const EC = require('elliptic').ec;
const ec = new EC('secp256k1');
const web3Utils = require('web3-utils');

// This has been tested with the real Ethereum network and Testrpc.
// Copied and edited from: https://gist.github.com/xavierlepretre/d5583222fde52ddfbc58b7cfa0d2d0a9
exports.assertReverts = (contractMethodCall, maxGasAvailable) => {
    return new Promise((resolve, reject) => {
        try {
            resolve(contractMethodCall())
        } catch (error) {
            reject(error)
        }
    })
        .then(tx => {
            assert.equal(tx.receipt.gasUsed, maxGasAvailable, "tx successful, the max gas available was not consumed")
        })
        .catch(error => {
            if ((error + "").indexOf("invalid opcode") < 0 && (error + "").indexOf("out of gas") < 0) {
                // Checks if the error is from TestRpc. If it is then ignore it.
                // Otherwise relay/throw the error produced by the above assertion.
                // Note that no error is thrown when using a real Ethereum network AND the assertion above is true.
                throw error
            }
        })
}

exports.listenForEvent = event => new Promise((resolve, reject) => {
    event({}, (error, response) => {
        if (!error) {
            resolve(response.args)
        } else {
            reject(error)
        }
        event.stopWatching()
    })
});

exports.eventValues = (receipt, eventName) => {
    if(receipt.events[eventName])
        return receipt.events[eventName].returnValues;
}

exports.eventAddress = (bytes32Address) => {
    return web3Utils.toChecksumAddress("0x"+bytes32Address.substring(26))
}

exports.addressToBytes32 = (address) => {
    const stringed = "0000000000000000000000000000000000000000000000000000000000000000" + address.slice(2);
    return "0x" + stringed.substring(stringed.length - 64, stringed.length); 
}


// OpenZeppelin's expectThrow helper -
// Source: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/test/helpers/expectThrow.js
exports.expectThrow = async promise => {
    try {
      await promise;
    } catch (error) {
      // TODO: Check jump destination to destinguish between a throw
      //       and an actual invalid jump.
      const invalidOpcode = error.message.search('invalid opcode') >= 0;
      // TODO: When we contract A calls contract B, and B throws, instead
      //       of an 'invalid jump', we get an 'out of gas' error. How do
      //       we distinguish this from an actual out of gas event? (The
      //       testrpc log actually show an 'invalid jump' event.)
      const outOfGas = error.message.search('out of gas') >= 0;
      const revert = error.message.search('revert') >= 0;
      assert(
        invalidOpcode || outOfGas || revert,
        'Expected throw, got \'' + error + '\' instead',
      );
      return;
    }
    assert.fail('Expected throw not received');
  };

  

exports.assertJump = (error) => {
    assert(error.message.search('revert') > -1, 'Revert should happen');
}


var callbackToResolve = function (resolve, reject) {
    return function (error, value) {
            if (error) {
                reject(error);
            } else {
                resolve(value);
            }
        };
};

exports.promisify = (func) =>
    (...args) => {
        return new Promise((resolve, reject) => {
        const callback = (err, data) => err ? reject(err) : resolve(data);
        func.apply(this, [...args, callback]);
        });
    }
        

// This has been tested with the real Ethereum network and Testrpc.
// Copied and edited from: https://gist.github.com/xavierlepretre/d5583222fde52ddfbc58b7cfa0d2d0a9
exports.assertReverts = (contractMethodCall, maxGasAvailable) => {
    return new Promise((resolve, reject) => {
        try {
            resolve(contractMethodCall())
        } catch (error) {
            reject(error)
        }
    })
        .then(tx => {
            assert.equal(tx.receipt.gasUsed, maxGasAvailable, "tx successful, the max gas available was not consumed")
        })
        .catch(error => {
            if ((error + "").indexOf("invalid opcode") < 0 && (error + "").indexOf("out of gas") < 0) {
                // Checks if the error is from TestRpc. If it is then ignore it.
                // Otherwise relay/throw the error produced by the above assertion.
                // Note that no error is thrown when using a real Ethereum network AND the assertion above is true.
                throw error
            }
        })
}

