// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of Open Ethereum.

// Open Ethereum 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.

// Open Ethereum 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 Open Ethereum.  If not, see <http://www.gnu.org/licenses/>.

//! EIP712 structs
use serde_json::{Value};
use std::collections::HashMap;
use ethereum_types::{U256, H256, Address};
use regex::Regex;
use validator::{Validate, ValidationError, ValidationErrors};
use lazy_static::lazy_static;

pub(crate) type MessageTypes = HashMap<String, Vec<FieldType>>;

lazy_static! {
	// match solidity identifier with the addition of '[(\d)*]*'
	static ref TYPE_REGEX: Regex = Regex::new(r"^[a-zA-Z_$][a-zA-Z_$0-9]*(\[([1-9]\d*)*\])*$").unwrap();
	static ref IDENT_REGEX: Regex = Regex::new(r"^[a-zA-Z_$][a-zA-Z_$0-9]*$").unwrap();
}

#[serde(rename_all = "camelCase")]
#[derive(Deserialize, Serialize, Validate, Debug, Clone)]
#[validate(schema(function = "validate_domain"))]
pub(crate) struct EIP712Domain {
	#[serde(skip_serializing_if="Option::is_none")]
	pub(crate) name: Option<String>,
	#[serde(skip_serializing_if="Option::is_none")]
	pub(crate) version: Option<String>,
	#[serde(skip_serializing_if="Option::is_none")]
	pub(crate) chain_id: Option<U256>,
	#[serde(skip_serializing_if="Option::is_none")]
	pub(crate) verifying_contract: Option<Address>,
	#[serde(skip_serializing_if="Option::is_none")]
	pub(crate) salt: Option<H256>,
}

fn validate_domain(domain: &EIP712Domain) -> Result<(), ValidationError> {
	match (domain.name.as_ref(), domain.version.as_ref(), domain.chain_id, domain.verifying_contract, domain.salt) {
		(None, None, None, None, None) => Err(ValidationError::new("EIP712Domain must include at least one field")),
		_ => Ok(())
	}
}

/// EIP-712 struct
#[serde(rename_all = "camelCase")]
#[serde(deny_unknown_fields)]
#[derive(Deserialize, Debug, Clone)]
pub struct EIP712 {
	pub(crate) types: MessageTypes,
	pub(crate) primary_type: String,
	pub(crate) message: Value,
	pub(crate) domain: EIP712Domain,
}

impl Validate for EIP712 {
	fn validate(&self) -> Result<(), ValidationErrors> {
		self.domain.validate()?;
		for field_types in self.types.values() {
			for field_type in field_types {
				field_type.validate()?;
			}
		}
		Ok(())
	}
}

#[derive(Serialize, Deserialize, Validate, Debug, Clone)]
pub(crate) struct FieldType {
	#[validate(regex = "IDENT_REGEX")]
	pub name: String,
	#[serde(rename = "type")]
	#[validate(regex = "TYPE_REGEX")]
	pub type_: String,
}

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

	#[test]
	fn test_regex() {
		let test_cases = vec!["unint bytes32", "Seun\\[]", "byte[]uint", "byte[7[]uint][]", "Person[0]"];
		for case in test_cases {
			assert_eq!(TYPE_REGEX.is_match(case), false)
		}

		let test_cases = vec!["bytes32", "Foo[]", "bytes1", "bytes32[][]", "byte[9]", "contents"];
		for case in test_cases {
			assert_eq!(TYPE_REGEX.is_match(case), true)
		}
	}

	#[test]
	fn test_deserialization() {
		let string = r#"{
			"primaryType": "Mail",
			"domain": {
				"name": "Ether Mail",
				"version": "1",
				"chainId": "0x1",
				"verifyingContract": "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC"
			},
			"message": {
				"from": {
					"name": "Cow",
					"wallet": "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826"
				},
				"to": {
					"name": "Bob",
					"wallet": "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB"
				},
				"contents": "Hello, Bob!"
			},
			"types": {
				"EIP712Domain": [
					{ "name": "name", "type": "string" },
					{ "name": "version", "type": "string" },
					{ "name": "chainId", "type": "uint256" },
					{ "name": "verifyingContract", "type": "address" }
				],
				"Person": [
					{ "name": "name", "type": "string" },
					{ "name": "wallet", "type": "address" }
				],
				"Mail": [
					{ "name": "from", "type": "Person" },
					{ "name": "to", "type": "Person" },
					{ "name": "contents", "type": "string" }
				]
			}
		}"#;
		let _ = from_str::<EIP712>(string).unwrap();
	}

	#[test]
	fn test_failing_deserialization() {
		let string = r#"{
			"primaryType": "Mail",
			"domain": {
				"name": "Ether Mail",
				"version": "1",
				"chainId": "0x1",
				"verifyingContract": "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC"
			},
			"message": {
				"from": {
					"name": "Cow",
					"wallet": "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826"
				},
				"to": {
					"name": "Bob",
					"wallet": "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB"
				},
				"contents": "Hello, Bob!"
			},
			"types": {
				"EIP712Domain": [
					{ "name": "name", "type": "string" },
					{ "name": "version", "type": "string" },
					{ "name": "chainId", "type": "7uint256[x] Seun" },
					{ "name": "verifyingContract", "type": "address" },
					{ "name": "salt", "type": "bytes32" }
				],
				"Person": [
					{ "name": "name", "type": "string" },
					{ "name": "wallet amen", "type": "address" }
				],
				"Mail": [
					{ "name": "from", "type": "Person" },
					{ "name": "to", "type": "Person" },
					{ "name": "contents", "type": "string" }
				]
			}
		}"#;
		let data = from_str::<EIP712>(string).unwrap();
		assert_eq!(data.validate().is_err(), true);
	}

    #[test]
	fn test_valid_domain() {
		let string = r#"{
			"primaryType": "Test",
			"domain": {
				"name": "Ether Mail",
				"version": "1",
				"chainId": "0x1",
				"verifyingContract": "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
				"salt": "0x0000000000000000000000000000000000000000000000000000000000000001"
			},
			"message": {
				"test": "It works!"
			},
			"types": {
				"EIP712Domain": [
					{ "name": "name", "type": "string" },
					{ "name": "version", "type": "string" },
					{ "name": "chainId", "type": "uint256" },
					{ "name": "verifyingContract", "type": "address" },
					{ "name": "salt", "type": "bytes32" }
				],
				"Test": [
					{ "name": "test", "type": "string" }
				]
			}
		}"#;
		let data = from_str::<EIP712>(string).unwrap();
		assert_eq!(data.validate().is_err(), false);
	}

	#[test]
	fn domain_needs_at_least_one_field() {
		let string = r#"{
			"primaryType": "Test",
			"domain": {},
			"message": {
				"test": "It works!"
			},
			"types": {
				"EIP712Domain": [
					{ "name": "name", "type": "string" },
					{ "name": "version", "type": "string" },
					{ "name": "chainId", "type": "uint256" },
					{ "name": "verifyingContract", "type": "address" }
				],
				"Test": [
					{ "name": "test", "type": "string" }
				]
			}
		}"#;
		let data = from_str::<EIP712>(string).unwrap();
		assert_eq!(data.validate().is_err(), true);
	}
}
