const { BN, expectRevert, expectEvent, constants } = require('@openzeppelin/test-helpers');
const { ZERO_ADDRESS } = constants;
const ethereumjsUtil = require('ethereumjs-util');

const { expect } = require('chai');

const Proxy = artifacts.require('Proxy');
const Implementation1 = artifacts.require('Implementation1');
const Implementation2 = artifacts.require('Implementation2');
const Implementation3 = artifacts.require('Implementation3');
const Implementation4 = artifacts.require('Implementation4');
const MigratableMockV1 = artifacts.require('MigratableMockV1');
const MigratableMockV2 = artifacts.require('MigratableMockV2');
const MigratableMockV3 = artifacts.require('MigratableMockV3');
const InitializableMock = artifacts.require('InitializableMock');
const DummyImplementation = artifacts.require('DummyImplementation');
const ClashingImplementation = artifacts.require('ClashingImplementation');

const IMPLEMENTATION_LABEL = 'eip1967.proxy.implementation';
const ADMIN_LABEL = 'eip1967.proxy.admin';

function toChecksumAddress (address) {
  return ethereumjsUtil.toChecksumAddress('0x' + address.replace(/^0x/, '').padStart(40, '0').substr(-40));
}

module.exports = function shouldBehaveLikeTransparentUpgradeableProxy (createProxy, accounts) {
  const [proxyAdminAddress, proxyAdminOwner, anotherAccount] = accounts;

  before(async function () {
    this.implementationV0 = (await DummyImplementation.new()).address;
    this.implementationV1 = (await DummyImplementation.new()).address;
  });

  beforeEach(async function () {
    const initializeData = Buffer.from('');
    this.proxy = await createProxy(this.implementationV0, proxyAdminAddress, initializeData, {
      from: proxyAdminOwner,
    });
    this.proxyAddress = this.proxy.address;
  });

  describe('implementation', function () {
    it('returns the current implementation address', async function () {
      const implementation = await this.proxy.implementation.call({ from: proxyAdminAddress });

      expect(implementation).to.be.equal(this.implementationV0);
    });

    it('delegates to the implementation', async function () {
      const dummy = new DummyImplementation(this.proxyAddress);
      const value = await dummy.get();

      expect(value).to.equal(true);
    });
  });

  describe('upgradeTo', function () {
    describe('when the sender is the admin', function () {
      const from = proxyAdminAddress;

      describe('when the given implementation is different from the current one', function () {
        it('upgrades to the requested implementation', async function () {
          await this.proxy.upgradeTo(this.implementationV1, { from });

          const implementation = await this.proxy.implementation.call({ from: proxyAdminAddress });
          expect(implementation).to.be.equal(this.implementationV1);
        });

        it('emits an event', async function () {
          expectEvent(
            await this.proxy.upgradeTo(this.implementationV1, { from }),
            'Upgraded', {
              implementation: this.implementationV1,
            },
          );
        });
      });

      describe('when the given implementation is the zero address', function () {
        it('reverts', async function () {
          await expectRevert(
            this.proxy.upgradeTo(ZERO_ADDRESS, { from }),
            'UpgradeableProxy: new implementation is not a contract',
          );
        });
      });
    });

    describe('when the sender is not the admin', function () {
      const from = anotherAccount;

      it('reverts', async function () {
        await expectRevert.unspecified(
          this.proxy.upgradeTo(this.implementationV1, { from }),
        );
      });
    });
  });

  describe('upgradeToAndCall', function () {
    describe('without migrations', function () {
      beforeEach(async function () {
        this.behavior = await InitializableMock.new();
      });

      describe('when the call does not fail', function () {
        const initializeData = new InitializableMock('').contract.methods['initializeWithX(uint256)'](42).encodeABI();

        describe('when the sender is the admin', function () {
          const from = proxyAdminAddress;
          const value = 1e5;

          beforeEach(async function () {
            this.receipt = await this.proxy.upgradeToAndCall(this.behavior.address, initializeData, { from, value });
          });

          it('upgrades to the requested implementation', async function () {
            const implementation = await this.proxy.implementation.call({ from: proxyAdminAddress });
            expect(implementation).to.be.equal(this.behavior.address);
          });

