// Copyright 2016-2019 Cargo-Bundle developers <https://github.com/burtonageo/cargo-bundle>
// Copyright 2019-2024 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

use std::{
  fs::{self, File},
  io::{self, BufWriter},
  path::Path,
};

/// Creates a new file at the given path, creating any parent directories as
/// needed.
pub fn create_file(path: &Path) -> crate::Result<BufWriter<File>> {
  if let Some(parent) = path.parent() {
    fs::create_dir_all(parent)?;
  }
  let file = File::create(path)?;
  Ok(BufWriter::new(file))
}

/// Creates the given directory path,
/// erasing it first if specified.
#[allow(dead_code)]
pub fn create_dir(path: &Path, erase: bool) -> crate::Result<()> {
  if erase && path.exists() {
    remove_dir_all(path)?;
  }
  Ok(fs::create_dir(path)?)
}

/// Creates all of the directories of the specified path,
/// erasing it first if specified.
#[allow(dead_code)]
pub fn create_dir_all(path: &Path, erase: bool) -> crate::Result<()> {
  if erase && path.exists() {
    remove_dir_all(path)?;
  }
  Ok(fs::create_dir_all(path)?)
}

/// Removes the directory and its contents if it exists.
#[allow(dead_code)]
pub fn remove_dir_all(path: &Path) -> crate::Result<()> {
  if path.exists() {
    Ok(fs::remove_dir_all(path)?)
  } else {
    Ok(())
  }
}

/// Makes a symbolic link to a directory.
#[cfg(unix)]
#[allow(dead_code)]
fn symlink_dir(src: &Path, dst: &Path) -> io::Result<()> {
  std::os::unix::fs::symlink(src, dst)
}

/// Makes a symbolic link to a directory.
#[cfg(windows)]
fn symlink_dir(src: &Path, dst: &Path) -> io::Result<()> {
  std::os::windows::fs::symlink_dir(src, dst)
}

/// Makes a symbolic link to a file.
#[cfg(unix)]
#[allow(dead_code)]
fn symlink_file(src: &Path, dst: &Path) -> io::Result<()> {
  std::os::unix::fs::symlink(src, dst)
}

/// Makes a symbolic link to a file.
#[cfg(windows)]
fn symlink_file(src: &Path, dst: &Path) -> io::Result<()> {
  std::os::windows::fs::symlink_file(src, dst)
}

/// Copies a regular file from one path to another, creating any parent
/// directories of the destination path as necessary. Fails if the source path
/// is a directory or doesn't exist.
pub fn copy_file(from: &Path, to: &Path) -> crate::Result<()> {
  if !from.exists() {
    return Err(crate::Error::GenericError(format!(
      "{from:?} does not exist"
    )));
  }
  if !from.is_file() {
    return Err(crate::Error::GenericError(format!(
      "{from:?} is not a file"
    )));
  }
  let dest_dir = to.parent().expect("No data in parent");
  fs::create_dir_all(dest_dir)?;
  fs::copy(from, to)?;
  Ok(())
}

/// Recursively copies a directory file from one path to another, creating any
/// parent directories of the destination path as necessary.  Fails if the
/// source path is not a directory or doesn't exist, or if the destination path
/// already exists.
#[allow(dead_code)]
pub fn copy_dir(from: &Path, to: &Path) -> crate::Result<()> {
  if !from.exists() {
    return Err(crate::Error::GenericError(format!(
      "{from:?} does not exist"
    )));
  }
  if !from.is_dir() {
    return Err(crate::Error::GenericError(format!(
      "{from:?} is not a Directory"
    )));
  }
  let parent = to.parent().expect("No data in parent");
  fs::create_dir_all(parent)?;
  for entry in walkdir::WalkDir::new(from) {
    let entry = entry?;
    debug_assert!(entry.path().starts_with(from));
    let rel_path = entry.path().strip_prefix(from)?;
    let dest_path = to.join(rel_path);
    if entry.file_type().is_symlink() {
      let target = fs::read_link(entry.path())?;
      if entry.path().is_dir() {
        symlink_dir(&target, &dest_path)?;
      } else {
        symlink_file(&target, &dest_path)?;
      }
    } else if entry.file_type().is_dir() {
      fs::create_dir_all(dest_path)?;
    } else {
      fs::copy(entry.path(), dest_path)?;
    }
  }
  Ok(())
}

