// 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/>.

//! Simple executive tracer.

use util::{Bytes, Address, U256};
use action_params::ActionParams;
use trace::trace::{Trace, Call, Create, Action, Res, CreateResult, CallResult, VMTrace, VMOperation, VMExecutedOperation, MemoryDiff, StorageDiff};
use trace::{Tracer, VMTracer};

/// Simple executive tracer. Traces all calls and creates. Ignores delegatecalls.
#[derive(Default)]
pub struct ExecutiveTracer {
	traces: Vec<Trace>,
}

impl Tracer for ExecutiveTracer {
	fn prepare_trace_call(&self, params: &ActionParams) -> Option<Call> {
		Some(Call::from(params.clone()))
	}

	fn prepare_trace_create(&self, params: &ActionParams) -> Option<Create> {
		Some(Create::from(params.clone()))
	}

	fn prepare_trace_output(&self) -> Option<Bytes> {
		Some(vec![])
	}

	fn trace_call(&mut self, call: Option<Call>, gas_used: U256, output: Option<Bytes>, depth: usize, subs: Vec<Trace>, delegate_call: bool) {
		// don't trace if it's DELEGATECALL or CALLCODE.
		if delegate_call {
			return;
		}

		let trace = Trace {
			depth: depth,
			subs: subs,
			action: Action::Call(call.expect("self.prepare_trace_call().is_some(): so we must be tracing: qed")),
			result: Res::Call(CallResult {
				gas_used: gas_used,
				output: output.expect("self.prepare_trace_output().is_some(): so we must be tracing: qed")
			})
		};
		self.traces.push(trace);
	}

	fn trace_create(&mut self, create: Option<Create>, gas_used: U256, code: Option<Bytes>, address: Address, depth: usize, subs: Vec<Trace>) {
		let trace = Trace {
			depth: depth,
			subs: subs,
			action: Action::Create(create.expect("self.prepare_trace_create().is_some(): so we must be tracing: qed")),
			result: Res::Create(CreateResult {
				gas_used: gas_used,
				code: code.expect("self.prepare_trace_output.is_some(): so we must be tracing: qed"),
				address: address
			})
		};
		self.traces.push(trace);
	}

	fn trace_failed_call(&mut self, call: Option<Call>, depth: usize, subs: Vec<Trace>, delegate_call: bool) {
		// don't trace if it's DELEGATECALL or CALLCODE.
		if delegate_call {
			return;
		}

		let trace = Trace {
			depth: depth,
			subs: subs,
			action: Action::Call(call.expect("self.prepare_trace_call().is_some(): so we must be tracing: qed")),
			result: Res::FailedCall,
		};
		self.traces.push(trace);
	}

	fn trace_failed_create(&mut self, create: Option<Create>, depth: usize, subs: Vec<Trace>) {
		let trace = Trace {
			depth: depth,
			subs: subs,
			action: Action::Create(create.expect("self.prepare_trace_create().is_some(): so we must be tracing: qed")),
			result: Res::FailedCreate,
		};
		self.traces.push(trace);
	}

	fn subtracer(&self) -> Self {
		ExecutiveTracer::default()
	}

	fn traces(self) -> Vec<Trace> {
		self.traces
	}
}

/// Simple VM tracer. Traces all operations.
#[derive(Default)]
pub struct ExecutiveVMTracer {
	data: VMTrace,
}

impl VMTracer for ExecutiveVMTracer {
	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: &U256) -> bool {
		self.data.operations.push(VMOperation {
			pc: pc,
			instruction: instruction,
			gas_cost: gas_cost.clone(),	
			executed: None,
		});
		true
	}

	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem_diff: Option<(usize, &[u8])>, store_diff: Option<(U256, U256)>) {
		let ex = VMExecutedOperation {
			gas_used: gas_used,
			stack_push: stack_push.iter().cloned().collect(),
			mem_diff: mem_diff.map(|(s, r)| MemoryDiff{ offset: s, data: r.iter().cloned().collect() }),
			store_diff: store_diff.map(|(l, v)| StorageDiff{ location: l, value: v }),
		};
		self.data.operations.last_mut().expect("trace_executed is always called after a trace_prepare_execute").executed = Some(ex);
	}

	fn prepare_subtrace(&self, code: &Bytes) -> Self {
		ExecutiveVMTracer { data: VMTrace {
			parent_step: self.data.operations.len(),
			code: code.clone(),
			operations: vec![],
			subs: vec![],
		}}
	}

	fn done_subtrace(&mut self, sub: Self) {
		self.data.subs.push(sub.data);
	}

	fn drain(mut self) -> Option<VMTrace> { self.data.subs.pop() }
}