// Copyright 2015, 2016 Ethcore (UK) Ltd.
// This file is part of Parity.

// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity.  If not, see <http://www.gnu.org/licenses/>.

//! Serializable wrapper around vector of bytes

use rustc_serialize::hex::ToHex;
use serde::{Serialize, Serializer, Deserialize, Deserializer, Error};
use serde::de::Visitor;
use util::common::FromHex;

/// Wrapper structure around vector of bytes.
#[derive(Debug, PartialEq, Eq, Default, Hash, Clone)]
pub struct Bytes(pub Vec<u8>);

impl Bytes {
	/// Simple constructor.
	pub fn new(bytes: Vec<u8>) -> Bytes {
		Bytes(bytes)
	}
	/// Convert back to vector
	pub fn to_vec(self) -> Vec<u8> {
		self.0
	}
}

impl From<Vec<u8>> for Bytes {
	fn from(bytes: Vec<u8>) -> Bytes {
		Bytes(bytes)
	}
}

impl Into<Vec<u8>> for Bytes {
	fn into(self) -> Vec<u8> {
		self.0
	}
}

impl Serialize for Bytes {
	fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
	where S: Serializer {
		let mut serialized = "0x".to_owned();
		serialized.push_str(self.0.to_hex().as_ref());
		serializer.serialize_str(serialized.as_ref())
	}
}

impl Deserialize for Bytes {
	fn deserialize<D>(deserializer: &mut D) -> Result<Bytes, D::Error>
	where D: Deserializer {
		deserializer.deserialize(BytesVisitor)
	}
}

struct BytesVisitor;

impl Visitor for BytesVisitor {
	type Value = Bytes;

	fn visit_str<E>(&mut self, value: &str) -> Result<Self::Value, E> where E: Error {
		if value.is_empty() {
			warn!(
				target: "deprecated",
				"Deserializing empty string as empty bytes. This is a non-standard behaviour that will be removed in future versions. Please update your code to send `0x` instead!"
			);
			Ok(Bytes::new(Vec::new()))
		} else if value.len() >= 2 && &value[0..2] == "0x" && value.len() & 1 == 0 {
			Ok(Bytes::new(try!(FromHex::from_hex(&value[2..]).map_err(|_| Error::custom("invalid hex")))))
		} else {
			Err(Error::custom("invalid format"))
		}
	}

	fn visit_string<E>(&mut self, value: String) -> Result<Self::Value, E> where E: Error {
		self.visit_str(value.as_ref())
	}
}


#[cfg(test)]
mod tests {
	use super::*;
	use serde_json;
	use rustc_serialize::hex::FromHex;

	#[test]
	fn test_bytes_serialize() {
		let bytes = Bytes("0123456789abcdef".from_hex().unwrap());
		let serialized = serde_json::to_string(&bytes).unwrap();
		assert_eq!(serialized, r#""0x0123456789abcdef""#);
	}

	#[test]
	fn test_bytes_deserialize() {
		// TODO [ToDr] Uncomment when Mist starts sending correct data
		// let bytes1: Result<Bytes, serde_json::Error> = serde_json::from_str(r#""""#);
		let bytes2: Result<Bytes, serde_json::Error> = serde_json::from_str(r#""0x123""#);
		let bytes3: Result<Bytes, serde_json::Error> = serde_json::from_str(r#""0xgg""#);

		let bytes4: Bytes = serde_json::from_str(r#""0x""#).unwrap();
		let bytes5: Bytes = serde_json::from_str(r#""0x12""#).unwrap();
		let bytes6: Bytes = serde_json::from_str(r#""0x0123""#).unwrap();

		// assert!(bytes1.is_err());
		assert!(bytes2.is_err());
		assert!(bytes3.is_err());
		assert_eq!(bytes4, Bytes(vec![]));
		assert_eq!(bytes5, Bytes(vec![0x12]));
		assert_eq!(bytes6, Bytes(vec![0x1, 0x23]));
	}

	// TODO [ToDr] Remove when Mist starts sending correct data
	#[test]
	fn test_bytes_lenient_against_the_spec_deserialize_for_empty_string_for_mist_compatibility() {
		let deserialized: Bytes = serde_json::from_str(r#""""#).unwrap();
		assert_eq!(deserialized, Bytes(Vec::new()));
	}
}

