import { BigNumber } from 'ethers';
import path from 'path';
import fs from 'fs-extra';
import debug from 'debug';
import yaml from 'js-yaml';

import { TypeId, EthereumValueKind, ValueKind } from './types';
import Decimal from 'decimal.js';

const log = debug('vulcanize:utils');

interface EventParam {
  name: string;
  value: any;
  kind: string;
}

interface Transaction {
  hash: string;
  index: number;
  from: string;
  to: string;
}

export interface Block {
  blockHash: string;
  blockNumber: string;
  timestamp: string;
  parentHash: string;
  stateRoot: string;
  td: string;
  txRoot: string;
  receiptRoot: string;
}

export interface EventData {
  block: Block;
  tx: Transaction;
  eventParams: EventParam[];
  eventIndex: number;
}

/**
 * Method to get value from graph-ts ethereum.Value wasm instance.
 * @param instanceExports
 * @param value
 * @returns
 */
export const fromEthereumValue = async (instanceExports: any, value: any): Promise<any> => {
  const {
    __getString,
    BigInt,
    Address
  } = instanceExports;

  const kind = await value.kind;

  switch (kind) {
    case EthereumValueKind.ADDRESS: {
      const address = Address.wrap(await value.toAddress());
      const addressStringPtr = await address.toHexString();
      return __getString(addressStringPtr);
    }

    case EthereumValueKind.BOOL: {
      const bool = await value.toBoolean();
      return Boolean(bool);
    }

    case EthereumValueKind.BYTES:
    case EthereumValueKind.FIXED_BYTES: {
      const bytes = await value.toBytes();
      const bytesStringPtr = await bytes.toHexString();
      return __getString(bytesStringPtr);
    }

    case EthereumValueKind.INT:
    case EthereumValueKind.UINT: {
      const bigInt = BigInt.wrap(await value.toBigInt());
      const bigIntStringPtr = await bigInt.toString();
      const bigIntString = __getString(bigIntStringPtr);
      return BigNumber.from(bigIntString);
    }

    default:
      break;
  }
};

/**
 * Method to get ethereum value for passing to wasm instance.
 * @param instanceExports
 * @param value
 * @param type
 * @returns
 */
export const toEthereumValue = async (instanceExports: any, value: any, type: string): Promise<any> => {
  const {
    __newString,
    ByteArray,
    Bytes,
    Address,
    ethereum,
    BigInt
  } = instanceExports;

  // For boolean type.
  if (type === 'bool') {
    return ethereum.Value.fromBoolean(value ? 1 : 0);
  }

  const [isIntegerOrEnum, isInteger, isUnsigned] = type.match(/^enum|((u?)int([0-9]+))/) || [false];

  // For uint/int type or enum type.
  if (isIntegerOrEnum) {
    const valueString = await __newString(value.toString());
    const bigInt = await BigInt.fromString(valueString);
    let ethereumValue = await ethereum.Value.fromUnsignedBigInt(bigInt);

    if (Boolean(isInteger) && !isUnsigned) {
      ethereumValue = await ethereum.Value.fromSignedBigInt(bigInt);
    }

    return ethereumValue;
  }

  if (type.startsWith('address')) {
    return ethereum.Value.fromAddress(await Address.fromString(await __newString(value)));
  }

  // TODO: Check between fixed bytes and dynamic bytes.
  if (type.startsWith('bytes')) {
    const byteArray = await ByteArray.fromHexString(await __newString(value));
    const bytes = await Bytes.fromByteArray(byteArray);
    return ethereum.Value.fromBytes(bytes);
  }

  // For string type.
  return ethereum.Value.fromString(await __newString(value));
};

/**
 * Method to create ethereum event.
 * @param instanceExports
 * @param contractAddress
 * @param eventParamsData
 * @returns
 */
export const createEvent = async (instanceExports: any, contractAddress: string, eventData: EventData): Promise<any> => {
  const {
    tx,
    eventIndex,
    eventParams: eventParamsData,
    block: blockData
  } = eventData;

  const {
    __newString,
    __newArray,
    Address,
    BigInt,
    ethereum,
    Bytes,
    ByteArray,
    id_of_type: idOfType
  } = instanceExports;

  const block = await createBlock(instanceExports, blockData);

