const { BN, constants, expectEvent, expectRevert } = require('openzeppelin-test-helpers');
const { expect } = require('chai');
const { ZERO_ADDRESS } = constants;
const { shouldSupportInterfaces } = require('../../introspection/SupportsInterface.behavior');

const ERC721ReceiverMock = artifacts.require('ERC721ReceiverMock.sol');

function shouldBehaveLikeERC721 (
  creator,
  minter,
  [owner, approved, anotherApproved, operator, other]
) {
  const firstTokenId = new BN(1);
  const secondTokenId = new BN(2);
  const unknownTokenId = new BN(3);
  const RECEIVER_MAGIC_VALUE = '0x150b7a02';

  describe('like an ERC721', function () {
    beforeEach(async function () {
      await this.token.mint(owner, firstTokenId, { from: minter });
      await this.token.mint(owner, secondTokenId, { from: minter });
      this.toWhom = other; // default to anyone for toWhom in context-dependent tests
    });

    describe('balanceOf', function () {
      context('when the given address owns some tokens', function () {
        it('returns the amount of tokens owned by the given address', async function () {
          expect(await this.token.balanceOf(owner)).to.be.bignumber.equal('2');
        });
      });

      context('when the given address does not own any tokens', function () {
        it('returns 0', async function () {
          expect(await this.token.balanceOf(other)).to.be.bignumber.equal('0');
        });
      });

      context('when querying the zero address', function () {
        it('throws', async function () {
          await expectRevert(
            this.token.balanceOf(ZERO_ADDRESS), 'ERC721: balance query for the zero address'
          );
        });
      });
    });

    describe('ownerOf', function () {
      context('when the given token ID was tracked by this token', function () {
        const tokenId = firstTokenId;

        it('returns the owner of the given token ID', async function () {
          expect(await this.token.ownerOf(tokenId)).to.be.equal(owner);
        });
      });

      context('when the given token ID was not tracked by this token', function () {
        const tokenId = unknownTokenId;

        it('reverts', async function () {
          await expectRevert(
            this.token.ownerOf(tokenId), 'ERC721: owner query for nonexistent token'
          );
        });
      });
    });

    describe('transfers', function () {
      const tokenId = firstTokenId;
      const data = '0x42';

      let logs = null;

      beforeEach(async function () {
        await this.token.approve(approved, tokenId, { from: owner });
        await this.token.setApprovalForAll(operator, true, { from: owner });
      });

      const transferWasSuccessful = function ({ owner, tokenId, approved }) {
        it('transfers the ownership of the given token ID to the given address', async function () {
          expect(await this.token.ownerOf(tokenId)).to.be.equal(this.toWhom);
        });

        it('clears the approval for the token ID', async function () {
          expect(await this.token.getApproved(tokenId)).to.be.equal(ZERO_ADDRESS);
        });

        if (approved) {
          it('emit only a transfer event', async function () {
            expectEvent.inLogs(logs, 'Transfer', {
              from: owner,
              to: this.toWhom,
              tokenId: tokenId,
            });
          });
        } else {
          it('emits only a transfer event', async function () {
            expectEvent.inLogs(logs, 'Transfer', {
              from: owner,
              to: this.toWhom,
              tokenId: tokenId,
            });
          });
        }

        it('adjusts owners balances', async function () {
          expect(await this.token.balanceOf(owner)).to.be.bignumber.equal('1');
        });

        it('adjusts owners tokens by index', async function () {
          if (!this.token.tokenOfOwnerByIndex) return;

          expect(await this.token.tokenOfOwnerByIndex(this.toWhom, 0)).to.be.bignumber.equal(tokenId);

          expect(await this.token.tokenOfOwnerByIndex(owner, 0)).to.be.bignumber.not.equal(tokenId);
        });
      };

      const shouldTransferTokensByUsers = function (transferFunction) {
        context('when called by the owner', function () {
          beforeEach(async function () {
            ({ logs } = await transferFunction.call(this, owner, this.toWhom, tokenId, { from: owner }));
          });
          transferWasSuccessful({ owner, tokenId, approved });
        });

