use std::{fs, path::Path};

pub fn is_text_file(path: &Path) -> bool {
    let text_extensions = [
        "txt", "md", "rs", "py", "js", "ts", "jsx", "tsx", "html", "css", "json", "xml", "csv",
        "yaml", "yml", "toml", "ini", "cfg", "conf", "log", "sh", "bat", "ps1", "sql", "c", "cpp",
        "h", "hpp", "java", "go", "rb", "php", "swift", "kt", "scala", "lua", "r", "m",
    ];

    if let Some(ext) = path.extension()
        && let Some(ext_str) = ext.to_str()
    {
        return text_extensions.contains(&ext_str.to_lowercase().as_str());
    }
    false
}

pub fn read_file_sample(path: &Path, max_chars: usize) -> Option<String> {
    use std::io::Read;
    let file = match fs::File::open(path) {
        Ok(f) => f,
        Err(_) => return None,
    };

    let mut buffer = Vec::new();
    let mut handle = file.take(max_chars as u64);
    if handle.read_to_end(&mut buffer).is_err() {
        return None;
    }

    String::from_utf8(buffer).ok()
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs::File;
    use std::io::Write;
    use std::path::Path;

    #[test]
    fn test_is_text_file_with_text_extensions() {
        assert!(is_text_file(Path::new("test.txt")));
        assert!(is_text_file(Path::new("test.rs")));
        assert!(is_text_file(Path::new("test.py")));
        assert!(is_text_file(Path::new("test.md")));
        assert!(is_text_file(Path::new("test.json")));
    }

    #[test]
    fn test_is_text_file_with_binary_extensions() {
        assert!(!is_text_file(Path::new("test.exe")));
        assert!(!is_text_file(Path::new("test.bin")));
        assert!(!is_text_file(Path::new("test.jpg")));
        assert!(!is_text_file(Path::new("test.pdf")));
    }

    #[test]
    fn test_is_text_file_case_insensitive() {
        assert!(is_text_file(Path::new("test.TXT")));
        assert!(is_text_file(Path::new("test.RS")));
        assert!(is_text_file(Path::new("test.Py")));
    }

    #[test]
    fn test_read_file_sample() {
        let temp_dir = tempfile::tempdir().unwrap();
        let file_path = temp_dir.path().join("test.txt");

        let mut file = File::create(&file_path).unwrap();
        file.write_all(b"Hello, World!").unwrap();

        let content = read_file_sample(&file_path, 1000);
        assert_eq!(content, Some("Hello, World!".to_string()));
    }

    #[test]
    fn test_read_file_sample_with_limit() {
        let temp_dir = tempfile::tempdir().unwrap();
        let file_path = temp_dir.path().join("test.txt");

        let mut file = File::create(&file_path).unwrap();
        file.write_all(b"Hello, World! This is a long text.")
            .unwrap();

        let content = read_file_sample(&file_path, 5);
        assert_eq!(content, Some("Hello".to_string()));
    }

    #[test]
    fn test_read_file_sample_binary_file() {
        let temp_dir = tempfile::tempdir().unwrap();
        let file_path = temp_dir.path().join("test.bin");

        let mut file = File::create(&file_path).unwrap();
        file.write_all(&[0x00, 0xFF, 0x80, 0x90]).unwrap();

        let content = read_file_sample(&file_path, 1000);
        assert_eq!(content, None);
    }

    #[test]
    fn test_read_file_sample_nonexistent() {
        let content = read_file_sample(Path::new("/nonexistent/file.txt"), 1000);
        assert_eq!(content, None);
    }
}