import {
  useCallback, useEffect, useReducer, useState,
} from 'react';
import { useSDK } from '@metamask/sdk-react';
import { Web3 } from 'web3';
import Button from 'react-bootstrap/Button';
import Tab from 'react-bootstrap/Tab';
import Tabs from 'react-bootstrap/Tabs';
import Container from 'react-bootstrap/Container';
import Row from 'react-bootstrap/Row';
import Col from 'react-bootstrap/Col';
import Stack from 'react-bootstrap/Stack';

import DAOArtifact from './assets/DAO.json';
import work1Artifact from './assets/Work1.json';

const contracts = {
  '0x539': { // Hardhat
    DAO: '0x635F46Ea745a14431B27c5dd5838306Be289B747',
    Work1: '0xEAefe601Aad7422307B99be65bbE005aeA966012',
  },
  '0xaa36a7': { // Sepolia
    DAO: '0x38AE4ABD47B10f6660CD70Cc8FF3401341E13d9e',
    Work1: '0x358A07B26F4c556140872ecdB69c58e8807E7178',
  },
};

const updateList = (list, action) => {
  switch (action.type) {
    case 'update': {
      const newList = [...list];
      newList[Number(action.item.id)] = action.item;
      return newList;
    }
    case 'refresh':
    default:
      return [];
  }
};

const useList = (initialValue) => useReducer(updateList, initialValue ?? []);

function App() {
  const {
    sdk, connected, provider, chainId, account, balance,
  } = useSDK();

  const [DAO, setDAO] = useState();
  const [work1, setWork1] = useState();
  const [work1Price, setWork1Price] = useState();
  const [balanceEther, setBalanceEther] = useState();
  const [reputation, setReputation] = useState();
  const [totalReputation, setTotalReputation] = useState();
  const [posts, dispatchPost] = useList();
  const [validationPools, dispatchValidationPool] = useList();
  const [availabilityStakes, dispatchAvailabilityStake] = useList();
  const [workRequests, dispatchWorkRequest] = useList();

  // In this effect, we initialize everything and add contract event listeners.
  // TODO: Refactor -- make separate, functional components?
  useEffect(() => {
    if (!provider || !chainId || !account || balance === undefined) return;
    if (!contracts[chainId]) return;

    const web3 = new Web3(provider);
    const DAOContract = new web3.eth.Contract(DAOArtifact.abi, contracts[chainId].DAO);
    const work1Contract = new web3.eth.Contract(work1Artifact.abi, contracts[chainId].Work1);

    /* -------------------------------------------------------------------------------- */
    /* --------------------------- BEGIN FETCHERS ------------------------------------- */
    /* -------------------------------------------------------------------------------- */

    const fetchPrice = async () => {
      const fetchedPrice = await work1Contract.methods.price().call();
      setWork1Price(web3.utils.fromWei(fetchedPrice, 'ether'));
    };

    const fetchReputation = async () => {
      setReputation(Number(await DAOContract.methods.balanceOf(account).call()));
      setTotalReputation(Number(await DAOContract.methods.totalSupply().call()));
    };

    const fetchPost = async (postIndex) => {
      const p = await DAOContract.methods.posts(postIndex).call();
      p.id = Number(p.id);
      dispatchPost({ type: 'update', item: p });
      return p;
    };

    const fetchPosts = async () => {
      const count = await DAOContract.methods.postCount().call();
      const promises = [];
      dispatchPost({ type: 'refresh' });
      for (let i = 0; i < count; i += 1) {
        promises.push(fetchPost(i));
      }
      await Promise.all(promises);
    };

    const fetchValidationPool = async (poolIndex) => {
      const getPoolStatus = (pool) => {
        if (pool.resolved) {
          return pool.outcome ? 'Accepted' : 'Rejected';
        }
        return pool.timeRemaining > 0 ? 'In Progress' : 'Ready to Evaluate';
      };
      const pool = await DAOContract.methods.validationPools(poolIndex).call();
      pool.id = Number(pool.id);
      pool.timeRemaining = new Date(Number(pool.endTime) * 1000) - new Date();
      pool.status = getPoolStatus(pool);
      dispatchValidationPool({ type: 'update', item: pool });