exports.listenForEvent = event => new Promise((resolve, reject) => {
    event({}, (error, response) => {
        if (!error) {
            resolve(response.args)
        } else {
            reject(error)
        }
        event.stopWatching()
    })
});

exports.eventValues = (receipt, eventName) => {
    if(receipt.events[eventName])
        return receipt.events[eventName].returnValues;
}

exports.addressToBytes32 = (address) => {
    const stringed = "0000000000000000000000000000000000000000000000000000000000000000" + address.slice(2);
    return "0x" + stringed.substring(stringed.length - 64, stringed.length); 
}


// OpenZeppelin's expectThrow helper -
// Source: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/test/helpers/expectThrow.js
exports.expectThrow = async promise => {
    try {
      await promise;
    } catch (error) {
      // TODO: Check jump destination to destinguish between a throw
      //       and an actual invalid jump.
      const invalidOpcode = error.message.search('invalid opcode') >= 0;
      // TODO: When we contract A calls contract B, and B throws, instead
      //       of an 'invalid jump', we get an 'out of gas' error. How do
      //       we distinguish this from an actual out of gas event? (The
      //       testrpc log actually show an 'invalid jump' event.)
      const outOfGas = error.message.search('out of gas') >= 0;
      const revert = error.message.search('revert') >= 0;
      assert(
        invalidOpcode || outOfGas || revert,
        'Expected throw, got \'' + error + '\' instead',
      );
      return;
    }
    assert.fail('Expected throw not received');
  };

exports.assertJump = (error) => {
    assert(error.message.search('revert') > -1, 'Revert should happen');
}

var callbackToResolve = function (resolve, reject) {
    return function (error, value) {
            if (error) {
                reject(error);
            } else {
                resolve(value);
            }
        };
};

exports.promisify = (func) =>
    (...args) => {
        return new Promise((resolve, reject) => {
        const callback = (err, data) => err ? reject(err) : resolve(data);
        func.apply(this, [...args, callback]);
        });
    }
    
exports.zeroAddress = '0x0000000000000000000000000000000000000000';
exports.zeroBytes32 = "0x0000000000000000000000000000000000000000000000000000000000000000";
exports.timeUnits = {
    seconds: 1,
    minutes: 60,
    hours: 60 * 60,
    days: 24 * 60 * 60,
    weeks: 7 * 24 * 60 * 60,
    years: 365 * 24 * 60 * 60
}

exports.ensureException = function(error) {
    assert(isException(error), error.toString());
};

function isException(error) {
    let strError = error.toString();
    return strError.includes('invalid opcode') || strError.includes('invalid JUMP') || strError.includes('revert');
}

exports.increaseTime = async (amount) => {
    return new Promise(function(resolve, reject) {
      web3.currentProvider.sendAsync(
        {
          jsonrpc: '2.0',
          method: 'evm_increaseTime',
          params: [+amount],
          id: new Date().getSeconds()
        },
        async (error) => {
          if (error) {
            console.log(error);
            return reject(err);
          }
          await web3.currentProvider.sendAsync(
            {
              jsonrpc: '2.0',
              method: 'evm_mine',
              params: [],
              id: new Date().getSeconds()
            }, (error) => {
              if (error) {
                console.log(error);
                return reject(err);
              }
              resolve();
            }
          )
        }
      )
    });
}

exports.generateXY = pub => {
  const stripped = pub.slice(2);
  const key = ec.keyFromPublic(stripped, 'hex');
  const pubPoint = key.getPublic();
  const x = '0x' + pubPoint.getX().toString(16);
  const y = '0x'+ pubPoint.getY().toString(16);
  return { x, y };
}

exports.keyFromXY = (X, Y) => {
  const x = Buffer.from(X.substring(2), 'hex');
  const y = Buffer.from(Y.substring(2), 'hex');
  const keys = ec.keyFromPublic({ x, y }, 'hex');
  return `0x${keys.getPublic().encode('hex')}`;
}