use std::{
    fs,
    io::{self, Write},
    path::Path,
};

use log::{debug, trace};
use serde::{Deserialize, Serialize};

use super::{
    cli::Cli,
    sharry::{Alias, File, Share},
};

#[derive(Serialize, Deserialize, Debug)]
pub struct AppState {
    alias: Alias,
    share: Share,
    files: Vec<File>,
}

impl AppState {
    fn load(file_name: impl AsRef<Path>) -> io::Result<Self> {
        let content = fs::read_to_string(file_name)?;
        let state = serde_json::from_str(&content).map_err(io::Error::other)?;

        Ok(state)
    }

    fn save(&self, file_name: impl AsRef<Path>) -> io::Result<()> {
        let json = serde_json::to_string_pretty(self).map_err(io::Error::other)?;
        let mut file = fs::File::create(file_name)?;
        file.write_all(json.as_bytes())?;

        Ok(())
    }

    pub fn try_resume(args: &Cli) -> Option<Self> {
        let file_name = dirs_next::cache_dir()?
            .join("shrupl")
            .join(format!("{}.json", args.get_hash()));

        trace!("loading from {}", file_name.display());

        Self::load(&file_name)
            .inspect_err(|e| debug!("could not resume from {}: {e}", file_name.display()))
            .ok()
    }
}