// Copyright 2015-2018 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/>.

//! JSON VM output.

use std::collections::HashMap;
use std::mem;

use ethereum_types::{U256, H256};
use bytes::ToPretty;
use ethcore::trace;

use display;
use info as vm;

/// JSON formatting informant.
#[derive(Default)]
pub struct Informant {
	code: Vec<u8>,
	depth: usize,
	pc: usize,
	instruction: u8,
	gas_cost: U256,
	gas_used: U256,
	stack: Vec<U256>,
	memory: Vec<u8>,
	storage: HashMap<H256, H256>,
	traces: Vec<String>,
	subtraces: Vec<String>,
	unmatched: bool,
}

impl vm::Informant for Informant {
	fn before_test(&mut self, name: &str, action: &str) {
		println!("{}", json!({"action": action, "test": name}));
	}

	fn set_gas(&mut self, gas: U256) {
		self.gas_used = gas;
	}

	fn finish(result: vm::RunResult<Self::Output>) {
		match result {
			Ok(success) => {
				for trace in success.traces.unwrap_or_else(Vec::new) {
					println!("{}", trace);
				}

				let success_msg = json!({
					"output": format!("0x{}", success.output.to_hex()),
					"gasUsed": format!("{:#x}", success.gas_used),
					"time": display::as_micros(&success.time),
				});

				println!("{}", success_msg)
			},
			Err(failure) => {
				for trace in failure.traces.unwrap_or_else(Vec::new) {
					println!("{}", trace);
				}

				let failure_msg = json!({
					"error": &failure.error.to_string(),
					"gasUsed": format!("{:#x}", failure.gas_used),
					"time": display::as_micros(&failure.time),
				});

				println!("{}", failure_msg)
			},
		}
	}
}

impl trace::VMTracer for Informant {
	type Output = Vec<String>;

	fn trace_next_instruction(&mut self, pc: usize, instruction: u8, _current_gas: U256) -> bool {
		self.pc = pc;
		self.instruction = instruction;
		self.unmatched = true;
		true
	}

	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: U256) {
		self.pc = pc;
		self.instruction = instruction;
		self.gas_cost = gas_cost;
	}

	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem_diff: Option<(usize, &[u8])>, store_diff: Option<(U256, U256)>) {
		let info = ::evm::Instruction::from_u8(self.instruction).map(|i| i.info());

		let trace = json!({
			"pc": self.pc,
			"op": self.instruction,
			"opName": info.map(|i| i.name).unwrap_or(""),
			"gas": format!("{:#x}", gas_used.saturating_add(self.gas_cost)),
			"gasCost": format!("{:#x}", self.gas_cost),
			"memory": format!("0x{}", self.memory.to_hex()),
			"stack": self.stack,
			"storage": self.storage,
			"depth": self.depth,
		});

		self.traces.push(trace.to_string());

		self.unmatched = false;
		self.gas_used = gas_used;

		let len = self.stack.len();
		let info_args = info.map(|i| i.args).unwrap_or(0);
		self.stack.truncate(if len > info_args { len - info_args } else { 0 });
		self.stack.extend_from_slice(stack_push);

		// TODO [ToDr] Align memory?
		if let Some((pos, data)) = mem_diff {
			if self.memory.len() < (pos + data.len()) {
				self.memory.resize(pos + data.len(), 0);
			}
			self.memory[pos..pos + data.len()].copy_from_slice(data);
		}

		if let Some((pos, val)) = store_diff {
			self.storage.insert(pos.into(), val.into());
		}

		if !self.subtraces.is_empty() {
			self.traces.extend(mem::replace(&mut self.subtraces, vec![]));
		}
	}

	fn prepare_subtrace(&self, code: &[u8]) -> Self where Self: Sized {
		let mut vm = Informant::default();
		vm.depth = self.depth + 1;
		vm.code = code.to_vec();
		vm.gas_used = self.gas_used;
		vm
	}

	fn done_subtrace(&mut self, sub: Self) {
		if let Some(subtraces) = sub.drain() {
			self.subtraces.extend(subtraces);
		}
	}

	fn drain(mut self) -> Option<Self::Output> {
		if self.unmatched {
			// print last line with final state:
			self.gas_cost = 0.into();
			let gas_used = self.gas_used;
			self.trace_executed(gas_used, &[], None, None);
		} else if !self.subtraces.is_empty() {
			self.traces.extend(mem::replace(&mut self.subtraces, vec![]));
		}
		Some(self.traces)
	}
}

