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

use walkdir::WalkDir;

pub fn path_to_lowercase(path: impl AsRef<Path>) -> PathBuf {
    PathBuf::from(path.as_ref().to_string_lossy().to_lowercase())
}

/// Searches for a path but ignores case. Returns the first it finds.
pub fn resolve_case_insensitive(
    base: impl AsRef<Path>,
    rel: impl AsRef<Path>,
) -> io::Result<Option<PathBuf>> {
    let mut current = base.as_ref().to_path_buf();

    for part in rel.as_ref().iter() {
        let target = part.to_string_lossy();

        let mut found = None;

        for entry in fs::read_dir(&current)? {
            let entry = entry?;
            let name = entry.file_name();
            let name = name.to_string_lossy();

            if name.eq_ignore_ascii_case(&target) {
                found = Some(entry.path());
                break;
            }
        }

        match found {
            Some(path) => current = path,
            None => {
                return Ok(None);
            }
        }
    }

    Ok(Some(current))
}

/// Use walkdir to walk all actual files in a dir
/// Returns early if any error occurs
pub fn walk_all_files(
    path: impl AsRef<Path>,
) -> Result<impl Iterator<Item = walkdir::DirEntry>, walkdir::Error> {
    let a = WalkDir::new(path)
        .into_iter()
        .collect::<Result<Vec<_>, walkdir::Error>>()?
        .into_iter()
        .filter(|entry| entry.file_type().is_file());

    Ok(a)
}

pub fn is_plugin_file(filename: impl AsRef<Path>) -> bool {
    filename
        .as_ref()
        .extension()
        .is_some_and(|ext| ext == "esp" || ext == "esm" || ext == "esl")
}