use ulid::Ulid;

use super::ids::AccountId;

#[derive(Debug, thiserror::Error)]
pub enum PathError {
    #[error("path is empty")]
    Empty,
    #[error("invalid ULID segment: {0}")]
    BadSegment(String),
}

#[derive(Clone)]
pub struct MaterializedPath(String);

impl MaterializedPath {
    pub fn parse(s: &str) -> Result<Self, PathError> {
        if s.is_empty() {
            return Err(PathError::Empty);
        }
        for seg in s.split('/') {
            Ulid::from_string(seg).map_err(|_| PathError::BadSegment(seg.to_string()))?;
        }
        Ok(MaterializedPath(s.to_string()))
    }
    pub fn as_str(&self) -> &str { &self.0 }
    pub fn depth(&self) -> usize { self.0.split('/').count() }
    pub fn is_ancestor_of(&self, other: &MaterializedPath) -> bool {
        other.0.starts_with(&self.0) && other.0.as_bytes().get(self.0.len()) == Some(&b'/')
    }
    pub fn with_child(&self, id: AccountId) -> MaterializedPath {
        MaterializedPath(format!("{}/{}", self.0, id.as_ulid()))
    }
    pub fn root(id: AccountId) -> MaterializedPath {
        MaterializedPath(id.as_ulid().to_string())
    }
}