treeboot-core 0.4.0

use std::io::ErrorKind;
use std::path::{Path, PathBuf};

use crate::context::resolve_worktree_path;
use crate::{Error, OutputEvent, Reporter, Result};

const DEFAULT_CONFIG_PATH: &str = ".treeboot.toml";
const DEFAULT_SCRIPT_PATH: &str = ".treeboot.sh";

const STARTER_CONFIG: &str = r#"#:schema https://github.com/jimeh/treeboot/releases/latest/download/config.schema.json

copy = [
  ".env.local",
]

symlink = [
]

commands = [
]
"#;

const STARTER_SCRIPT: &str = r#"#!/usr/bin/env sh
set -eu

root_path="$1"

printf 'treeboot root directory: %s\n' "$root_path"
printf 'treeboot worktree directory: %s\n' "$(pwd)"
"#;

/// Init file type to create.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
pub enum InitKind {
    /// Create a starter TOML config.
    #[default]
    Config,
    /// Create an executable init script.
    Script,
}

/// Options for `treeboot init`.
#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct InitOptions {
    /// Directory in which the init target is created.
    pub cwd: Option<PathBuf>,
    /// Init file type to create. Defaults to a starter TOML config.
    pub kind: InitKind,
    /// Output path. Defaults depend on the selected kind.
    pub path: Option<PathBuf>,
}

/// Result summary for `treeboot init`.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct InitReport {
    /// Init file type that was created.
    pub kind: InitKind,
    /// Created path.
    pub path: PathBuf,
}

/// Creates a starter treeboot config or init script.
///
/// Writes the selected init artifact to the requested path, or to the default
/// path for its kind. Script artifacts are marked executable on Unix.
///
/// # Errors
///
/// Returns an error if the current directory cannot be resolved, the target
/// already exists, or the target directory or file cannot be written.
pub fn init(options: InitOptions, reporter: &mut dyn Reporter) -> Result<InitReport> {
    let cwd = options.cwd.as_ref().map_or_else(
        || std::env::current_dir().map_err(|source| Error::CurrentDir { source }),
        |path| Ok(path.clone()),
    )?;
    let kind = options.kind;
    let path = options.path.unwrap_or_else(|| default_path(kind));
    let path = resolve_worktree_path(&cwd, &path);

    if target_exists(&path)? {
        return Err(Error::InitTargetExists(path));
    }

    if let Some(parent) = path.parent() {
        std::fs::create_dir_all(parent).map_err(|source| Error::InitIo {
            path: parent.to_path_buf(),
            source,
        })?;
    }

    let content = match kind {
        InitKind::Config => STARTER_CONFIG,
        InitKind::Script => STARTER_SCRIPT,
    };

    std::fs::write(&path, content).map_err(|source| Error::InitIo {
        path: path.clone(),
        source,
    })?;

    if kind == InitKind::Script {
        make_executable(&path)?;
    }

    reporter
        .report(OutputEvent::InitCreated { path: path.clone() })
        .map_err(|source| Error::Output { source })?;

    Ok(InitReport { kind, path })
}

fn default_path(kind: InitKind) -> PathBuf {
    match kind {
        InitKind::Config => PathBuf::from(DEFAULT_CONFIG_PATH),
        InitKind::Script => PathBuf::from(DEFAULT_SCRIPT_PATH),
    }
}

fn target_exists(path: &Path) -> Result<bool> {
    match std::fs::symlink_metadata(path) {
        Ok(_) => Ok(true),
        Err(source) if source.kind() == ErrorKind::NotFound => Ok(false),
        Err(source) => Err(Error::InitIo {
            path: path.to_path_buf(),
            source,
        }),
    }
}

#[cfg(unix)]
fn make_executable(path: &std::path::Path) -> Result<()> {
    use std::os::unix::fs::PermissionsExt;

    let mut permissions = std::fs::metadata(path)
        .map_err(|source| Error::InitIo {
            path: path.to_path_buf(),
            source,
        })?
        .permissions();
    permissions.set_mode(permissions.mode() | 0o111);
    std::fs::set_permissions(path, permissions).map_err(|source| Error::InitIo {
        path: path.to_path_buf(),
        source,
    })
}

#[cfg(not(unix))]
fn make_executable(_path: &std::path::Path) -> Result<()> {
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    use tempfile::TempDir;

    #[derive(Default)]
    struct VecReporter {
        events: Vec<OutputEvent>,
    }

    impl Reporter for VecReporter {
        fn report(&mut self, event: OutputEvent) -> std::io::Result<()> {
            self.events.push(event);
            Ok(())
        }
    }

    #[test]
    fn init_should_refuse_existing_file() {
        let dir = TempDir::new().expect("tempdir should be created");
        let config = dir.path().join(".treeboot.toml");
        std::fs::write(&config, "old\n").expect("config should be written");
        let mut reporter = VecReporter::default();

        let err = init(
            InitOptions {
                cwd: Some(dir.path().to_path_buf()),
                kind: InitKind::Config,
                path: None,
            },
            &mut reporter,
        )
        .expect_err("existing target should be rejected");

        match err {
            Error::InitTargetExists(path) => assert_eq!(path, config),
            other => panic!("expected InitTargetExists, got {other:?}"),
        }
        assert_eq!(
            std::fs::read_to_string(config).expect("config should be readable"),
            "old\n"
        );
        assert!(reporter.events.is_empty());
    }

    #[cfg(unix)]
    #[test]
    fn init_should_refuse_existing_symlink_without_writing_through_it() {
        use std::os::unix::fs::symlink;

        let dir = TempDir::new().expect("tempdir should be created");
        let target = dir.path().join("target.toml");
        let link = dir.path().join(".treeboot.toml");
        std::fs::write(&target, "old\n").expect("target should be written");
        symlink(&target, &link).expect("symlink should be created");
        let mut reporter = VecReporter::default();

        let err = init(
            InitOptions {
                cwd: Some(dir.path().to_path_buf()),
                kind: InitKind::Config,
                path: None,
            },
            &mut reporter,
        )
        .expect_err("existing symlink should be rejected");

        match err {
            Error::InitTargetExists(path) => assert_eq!(path, link),
            other => panic!("expected InitTargetExists, got {other:?}"),
        }
        assert_eq!(
            std::fs::read_to_string(target).expect("target should be readable"),
            "old\n"
        );
        assert!(
            std::fs::symlink_metadata(link)
                .expect("link metadata should load")
                .file_type()
                .is_symlink()
        );
        assert!(reporter.events.is_empty());
    }
}