          it('emits an event', function () {
            expectEvent(this.receipt, 'Upgraded', { implementation: this.behavior.address });
          });

          it('calls the initializer function', async function () {
            const migratable = new InitializableMock(this.proxyAddress);
            const x = await migratable.x();
            expect(x).to.be.bignumber.equal('42');
          });

          it('sends given value to the proxy', async function () {
            const balance = await web3.eth.getBalance(this.proxyAddress);
            expect(balance.toString()).to.be.bignumber.equal(value.toString());
          });

          it.skip('uses the storage of the proxy', async function () {
            // storage layout should look as follows:
            //  - 0: Initializable storage
            //  - 1-50: Initailizable reserved storage (50 slots)
            //  - 51: initializerRan
            //  - 52: x
            const storedValue = await Proxy.at(this.proxyAddress).getStorageAt(52);
            expect(parseInt(storedValue)).to.eq(42);
          });
        });

        describe('when the sender is not the admin', function () {
          it('reverts', async function () {
            await expectRevert.unspecified(
              this.proxy.upgradeToAndCall(this.behavior.address, initializeData, { from: anotherAccount }),
            );
          });
        });
      });

      describe('when the call does fail', function () {
        const initializeData = new InitializableMock('').contract.methods.fail().encodeABI();

        it('reverts', async function () {
          await expectRevert.unspecified(
            this.proxy.upgradeToAndCall(this.behavior.address, initializeData, { from: proxyAdminAddress }),
          );
        });
      });
    });

    describe('with migrations', function () {
      describe('when the sender is the admin', function () {
        const from = proxyAdminAddress;
        const value = 1e5;

        describe('when upgrading to V1', function () {
          const v1MigrationData = new MigratableMockV1('').contract.methods.initialize(42).encodeABI();

          beforeEach(async function () {
            this.behaviorV1 = await MigratableMockV1.new();
            this.balancePreviousV1 = new BN(await web3.eth.getBalance(this.proxyAddress));
            this.receipt = await this.proxy.upgradeToAndCall(this.behaviorV1.address, v1MigrationData, { from, value });
          });

          it('upgrades to the requested version and emits an event', async function () {
            const implementation = await this.proxy.implementation.call({ from: proxyAdminAddress });
            expect(implementation).to.be.equal(this.behaviorV1.address);
            expectEvent(this.receipt, 'Upgraded', { implementation: this.behaviorV1.address });
          });

          it('calls the \'initialize\' function and sends given value to the proxy', async function () {
            const migratable = new MigratableMockV1(this.proxyAddress);

            const x = await migratable.x();
            expect(x).to.be.bignumber.equal('42');

            const balance = await web3.eth.getBalance(this.proxyAddress);
            expect(new BN(balance)).to.be.bignumber.equal(this.balancePreviousV1.addn(value));
          });

          describe('when upgrading to V2', function () {
            const v2MigrationData = new MigratableMockV2('').contract.methods.migrate(10, 42).encodeABI();

            beforeEach(async function () {
              this.behaviorV2 = await MigratableMockV2.new();
              this.balancePreviousV2 = new BN(await web3.eth.getBalance(this.proxyAddress));
              this.receipt =
                await this.proxy.upgradeToAndCall(this.behaviorV2.address, v2MigrationData, { from, value });
            });

            it('upgrades to the requested version and emits an event', async function () {
              const implementation = await this.proxy.implementation.call({ from: proxyAdminAddress });
              expect(implementation).to.be.equal(this.behaviorV2.address);
              expectEvent(this.receipt, 'Upgraded', { implementation: this.behaviorV2.address });
            });

            it('calls the \'migrate\' function and sends given value to the proxy', async function () {
              const migratable = new MigratableMockV2(this.proxyAddress);

              const x = await migratable.x();
              expect(x).to.be.bignumber.equal('10');

              const y = await migratable.y();
              expect(y).to.be.bignumber.equal('42');

