git-stk 0.1.0

use std::process::{Command, Stdio};

use anyhow::{Context, Result, anyhow, bail};

pub fn current_branch() -> Result<String> {
    output(&["symbolic-ref", "--quiet", "--short", "HEAD"])
        .context("failed to determine current branch")
}

pub fn local_branches() -> Result<Vec<String>> {
    let output = output(&["for-each-ref", "--format=%(refname:short)", "refs/heads"])?;
    Ok(output.lines().map(str::to_owned).collect())
}

pub fn git_path(path: &str) -> Result<String> {
    output(&["rev-parse", "--git-path", path])
}

pub fn remote_url(remote: &str) -> Result<Option<String>> {
    let output = Command::new("git")
        .args(["remote", "get-url", remote])
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .output()
        .with_context(|| format!("failed to read git remote {remote}"))?;

    match output.status.code() {
        Some(0) => Ok(Some(
            String::from_utf8_lossy(&output.stdout).trim().to_owned(),
        )),
        Some(2) => Ok(None),
        _ => Err(command_error("git remote get-url", &output.stderr)),
    }
}

pub fn checkout(branch: &str) -> Result<()> {
    status(&["switch", branch]).with_context(|| format!("failed to check out {branch}"))
}

pub fn create_branch(branch: &str) -> Result<()> {
    status(&["switch", "-c", branch]).with_context(|| format!("failed to create branch {branch}"))
}

pub fn delete_branch(branch: &str) -> Result<()> {
    status(&["branch", "-d", branch]).with_context(|| format!("failed to delete branch {branch}"))
}

pub fn rebase(parent: &str, branch: &str, update_refs: bool) -> Result<()> {
    let mut args = vec!["rebase"];
    if update_refs {
        args.push("--update-refs");
    }
    args.extend([parent, branch]);

    status(&args).with_context(|| format!("failed to rebase {branch} onto {parent}"))
}

pub fn supports_rebase_update_refs() -> Result<bool> {
    let output = Command::new("git")
        .args(["rebase", "-h"])
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .output()
        .context("failed to inspect git rebase help")?;

    let help = format!(
        "{}{}",
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr)
    );
    Ok(help.contains("--update-refs"))
}

pub fn rebase_continue() -> Result<()> {
    status(&["rebase", "--continue"]).context("failed to continue rebase")
}

pub fn rebase_abort() -> Result<()> {
    status(&["rebase", "--abort"]).context("failed to abort rebase")
}

pub fn config_get(key: &str) -> Result<Option<String>> {
    let output = Command::new("git")
        .args(["config", "--get", key])
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .output()
        .with_context(|| format!("failed to read git config {key}"))?;

    match output.status.code() {
        Some(0) => Ok(Some(
            String::from_utf8_lossy(&output.stdout).trim().to_owned(),
        )),
        Some(1) => Ok(None),
        _ => Err(command_error("git config --get", &output.stderr)),
    }
}

pub fn config_get_bool(key: &str) -> Result<Option<bool>> {
    let output = Command::new("git")
        .args(["config", "--type=bool", "--get", key])
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .output()
        .with_context(|| format!("failed to read git config {key}"))?;

    match output.status.code() {
        Some(0) => {
            let value = String::from_utf8_lossy(&output.stdout).trim().to_owned();
            match value.as_str() {
                "true" => Ok(Some(true)),
                "false" => Ok(Some(false)),
                _ => bail!("git config {key} is not a boolean: {value}"),
            }
        }
        Some(1) => Ok(None),
        _ => Err(command_error(
            "git config --type=bool --get",
            &output.stderr,
        )),
    }
}

pub fn config_set(key: &str, value: &str) -> Result<()> {
    status(&["config", key, value]).with_context(|| format!("failed to set git config {key}"))
}

pub fn config_unset(key: &str) -> Result<()> {
    let output = Command::new("git")
        .args(["config", "--unset", key])
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .output()
        .with_context(|| format!("failed to unset git config {key}"))?;

    match output.status.code() {
        Some(0) | Some(5) => Ok(()),
        _ => Err(command_error("git config --unset", &output.stderr)),
    }
}

fn output(args: &[&str]) -> Result<String> {
    let output = Command::new("git")
        .args(args)
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .output()
        .context("failed to run git")?;

    if output.status.success() {
        Ok(String::from_utf8_lossy(&output.stdout).trim().to_owned())
    } else {
        Err(command_error("git", &output.stderr))
    }
}

fn status(args: &[&str]) -> Result<()> {
    let status = Command::new("git")
        .args(args)
        .status()
        .context("failed to run git")?;

    if status.success() {
        Ok(())
    } else {
        bail!("git exited with status {status}")
    }
}

fn command_error(command: &str, stderr: &[u8]) -> anyhow::Error {
    let stderr = String::from_utf8_lossy(stderr).trim().to_owned();
    if stderr.is_empty() {
        anyhow!("{command} failed")
    } else {
        anyhow!("{command} failed: {stderr}")
    }
}