/// Copies user-defined files specified in the configuration file to the package.
///
/// The configuration object maps the path in the package to the path of the file on the filesystem,
/// relative to the tauri.conf.json file.
///
/// Expects a HashMap of PathBuf entries, representing destination and source paths,
/// and also a path of a directory. The files will be stored with respect to this directory.
#[cfg(any(
  target_os = "linux",
  target_os = "dragonfly",
  target_os = "freebsd",
  target_os = "netbsd",
  target_os = "openbsd"
))]
pub fn copy_custom_files(
  files_map: &std::collections::HashMap<std::path::PathBuf, std::path::PathBuf>,
  data_dir: &Path,
) -> crate::Result<()> {
  for (pkg_path, path) in files_map.iter() {
    let pkg_path = if pkg_path.is_absolute() {
      pkg_path.strip_prefix("/").unwrap()
    } else {
      pkg_path
    };
    if path.is_file() {
      copy_file(path, &data_dir.join(pkg_path))?;
    } else {
      copy_dir(path, &data_dir.join(pkg_path))?;
    }
  }
  Ok(())
}

#[cfg(test)]
mod tests {
  use super::create_file;
  use std::io::Write;

  #[test]
  fn create_file_with_parent_dirs() {
    let tmp = tempfile::tempdir().expect("Unable to create temp dir");
    assert!(!tmp.path().join("parent").exists());
    {
      let mut file =
        create_file(&tmp.path().join("parent/file.txt")).expect("Failed to create file");
      writeln!(file, "Hello, world!").expect("unable to write file");
    }
    assert!(tmp.path().join("parent").is_dir());
    assert!(tmp.path().join("parent/file.txt").is_file());
  }

  #[cfg(not(windows))]
  #[test]
  fn copy_dir_with_symlinks() {
    use std::path::PathBuf;

    // Create a directory structure that looks like this:
    //   ${TMP}/orig/
    //       sub/
    //           file.txt
    //       link -> sub/file.txt
    let tmp = tempfile::tempdir().expect("unable to create tempdir");
    {
      let mut file =
        create_file(&tmp.path().join("orig/sub/file.txt")).expect("Unable to create file");
      writeln!(file, "Hello, world!").expect("Unable to write to file");
    }
    super::symlink_file(
      &PathBuf::from("sub/file.txt"),
      &tmp.path().join("orig/link"),
    )
    .expect("Failed to create symlink");
    assert_eq!(
      std::fs::read(tmp.path().join("orig/link"))
        .expect("Failed to read file")
        .as_slice(),
      b"Hello, world!\n"
    );
    // Copy ${TMP}/orig to ${TMP}/parent/copy, and make sure that the
    // directory structure, file, and symlink got copied correctly.
    super::copy_dir(&tmp.path().join("orig"), &tmp.path().join("parent/copy"))
      .expect("Failed to copy dir");
    assert!(tmp.path().join("parent/copy").is_dir());
    assert!(tmp.path().join("parent/copy/sub").is_dir());
    assert!(tmp.path().join("parent/copy/sub/file.txt").is_file());
    assert_eq!(
      std::fs::read(tmp.path().join("parent/copy/sub/file.txt"))
        .expect("Failed to read file")
        .as_slice(),
      b"Hello, world!\n"
    );
    assert!(tmp.path().join("parent/copy/link").exists());
    assert_eq!(
      std::fs::read_link(tmp.path().join("parent/copy/link")).expect("Failed to read from symlink"),
      PathBuf::from("sub/file.txt")
    );
    assert_eq!(
      std::fs::read(tmp.path().join("parent/copy/link"))
        .expect("Failed to read from file")
        .as_slice(),
      b"Hello, world!\n"
    );
  }
}