        context('when called by the approved individual', function () {
          beforeEach(async function () {
            ({ logs } = await transferFunction.call(this, owner, this.toWhom, tokenId, { from: approved }));
          });
          transferWasSuccessful({ owner, tokenId, approved });
        });

        context('when called by the operator', function () {
          beforeEach(async function () {
            ({ logs } = await transferFunction.call(this, owner, this.toWhom, tokenId, { from: operator }));
          });
          transferWasSuccessful({ owner, tokenId, approved });
        });

        context('when called by the owner without an approved user', function () {
          beforeEach(async function () {
            await this.token.approve(ZERO_ADDRESS, tokenId, { from: owner });
            ({ logs } = await transferFunction.call(this, owner, this.toWhom, tokenId, { from: operator }));
          });
          transferWasSuccessful({ owner, tokenId, approved: null });
        });

        context('when sent to the owner', function () {
          beforeEach(async function () {
            ({ logs } = await transferFunction.call(this, owner, owner, tokenId, { from: owner }));
          });

          it('keeps ownership of the token', async function () {
            expect(await this.token.ownerOf(tokenId)).to.be.equal(owner);
          });

          it('clears the approval for the token ID', async function () {
            expect(await this.token.getApproved(tokenId)).to.be.equal(ZERO_ADDRESS);
          });

          it('emits only a transfer event', async function () {
            expectEvent.inLogs(logs, 'Transfer', {
              from: owner,
              to: owner,
              tokenId: tokenId,
            });
          });

          it('keeps the owner balance', async function () {
            expect(await this.token.balanceOf(owner)).to.be.bignumber.equal('2');
          });

          it('keeps same tokens by index', async function () {
            if (!this.token.tokenOfOwnerByIndex) return;
            const tokensListed = await Promise.all(
              [0, 1].map(i => this.token.tokenOfOwnerByIndex(owner, i))
            );
            expect(tokensListed.map(t => t.toNumber())).to.have.members(
              [firstTokenId.toNumber(), secondTokenId.toNumber()]
            );
          });
        });

        context('when the address of the previous owner is incorrect', function () {
          it('reverts', async function () {
            await expectRevert(
              transferFunction.call(this, other, other, tokenId, { from: owner }),
              'ERC721: transfer of token that is not own'
            );
          });
        });

        context('when the sender is not authorized for the token id', function () {
          it('reverts', async function () {
            await expectRevert(
              transferFunction.call(this, owner, other, tokenId, { from: other }),
              'ERC721: transfer caller is not owner nor approved'
            );
          });
        });

        context('when the given token ID does not exist', function () {
          it('reverts', async function () {
            await expectRevert(
              transferFunction.call(this, owner, other, unknownTokenId, { from: owner }),
              'ERC721: operator query for nonexistent token'
            );
          });
        });

        context('when the address to transfer the token to is the zero address', function () {
          it('reverts', async function () {
            await expectRevert(
              transferFunction.call(this, owner, ZERO_ADDRESS, tokenId, { from: owner }),
              'ERC721: transfer to the zero address'
            );
          });
        });
      };

      describe('via transferFrom', function () {
        shouldTransferTokensByUsers(function (from, to, tokenId, opts) {
          return this.token.transferFrom(from, to, tokenId, opts);
        });
      });

      describe('via safeTransferFrom', function () {
        const safeTransferFromWithData = function (from, to, tokenId, opts) {
          return this.token.methods['safeTransferFrom(address,address,uint256,bytes)'](from, to, tokenId, data, opts);
        };

        const safeTransferFromWithoutData = function (from, to, tokenId, opts) {
          return this.token.methods['safeTransferFrom(address,address,uint256)'](from, to, tokenId, opts);
        };

        const shouldTransferSafely = function (transferFun, data) {
          describe('to a user account', function () {
            shouldTransferTokensByUsers(transferFun);
          });

          describe('to a valid receiver contract', function () {
            beforeEach(async function () {
              this.receiver = await ERC721ReceiverMock.new(RECEIVER_MAGIC_VALUE, false);
              this.toWhom = this.receiver.address;
            });

            shouldTransferTokensByUsers(transferFun);

