// 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/>.

//! Tracing

mod config;
mod db;
mod executive_tracer;
mod import;
mod noop_tracer;
mod types;

pub use self::config::Config;
pub use self::db::TraceDB;
pub use self::noop_tracer::{NoopTracer, NoopVMTracer};
pub use self::executive_tracer::{ExecutiveTracer, ExecutiveVMTracer};
pub use self::import::ImportRequest;
pub use self::localized::LocalizedTrace;

pub use self::types::{filter, flat, localized, trace};
pub use self::types::error::Error as TraceError;
pub use self::types::trace::{VMTrace, VMOperation, VMExecutedOperation, MemoryDiff, StorageDiff, RewardType};
pub use self::types::flat::{FlatTrace, FlatTransactionTraces, FlatBlockTraces};
pub use self::types::filter::{Filter, AddressesFilter};

use ethereum_types::{H256, U256, Address};
use kvdb::DBTransaction;
use bytes::Bytes;
use self::trace::{Call, Create};
use vm::ActionParams;
use header::BlockNumber;

/// This trait is used by executive to build traces.
pub trait Tracer: Send {
	/// Data returned when draining the Tracer.
	type Output;

	/// Prepares call trace for given params. Noop tracer should return None.
	fn prepare_trace_call(&self, params: &ActionParams) -> Option<Call>;

	/// Prepares create trace for given params. Noop tracer should return None.
	fn prepare_trace_create(&self, params: &ActionParams) -> Option<Create>;

	/// Prepare trace output. Noop tracer should return None.
	fn prepare_trace_output(&self) -> Option<Bytes>;

	/// Stores trace call info.
	fn trace_call(
		&mut self,
		call: Option<Call>,
		gas_used: U256,
		output: Option<Bytes>,
		subs: Vec<Self::Output>,
	);

	/// Stores trace create info.
	fn trace_create(
		&mut self,
		create: Option<Create>,
		gas_used: U256,
		code: Option<Bytes>,
		address: Address,
		subs: Vec<Self::Output>
	);

	/// Stores failed call trace.
	fn trace_failed_call(&mut self, call: Option<Call>, subs: Vec<Self::Output>, error: TraceError);

	/// Stores failed create trace.
	fn trace_failed_create(&mut self, create: Option<Create>, subs: Vec<Self::Output>, error: TraceError);

	/// Stores suicide info.
	fn trace_suicide(&mut self, address: Address, balance: U256, refund_address: Address);

	/// Stores reward info.
	fn trace_reward(&mut self, author: Address, value: U256, reward_type: RewardType);

	/// Spawn subtracer which will be used to trace deeper levels of execution.
	fn subtracer(&self) -> Self where Self: Sized;

	/// Consumes self and returns all traces.
	fn drain(self) -> Vec<Self::Output>;
}

/// Used by executive to build VM traces.
pub trait VMTracer: Send {

	/// Data returned when draining the VMTracer.
	type Output;

	/// Trace the progression of interpreter to next instruction.
	/// If tracer returns `false` it won't be called again.
	/// @returns true if `trace_prepare_execute` and `trace_executed` should be called.
	fn trace_next_instruction(&mut self, _pc: usize, _instruction: u8, _current_gas: U256) -> bool { false }

	/// Trace the preparation to execute a single valid instruction.
	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256) {}

	/// Trace the finalised execution of a single valid instruction.
	fn trace_executed(&mut self, _gas_used: U256, _stack_push: &[U256], _mem_diff: Option<(usize, &[u8])>, _store_diff: Option<(U256, U256)>) {}

	/// Spawn subtracer which will be used to trace deeper levels of execution.
	fn prepare_subtrace(&self, code: &[u8]) -> Self where Self: Sized;

	/// Finalize subtracer.
	fn done_subtrace(&mut self, sub: Self) where Self: Sized;

	/// Consumes self and returns the VM trace.
	fn drain(self) -> Option<Self::Output>;
}

/// `DbExtras` provides an interface to query extra data which is not stored in tracesdb,
/// but necessary to work correctly.
pub trait DatabaseExtras {
	/// Returns hash of given block number.
	fn block_hash(&self, block_number: BlockNumber) -> Option<H256>;

	/// Returns hash of transaction at given position.
	fn transaction_hash(&self, block_number: BlockNumber, tx_position: usize) -> Option<H256>;
}

/// Db provides an interface to query tracesdb.
pub trait Database {
	/// Returns true if tracing is enabled. Otherwise false.
	fn tracing_enabled(&self) -> bool;

	/// Imports new block traces.
	fn import(&self, batch: &mut DBTransaction, request: ImportRequest);

	/// Returns localized trace at given position.
	fn trace(&self, block_number: BlockNumber, tx_position: usize, trace_position: Vec<usize>) -> Option<LocalizedTrace>;

	/// Returns localized traces created by a single transaction.
	fn transaction_traces(&self, block_number: BlockNumber, tx_position: usize) -> Option<Vec<LocalizedTrace>>;

	/// Returns localized traces created in given block.
	fn block_traces(&self, block_number: BlockNumber) -> Option<Vec<LocalizedTrace>>;

	/// Filter traces matching given filter.
	fn filter(&self, filter: &Filter) -> Vec<LocalizedTrace>;
}