use std::{fs, path::PathBuf};

use anyhow::{Result, bail};
use directories::ProjectDirs;
use serde::{Deserialize, Serialize};

#[derive(Clone)]
pub struct Persistence {
    config_dir: Option<PathBuf>,
}

impl Persistence {
    pub fn new() -> Self {
        Self {
            config_dir: init_config_dir(),
        }
    }

    pub fn save_config<T: Serialize>(&self, file: &str, data: &T) -> Result<()> {
        if let Some(config_dir) = self.config_dir.as_ref() {
            let bytes = serde_json::to_vec_pretty(data)?;
            let filename = config_dir.join(file).with_extension("json");
            fs::write(&filename, bytes)?;
        }
        Ok(())
    }

    pub fn load_config<T: for<'a> Deserialize<'a>>(&self, file: &str) -> Result<T> {
        let Some(config_dir) = self.config_dir.as_ref() else {
            bail!("config directory not found");
        };
        let filename = config_dir.join(file).with_extension("json");
        let bytes = fs::read(filename)?;
        Ok(serde_json::from_slice(&bytes)?)
    }
}

fn init_config_dir() -> Option<PathBuf> {
    let config_dir = project_dirs()?.config_dir().to_path_buf();
    fs::create_dir_all(&config_dir).ok()?;
    Some(config_dir)
}

pub fn init_data_dir() -> Option<PathBuf> {
    let data_dir = project_dirs()?.data_dir().to_path_buf();
    fs::create_dir_all(&data_dir).ok()?;
    Some(data_dir)
}

fn project_dirs() -> Option<ProjectDirs> {
    ProjectDirs::from("com", "virtual-boy", "Lemur")
}