto: String,
}

#[derive(Serialize, Deserialize, Clone)]
struct AuthInfo {
    access_token: AccessToken,
    refresh_token: Option<RefreshToken>,
}

#[derive(Clone, Copy, Debug)]
// these are the messages that the webserver can send the api thread
pub enum InterfaceRequest {
    FlashLights,
}

const KEY_REFRESH_INTERVAL: Duration = Duration::from_secs(6 * 60 * 60);

impl TeslaInterface {
    pub async fn load(auth_path: PathBuf) -> Result<Self, AuthLoadError> {
        let key: AuthInfo = ron::from_str(&std::fs::read_to_string(&auth_path)?)?;
        let mut api = FleetApi::new(key.access_token, key.refresh_token);
        api.refresh().await?;
        let last_refresh = Instant::now();
        info!("Refreshed auth key");
        let vehicle = api
            .products()
            .await?
            .into_iter()
            .filter_map(|v| match v {
                teslatte::products::Product::Vehicle(vehicle) => Some(vehicle),
                _ => None,
            })
            .next()
            .ok_or(AuthLoadError::NoVehicles)?;

        let metrics = Metrics::new();

        let interface = Self {
            state: Arc::new(RwLock::new(Default::default())),
            api,
            last_refresh,
            auth_path,
            vehicle,
            metrics,
            last_cop_state: String::new(),
            last_climate_keeper: String::new(),
            last_hvac_auto: String::new(),
        };
        interface.save_key()?;

        Ok(interface)
    }

    fn save_key(&self) -> Result<(), SaveError> {
        std::fs::write(
            self.auth_path.clone(),
            ron::ser::to_string(&AuthInfo {
                access_token: self.api.access_token.clone(),
                refresh_token: self.api.refresh_token.clone(),
            })?,
        )?;
        info!("Auth successfully saved");
        Ok(())
    }

    pub async fn refresh(&mut self) {
        info!("refreshing...");
        self.refresh_keys().await;
        self.refresh_state().await;
    }

    pub async fn process_request(&mut self, request: InterfaceRequest) {
        match request {
            InterfaceRequest::FlashLights => {
                let _ = self.api.flash_lights(&self.vehicle.vin).await;
            }
        }
    }

    async fn refresh_state(&mut self) {
        match self.get_state().await {
            Ok(new_state) => {
                self.metrics.tesla_online.set(1.);
                let mut state = self
                    .state
                    .write()
                    .expect("Tesla API state handler panicked!!");

                if let Some(new_charge_state) = new_state.charge_state {
                    self.metrics
                        .battery_level
                        .set(new_charge_state.battery_level as f64);
                    self.metrics.charge_rate.set(new_charge_state.charge_rate);
                    self.metrics
                        .charge_request
                        .set(new_charge_state.charge_current_request as f64);
                    state.charge_state = Some(new_charge_state);
                }
                if let Some(new_location_data) = new_state.location_data {
                    state.location_data = Some(new_location_data);
                }
                if let Some(new_climate_state) = new_state.climate_state {
                    self.metrics.inside_temp.set(new_climate_state.inside_temp);
                    self.metrics
                        .outside_temp
                        .set(new_climate_state.outside_temp);
                    self.metrics
                        .battery_heater
                        .set(bf(new_climate_state.battery_heater));
                    self.metrics
                        .climate_on
                        .set(bf(new_climate_state.climate_on));
                    self.metrics
                        .preconditioning
                        .set(bf(new_climate_state.preconditioning));
                    self.metrics
                        .remote_heater_control_enabled
                        .set(bf(new_climate_state.remote_heater_control_enabled));
                    state.climate_state = Some(new_climate_state);
                }
            }
            Err(e) => {
                self.metrics.tesla_online.set(0.);
                if let RequestError::Teslatte(teslatte::error::TeslatteError::DecodeJsonError {
                    source: _,
                    request: _,
                    body,
                }) = &e
                {
                    if body.contains("vehicle is offline or asleep") {
                        return;
                    }
                }

                match e {
                    RequestError::StdIo(e) => log::error!("Stdio error: {e:?}"),
                    RequestError::RonSpanned(e) => log::error!("RON parsing error: {e:?}"),
                    RequestError::Teslatte(teslatte::error::TeslatteError::DecodeJsonError {
                        source,
                        request: _,
                        body,
                    }) => {
                        log::error!("Error {source} getting state: {body}")
                    }
                    RequestError::Teslatte(e) => log::error!("Teslatte error: {e:?}"),
                    RequestError::Save(e) => log::error!("Save error: {e:?}"),
                }
            }
        }
    }

    async fn refresh_keys(&mut self) {
        // refresh our Tesla (the company's web servers, not the car) access token
        if Instant::now().duration_since(self.last_refresh) >= KEY_REFRESH_INTERVAL {
            log::warn!("refreshing keys...");
            if self
                .api
                .refresh()
                .await
                .some_or_print_with("refreshing key")
                .is_some()
            {
                let now = Instant::now();
                if self.save_key().some_or_print_with("saving key").is_some() {
                    self.last_refresh = now;
                }
            }
        }
    }

    async fn get_state(&mut self) -> Result<CarState, RequestError> {
        // Endpoint::VehicleDataCombo or multiple Endpoints in one request
        // doesn't seem to reliably get them all,
        // so for each endpoint we do a new request
        let charge_state = self
            .api
            .vehicle_data(&GetVehicleData {
                vehicle_id: self.vehicle.id,
                endpoints: vec![Endpoint::ChargeState].into(),
            })
            .await?
            .charge_state
            .map(|v| v.into());

        let location_data = self
            .api
            .vehicle_data(&GetVehicleData {
                vehicle_id: self.vehicle.id,
                endpoints: vec![Endpoint::LocationData].into(),
            })
            .await?
            .drive_state
            .and_then(|v| v.try_into().ok());

        let climate_state = self
            .api
            .vehicle_data(&GetVehicleData {
                vehicle_id: self.vehicle.id,
                endpoints: vec![Endpoint::ClimateState].into(),
            })
            .await?
            .climate_state
            .and_then(|v| {
                if self.last_cop_state != v.cabin_overheat_protection {
                    log::warn!(
                        "Current cabin overheat protection state: {}",
                        v.cabin_overheat_protection
                    );
                    self.last_cop_state = v.cabin_overheat_protection.clone();
                }
                if self.last_climate_keeper != v.climate_keeper_mode {
                    log::warn!("Current climate keeper mode: {}", v.climate_keeper_mode);
                    self.last_climate_keeper = v.climate_keeper_mode.clone();
                }
                if self.last_hvac_auto != v.hvac_auto_request {
                    log::warn!("HVAC auto request set to: {}", v.hvac_auto_request);
                    self.last_hvac_auto = v.hvac_auto_request.clone();
                }
                v.try_into().ok()
            });

        Ok(CarState {
            charge_state,
            location_data,
            climate_state,
        })
    }
}

fn bf(value: bool) -> f64 {
    if value {
        1.0
    } else {
        0.0
    }
}