use std::{
	fs::File,
	io::{self, Write},
	path::Path,
};

use digest::{self, Digest};
use olpc_cjson::CanonicalFormatter;
use serde::Serialize;
use serde_json::error::Result;

pub fn new_serializer<W: Write>(writer: W) -> serde_json::Serializer<W, CanonicalFormatter> {
	serde_json::Serializer::with_formatter(writer, CanonicalFormatter::new())
}

pub fn to_writer<W: Write, T: ?Sized + Serialize>(writer: W, value: &T) -> Result<()> {
	let mut ser = new_serializer(writer);
	value.serialize(&mut ser)
}

pub fn to_file<P: AsRef<Path>, T: ?Sized + Serialize>(path: P, value: &T) -> io::Result<()> {
	let file = File::create(path)?;
	to_writer(&file, value)?;
	file.sync_all()
}

pub fn to_string<T: ?Sized + Serialize>(value: &T) -> Result<String> {
	let mut ret = Vec::new();
	to_writer(&mut ret, value)?;
	Ok(String::from_utf8(ret).unwrap())
}

pub fn digest<D: Digest + Write, T: ?Sized + Serialize>(value: &T) -> Result<digest::Output<D>> {
	let mut digest = <D as Digest>::new();
	to_writer(&mut digest, value)?;
	Ok(digest.finalize())
}