use core::fmt;
use std::fmt::Display;

use serde::{Deserialize, Serialize};

use super::Path;

#[derive(Serialize, Deserialize, Clone, PartialEq, Eq)]
pub struct Hash(String);

impl From<Path> for Hash {
    fn from(path: Path) -> Self {
	path.hash 
    }
}

impl Display for Hash {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
	f.write_str(self.0.as_ref())
    }
}

impl fmt::Debug for Hash {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	Display::fmt(self, f)
    }
}

impl Hash {
    pub fn parse<S: AsRef<str>>(str: S) -> Result<Self, (usize, char)> {
	let str = str.as_ref();
	let match_closure = |acc, c|
	match acc {
	    Ok(i) => match c {
		'a'..='z' | '0'..='9' => Ok(i + 1),
		_ => Err((i, c)),
	    }
	    Err(x) => Err(x)
	};

	match str.chars().fold(Ok(0usize), match_closure) {
	    Ok(_) => Ok(Hash(str.into())),
	    Err(err) => Err(err),
	}
    }

    pub fn to_string(self) -> String {
	self.0
    }
}