git-ai 1.1.1

use std::path::{Path, PathBuf};
use std::{env, fs};
use std::os::unix::fs::symlink as symlink_unix;

use anyhow::{bail, Context, Result};
use git2::{Repository, RepositoryOpenFlags as Flags};

/// Error messages for filesystem operations
const ERR_CURRENT_DIR: &str = "Failed to get current directory";

/// Represents the filesystem structure for git-ai.
/// Handles paths for hooks and binaries.
#[derive(Debug, Clone)]
pub struct Filesystem {
  git_ai_hook_bin_path: PathBuf,
  git_hooks_path:       PathBuf
}

/// Represents a file in the filesystem.
/// Provides operations for file manipulation.
#[derive(Debug, Clone)]
pub struct File {
  path: PathBuf
}

impl File {
  /// Creates a new File instance.
  ///
  /// # Arguments
  /// * `path` - The path to the file
  pub fn new(path: PathBuf) -> Self {
    Self { path }
  }

  /// Checks if the file exists.
  ///
  /// # Returns
  /// * `bool` - true if the file exists, false otherwise
  pub fn exists(&self) -> bool {
    self.path.exists()
  }

  /// Deletes the file from the filesystem.
  ///
  /// # Returns
  /// * `Result<()>` - Success or an error if deletion fails
  pub fn delete(&self) -> Result<()> {
    log::debug!("Removing file at {self}");
    fs::remove_file(&self.path).with_context(|| format!("Failed to remove file at {self}"))
  }

  /// Creates a symbolic link to the target file.
  ///
  /// # Arguments
  /// * `target` - The file to link to
  ///
  /// # Returns
  /// * `Result<()>` - Success or an error if link creation fails
  pub fn symlink(&self, target: &File) -> Result<()> {
    log::debug!("Symlinking {target} to {self}");
    symlink_unix(&target.path, &self.path).with_context(|| format!("Failed to symlink {target} to {self}"))
  }

  /// Gets the relative path from the current directory.
  ///
  /// # Returns
  /// * `Result<Dir>` - The relative path as a Dir or an error
  pub fn relative_path(&self) -> Result<Dir> {
    let current_dir = env::current_dir().context(ERR_CURRENT_DIR)?;
    let relative = self
      .path
      .strip_prefix(&current_dir)
      .with_context(|| format!("Failed to strip prefix from {}", self.path.display()))?;

    Ok(Dir::new(relative.to_path_buf()))
  }

  /// Gets the parent directory of the file.
  ///
  /// # Returns
  /// * `Dir` - The parent directory
  pub fn parent(&self) -> Dir {
    Dir::new(self.path.parent().unwrap_or(Path::new("")).to_path_buf())
  }
}

impl From<&File> for Dir {
  fn from(file: &File) -> Self {
    file.parent()
  }
}

impl std::fmt::Display for File {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    let path = self.relative_path().unwrap_or_else(|_| self.into());
    write!(f, "{}", path.path.display())
  }
}

impl From<File> for Result<File> {
  fn from(file: File) -> Result<File> {
    Ok(file)
  }
}

/// Represents a directory in the filesystem.
/// Provides operations for directory manipulation.
#[derive(Debug, Clone)]
pub struct Dir {
  path: PathBuf
}

impl Dir {
  /// Creates a new Dir instance.
  ///
  /// # Arguments
  /// * `path` - The path to the directory
  pub fn new(path: PathBuf) -> Self {
    Self { path }
  }

  /// Checks if the directory exists.
  ///
  /// # Returns
  /// * `bool` - true if the directory exists, false otherwise
  pub fn exists(&self) -> bool {
    self.path.exists()
  }

  /// Creates the directory and all parent directories if they don't exist.
  ///
  /// # Returns
  /// * `Result<()>` - Success or an error if creation fails
  pub fn create_dir_all(&self) -> Result<()> {
    log::debug!("Creating directory at {self}");
    fs::create_dir_all(&self.path).with_context(|| format!("Failed to create directory at {self}"))
  }

  /// Gets the relative path from the current directory.
  ///
  /// # Returns
  /// * `Result<Self>` - The relative path or an error
  pub fn relative_path(&self) -> Result<Self> {
    let current_dir = env::current_dir().context(ERR_CURRENT_DIR)?;
    let relative = self
      .path
      .strip_prefix(&current_dir)
      .with_context(|| format!("Failed to strip prefix from {}", self.path.display()))?;

    Ok(Self::new(relative.to_path_buf()))
  }
}

impl std::fmt::Display for Dir {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    write!(f, "{}", self.path.display())
  }
}

impl From<Dir> for Result<Dir> {
  fn from(dir: Dir) -> Result<Dir> {
    Ok(dir)
  }
}

impl Filesystem {
  /// Creates a new Filesystem instance.
  /// Initializes paths for git hooks and binaries.
  ///
  /// # Returns
  /// * `Result<Self>` - The initialized filesystem or an error
  pub fn new() -> Result<Self> {
    // Get current directory
    let current_dir = env::current_dir().context(ERR_CURRENT_DIR)?;

    // Get executable path
    let git_ai_bin_path = env::current_exe().context("Failed to get current executable")?;

    // Open git repository
    let repo = Repository::open_ext(&current_dir, Flags::empty(), Vec::<&Path>::new())
      .with_context(|| format!("Failed to open repository at {}", current_dir.display()))?;

    // Get git path and ensure it's absolute
    let git_path = {
      let mut path = repo.path().to_path_buf();
      if path.is_relative() {
        path = current_dir.join(path);
      }
      path
    };

    // Get hook binary path
    let git_ai_hook_bin_path = {
      let hook_path = git_ai_bin_path
        .parent()
        .with_context(|| format!("Failed to get parent directory of {}", git_ai_bin_path.display()))?
        .join("git-ai-hook");

      if !hook_path.exists() {
        bail!("Hook binary not found at {}", hook_path.display());
      }
      hook_path
    };

    Ok(Self {
      git_ai_hook_bin_path,
      git_hooks_path: git_path.join("hooks")
    })
  }

  /// Gets the path to the git-ai hook binary.
  ///
  /// # Returns
  /// * `Result<File>` - The hook binary path or an error
  pub fn git_ai_hook_bin_path(&self) -> Result<File> {
    Ok(File::new(self.git_ai_hook_bin_path.clone()))
  }

  /// Gets the path to the prepare-commit-msg hook.
  ///
  /// # Returns
  /// * `Result<File>` - The hook path or an error
  pub fn prepare_commit_msg_path(&self) -> Result<File> {
    if !self.git_hooks_path.exists() {
      bail!("Hooks directory not found at {}", self.git_hooks_path.display());
    }

    Ok(File::new(self.git_hooks_path.join("prepare-commit-msg")))
  }
}