use super::*;

pub struct CircularPathBuffer {
    buffer: [u8; 256],
    pointer: u8,
}

impl CircularPathBuffer {
    pub fn new() -> Self {
        Self { buffer: [0; 256] , pointer: 0 }
    }

    pub fn clear(&mut self) {
        self.buffer.fill(0);
        self.pointer = 0;
    }

    pub fn populate(&mut self, bytes: &[u8]) {
        self.clear();
        if bytes.len() > 255 {
            unreachable!(
                "Attempted to populate CircularPathBuffer with {} bytes: {:?}",
                bytes.len(), String::from_utf8_lossy(bytes)
            )
        }
        let self_slice = &mut self.buffer[..bytes.len()];
        self_slice.copy_from_slice(&bytes);
    }

    pub fn set_pointer(&mut self, value: u8) {
        self.pointer = 0;
        if value != 0x00 {
            for (i, c) in self.buffer.iter().enumerate() {
                match c {
                    b'/' => self.pointer = (i + 1) as u8,
                    0x00 => break,
                    _ => continue,
                }
            }
        }
    }

    pub fn read_byte(&mut self) -> u8 {
        let pointer = self.pointer as usize;
        self.pointer = self.pointer.wrapping_add(1);
        self.buffer[pointer]
    }

    // Returns an unsanitized relative path.
    pub fn push_byte(&mut self, value: u8) -> Option<PathBuf> {
        if value == 0x00 {
            let pointer = self.pointer as usize;
            let path = bytes_to_path(&self.buffer[..pointer]);
            self.clear();
            Some(path)
        } else {
            let pointer = self.pointer as usize;
            self.pointer = self.pointer.wrapping_add(1);
            self.buffer[pointer] = value;
            None
        }
    }
}