// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

use std::path::Component;
use std::path::Path;
use std::path::PathBuf;

use url::Url;

/// Extension to path_clean::PathClean
pub trait PathClean<T> {
  fn clean(&self) -> T;
}

impl PathClean<PathBuf> for PathBuf {
  fn clean(&self) -> PathBuf {
    fn is_clean_path(path: &Path) -> bool {
      let path = path.to_string_lossy();
      let mut current_index = 0;
      while let Some(index) = path[current_index..].find("\\.") {
        let trailing_index = index + current_index + 2;
        let mut trailing_chars = path[trailing_index..].chars();
        match trailing_chars.next() {
          Some('.') => match trailing_chars.next() {
            Some('/') | Some('\\') | None => {
              return false;
            }
            _ => {}
          },
          Some('/') | Some('\\') => {
            return false;
          }
          _ => {}
        }
        current_index = trailing_index;
      }
      true
    }

    let path = path_clean::PathClean::clean(self);
    if cfg!(windows) && !is_clean_path(&path) {
      // temporary workaround because path_clean::PathClean::clean is
      // not good enough on windows
      let mut components = Vec::new();

      for component in path.components() {
        match component {
          Component::CurDir => {
            // skip
          }
          Component::ParentDir => {
            let maybe_last_component = components.pop();
            if !matches!(maybe_last_component, Some(Component::Normal(_))) {
              panic!("Error normalizing: {}", path.display());
            }
          }
          Component::Normal(_) | Component::RootDir | Component::Prefix(_) => {
            components.push(component);
          }
        }
      }
      components.into_iter().collect::<PathBuf>()
    } else {
      path
    }
  }
}

pub(crate) fn to_file_specifier(path: &Path) -> Url {
  match Url::from_file_path(path) {
    Ok(url) => url,
    Err(_) => panic!("Invalid path: {}", path.display()),
  }
}

// todo(dsherret): we have the below code also in deno_core and it
// would be good to somehow re-use it in both places (we don't want
// to create a dependency on deno_core here)

#[cfg(not(windows))]
#[inline]
pub fn strip_unc_prefix(path: PathBuf) -> PathBuf {
  path
}

/// Strips the unc prefix (ex. \\?\) from Windows paths.
#[cfg(windows)]
pub fn strip_unc_prefix(path: PathBuf) -> PathBuf {
  use std::path::Component;
  use std::path::Prefix;

  let mut components = path.components();
  match components.next() {
    Some(Component::Prefix(prefix)) => {
      match prefix.kind() {
        // \\?\device
        Prefix::Verbatim(device) => {
          let mut path = PathBuf::new();
          path.push(format!(r"\\{}\", device.to_string_lossy()));
          path.extend(components.filter(|c| !matches!(c, Component::RootDir)));
          path
        }
        // \\?\c:\path
        Prefix::VerbatimDisk(_) => {
          let mut path = PathBuf::new();
          path.push(prefix.as_os_str().to_string_lossy().replace(r"\\?\", ""));
          path.extend(components);
          path
        }
        // \\?\UNC\hostname\share_name\path
        Prefix::VerbatimUNC(hostname, share_name) => {
          let mut path = PathBuf::new();
          path.push(format!(
            r"\\{}\{}\",
            hostname.to_string_lossy(),
            share_name.to_string_lossy()
          ));
          path.extend(components.filter(|c| !matches!(c, Component::RootDir)));
          path
        }
        _ => path,
      }
    }
    _ => path,
  }
}

#[cfg(test)]
mod test {
  #[cfg(windows)]
  #[test]
  fn test_path_clean() {
    use super::*;

    run_test("C:\\test\\./file.txt", "C:\\test\\file.txt");
    run_test("C:\\test\\../other/file.txt", "C:\\other\\file.txt");
    run_test("C:\\test\\../other\\file.txt", "C:\\other\\file.txt");

    fn run_test(input: &str, expected: &str) {
      assert_eq!(PathBuf::from(input).clean(), PathBuf::from(expected));
    }
  }

  #[cfg(windows)]
  #[test]
  fn test_strip_unc_prefix() {
    use std::path::PathBuf;

    run_test(r"C:\", r"C:\");
    run_test(r"C:\test\file.txt", r"C:\test\file.txt");

    run_test(r"\\?\C:\", r"C:\");
    run_test(r"\\?\C:\test\file.txt", r"C:\test\file.txt");

    run_test(r"\\.\C:\", r"\\.\C:\");
    run_test(r"\\.\C:\Test\file.txt", r"\\.\C:\Test\file.txt");

    run_test(r"\\?\UNC\localhost\", r"\\localhost");
    run_test(r"\\?\UNC\localhost\c$\", r"\\localhost\c$");
    run_test(
      r"\\?\UNC\localhost\c$\Windows\file.txt",
      r"\\localhost\c$\Windows\file.txt",
    );
    run_test(r"\\?\UNC\wsl$\deno.json", r"\\wsl$\deno.json");

    run_test(r"\\?\server1", r"\\server1");
    run_test(r"\\?\server1\e$\", r"\\server1\e$\");
    run_test(
      r"\\?\server1\e$\test\file.txt",
      r"\\server1\e$\test\file.txt",
    );

    fn run_test(input: &str, expected: &str) {
      assert_eq!(
        super::strip_unc_prefix(PathBuf::from(input)),
        PathBuf::from(expected)
      );
    }
  }
}