      // When remaing time expires, we want to update the status for this pool
      if (pool.timeRemaining > 0) {
        setTimeout(() => {
          pool.timeRemaining = 0;
          pool.status = getPoolStatus(pool);
          dispatchValidationPool({ type: 'update', item: pool });
        }, pool.timeRemaining);
      }
    };

    const fetchValidationPools = async () => {
      // TODO: Pagination
      // TODO: Memoization
      // TODO: Caching
      const count = await DAOContract.methods.validationPoolCount().call();
      const promises = [];
      dispatchValidationPool({ type: 'refresh' });
      for (let i = 0; i < count; i += 1) {
        promises.push(fetchValidationPool(i));
      }
      await Promise.all(promises);
    };

    const fetchAvailabilityStake = async (stakeIndex) => {
      const s = await work1Contract.methods.stakes(stakeIndex).call();
      Object.assign(s, {
        id: Number(stakeIndex),
        currentUserIsWorker: () => s.worker.toLowerCase() === account.toString().toLowerCase(),
        timeRemaining: new Date(Number(s.endTime) * 1000) - new Date(),
      });
      dispatchAvailabilityStake({ type: 'update', item: s });
      if (s.timeRemaining > 0) {
        setTimeout(() => {
          s.timeRemaining = 0;
          dispatchAvailabilityStake({ type: 'update', item: s });
        }, s.timeRemaining);
      }
      return s;
    };

    const fetchAvailabilityStakes = async () => {
      const count = await work1Contract.methods.stakeCount().call();
      const promises = [];
      dispatchAvailabilityStake({ type: 'refresh' });
      for (let i = 0; i < count; i += 1) {
        promises.push(fetchAvailabilityStake(i));
      }
      await Promise.all(promises);
    };

    const fetchWorkRequest = async (requestIndex) => {
      const getRequestStatus = (request) => {
        switch (Number(request.status)) {
          case -1:
            return 'Requested';
          case 0:
            return 'Evidence Submitted';
          case 1:
            return 'Approval Submitted';
          case 2:
            return 'Complete';
          default:
            return 'Unknown';
        }
      };
      const r = await work1Contract.methods.requests(requestIndex).call();
      Object.assign(r, {
        id: Number(requestIndex),
        statusString: getRequestStatus(r),
        feeEther: web3.utils.fromWei(r.fee, 'ether'),
        currentUserIsCustomer: () => r.customer.toLowerCase()
            === account.toString().toLowerCase(),
      });
      dispatchWorkRequest({ type: 'update', item: r });
      return r;
    };

    const fetchWorkRequests = async () => {
      const count = await work1Contract.methods.requestCount().call();
      const promises = [];
      dispatchWorkRequest({ type: 'refresh' });
      for (let i = 0; i < count; i += 1) {
        promises.push(fetchWorkRequest(i));
      }
      await Promise.all(promises);
    };

    /* -------------------------------------------------------------------------------- */
    /* --------------------------- END FETCHERS --------------------------------------- */
    /* -------------------------------------------------------------------------------- */

    fetchPrice();
    fetchReputation();
    fetchPosts();
    fetchValidationPools();
    fetchAvailabilityStakes();
    fetchWorkRequests();

    setWork1(work1Contract);
    setDAO(DAOContract);

    DAOContract.events.PostAdded({ fromBlock: 'latest' }).on('data', (event) => {
      console.log('event: post added', event);
      fetchPost(event.returnValues.postIndex);
    });

    DAOContract.events.ValidationPoolInitiated({ fromBlock: 'latest' }).on('data', (event) => {
      console.log('event: validation pool initiated', event);
      fetchValidationPool(event.returnValues.poolIndex);
    });

    DAOContract.events.ValidationPoolResolved({ fromBlock: 'latest' }).on('data', (event) => {
      console.log('event: validation pool resolved', event);
      fetchReputation();
      fetchValidationPool(event.returnValues.poolIndex);
    });

    work1Contract.events.AvailabilityStaked({ fromBlock: 'latest' }).on('data', (event) => {
      console.log('event: availability staked', event);
      fetchAvailabilityStake(event.returnValues.stakeIndex);
      fetchReputation();
    });

    work1Contract.events.WorkAssigned({ fromBlock: 'latest' }).on('data', (event) => {
      console.log('event: work assigned', event);
      const r = fetchWorkRequest(event.returnValues.requestIndex);
      fetchAvailabilityStake(r.stakeIndex);
    });

