// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
use std::env::current_dir;
use std::fs::OpenOptions;
use std::io::Write;
use std::path::{Component, Path, PathBuf};

use deno_core::ErrBox;
use walkdir::WalkDir;

pub fn write_file<T: AsRef<[u8]>>(
  filename: &Path,
  data: T,
  mode: u32,
) -> std::io::Result<()> {
  write_file_2(filename, data, true, mode, true, false)
}

pub fn write_file_2<T: AsRef<[u8]>>(
  filename: &Path,
  data: T,
  update_mode: bool,
  mode: u32,
  is_create: bool,
  is_append: bool,
) -> std::io::Result<()> {
  let mut file = OpenOptions::new()
    .read(false)
    .write(true)
    .append(is_append)
    .truncate(!is_append)
    .create(is_create)
    .open(filename)?;

  if update_mode {
    #[cfg(unix)]
    {
      use std::os::unix::fs::PermissionsExt;
      let mode = mode & 0o777;
      let permissions = PermissionsExt::from_mode(mode);
      file.set_permissions(permissions)?;
    }
    #[cfg(not(unix))]
    let _ = mode;
  }

  file.write_all(data.as_ref())
}

/// Normalize all itermediate components of the path (ie. remove "./" and "../" components).
/// Similar to `fs::canonicalize()` but doesn't resolve symlinks.
///
/// Taken from Cargo
/// https://github.com/rust-lang/cargo/blob/af307a38c20a753ec60f0ad18be5abed3db3c9ac/src/cargo/util/paths.rs#L60-L85
pub fn normalize_path(path: &Path) -> PathBuf {
  let mut components = path.components().peekable();
  let mut ret =
    if let Some(c @ Component::Prefix(..)) = components.peek().cloned() {
      components.next();
      PathBuf::from(c.as_os_str())
    } else {
      PathBuf::new()
    };

  for component in components {
    match component {
      Component::Prefix(..) => unreachable!(),
      Component::RootDir => {
        ret.push(component.as_os_str());
      }
      Component::CurDir => {}
      Component::ParentDir => {
        ret.pop();
      }
      Component::Normal(c) => {
        ret.push(c);
      }
    }
  }
  ret
}

pub fn resolve_from_cwd(path: &Path) -> Result<PathBuf, ErrBox> {
  let resolved_path = if path.is_absolute() {
    path.to_owned()
  } else {
    let cwd = current_dir().unwrap();
    cwd.join(path)
  };

  Ok(normalize_path(&resolved_path))
}

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

  #[test]
  fn resolve_from_cwd_child() {
    let cwd = current_dir().unwrap();
    assert_eq!(resolve_from_cwd(Path::new("a")).unwrap(), cwd.join("a"));
  }

  #[test]
  fn resolve_from_cwd_dot() {
    let cwd = current_dir().unwrap();
    assert_eq!(resolve_from_cwd(Path::new(".")).unwrap(), cwd);
  }

  #[test]
  fn resolve_from_cwd_parent() {
    let cwd = current_dir().unwrap();
    assert_eq!(resolve_from_cwd(Path::new("a/..")).unwrap(), cwd);
  }

  #[test]
  fn test_normalize_path() {
    assert_eq!(normalize_path(Path::new("a/../b")), PathBuf::from("b"));
    assert_eq!(normalize_path(Path::new("a/./b/")), PathBuf::from("a/b/"));
    assert_eq!(
      normalize_path(Path::new("a/./b/../c")),
      PathBuf::from("a/c")
    );

    if cfg!(windows) {
      assert_eq!(
        normalize_path(Path::new("C:\\a\\.\\b\\..\\c")),
        PathBuf::from("C:\\a\\c")
      );
    }
  }

  // TODO: Get a good expected value here for Windows.
  #[cfg(not(windows))]
  #[test]
  fn resolve_from_cwd_absolute() {
    let expected = Path::new("/a");
    assert_eq!(resolve_from_cwd(expected).unwrap(), expected);
  }
}

pub fn files_in_subtree<F>(root: PathBuf, filter: F) -> Vec<PathBuf>
where
  F: Fn(&Path) -> bool,
{
  assert!(root.is_dir());

  WalkDir::new(root)
    .into_iter()
    .filter_map(|e| e.ok())
    .map(|e| e.path().to_owned())
    .filter(|p| if p.is_dir() { false } else { filter(&p) })
    .collect()
}