// Copyright 2015-2019 Parity Technologies (UK) Ltd.
// This file is part of Parity Ethereum.

// Parity 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.

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

use ethereum_types::{H160, H256, U256};
use fixture::{Assert, CallLocator, Fixture, Source};
use rustc_hex::ToHex;
use std::{
    fmt, fs,
    io::{self, Read},
    path,
    sync::Arc,
};
use vm::{self, tests::FakeExt, ActionParams, ActionValue, Exec, GasLeft, ParamsType};
use wasm::WasmInterpreter;

fn load_code<P: AsRef<path::Path>>(p: P) -> io::Result<Vec<u8>> {
    let mut result = Vec::new();
    let mut f = fs::File::open(p)?;
    f.read_to_end(&mut result)?;
    Ok(result)
}

fn wasm_interpreter(params: ActionParams) -> Box<WasmInterpreter> {
    Box::new(WasmInterpreter::new(params))
}

#[derive(Debug)]
pub enum SpecNonconformity {
    Address,
}

#[derive(Debug)]
pub enum Fail {
    Return {
        expected: Vec<u8>,
        actual: Vec<u8>,
    },
    UsedGas {
        expected: u64,
        actual: u64,
    },
    Runtime(String),
    Load(io::Error),
    NoCall(CallLocator),
    StorageMismatch {
        key: H256,
        expected: H256,
        actual: Option<H256>,
    },
    Nonconformity(SpecNonconformity),
}

impl Fail {
    fn runtime(err: vm::Error) -> Vec<Fail> {
        vec![Fail::Runtime(format!("{}", err))]
    }

    fn load(err: io::Error) -> Vec<Fail> {
        vec![Fail::Load(err)]
    }

    fn nononformity(kind: SpecNonconformity) -> Vec<Fail> {
        vec![Fail::Nonconformity(kind)]
    }
}

impl fmt::Display for Fail {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::Fail::*;
        match *self {
            Return {
                ref expected,
                ref actual,
            } => write!(
                f,
                "Expected to return result: 0x{} ({} bytes), but got 0x{} ({} bytes)",
                expected.to_hex(),
                expected.len(),
                actual.to_hex(),
                actual.len()
            ),

            UsedGas { expected, actual } => write!(
                f,
                "Expected to use gas: {}, but got actual gas used: {}",
                expected, actual
            ),

            Runtime(ref s) => write!(f, "WASM Runtime error: {}", s),

            Load(ref e) => write!(f, "Load i/o error: {}", e),

            NoCall(ref call) => write!(f, "Call not found: {:?}", call),

            StorageMismatch {
                ref key,
                ref expected,
                actual: Some(ref actual),
            } => write!(
                f,
                "Storage key {} value mismatch, expected {}, got: {}",
                key.to_vec().to_hex(),
                expected.to_vec().to_hex(),
                actual.to_vec().to_hex(),
            ),

            StorageMismatch {
                ref key,
                ref expected,
                actual: None,
            } => write!(
                f,
                "No expected storage value for key {} found, expected {}",
                key.to_vec().to_hex(),
                expected.to_vec().to_hex(),
            ),

            Nonconformity(SpecNonconformity::Address) => {
                write!(f, "Cannot use address when constructor is specified!")
            }
        }
    }
}

pub fn construct(
    ext: &mut dyn vm::Ext,
    source: Vec<u8>,
    arguments: Vec<u8>,
    sender: H160,
    at: H160,
) -> Result<Vec<u8>, vm::Error> {
    let mut params = ActionParams::default();
    params.sender = sender;
    params.address = at;
    params.gas = U256::from(100_000_000);
    params.data = Some(arguments);
    params.code = Some(Arc::new(source));
    params.params_type = ParamsType::Separate;

