// Big modules
import { BigNumber } from 'ethers'
import { existsSync, mkdirSync, readFileSync, createWriteStream } from 'fs'
import { opendir, readFile, rm } from 'fs/promises'
import { createInterface } from 'readline'

// Local logic
import { AsyncUtils, NumberUtils, ErrorUtils } from '@tornado/sdk-utils'

// PouchDB
import PouchDB from 'pouchdb'
import * as PouchDBAdapterMemory from 'pouchdb-adapter-memory'

// Archiving
import archiver from 'archiver'

// @ts-ignore
import { toIndexableString } from 'pouchdb-collate'

// Register plugins
PouchDB.plugin(PouchDBAdapterMemory)

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DECLARATIONS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

export interface TornadoInstance {
  network: number
  symbol: string
  decimals: number
  denomination: number
  deployBlock: number
  address: string
}

export interface ClassicInstance extends TornadoInstance {
  anonymityMiningEnabled: boolean
}

export interface TokenData {
  network: number
  decimals: number
  address: string
}

export namespace Keys {
  export interface InstanceLookup {
    network: string
    token: string
    denomination: string
  }
}

export interface RelayerProperties {
  address: string
  version: string
  serviceFeePercent: number
  miningFeePercent: number
  status: string
  chainId: number
  prices: Map<string, BigNumber>
}

export namespace Options {
  export interface Cache {
    adapter?: string
    cachePath?: string
    persistent?: boolean
  }
}

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ REST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

export namespace Files {
  export type PathGetter = (relative: string) => string

  export const getModulesPath = (relative: string, prefix?: string): string =>
    (prefix ?? __dirname + '/../../node_modules/') + relative
  export const getResourcePath = (relative: string, prefix?: string): string =>
    (prefix ?? __dirname + '/../resources/') + relative
  export const getCachePath = (relative: string, prefix?: string): string =>
    (prefix ?? process.cwd() + '/cache/') + relative

  export const cacheDirExists = (prefix?: string): boolean => existsSync(getCachePath('', prefix))
  export const makeCacheDir = (prefix?: string): void => mkdirSync(getCachePath('', prefix))

  export const loadRaw = (relative: string): Promise<Buffer> => readFile(getResourcePath(relative))
  export const loadRawSync = (relative: string): Buffer => readFileSync(getResourcePath(relative))

  export async function wipeCache(prompt: boolean = true): Promise<void> {
    const dir = await opendir(getCachePath(''))
    const toRemove: string[] = []
    const userInput = createInterface({ input: process.stdin, output: process.stdout })
    for await (const entry of dir) {
      if (entry.name.match('(Deposit.*)|(Withdrawal.*)|(Note.*)|(Invoice.*)'))
        toRemove.push(getCachePath(entry.name))
    }
    if (toRemove.length != 0) {
      if (prompt) {
        const promptString = `\nCache wipe requested, following would be wiped:\n\n${toRemove.join(
          '\n'
        )}\n\nContinue? (y/n): `
        function wipeCachePrompt(prompt: string, resolve: any): void {
          userInput.question(prompt, (answer) => {
            if (answer == 'y') {
              userInput.close()
              resolve(true)
            } else if (answer == 'n') {
              userInput.close()
              resolve(false)
            } else wipeCachePrompt('', resolve)
          })
        }
        const answer = await new Promise((resolve) => wipeCachePrompt(promptString, resolve))
        if (answer)
          await Promise.all(toRemove.map((entry) => rm(entry, { recursive: true, force: true }))).catch(
            (err) => {
              throw ErrorUtils.ensureError(err)
            }
          )
      } else {
        await Promise.all(toRemove.map((entry) => rm(entry, { recursive: true, force: true }))).catch(
          (err) => {
            throw ErrorUtils.ensureError(err)
          }
        )
      }
    }
  }
}

export namespace Json {
  const cachedJsonData = new Map<string, any>()