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

	#[derive(Serialize, Deserialize, Debug, PartialEq)]
	#[serde(rename_all = "camelCase")]
	struct TestTrace {
		pc: usize,
		#[serde(rename = "op")]
		instruction: u8,
		op_name: String,
		#[serde(rename = "gas")]
		gas_used: U256,
		gas_cost: U256,
		memory: String,
		stack: Vec<U256>,
		storage: HashMap<H256, H256>,
		depth: usize,
	}

	fn assert_traces_eq(
		a: &[String],
		b: &[String],
	) {
		let mut ita = a.iter();
		let mut itb = b.iter();

		loop {
			match (ita.next(), itb.next()) {
				(Some(a), Some(b)) => {
					// Compare both without worrying about the order of the fields
					let actual: TestTrace = serde_json::from_str(a).unwrap();
					let expected: TestTrace = serde_json::from_str(b).unwrap();
					assert_eq!(actual, expected);
					println!("{}", a);
				},
				(None, None) => return,
				e => {
					panic!("Traces mismatch: {:?}", e);
				}
			}
		}
	}

	fn compare_json(traces: Option<Vec<String>>, expected: &str) {
		let expected = expected.split("\n")
			.map(|x| x.trim())
			.map(|x| x.to_owned())
			.filter(|x| !x.is_empty())
			.collect::<Vec<_>>();
		assert_traces_eq(&traces.unwrap(), &expected);
	}

	#[test]
	fn should_trace_failure() {
		run_test(
			Informant::default(),
			&compare_json,
			"60F8d6",
			0xffff,
			r#"
{"pc":0,"op":96,"opName":"PUSH1","gas":"0xffff","gasCost":"0x3","memory":"0x","stack":[],"storage":{},"depth":1}
{"pc":2,"op":214,"opName":"","gas":"0xfffc","gasCost":"0x0","memory":"0x","stack":["0xf8"],"storage":{},"depth":1}
			"#,
		);

		run_test(
			Informant::default(),
			&compare_json,
			"F8d6",
			0xffff,
			r#"
{"pc":0,"op":248,"opName":"","gas":"0xffff","gasCost":"0x0","memory":"0x","stack":[],"storage":{},"depth":1}
			"#,
		);
	}

