use std::{
    fs::File,
    io::{BufRead, BufReader, ErrorKind},
    path::PathBuf,
};

use clap::Args;
use directories::ProjectDirs;

use crate::{session::SessionWriter, Session};

#[derive(Debug, Clone, Args)]
#[group(skip)]
pub struct History {
    /// Update the history file from the current sessions
    #[arg(short, long)]
    pub update: bool,

    /// path to history file [default: $XDG_DATA_HOME/sshr/history]
    #[arg(short = 'f', long = "history_file")]
    path: Option<PathBuf>,
}

impl History {
    pub fn new(History { update, path }: History) -> Self {
        Self {
            path: path.or_else(History::default_path),
            update,
        }
    }

    pub fn read(&self) -> Result<Vec<Session>, std::io::Error> {
        let Some(path) = &self.path() else {
            tracing::warn!(?self.path, "History file does not exist");
            return Ok(Vec::new());
        };

        let sessions = BufReader::new(File::open(path)?)
            .lines()
            .flatten()
            .flat_map(|item| ron::from_str(&item))
            .collect();

        Ok(sessions)
    }

    fn default_path() -> Option<PathBuf> {
        ProjectDirs::from("", "", env!("CARGO_CRATE_NAME"))?
            .state_dir()?
            .join("history")
            .into()
    }

    pub fn path(&self) -> Option<PathBuf> {
        self.path.clone().or_else(History::default_path)
    }
}

impl SessionWriter for History {
    type Writer = File;
    type Error = ron::Error;

    fn format(&self, session: &Session) -> Result<String, Self::Error> {
        ron::to_string(session)
    }

    fn filter(&self, session: &Session) -> bool {
        self.update && !matches!(session.state, crate::State::Discovered)
    }

    fn writer(&self) -> Result<Self::Writer, std::io::Error> {
        match &self.path {
            Some(path) => File::create(path),
            None => Err(std::io::Error::from(ErrorKind::NotFound)),
        }
    }
}