    work1Contract.events.WorkEvidenceSubmitted({ fromBlock: 'latest' }).on('data', (event) => {
      console.log('event: work evidence submitted', event);
      fetchWorkRequest(event.returnValues.requestIndex);
    });

    work1Contract.events.WorkApprovalSubmitted({ fromBlock: 'latest' }).on('data', (event) => {
      console.log('event: work approval submitted', event);
      fetchWorkRequest(event.returnValues.requestIndex);
    });
  }, [provider, account, chainId, balance, setReputation, dispatchAvailabilityStake,
    dispatchValidationPool, dispatchWorkRequest, dispatchPost]);

  /* -------------------------------------------------------------------------------- */
  /* --------------------------- END MAIN INITIALIZION EFFECT ----------------------- */
  /* -------------------------------------------------------------------------------- */

  useEffect(() => {
    if (!provider || balance === undefined) return;
    const web3 = new Web3(provider);
    setBalanceEther(web3.utils.fromWei(balance, 'ether'));
  }, [provider, balance]);

  /* -------------------------------------------------------------------------------- */
  /* --------------------------- BEGIN UI ACTIONS ----------------------------------- */
  /* -------------------------------------------------------------------------------- */

  const connect = useCallback(async () => {
    try {
      await sdk?.connect();
    } catch (err) {
      console.warn('failed to connect..', err);
    }
  }, [sdk]);

  const disconnect = useCallback(async () => {
    try {
      sdk?.terminate();
    } catch (err) {
      console.warn('failed to disconnect..', err);
    }
  }, [sdk]);

  // const watchReputationToken = useCallback(async () => {
  //   await provider.request({
  //     method: 'wallet_watchAsset',
  //     params: {
  //       type: 'ERC20',
  //       options: {
  //         address: DAOAddress,
  //       },
  //     },
  //   });
  // }, [provider]);

  const addPost = useCallback(async () => {
    await DAO.methods.addPost(account).send({
      from: account,
      gas: 1000000,
    });
  }, [DAO, account]);

  const initiateValidationPool = useCallback(async (postIndex, poolDuration) => {
    await DAO.methods.initiateValidationPool(postIndex, poolDuration ?? 3600).send({
      from: account,
      gas: 1000000,
      value: 100,
    });
  }, [DAO, account]);

  const stake = useCallback(async (poolIndex, amount, inFavor) => {
    console.log(`Attempting to stake ${amount} ${inFavor ? 'for' : 'against'} pool ${poolIndex}`);
    await DAO.methods.stake(poolIndex, amount, inFavor).send({
      from: account,
      gas: 999999,
    });

    // Since this is the result we expect from the server, we preemptively set it here.
    // We can let this value be negative -- this would just mean we'll be getting
    // at least one error from the server, and a corrected reputation.
    setReputation((current) => current - stake);
  }, [DAO, account, setReputation]);

  const stakeAllInFavor = useCallback(async (poolIndex) => {
    await stake(poolIndex, reputation, true);
  }, [stake, reputation]);

  const evaluateOutcome = useCallback(async (poolIndex) => {
    await DAO.methods.evaluateOutcome(poolIndex).send({
      from: account,
      gas: 1000000,
    });
  }, [DAO, account]);

  const stakeAvailability = useCallback(async (duration) => {
    const target = contracts[chainId].Work1;
    await DAO.methods.stakeAvailability(target, reputation, duration).send({
      from: account,
      gas: 1000000,
    });
    // Note that as with validation pool stakes, we should keep track locally of our reputation
    setReputation(0);
  }, [DAO, account, chainId, reputation, setReputation]);

  const reclaimAvailabilityStake = useCallback(async (stakeIndex) => {
    await work1.methods.reclaimAvailability(stakeIndex).send({
      from: account,
      gas: 1000000,
    });
  }, [work1, account]);

  const extendAvailabilityStake = useCallback(async (stakeIndex, duration) => {
    await work1.methods.extendAvailability(stakeIndex, duration).send({
      from: account,
      gas: 1000000,
    });
  }, [work1, account]);