    Ok(
        match wasm_interpreter(params)
            .exec(ext)
            .ok()
            .expect("Wasm interpreter always calls with trap=false; trap never happens; qed")?
        {
            GasLeft::Known(_) => Vec::new(),
            GasLeft::NeedsReturn { data, .. } => data.to_vec(),
        },
    )
}

pub fn run_fixture(fixture: &Fixture) -> Vec<Fail> {
    let mut params = ActionParams::default();

    let source = match load_code(fixture.source.as_ref()) {
        Ok(code) => code,
        Err(e) => {
            return Fail::load(e);
        }
    };

    let mut ext = FakeExt::new().with_wasm();
    params.code = Some(Arc::new(
        if let Source::Constructor {
            ref arguments,
            ref sender,
            ref at,
            ..
        } = fixture.source
        {
            match construct(
                &mut ext,
                source,
                arguments.clone().into(),
                sender.clone().into(),
                at.clone().into(),
            ) {
                Ok(code) => code,
                Err(e) => {
                    return Fail::runtime(e);
                }
            }
        } else {
            source
        },
    ));

    if let Some(ref sender) = fixture.sender {
        params.sender = sender.clone().into();
    }

    if let Some(ref address) = fixture.address {
        if let Source::Constructor { .. } = fixture.source {
            return Fail::nononformity(SpecNonconformity::Address);
        }

        params.address = address.clone().into();
    } else if let Source::Constructor { ref at, .. } = fixture.source {
        params.address = at.clone().into();
    }

    if let Some(gas_limit) = fixture.gas_limit {
        params.gas = U256::from(gas_limit);
    }

    if let Some(ref data) = fixture.payload {
        params.data = Some(data.clone().into())
    }

    if let Some(value) = fixture.value {
        params.value = ActionValue::Transfer(value.clone().into())
    }

    if let Some(ref storage) = fixture.storage {
        for storage_entry in storage.iter() {
            let key: U256 = storage_entry.key.into();
            let val: U256 = storage_entry.value.into();
            ext.store.insert(key.into(), val.into());
        }
    }

    let interpreter = wasm_interpreter(params);

    let interpreter_return = match interpreter
        .exec(&mut ext)
        .ok()
        .expect("Wasm interpreter always calls with trap=false; trap never happens; qed")
    {
        Ok(ret) => ret,
        Err(e) => {
            return Fail::runtime(e);
        }
    };
    let (gas_left, result) = match interpreter_return {
        GasLeft::Known(gas) => (gas, Vec::new()),
        GasLeft::NeedsReturn {
            gas_left: gas,
            data: result,
            apply_state: _apply,
        } => (gas, result.to_vec()),
    };

    let mut fails = Vec::new();

    for assert in fixture.asserts.iter() {
        match *assert {
            Assert::Return(ref data) => {
                if &data[..] != &result[..] {
                    fails.push(Fail::Return {
                        expected: (&data[..]).to_vec(),
                        actual: (&result[..]).to_vec(),
                    })
                }
            }
            Assert::UsedGas(gas) => {
                let used_gas = fixture.gas_limit.unwrap_or(0) - gas_left.low_u64();
                if gas != used_gas {
                    fails.push(Fail::UsedGas {
                        expected: gas,
                        actual: used_gas,
                    });
                }
            }
            Assert::HasCall(ref locator) => {
                let mut found = false;

                for fake_call in ext.calls.iter() {
                    let mut match_ = true;
                    if let Some(ref data) = locator.data {
                        if data.as_ref() != &fake_call.data[..] {
                            match_ = false;
                        }
                    }

                    if let Some(ref code_addr) = locator.code_address {
                        if fake_call.code_address.unwrap_or(H160::zero())
                            != code_addr.clone().into()
                        {
                            match_ = false
                        }
                    }

                    if let Some(ref sender) = locator.sender {
                        if fake_call.sender_address.unwrap_or(H160::zero()) != sender.clone().into()
                        {
                            match_ = false
                        }
                    }

                    if let Some(ref receiver) = locator.receiver {
                        if fake_call.receive_address.unwrap_or(H160::zero())
                            != receiver.clone().into()
                        {
                            match_ = false
                        }
                    }

                    if match_ {
                        found = true;
                        break;
                    }
                }

                if !found {
                    fails.push(Fail::NoCall(locator.clone()))
                }
            }
            Assert::HasStorage(ref storage_entry) => {
                let expected_storage_key: H256 = storage_entry.key.clone().into();
                let expected_storage_value: H256 = storage_entry.value.clone().into();
                let val = ext.store.get(&expected_storage_key);

                if let Some(val) = val {
                    if val != &expected_storage_value {
                        fails.push(Fail::StorageMismatch {
                            key: expected_storage_key,
                            expected: expected_storage_value,
                            actual: Some(val.clone()),
                        })
                    }
                } else {
                    fails.push(Fail::StorageMismatch {
                        key: expected_storage_key,
                        expected: expected_storage_value,
                        actual: None,
                    })
                }
            }
        }
    }
    fails
}