  // Fill transaction data.
  const txHashByteArray = await ByteArray.fromHexString(await __newString(tx.hash));
  const txHash = await Bytes.fromByteArray(txHashByteArray);

  const txIndex = await BigInt.fromI32(tx.index);

  const txFrom = await Address.fromString(await __newString(tx.from));

  const txTo = tx.to && await Address.fromString(await __newString(tx.to));

  // Missing fields from watcher in transaction data:
  // value
  // gasLimit
  // gasPrice
  // input
  const transaction = await ethereum.Transaction.__new(
    txHash,
    txIndex,
    txFrom,
    txTo,
    await BigInt.fromI32(0),
    await BigInt.fromI32(0),
    await BigInt.fromI32(0),
    await Bytes.empty()
  );

  const eventParamArrayPromise = eventParamsData.map(async data => {
    const { name, value, kind } = data;

    const ethValue = await toEthereumValue(instanceExports, value, kind);

    return ethereum.EventParam.__new(
      await __newString(name),
      ethValue
    );
  });

  const eventParamArray = await Promise.all(eventParamArrayPromise);
  const eventParams = await __newArray(await idOfType(TypeId.ArrayEventParam), eventParamArray);

  const addStrPtr = await __newString(contractAddress);

  // Create event to be passed to handler.
  return ethereum.Event.__new(
    await Address.fromString(addStrPtr),
    await BigInt.fromI32(eventIndex),
    await BigInt.fromI32(0),
    null,
    block,
    transaction,
    eventParams
  );
};

export const createBlock = async (instanceExports: any, blockData: Block): Promise<any> => {
  const {
    __newString,
    Address,
    BigInt,
    ethereum,
    Bytes,
    ByteArray
  } = instanceExports;

  // Fill block data.
  const blockHashByteArray = await ByteArray.fromHexString(await __newString(blockData.blockHash));
  const blockHash = await Bytes.fromByteArray(blockHashByteArray);

  const parentHashByteArray = await ByteArray.fromHexString(await __newString(blockData.parentHash));
  const parentHash = await Bytes.fromByteArray(parentHashByteArray);

  const blockNumber = await BigInt.fromString(await __newString(blockData.blockNumber));

  const blockTimestamp = await BigInt.fromString(await __newString(blockData.timestamp));

  const stateRootByteArray = await ByteArray.fromHexString(await __newString(blockData.stateRoot));
  const stateRoot = await Bytes.fromByteArray(stateRootByteArray);

  const transactionsRootByteArray = await ByteArray.fromHexString(await __newString(blockData.txRoot));
  const transactionsRoot = await Bytes.fromByteArray(transactionsRootByteArray);

  const receiptsRootByteArray = await ByteArray.fromHexString(await __newString(blockData.receiptRoot));
  const receiptsRoot = await Bytes.fromByteArray(receiptsRootByteArray);

  const totalDifficulty = await BigInt.fromString(await __newString(blockData.td));

  // Missing fields from watcher in block data:
  // unclesHash
  // author
  // gasUsed
  // gasLimit
  // difficulty
  // size
  return await ethereum.Block.__new(
    blockHash,
    parentHash,
    await Bytes.empty(),
    await Address.zero(),
    stateRoot,
    transactionsRoot,
    receiptsRoot,
    blockNumber,
    await BigInt.fromI32(0),
    await BigInt.fromI32(0),
    blockTimestamp,
    await BigInt.fromI32(0),
    totalDifficulty,
    null
  );
};

export const getSubgraphConfig = async (subgraphPath: string): Promise<any> => {
  const configFilePath = path.resolve(path.join(subgraphPath, 'subgraph.yaml'));
  const fileExists = await fs.pathExists(configFilePath);

