use std::path::PathBuf;

use rustyline::{Editor, history::FileHistory};

fn xdg_state_dir() -> Option<PathBuf> {
    if let Ok(dir) = std::env::var("XDG_STATE_DIR") {
        Some(PathBuf::from(dir))
    } else if let Ok(home) = std::env::var("HOME") {
        if home.is_empty() {
            None
        } else {
            Some(PathBuf::from(home).join(".local/state"))
        }
    } else {
        None
    }
}

fn state_dir() -> Option<PathBuf> {
    if let Some(dir) = xdg_state_dir() {
        let dir = dir.join("osdb");
        std::fs::create_dir_all(&dir).ok()?;
        Some(dir)
    } else {
        None
    }
}

pub fn history_file() -> Option<std::path::PathBuf> {
    if let Some(state) = state_dir() {
        Some(state.join("cli_history"))
    } else {
        eprintln!("Warning: failed to find or create XDG_STATE_DIR for osdb.");
        eprintln!(
            "Warning: either set XDG_STATE_DIR or HOME, and ensure osdb has write permissions to that directory."
        );
        None
    }
}

pub fn read_input(rl: &mut Editor<(), FileHistory>) -> Option<String> {
    if let Ok(result) = rl.readline("osdb> ") {
        let _ = rl.add_history_entry(&result);
        Some(result)
    } else {
        None
    }
}