  export async function load(
    relativePath: string,
    encoding: BufferEncoding = 'utf8',
    pathGetter: Files.PathGetter = Files.getResourcePath
  ): Promise<any> {
    if (cachedJsonData.has(relativePath)) return cachedJsonData.get(relativePath)
    else {
      const obj = JSON.parse(await readFile(pathGetter(relativePath), encoding))
      cachedJsonData.set(relativePath, obj)
      return obj
    }
  }

  export function loadSync(
    relativePath: string,
    encoding: BufferEncoding = 'utf8',
    pathGetter: Files.PathGetter = Files.getResourcePath
  ): any {
    if (cachedJsonData.has(relativePath)) return cachedJsonData.get(relativePath)
    else {
      const obj = JSON.parse(readFileSync(pathGetter(relativePath), encoding))
      cachedJsonData.set(relativePath, obj)
      return obj
    }
  }

  export function toMap<V>(jsonData: any): Map<string, V> {
    return new Map<string, V>(Object.entries(jsonData))
  }

  export async function loadMap<V>(
    relativePath: string,
    encoding: BufferEncoding = 'utf8'
  ): Promise<Map<string, V>> {
    return toMap<V>(await load(relativePath, encoding))
  }

  export function getError(...values: any[]): Error {
    return ErrorUtils.getError(`there is no such entry for the key-value path [${values.join('][')}]`)
  }

  export function throwError(...values: any[]): void {
    throw getError(...values)
  }

  export function getValue(jsonObj: any, keys: any[]): any {
    for (let i = 0; i < keys.length; i++) {
      jsonObj = jsonObj[keys[i]] ?? throwError(...keys.slice(0, i + 1))
    }
    return jsonObj
  }
}

// TODO: Decide whether to also cache the data instead of just loading it for the function call

export namespace Onchain {
  export async function getClassicInstanceData(
    network: string,
    token: string,
    denomination: string
  ): Promise<ClassicInstance> {
    const instanceData = Json.getValue(await Json.load('onchain/instances.json'), [network, token])
    return {
      network: +network,
      symbol: token.toUpperCase(),
      decimals: Json.getValue(instanceData, ['decimals']),
      denomination: +denomination,
      deployBlock: Json.getValue(instanceData, ['deployedBlockNumber', denomination]),
      address: Json.getValue(instanceData, ['instanceAddress', denomination]),
      anonymityMiningEnabled: Json.getValue(instanceData, ['miningEnabled'])
    }
  }

  export function getClassicInstanceDataSync(
    network: string,
    token: string,
    denomination: string
  ): ClassicInstance {
    const instanceData = Json.getValue(Json.loadSync('onchain/instances.json'), [network, token])
    return {
      network: +network,
      symbol: token.toUpperCase(),
      decimals: Json.getValue(instanceData, ['decimals']),
      denomination: +denomination,
      deployBlock: Json.getValue(instanceData, ['deployedBlockNumber', denomination]),
      address: Json.getValue(instanceData, ['instanceAddress', denomination]),
      anonymityMiningEnabled: Json.getValue(instanceData, ['miningEnabled'])
    }
  }

  export async function getInstanceLookupKeys(instanceAddress: string): Promise<Keys.InstanceLookup> {
    // lookup some stuff first
    const lookupObj: { [key: string]: string } = await Json.load('onchain/instanceAddresses.json')

    const pathstring: string = Object.entries(lookupObj).find((el) => el[1] === instanceAddress)![0]

    const network = pathstring.match('[0-9]+')![0],
      token = pathstring.substring(network.length).match('[a-z]+')![0],
      denomination = pathstring.substring(network.length + token.length)

    return {
      network: network,
      token: token,
      denomination: denomination
    }
  }

  export function getInstanceLookupKeysSync(instanceAddress: string): Keys.InstanceLookup {
    // lookup some stuff first
    const lookupObj: { [key: string]: string } = Json.loadSync('onchain/instanceAddresses.json')

    const pathstring: string = Object.entries(lookupObj).find((el) => el[1] === instanceAddress)![0]

    const network = pathstring.match('[0-9]+')![0],
      token = pathstring.substring(network.length).match('[a-z]+')![0],
      denomination = pathstring.substring(network.length + token.length)