              const balance = new BN(await web3.eth.getBalance(this.proxyAddress));
              expect(balance).to.be.bignumber.equal(this.balancePreviousV2.addn(value));
            });

            describe('when upgrading to V3', function () {
              const v3MigrationData = new MigratableMockV3('').contract.methods['migrate()']().encodeABI();

              beforeEach(async function () {
                this.behaviorV3 = await MigratableMockV3.new();
                this.balancePreviousV3 = new BN(await web3.eth.getBalance(this.proxyAddress));
                this.receipt =
                  await this.proxy.upgradeToAndCall(this.behaviorV3.address, v3MigrationData, { from, value });
              });

              it('upgrades to the requested version and emits an event', async function () {
                const implementation = await this.proxy.implementation.call({ from: proxyAdminAddress });
                expect(implementation).to.be.equal(this.behaviorV3.address);
                expectEvent(this.receipt, 'Upgraded', { implementation: this.behaviorV3.address });
              });

              it('calls the \'migrate\' function and sends given value to the proxy', async function () {
                const migratable = new MigratableMockV3(this.proxyAddress);

                const x = await migratable.x();
                expect(x).to.be.bignumber.equal('42');

                const y = await migratable.y();
                expect(y).to.be.bignumber.equal('10');

                const balance = new BN(await web3.eth.getBalance(this.proxyAddress));
                expect(balance).to.be.bignumber.equal(this.balancePreviousV3.addn(value));
              });
            });
          });
        });
      });

      describe('when the sender is not the admin', function () {
        const from = anotherAccount;

        it('reverts', async function () {
          const behaviorV1 = await MigratableMockV1.new();
          const v1MigrationData = new MigratableMockV1('').contract.methods.initialize(42).encodeABI();
          await expectRevert.unspecified(
            this.proxy.upgradeToAndCall(behaviorV1.address, v1MigrationData, { from }),
          );
        });
      });
    });
  });

  describe('changeAdmin', function () {
    describe('when the new proposed admin is not the zero address', function () {
      const newAdmin = anotherAccount;

      describe('when the sender is the admin', function () {
        beforeEach('transferring', async function () {
          this.receipt = await this.proxy.changeAdmin(newAdmin, { from: proxyAdminAddress });
        });

        it('assigns new proxy admin', async function () {
          const newProxyAdmin = await this.proxy.admin.call({ from: newAdmin });
          expect(newProxyAdmin).to.be.equal(anotherAccount);
        });

        it('emits an event', function () {
          expectEvent(this.receipt, 'AdminChanged', {
            previousAdmin: proxyAdminAddress,
            newAdmin: newAdmin,
          });
        });
      });

      describe('when the sender is not the admin', function () {
        it('reverts', async function () {
          await expectRevert.unspecified(this.proxy.changeAdmin(newAdmin, { from: anotherAccount }));
        });
      });
    });

    describe('when the new proposed admin is the zero address', function () {
      it('reverts', async function () {
        await expectRevert(
          this.proxy.changeAdmin(ZERO_ADDRESS, { from: proxyAdminAddress }),
          'TransparentUpgradeableProxy: new admin is the zero address',
        );
      });
    });
  });

  describe('storage', function () {
    it('should store the implementation address in specified location', async function () {
      const slot = '0x' + new BN(ethereumjsUtil.keccak256(Buffer.from(IMPLEMENTATION_LABEL))).subn(1).toString(16);
      const implementation = toChecksumAddress(await web3.eth.getStorageAt(this.proxyAddress, slot));
      expect(implementation).to.be.equal(this.implementationV0);
    });

    it('should store the admin proxy in specified location', async function () {
      const slot = '0x' + new BN(ethereumjsUtil.keccak256(Buffer.from(ADMIN_LABEL))).subn(1).toString(16);
      const proxyAdmin = toChecksumAddress(await web3.eth.getStorageAt(this.proxyAddress, slot));
      expect(proxyAdmin).to.be.equal(proxyAdminAddress);
    });
  });

  describe('transparent proxy', function () {
    beforeEach('creating proxy', async function () {
      const initializeData = Buffer.from('');
      this.impl = await ClashingImplementation.new();
      this.proxy = await createProxy(this.impl.address, proxyAdminAddress, initializeData, { from: proxyAdminOwner });