	#[test]
	fn should_trace_create_correctly() {
		run_test(
			Informant::default(),
			&compare_json,
			"32343434345830f138343438323439f0",
			0xffff,
			r#"
{"pc":0,"op":50,"opName":"ORIGIN","gas":"0xffff","gasCost":"0x2","memory":"0x","stack":[],"storage":{},"depth":1}
{"pc":1,"op":52,"opName":"CALLVALUE","gas":"0xfffd","gasCost":"0x2","memory":"0x","stack":["0x0"],"storage":{},"depth":1}
{"pc":2,"op":52,"opName":"CALLVALUE","gas":"0xfffb","gasCost":"0x2","memory":"0x","stack":["0x0","0x0"],"storage":{},"depth":1}
{"pc":3,"op":52,"opName":"CALLVALUE","gas":"0xfff9","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0"],"storage":{},"depth":1}
{"pc":4,"op":52,"opName":"CALLVALUE","gas":"0xfff7","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0","0x0"],"storage":{},"depth":1}
{"pc":5,"op":88,"opName":"PC","gas":"0xfff5","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0","0x0","0x0"],"storage":{},"depth":1}
{"pc":6,"op":48,"opName":"ADDRESS","gas":"0xfff3","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0","0x0","0x0","0x5"],"storage":{},"depth":1}
{"pc":7,"op":241,"opName":"CALL","gas":"0xfff1","gasCost":"0x61d0","memory":"0x","stack":["0x0","0x0","0x0","0x0","0x0","0x5","0x0"],"storage":{},"depth":1}
{"pc":8,"op":56,"opName":"CODESIZE","gas":"0x9e21","gasCost":"0x2","memory":"0x","stack":["0x1"],"storage":{},"depth":1}
{"pc":9,"op":52,"opName":"CALLVALUE","gas":"0x9e1f","gasCost":"0x2","memory":"0x","stack":["0x1","0x10"],"storage":{},"depth":1}
{"pc":10,"op":52,"opName":"CALLVALUE","gas":"0x9e1d","gasCost":"0x2","memory":"0x","stack":["0x1","0x10","0x0"],"storage":{},"depth":1}
{"pc":11,"op":56,"opName":"CODESIZE","gas":"0x9e1b","gasCost":"0x2","memory":"0x","stack":["0x1","0x10","0x0","0x0"],"storage":{},"depth":1}
{"pc":12,"op":50,"opName":"ORIGIN","gas":"0x9e19","gasCost":"0x2","memory":"0x","stack":["0x1","0x10","0x0","0x0","0x10"],"storage":{},"depth":1}
{"pc":13,"op":52,"opName":"CALLVALUE","gas":"0x9e17","gasCost":"0x2","memory":"0x","stack":["0x1","0x10","0x0","0x0","0x10","0x0"],"storage":{},"depth":1}
{"pc":14,"op":57,"opName":"CODECOPY","gas":"0x9e15","gasCost":"0x9","memory":"0x","stack":["0x1","0x10","0x0","0x0","0x10","0x0","0x0"],"storage":{},"depth":1}
{"pc":15,"op":240,"opName":"CREATE","gas":"0x9e0c","gasCost":"0x9e0c","memory":"0x32343434345830f138343438323439f0","stack":["0x1","0x10","0x0","0x0"],"storage":{},"depth":1}
{"pc":0,"op":50,"opName":"ORIGIN","gas":"0x210c","gasCost":"0x2","memory":"0x","stack":[],"storage":{},"depth":2}
{"pc":1,"op":52,"opName":"CALLVALUE","gas":"0x210a","gasCost":"0x2","memory":"0x","stack":["0x0"],"storage":{},"depth":2}
{"pc":2,"op":52,"opName":"CALLVALUE","gas":"0x2108","gasCost":"0x2","memory":"0x","stack":["0x0","0x0"],"storage":{},"depth":2}
{"pc":3,"op":52,"opName":"CALLVALUE","gas":"0x2106","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0"],"storage":{},"depth":2}
{"pc":4,"op":52,"opName":"CALLVALUE","gas":"0x2104","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0","0x0"],"storage":{},"depth":2}
{"pc":5,"op":88,"opName":"PC","gas":"0x2102","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0","0x0","0x0"],"storage":{},"depth":2}
{"pc":6,"op":48,"opName":"ADDRESS","gas":"0x2100","gasCost":"0x2","memory":"0x","stack":["0x0","0x0","0x0","0x0","0x0","0x5"],"storage":{},"depth":2}
{"pc":7,"op":241,"opName":"CALL","gas":"0x20fe","gasCost":"0x0","memory":"0x","stack":["0x0","0x0","0x0","0x0","0x0","0x5","0xbd770416a3345f91e4b34576cb804a576fa48eb1"],"storage":{},"depth":2}
"#,
		);

		run_test(
			Informant::default(),
			&compare_json,
			"3260D85554",
			0xffff,
			r#"
{"pc":0,"op":50,"opName":"ORIGIN","gas":"0xffff","gasCost":"0x2","memory":"0x","stack":[],"storage":{},"depth":1}
{"pc":1,"op":96,"opName":"PUSH1","gas":"0xfffd","gasCost":"0x3","memory":"0x","stack":["0x0"],"storage":{},"depth":1}
{"pc":3,"op":85,"opName":"SSTORE","gas":"0xfffa","gasCost":"0x1388","memory":"0x","stack":["0x0","0xd8"],"storage":{},"depth":1}
{"pc":4,"op":84,"opName":"SLOAD","gas":"0xec72","gasCost":"0x0","memory":"0x","stack":[],"storage":{"0x00000000000000000000000000000000000000000000000000000000000000d8":"0x0000000000000000000000000000000000000000000000000000000000000000"},"depth":1}
"#,
		)
	}
}