use std::ffi::OsStr;
use std::path::Path;
use util::process;


pub fn init<P: AsRef<Path>>(path: P) -> ::Result<()> {
    process::inherit("git")
        .arg("init")
        .arg(path.as_ref().as_os_str())
        .status()
        .map_err(Into::into)
        .and_then(|st| match st.code() {
            Some(0) => Ok(()),
            st => Err(format!("command 'git' is exited with return code {:?}.", st).into()),
        })
}

pub fn clone<P, U, I, S>(url: U, path: P, args: I) -> ::Result<()>
where
    P: AsRef<Path>,
    U: AsRef<str>,
    I: IntoIterator<Item = S>,
    S: AsRef<OsStr>,
{
    let path = format!("{}", path.as_ref().display());
    process::inherit("git")
        .arg("clone")
        .args(&[url.as_ref(), &path])
        .args(args)
        .status()
        .map_err(Into::into)
        .and_then(|st| match st.code() {
            Some(0) => Ok(()),
            st => Err(format!("command 'git' is exited with return code {:?}.", st).into()),
        })
}

pub fn get_remote_url<P: AsRef<Path>>(repo_path: P) -> ::Result<Option<String>> {
    // 1. get current branch name.
    let output = process::piped("git")
        .current_dir(&repo_path)
        .args(&["rev-parse", "--abbrev-ref", "HEAD"])
        .output()?;
    if !output.status.success() {
        Err("failed to get branch name")?;
    }
    let branch = String::from_utf8_lossy(&output.stdout).trim().to_owned();

    // 2. get remote name of upstream ref
    let arg = format!("{}@{{upstream}}", branch);
    let output = process::piped("git")
        .current_dir(&repo_path)
        .args(&["rev-parse", "--abbrev-ref", &arg])
        .output()?;
    if !output.status.success() {
        return Ok(None);
    }
    let upstream = String::from_utf8_lossy(&output.stdout)
        .trim()
        .trim_right_matches(&format!("/{}", branch))
        .to_owned();

    // 3. get remote URL of upstream ref
    let output = process::piped("git")
        .current_dir(repo_path)
        .args(&["remote", "get-url", &upstream])
        .output()?;
    if !output.status.success() {
        return Ok(None);
    }
    let url = String::from_utf8_lossy(&output.stdout).trim().to_owned();
    if url == "" {
        Ok(None)
    } else {
        Ok(Some(url))
    }
}

pub fn set_remote<P: AsRef<Path>>(path: P, url: &str) -> ::Result<()> {
    let st = process::piped("git")
        .args(&["remote", "add", "origin", url])
        .current_dir(path)
        .status()?;
    match st.code() {
        Some(0) => Ok(()),
        st => Err(format!("command 'git' is exited with return code {:?}.", st).into()),
    }
}