// Copyright 2015-2017 Parity Technologies (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/>.

//! State of all accounts in the system expressed in Plain Old Data.

use std::fmt;
use std::collections::BTreeMap;
use itertools::Itertools;
use bigint::hash::H256;
use triehash::sec_trie_root;
use util::*;
use pod_account::{self, PodAccount};
use types::state_diff::StateDiff;
use ethjson;

/// State of all accounts in the system expressed in Plain Old Data.
#[derive(Debug, Clone, PartialEq, Eq, Default)]
pub struct PodState (BTreeMap<Address, PodAccount>);

impl PodState {
	/// Contruct a new object from the `m`.
	pub fn new() -> PodState { Default::default() }

	/// Contruct a new object from the `m`.
	pub fn from(m: BTreeMap<Address, PodAccount>) -> PodState { PodState(m) }

	/// Get the underlying map.
	pub fn get(&self) -> &BTreeMap<Address, PodAccount> { &self.0 }

	/// Get the root hash of the trie of the RLP of this.
	pub fn root(&self) -> H256 {
		sec_trie_root(self.0.iter().map(|(k, v)| (k.to_vec(), v.rlp())).collect())
	}

	/// Drain object to get the underlying map.
	pub fn drain(self) -> BTreeMap<Address, PodAccount> { self.0 }
}

impl From<ethjson::blockchain::State> for PodState {
	fn from(s: ethjson::blockchain::State) -> PodState {
		let state = s.into_iter().map(|(addr, acc)| (addr.into(), PodAccount::from(acc))).collect();
		PodState(state)
	}
}

impl From<ethjson::spec::State> for PodState {
	fn from(s: ethjson::spec::State) -> PodState {
		let state: BTreeMap<_,_> = s.into_iter()
			.filter(|pair| !pair.1.is_empty())
			.map(|(addr, acc)| (addr.into(), PodAccount::from(acc)))
			.collect();
		PodState(state)
	}
}

impl fmt::Display for PodState {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		for (add, acc) in &self.0 {
			writeln!(f, "{} => {}", add, acc)?;
		}
		Ok(())
	}
}

/// Calculate and return diff between `pre` state and `post` state.
pub fn diff_pod(pre: &PodState, post: &PodState) -> StateDiff {
	StateDiff { raw: pre.get().keys().merge(post.get().keys()).filter_map(|acc| pod_account::diff_pod(pre.get().get(acc), post.get().get(acc)).map(|d|(acc.clone(), d))).collect() }
}

#[cfg(test)]
mod test {
	use std::collections::BTreeMap;
	use types::state_diff::*;
	use types::account_diff::*;
	use pod_account::PodAccount;
	use super::PodState;

	#[test]
	fn create_delete() {
		let a = PodState::from(map![ 1.into() => PodAccount::new(69.into(), 0.into(), vec![], map![]) ]);
		assert_eq!(super::diff_pod(&a, &PodState::new()), StateDiff { raw: map![
			1.into() => AccountDiff{
				balance: Diff::Died(69.into()),
				nonce: Diff::Died(0.into()),
				code: Diff::Died(vec![]),
				storage: map![],
			}
		]});
		assert_eq!(super::diff_pod(&PodState::new(), &a), StateDiff{ raw: map![
			1.into() => AccountDiff{
				balance: Diff::Born(69.into()),
				nonce: Diff::Born(0.into()),
				code: Diff::Born(vec![]),
				storage: map![],
			}
		]});
	}

	#[test]
	fn create_delete_with_unchanged() {
		let a = PodState::from(map![ 1.into() => PodAccount::new(69.into(), 0.into(), vec![], map![]) ]);
		let b = PodState::from(map![
			1.into() => PodAccount::new(69.into(), 0.into(), vec![], map![]),
			2.into() => PodAccount::new(69.into(), 0.into(), vec![], map![])
		]);
		assert_eq!(super::diff_pod(&a, &b), StateDiff { raw: map![
			2.into() => AccountDiff{
				balance: Diff::Born(69.into()),
				nonce: Diff::Born(0.into()),
				code: Diff::Born(vec![]),
				storage: map![],
			}
		]});
		assert_eq!(super::diff_pod(&b, &a), StateDiff { raw: map![
			2.into() => AccountDiff{
				balance: Diff::Died(69.into()),
				nonce: Diff::Died(0.into()),
				code: Diff::Died(vec![]),
				storage: map![],
			}
		]});
	}

	#[test]
	fn change_with_unchanged() {
		let a = PodState::from(map![
			1.into() => PodAccount::new(69.into(), 0.into(), vec![], map![]),
			2.into() => PodAccount::new(69.into(), 0.into(), vec![], map![])
		]);
		let b = PodState::from(map![
			1.into() => PodAccount::new(69.into(), 1.into(), vec![], map![]),
			2.into() => PodAccount::new(69.into(), 0.into(), vec![], map![])
		]);
		assert_eq!(super::diff_pod(&a, &b), StateDiff { raw: map![
			1.into() => AccountDiff{
				balance: Diff::Same,
				nonce: Diff::Changed(0.into(), 1.into()),
				code: Diff::Same,
				storage: map![],
			}
		]});
	}

}