      this.clashing = new ClashingImplementation(this.proxy.address);
    });

    it('proxy admin cannot call delegated functions', async function () {
      await expectRevert(
        this.clashing.delegatedFunction({ from: proxyAdminAddress }),
        'TransparentUpgradeableProxy: admin cannot fallback to proxy target',
      );
    });

    context('when function names clash', function () {
      it('when sender is proxy admin should run the proxy function', async function () {
        const value = await this.proxy.admin.call({ from: proxyAdminAddress });
        expect(value).to.be.equal(proxyAdminAddress);
      });

      it('when sender is other should delegate to implementation', async function () {
        const value = await this.proxy.admin.call({ from: anotherAccount });
        expect(value).to.be.equal('0x0000000000000000000000000000000011111142');
      });
    });
  });

  describe('regression', () => {
    const initializeData = Buffer.from('');

    it('should add new function', async () => {
      const instance1 = await Implementation1.new();
      const proxy = await createProxy(instance1.address, proxyAdminAddress, initializeData, { from: proxyAdminOwner });

      const proxyInstance1 = new Implementation1(proxy.address);
      await proxyInstance1.setValue(42);

      const instance2 = await Implementation2.new();
      await proxy.upgradeTo(instance2.address, { from: proxyAdminAddress });

      const proxyInstance2 = new Implementation2(proxy.address);
      const res = await proxyInstance2.getValue();
      expect(res.toString()).to.eq('42');
    });

    it('should remove function', async () => {
      const instance2 = await Implementation2.new();
      const proxy = await createProxy(instance2.address, proxyAdminAddress, initializeData, { from: proxyAdminOwner });

      const proxyInstance2 = new Implementation2(proxy.address);
      await proxyInstance2.setValue(42);
      const res = await proxyInstance2.getValue();
      expect(res.toString()).to.eq('42');

      const instance1 = await Implementation1.new();
      await proxy.upgradeTo(instance1.address, { from: proxyAdminAddress });

      const proxyInstance1 = new Implementation2(proxy.address);
      await expectRevert.unspecified(proxyInstance1.getValue());
    });

    it('should change function signature', async () => {
      const instance1 = await Implementation1.new();
      const proxy = await createProxy(instance1.address, proxyAdminAddress, initializeData, { from: proxyAdminOwner });

      const proxyInstance1 = new Implementation1(proxy.address);
      await proxyInstance1.setValue(42);

      const instance3 = await Implementation3.new();
      await proxy.upgradeTo(instance3.address, { from: proxyAdminAddress });
      const proxyInstance3 = new Implementation3(proxy.address);

      const res = await proxyInstance3.getValue(8);
      expect(res.toString()).to.eq('50');
    });

    it('should add fallback function', async () => {
      const initializeData = Buffer.from('');
      const instance1 = await Implementation1.new();
      const proxy = await createProxy(instance1.address, proxyAdminAddress, initializeData, { from: proxyAdminOwner });

      const instance4 = await Implementation4.new();
      await proxy.upgradeTo(instance4.address, { from: proxyAdminAddress });
      const proxyInstance4 = new Implementation4(proxy.address);

      const data = '0x';
      await web3.eth.sendTransaction({ to: proxy.address, from: anotherAccount, data });

      const res = await proxyInstance4.getValue();
      expect(res.toString()).to.eq('1');
    });

    it('should remove fallback function', async () => {
      const instance4 = await Implementation4.new();
      const proxy = await createProxy(instance4.address, proxyAdminAddress, initializeData, { from: proxyAdminOwner });

      const instance2 = await Implementation2.new();
      await proxy.upgradeTo(instance2.address, { from: proxyAdminAddress });

      const data = '0x';
      await expectRevert.unspecified(
        web3.eth.sendTransaction({ to: proxy.address, from: anotherAccount, data }),
      );

      const proxyInstance2 = new Implementation2(proxy.address);
      const res = await proxyInstance2.getValue();
      expect(res.toString()).to.eq('0');
    });
  });
};
