use std::io::{Cursor, Read};

pub trait CursorExt {
    fn read_u8(&mut self) -> anyhow::Result<u8>;
    fn read_u16(&mut self) -> anyhow::Result<u16>;
    fn read_u32(&mut self) -> anyhow::Result<u32>;
    fn read_bytes(&mut self, len: usize) -> anyhow::Result<Vec<u8>>;
    fn read_string(&mut self, len: usize) -> anyhow::Result<String>;
}

impl CursorExt for Cursor<&[u8]> {
    fn read_u8(&mut self) -> anyhow::Result<u8> {
        let mut result = [0u8; 1];
        self.read_exact(&mut result)?;
        Ok(result[0])
    }

    fn read_u16(&mut self) -> anyhow::Result<u16> {
        let mut result = [0u8; 2];
        self.read_exact(&mut result)?;
        Ok(u16::from_be_bytes(result))
    }

    fn read_u32(&mut self) -> anyhow::Result<u32> {
        let mut result = [0u8; 4];
        self.read_exact(&mut result)?;
        Ok(u32::from_be_bytes(result))
    }

    fn read_bytes(&mut self, len: usize) -> anyhow::Result<Vec<u8>> {
        let mut result = vec![0u8; len];
        self.read_exact(&mut result)?;
        Ok(result)
    }

    fn read_string(&mut self, len: usize) -> anyhow::Result<String> {
        let result = self.read_bytes(len)?;
        Ok(String::from_utf8_lossy(&result).to_string())
    }
}