            it('should call onERC721Received', async function () {
              const receipt = await transferFun.call(this, owner, this.receiver.address, tokenId, { from: owner });

              await expectEvent.inTransaction(receipt.tx, ERC721ReceiverMock, 'Received', {
                operator: owner,
                from: owner,
                tokenId: tokenId,
                data: data,
              });
            });

            it('should call onERC721Received from approved', async function () {
              const receipt = await transferFun.call(this, owner, this.receiver.address, tokenId, { from: approved });

              await expectEvent.inTransaction(receipt.tx, ERC721ReceiverMock, 'Received', {
                operator: approved,
                from: owner,
                tokenId: tokenId,
                data: data,
              });
            });

            describe('with an invalid token id', function () {
              it('reverts', async function () {
                await expectRevert(
                  transferFun.call(
                    this,
                    owner,
                    this.receiver.address,
                    unknownTokenId,
                    { from: owner },
                  ),
                  'ERC721: operator query for nonexistent token'
                );
              });
            });
          });
        };

        describe('with data', function () {
          shouldTransferSafely(safeTransferFromWithData, data);
        });

        describe('without data', function () {
          shouldTransferSafely(safeTransferFromWithoutData, null);
        });

        describe('to a receiver contract returning unexpected value', function () {
          it('reverts', async function () {
            const invalidReceiver = await ERC721ReceiverMock.new('0x42', false);
            await expectRevert(
              this.token.safeTransferFrom(owner, invalidReceiver.address, tokenId, { from: owner }),
              'ERC721: transfer to non ERC721Receiver implementer'
            );
          });
        });

        describe('to a receiver contract that throws', function () {
          it('reverts', async function () {
            const invalidReceiver = await ERC721ReceiverMock.new(RECEIVER_MAGIC_VALUE, true);
            await expectRevert(
              this.token.safeTransferFrom(owner, invalidReceiver.address, tokenId, { from: owner }),
              'ERC721ReceiverMock: reverting'
            );
          });
        });

        describe('to a contract that does not implement the required function', function () {
          it('reverts', async function () {
            const invalidReceiver = this.token;
            await expectRevert.unspecified(
              this.token.safeTransferFrom(owner, invalidReceiver.address, tokenId, { from: owner })
            );
          });
        });
      });
    });

    describe('approve', function () {
      const tokenId = firstTokenId;

      let logs = null;

      const itClearsApproval = function () {
        it('clears approval for the token', async function () {
          expect(await this.token.getApproved(tokenId)).to.be.equal(ZERO_ADDRESS);
        });
      };

      const itApproves = function (address) {
        it('sets the approval for the target address', async function () {
          expect(await this.token.getApproved(tokenId)).to.be.equal(address);
        });
      };

      const itEmitsApprovalEvent = function (address) {
        it('emits an approval event', async function () {
          expectEvent.inLogs(logs, 'Approval', {
            owner: owner,
            approved: address,
            tokenId: tokenId,
          });
        });
      };

      context('when clearing approval', function () {
        context('when there was no prior approval', function () {
          beforeEach(async function () {
            ({ logs } = await this.token.approve(ZERO_ADDRESS, tokenId, { from: owner }));
          });

          itClearsApproval();
          itEmitsApprovalEvent(ZERO_ADDRESS);
        });

        context('when there was a prior approval', function () {
          beforeEach(async function () {
            await this.token.approve(approved, tokenId, { from: owner });
            ({ logs } = await this.token.approve(ZERO_ADDRESS, tokenId, { from: owner }));
          });

          itClearsApproval();
          itEmitsApprovalEvent(ZERO_ADDRESS);
        });
      });

      context('when approving a non-zero address', function () {
        context('when there was no prior approval', function () {
          beforeEach(async function () {
            ({ logs } = await this.token.approve(approved, tokenId, { from: owner }));
          });

          itApproves(approved);
          itEmitsApprovalEvent(approved);
        });

        context('when there was a prior approval to the same address', function () {
          beforeEach(async function () {
            await this.token.approve(approved, tokenId, { from: owner });
            ({ logs } = await this.token.approve(approved, tokenId, { from: owner }));
          });

