use crate::gopher;
use std::{
    fs::{File, OpenOptions},
    io::{prelude::*, BufReader, Result, Write},
};

pub const DIR: &str = "~/.config/phetch/";

// Loads a file in the config directory for reading.
pub fn load(filename: &str) -> Result<BufReader<File>> {
    path().and_then(|dotdir| {
        let path = dotdir.join(filename);
        if let Ok(file) = OpenOptions::new().read(true).open(&path) {
            Ok(BufReader::new(file))
        } else {
            Err(error!("Couldn't open {:?}", path))
        }
    })
}

// Append a menu item as a line to a file in the config dir.
pub fn append(filename: &str, label: &str, url: &str) -> Result<()> {
    path().and_then(|dotdir| {
        let path = dotdir.join(filename);
        if let Ok(mut file) = OpenOptions::new().append(true).create(true).open(path) {
            let (t, host, port, sel) = gopher::parse_url(&url);
            file.write_all(
                format!(
                    "{}{}\t{}\t{}\t{}\r\n",
                    t.to_char().unwrap_or('i'),
                    label,
                    sel,
                    host,
                    port
                )
                .as_ref(),
            );
            Ok(())
        } else {
            Err(error!("Can't open file for writing: {:?}", filename))
        }
    })
}

// Add a menu item as the first line in a file in the config dir.
pub fn prepend(filename: &str, label: &str, url: &str) -> Result<()> {
    path().and_then(|dotdir| {
        let path = dotdir.join(filename);
        if let Ok(mut file) = OpenOptions::new()
            .write(true)
            .read(true)
            .create(true)
            .open(path)
        {
            let (t, host, port, sel) = gopher::parse_url(&url);
            let mut buf = vec![];
            file.read_to_end(&mut buf);
            file.seek(std::io::SeekFrom::Start(0));
            file.write_all(
                format!(
                    "{}{}\t{}\t{}\t{}\r\n",
                    t.to_char().unwrap_or('i'),
                    label,
                    sel,
                    host,
                    port
                )
                .as_ref(),
            );
            file.write_all(&buf);
            Ok(())
        } else {
            Err(error!("Can't open file for writing: {:?}", filename))
        }
    })
}

// PathBuf to expanded config dir if it exists.
// None if the config dir doesn't exist.
pub fn path() -> Result<std::path::PathBuf> {
    let homevar = std::env::var("HOME");
    if homevar.is_err() {
        return Err(error!("$HOME not set, can't decode `~`"));
    }

    let dotdir = DIR.replace('~', &homevar.unwrap());
    let dotdir = std::path::Path::new(&dotdir);
    if dotdir.exists() {
        Ok(std::path::PathBuf::from(dotdir))
    } else {
        Err(error!("Config dir not found: {}", DIR))
    }
}