  const requestWork = useCallback(async () => {
    const web3 = new Web3(provider);
    const priceWei = BigInt(web3.utils.toWei(work1Price, 'ether'));
    await work1.methods.requestWork().send({
      from: account,
      gas: 1000000,
      value: priceWei,
    });
  }, [provider, work1, account, work1Price]);

  const submitWorkEvidence = useCallback(async (requestIndex) => {
    await work1.methods.submitWorkEvidence(requestIndex).send({
      from: account,
      gas: 1000000,
    });
  }, [work1, account]);

  const submitWorkApproval = useCallback(async (requestIndex) => {
    await work1.methods.submitWorkApproval(requestIndex, true).send({
      from: account,
      gas: 1000000,
    });
  }, [work1, account]);

  const submitWorkDisapproval = useCallback(async (requestIndex) => {
    await work1.methods.submitWorkApproval(requestIndex, false).send({
      from: account,
      gas: 1000000,
    });
  }, [work1, account]);

  /* -------------------------------------------------------------------------------- */
  /* --------------------------- END UI ACTIONS ------------------------------------- */
  /* -------------------------------------------------------------------------------- */

  return (
    <>
      {!connected && <Button onClick={() => connect()}>Connect</Button>}

      {connected && (
        <>
          <Container>
            <Row>
              <Col>
                {!contracts[chainId] && (
                <div>
                  Please switch MetaMask to Sepolia testnet!
                </div>

                )}
              </Col>
            </Row>
            <Row>
              <Col>
                <Stack>
                  <div>
                    {chainId && `Chain ID: ${chainId}`}
                  </div>
                  <div>
                    {`Account: ${account}`}
                  </div>
                  <div>
                    {`Balance: ${balanceEther} ETH`}
                  </div>
                </Stack>
              </Col>
              <Col>
                <Stack>
                  <div>
                    {`Your REP: ${reputation}`}
                  </div>
                  <div>
                    {`Total REP: ${totalReputation}`}
                  </div>
                  <div>
                    <Button onClick={() => disconnect()}>Disconnect</Button>
                  </div>
                </Stack>
              </Col>
            </Row>
          </Container>
          <Tabs>
            <Tab eventKey="admin" title="Admin">