          itApproves(approved);
          itEmitsApprovalEvent(approved);
        });

        context('when there was a prior approval to a different address', function () {
          beforeEach(async function () {
            await this.token.approve(anotherApproved, tokenId, { from: owner });
            ({ logs } = await this.token.approve(anotherApproved, tokenId, { from: owner }));
          });

          itApproves(anotherApproved);
          itEmitsApprovalEvent(anotherApproved);
        });
      });

      context('when the address that receives the approval is the owner', function () {
        it('reverts', async function () {
          await expectRevert(
            this.token.approve(owner, tokenId, { from: owner }), 'ERC721: approval to current owner'
          );
        });
      });

      context('when the sender does not own the given token ID', function () {
        it('reverts', async function () {
          await expectRevert(this.token.approve(approved, tokenId, { from: other }),
            'ERC721: approve caller is not owner nor approved');
        });
      });

      context('when the sender is approved for the given token ID', function () {
        it('reverts', async function () {
          await this.token.approve(approved, tokenId, { from: owner });
          await expectRevert(this.token.approve(anotherApproved, tokenId, { from: approved }),
            'ERC721: approve caller is not owner nor approved for all');
        });
      });

      context('when the sender is an operator', function () {
        beforeEach(async function () {
          await this.token.setApprovalForAll(operator, true, { from: owner });
          ({ logs } = await this.token.approve(approved, tokenId, { from: operator }));
        });

        itApproves(approved);
        itEmitsApprovalEvent(approved);
      });

      context('when the given token ID does not exist', function () {
        it('reverts', async function () {
          await expectRevert(this.token.approve(approved, unknownTokenId, { from: operator }),
            'ERC721: owner query for nonexistent token');
        });
      });
    });

    describe('setApprovalForAll', function () {
      context('when the operator willing to approve is not the owner', function () {
        context('when there is no operator approval set by the sender', function () {
          it('approves the operator', async function () {
            await this.token.setApprovalForAll(operator, true, { from: owner });

            expect(await this.token.isApprovedForAll(owner, operator)).to.equal(true);
          });

          it('emits an approval event', async function () {
            const { logs } = await this.token.setApprovalForAll(operator, true, { from: owner });

            expectEvent.inLogs(logs, 'ApprovalForAll', {
              owner: owner,
              operator: operator,
              approved: true,
            });
          });
        });

        context('when the operator was set as not approved', function () {
          beforeEach(async function () {
            await this.token.setApprovalForAll(operator, false, { from: owner });
          });

          it('approves the operator', async function () {
            await this.token.setApprovalForAll(operator, true, { from: owner });

            expect(await this.token.isApprovedForAll(owner, operator)).to.equal(true);
          });

          it('emits an approval event', async function () {
            const { logs } = await this.token.setApprovalForAll(operator, true, { from: owner });

            expectEvent.inLogs(logs, 'ApprovalForAll', {
              owner: owner,
              operator: operator,
              approved: true,
            });
          });

          it('can unset the operator approval', async function () {
            await this.token.setApprovalForAll(operator, false, { from: owner });

            expect(await this.token.isApprovedForAll(owner, operator)).to.equal(false);
          });
        });

        context('when the operator was already approved', function () {
          beforeEach(async function () {
            await this.token.setApprovalForAll(operator, true, { from: owner });
          });

          it('keeps the approval to the given address', async function () {
            await this.token.setApprovalForAll(operator, true, { from: owner });

            expect(await this.token.isApprovedForAll(owner, operator)).to.equal(true);
          });

          it('emits an approval event', async function () {
            const { logs } = await this.token.setApprovalForAll(operator, true, { from: owner });

            expectEvent.inLogs(logs, 'ApprovalForAll', {
              owner: owner,
              operator: operator,
              approved: true,
            });
          });
        });
      });

      context('when the operator is the owner', function () {
        it('reverts', async function () {
          await expectRevert(this.token.setApprovalForAll(owner, true, { from: owner }),
            'ERC721: approve to caller');
        });
      });
    });

    shouldSupportInterfaces([
      'ERC165',
      'ERC721',
    ]);
  });
}

module.exports = {
  shouldBehaveLikeERC721,
};
