#![feature(never_type)]

#[macro_use]
extern crate rocket;

use api_interface::TeslaInterface;
use charge_controllers::pl::Pli;
use clap::{Parser, Subcommand};
use config::{access_config, CONFIG_PATH};
use errors::PrintErrors;
use std::path::PathBuf;
use tesla_charge_rate::TeslaChargeRateController;

use crate::config::Config;

mod api_interface;
mod charge_controllers;
mod config;
mod errors;
mod server;
mod tesla_charge_rate;
mod types;

#[derive(Parser, Debug, Clone)]
#[clap(author, version, about, long_about = None)]
struct Args {
    #[command(subcommand)]
    command: Commands,
    #[clap(long, default_value = "/etc/tesla-charge-controller")]
    config_dir: PathBuf,
}

#[derive(Subcommand, Debug, Clone)]
enum Commands {
    /// Run charge controller server
    Watch,
    /// Print the default config file
    GenerateConfig,
}

#[tokio::main]
async fn main() {
    let args = Args::parse();
    env_logger::builder()
        .format_module_path(false)
        .format_timestamp(
            if std::env::var("LOG_TIMESTAMP").is_ok_and(|v| v == "false") {
                None
            } else {
                Some(env_logger::TimestampPrecision::Seconds)
            },
        )
        .init();

    let auth_path = args.config_dir.join("auth");

    let _ = CONFIG_PATH.set(args.config_dir.join("config"));

    let _recorder = metrics_prometheus::install();

    match args.command {
        Commands::GenerateConfig => {
            println!(
                "{}",
                ron::ser::to_string_pretty(&Config::default(), Default::default()).unwrap()
            );
        }
        Commands::Watch => {
            if let Some(mut interface) = TeslaInterface::load(auth_path)
                .await
                .some_or_print_with("loading tesla interface")
            {
                let config = access_config();
                // build the channel that takes messages from the webserver thread to the api thread
                let (api_requests, api_receiver) = async_channel::unbounded();
                // and to the pli thread
                let (pli_requests, pli_receiver) = async_channel::unbounded();
                // and to the charge rate controller thread
                let (tcrc_requests, tcrc_receiver) = async_channel::unbounded();

                charge_controllers::register_metrics();

                // try to spawn the pli loop
                let pl_state = match Pli::new(
                    config.serial_port.clone(),
                    config.baud_rate,
                    config.pl_timeout_milliseconds,
                ) {
                    Ok(mut pli) => {
                        let pl_state = pli.state.clone();
                        tokio::task::spawn(async move {
                            let mut interval = tokio::time::interval(
                                std::time::Duration::from_secs(config.pl_watch_interval_seconds),
                            );
                            loop {
                                tokio::select! {
                                    _ = interval.tick() => pli.refresh(),
                                    message = pli_receiver.recv() => match message {
                                        Ok(message) => pli.process_request(message),
                                        Err(e) => panic!("Error on PLI receive channel: {e:?}")
                                    }
                                }
                            }
                        });
                        Some(pl_state)
                    }
                    Err(e) => {
                        log::error!("Error connecting to serial device for PLI: {e:?}");
                        None
                    }
                };

                let mut tesla_charge_rate_controller =
                    TeslaChargeRateController::new(interface.state.clone(), pl_state.clone());

                let server_handle = server::launch_server(server::ServerState {
                    car_state: interface.state.clone(),
                    pl_state,
                    tcrc_state: tesla_charge_rate_controller.tcrc_state.clone(),
                    api_requests,
                    pli_requests,
                    tcrc_requests,
                });

                // spawn the api loop
                tokio::task::spawn(async move {
                    let mut interval = tokio::time::interval(std::time::Duration::from_secs(
                        config.tesla_update_interval_seconds,
                    ));
                    let mut charge_interval =
                        tokio::time::interval(std::time::Duration::from_secs(
                            config.tesla_update_interval_while_charging_seconds,
                        ));
                    loop {
                        // await either the next interval OR a message from the other thread
                        tokio::select! {
                            _ = interval.tick() => {
                                if !interface.state.read().unwrap().is_charging_at_home() {
                                    interface.refresh().await
                                }
                            },
                            _ = charge_interval.tick() => {
                                if interface.state.read().unwrap().is_charging_at_home() {
                                    if let Some(request) = tesla_charge_rate_controller.control_charge_rate() {
                                        interface.process_request(request).await;
                                    }
                                    interface.refresh().await
                                }
                            }
                            api_message = api_receiver.recv() => match api_message {
                                Ok(message) => interface.process_request(message).await,
                                Err(e) => panic!("Error on Tesla receive channel: {e:?}")
                            },
                            tcrc_message = tcrc_receiver.recv() => match tcrc_message {
                                Ok(message) => tesla_charge_rate_controller.process_request(message),
                                Err(e) => panic!("Error on TCRC receive channel: {e:?}")
                            }
                        }
                    }
                });

                server_handle.await;
            }
        }
    }
}