  if (!fileExists) {
    throw new Error(`Config file not found: ${configFilePath}`);
  }

  const config = yaml.load(await fs.readFile(configFilePath, 'utf8'));
  log('config', JSON.stringify(config, null, 2));

  return config;
};

export const toEntityValue = async (instanceExports: any, entityInstance: any, data: any, type: string, key: string) => {
  const { __newString, BigInt: ExportBigInt, Value, ByteArray, Bytes, BigDecimal } = instanceExports;
  const entityKey = await __newString(key);
  const value = data[key];

  switch (type) {
    case 'varchar': {
      const entityValue = await __newString(value);

      const graphValue = Value.wrap(await entityInstance.get(entityKey));

      const kind = await graphValue.kind;

      switch (kind) {
        case ValueKind.BYTES: {
          const byteArray = await ByteArray.fromHexString(entityValue);
          const bytes = await Bytes.fromByteArray(byteArray);
          return entityInstance.setBytes(entityKey, bytes);
        }

        default:
          return entityInstance.setString(entityKey, entityValue);
      }
    }

    case 'integer': {
      return entityInstance.setI32(entityKey, value);
    }

    case 'bigint': {
      const bigInt = await ExportBigInt.fromString(await __newString(value.toString()));

      return entityInstance.setBigInt(entityKey, bigInt);
    }

    case 'boolean': {
      return entityInstance.setBoolean(entityKey, value ? 1 : 0);
    }

    case 'enum': {
      const entityValue = await __newString(value);
      return entityInstance.setString(entityKey, entityValue);
    }

    case 'numeric': {
      const bigDecimal = await BigDecimal.fromString(await __newString(value.toString()));
      return entityInstance.setBigDecimal(entityKey, bigDecimal);
    }

    // TODO: Support more types.
    default:
      throw new Error(`Unsupported type: ${type}`);
  }
};

export const fromEntityValue = async (instanceExports: any, entityInstance: any, type: string, key: string): Promise<any> => {
  const { __newString, __getString, BigInt: ExportBigInt, Value, BigDecimal, Bytes } = instanceExports;
  const entityKey = await __newString(key);

  switch (type) {
    case 'varchar': {
      const value = Value.wrap(await entityInstance.get(entityKey));

      const kind = await value.kind;

      switch (kind) {
        case ValueKind.BYTES: {
          const bytes = await Bytes.wrap(await value.toBytes());
          const bytesStringPtr = await bytes.toHexString();
          return __getString(bytesStringPtr);
        }

        default:
          return __getString(await entityInstance.getString(entityKey));
      }
    }

    case 'integer': {
      return entityInstance.getI32(entityKey);
    }

    case 'bigint': {
      const bigInt = ExportBigInt.wrap(await entityInstance.getBigInt(entityKey));
      return BigInt(__getString(await bigInt.toString()));
    }

    case 'boolean': {
      return Boolean(await entityInstance.getBoolean(entityKey));
    }

    case 'enum': {
      return __getString(await entityInstance.getString(entityKey));
    }

    case 'numeric': {
      const bigDecimal = BigDecimal.wrap(await entityInstance.getBigDecimal(entityKey));
      return new Decimal(__getString(await bigDecimal.toString()));
    }

    // TODO: Support more types.
    default:
      throw new Error(`Unsupported type: ${type}`);
  }
};

export const resolveEntityFieldConflicts = (entity: any): any => {
  if (entity) {
    // Remove fields blockHash and blockNumber from the entity.
    delete entity.blockHash;
    delete entity.blockNumber;

    // Rename _blockHash -> blockHash.
    if ('_blockHash' in entity) {
      entity.blockHash = entity._blockHash;
      delete entity._blockHash;
    }

    // Rename _blockNumber -> blockNumber.
    if ('_blockNumber' in entity) {
      entity.blockNumber = entity._blockNumber;
      delete entity._blockNumber;
    }
  }

  return entity;
};