// SPDX-FileCopyrightText: 2025 Tomasz Kramkowski <tomasz@kramkow.ski>
// SPDX-License-Identifier: GPL-3.0-or-later

use std::{
    fs, io,
    path::{Path, PathBuf},
    process,
    time::Duration,
};

use rumqttc::{Client, Connection, MqttOptions};
use serde::Deserialize;

use crate::PROGRAM;

#[derive(Deserialize)]
pub struct Credentials {
    pub username: String,
    pub password: String,
}

fn default_root() -> PathBuf {
    option_env!("DEFAULT_ROOT")
        .unwrap_or(&format!("/var/run/{PROGRAM}"))
        .into()
}

fn default_host() -> String {
    "localhost".to_string()
}

fn default_port() -> u16 {
    1883
}

fn default_id() -> String {
    PROGRAM.to_string()
}

#[derive(Deserialize)]
pub struct Config {
    #[serde(default = "default_root")]
    pub root: PathBuf,
    #[serde(default = "default_host")]
    pub host: String,
    #[serde(default = "default_port")]
    pub port: u16,
    pub credentials: Option<Credentials>,
    #[serde(default = "default_id")]
    pub id: String,
}

impl Config {
    pub fn mqtt_client(&self) -> (Client, Connection) {
        let client_id = format!("{}_{}", self.id, process::id());
        let mut options = MqttOptions::new(client_id, &self.host, self.port);
        if let Some(credentials) = &self.credentials {
            options.set_credentials(&credentials.username, &credentials.password);
        }
        options.set_keep_alive(Duration::from_secs(5));
        options.set_max_packet_size(10 * 1024 * 1024, 10 * 1024 * 1024);
        Client::new(options, 10)
    }
}

pub fn load<P: AsRef<Path>>(path: P) -> anyhow::Result<Config> {
    let config = match fs::read_to_string(&path) {
        Ok(s) => Ok(s),
        Err(e) if e.kind() == io::ErrorKind::NotFound => Ok(String::new()),
        Err(e) => Err(e),
    }?;
    Ok(toml::from_str(&config)?)
}