              <div>
                {`Posts count: ${posts.length}`}
              </div>
              <div>
                <table className="table">
                  <thead>
                    <tr>
                      <th>ID</th>
                      <th>Author</th>
                      <th>Sender</th>
                      <th>Actions</th>
                    </tr>
                  </thead>
                  <tbody>
                    {posts.filter((x) => !!x).map((post) => (
                      <tr key={post.id}>
                        <td>{post.id.toString()}</td>
                        <td>{post.author}</td>
                        <td>{post.sender}</td>
                        <td>
                          Initiate Validation Pool
                          {' '}
                          <Button onClick={() => initiateValidationPool(post.id, 60)}>
                            1 Min.
                          </Button>
                          {' '}
                          <Button onClick={() => initiateValidationPool(post.id, 3600)}>
                            1 Hr.
                          </Button>
                          {' '}
                          <Button onClick={() => initiateValidationPool(post.id, 86400)}>
                            1 Day
                          </Button>
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
              <div>
                <Button onClick={() => addPost()}>Add Post</Button>
              </div>
              <div>
                {`Validation Pool Count: ${validationPools.length}`}
              </div>
              <div>
                <table className="table">
                  <thead>
                    <tr>
                      <th>ID</th>
                      <th>Post ID</th>
                      <th>Fee</th>
                      <th>Duration</th>
                      <th>End Time</th>
                      <th>
                        Stake
                        <br />
                        Count
                      </th>
                      <th>Status</th>
                      <th>Actions</th>
                    </tr>
                  </thead>
                  <tbody>
                    {validationPools.filter((x) => !!x).map((pool) => (
                      <tr key={pool.id}>
                        <td>{pool.id.toString()}</td>
                        <td>{pool.postIndex.toString()}</td>
                        <td>{pool.fee.toString()}</td>
                        <td>{pool.duration.toString()}</td>
                        <td>{new Date(Number(pool.endTime) * 1000).toLocaleString()}</td>
                        <td>{pool.stakeCount.toString()}</td>
                        <td>{pool.status}</td>
                        <td>
                          {!pool.resolved && reputation > 0 && pool.timeRemaining > 0 && (
                          <>
                            <Button onClick={() => stakeAllInFavor(pool.id)}>
                              Stake
                            </Button>
                            {' '}
                          </>
                          )}
                          {!pool.resolved && pool.timeRemaining <= 0 && (
                          <Button onClick={() => evaluateOutcome(pool.id)}>
                            Evaluate Outcome
                          </Button>
                          )}
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
              <div>
                <h2>Work Contract 1</h2>
                <div>
                  {`Price: ${work1Price} ETH`}
                </div>
                <div>
                  Stake Availability:
                  {' '}
                  {!reputation && <>No reputation available to stake</>}
                  {reputation > 0 && (
                  <>
                    <Button onClick={() => stakeAvailability(300)}>5 Min.</Button>
                    {' '}
                    <Button onClick={() => stakeAvailability(7200)}>2 Hr.</Button>
                  </>
                  )}
                </div>
                <div>
                  Availability Stake Count:
                  {' '}
                  {availabilityStakes.length}
                </div>
                <div>
                  <table className="table">
                    <thead>
                      <tr>
                        <th>ID</th>
                        <th>Worker</th>
                        <th>Amount</th>
                        <th>End Time</th>
                        <th>Assigned</th>
                        <th>Reclaimed</th>
                        <th>Actions</th>
                      </tr>
                    </thead>
                    <tbody>
                      {availabilityStakes.filter((x) => !!x).map((s) => (
                        <tr key={s.id}>
                          <td>{s.id.toString()}</td>
                          <td>{s.worker.toString()}</td>
                          <td>{s.amount.toString()}</td>
                          <td>{new Date(Number(s.endTime) * 1000).toLocaleString()}</td>
                          <td>{s.assigned.toString()}</td>
                          <td>{s.reclaimed.toString()}</td>
                          <td>
                            {s.currentUserIsWorker() && (
                            <Button onClick={() => extendAvailabilityStake(s.id, 3600)}>
                              Extend 1 Hr.
                            </Button>
                            )}
                            {s.currentUserIsWorker() && s.timeRemaining <= 0
                          && !s.assigned && !s.reclaimed && (
                            <>
                              {' '}
                              <Button onClick={() => reclaimAvailabilityStake(s.id)}>
                                Reclaim
                              </Button>
                            </>
                            )}
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
                <div>
                  <Button onClick={() => requestWork()}>Request Work</Button>
                </div>
                <div>
                  Work Request Count:
                  {' '}
                  {workRequests.length}
                </div>
                <div>
                  <table className="table">
                    <thead>
                      <tr>
                        <th>ID</th>
                        <th>Customer</th>
                        <th>Fee</th>
                        <th>Status</th>
                        <th>Stake ID</th>
                        <th>Approval</th>
                        <th>Pool ID</th>
                        <th>Actions</th>
                      </tr>
                    </thead>
                    <tbody>
                      {workRequests.filter((x) => !!x).map((request) => (
                        <tr key={request.id}>
                          <td>{request.id.toString()}</td>
                          <td>{request.customer.toString()}</td>
                          <td>
                            {request.feeEther}
                            {' '}
                            ETH
                          </td>
                          <td>{request.statusString}</td>
                          <td>{request.stakeIndex.toString()}</td>
                          <td>{request.approval.toString()}</td>
                          <td>{request.poolIndex.toString()}</td>
                          <td>
                            {availabilityStakes.length > 0
                          && availabilityStakes[Number(request.stakeIndex)]?.currentUserIsWorker()
                          && Number(request.status) === 0 && (
                          <Button onClick={() => submitWorkEvidence(request.id)}>
                            Submit Work Evidence
                          </Button>
                            )}
                            {request.currentUserIsCustomer()
                          && Number(request.status) === 1 && (
                            <>
                              <Button onClick={() => submitWorkApproval(request.id)}>
                                Submit Approval
                              </Button>
                              <Button onClick={() => submitWorkDisapproval(request.id)}>
                                Submit Dispproval
                              </Button>
                            </>
                            )}
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
              </div>
            </Tab>
            <Tab eventKey="worker" title="Worker">
              TBD
            </Tab>
            <Tab eventKey="customer" title="Customer">
              TBD
            </Tab>
          </Tabs>
        </>
      )}
    </>
  );
}

export default App;