    return {
      network: network,
      token: token,
      denomination: denomination
    }
  }

  export async function getPathstringBasedContent<T>(
    filepath: string,
    paths: Array<{
      network?: string
      token?: string
      denomination?: string
    }>
  ): Promise<Array<T>> {
    const obj = await Json.load(filepath)
    return await Promise.all(
      paths.map((path) =>
        Json.getValue(obj, [`${path.network ?? ''}${path.token ?? ''}${path.denomination ?? ''}`])
      )
    )
  }

  export function getPathstringBasedContentSync<T>(
    filepath: string,
    paths: Array<{
      network?: string
      token?: string
      denomination?: string
    }>
  ): Array<T> {
    return paths.map((path) =>
      Json.getValue(Json.loadSync(filepath), [
        `${path.network ?? ''}${path.token ?? ''}${path.denomination ?? ''}`
      ])
    )
  }

  export async function getNetworkSymbol(networkId: string): Promise<string> {
    return (
      await getPathstringBasedContent<string>('onchain/networkSymbols.json', [{ network: networkId }])
    )[0]
  }

  export function getNetworkSymbolSync(networkId: string): string {
    return getPathstringBasedContentSync<string>('onchain/networkSymbols.json', [{ network: networkId }])[0]
  }

  export function getInstanceAddresses(
    paths: Array<{
      network: string
      token: string
      denomination: string
    }>
  ): Promise<Array<string>> {
    return getPathstringBasedContent<string>('onchain/instanceAddresses.json', paths)
  }

  export function getInstanceAddressesSync(
    paths: Array<{
      network: string
      token: string
      denomination: string
    }>
  ): Array<string> {
    return getPathstringBasedContentSync<string>('onchain/instanceAddresses.json', paths)
  }

  export async function getInstanceAddress(
    network: string,
    token: string,
    denomination: string
  ): Promise<string> {
    return (await getInstanceAddresses([{ network: network, token: token, denomination: denomination }]))[0]
  }

  export function getInstanceAddressSync(network: string, token: string, denomination: string): string {
    return getInstanceAddressesSync([{ network: network, token: token, denomination: denomination }])[0]
  }

  export function getInstanceDeployBlockNums(
    paths: Array<{
      network: string
      token: string
      denomination: string
    }>
  ): Promise<Array<number>> {
    return getPathstringBasedContent<number>('onchain/deployedBlockNumbers.json', paths)
  }

  export function getInstanceDeployBlockNumsSync(
    paths: Array<{
      network: string
      token: string
      denomination: string
    }>
  ): Array<number> {
    return getPathstringBasedContentSync<number>('onchain/deployedBlockNumbers.json', paths)
  }

  export async function getInstanceDeployBlockNum(
    network: string,
    token: string,
    denomination: string
  ): Promise<number> {
    return (
      await getInstanceDeployBlockNums([{ network: network, token: token, denomination: denomination }])
    )[0]
  }

  export function getInstanceDeployBlockNumSync(
    network: string,
    token: string,
    denomination: string
  ): number {
    return getInstanceDeployBlockNumsSync([{ network: network, token: token, denomination: denomination }])[0]
  }

  export async function getProxyAddress(network: string): Promise<string> {
    return Json.getValue(await Json.load('onchain/infrastructure.json'), [network, 'proxy'])
  }

  export async function getMulticallAddress(network: string): Promise<string> {
    return Json.getValue(await Json.load('onchain/infrastructure.json'), [network, 'multicall'])
  }

  export async function getMulticall3Address(network: string): Promise<string> {
    return Json.getValue(await Json.load('onchain/infrastructure.json'), [network, 'multicall3'])
  }

  export function getProxyAddressSync(network: string): string {
    return Json.getValue(Json.loadSync('onchain/infrastructure.json'), [network, 'proxy'])
  }

  export function getMulticallAddressSync(network: string): string {
    return Json.getValue(Json.loadSync('onchain/infrastructure.json'), [network, 'multicall'])
  }

  export function getMulticall3AddressSync(network: string): string {
    return Json.getValue(Json.loadSync('onchain/infrastructure.json'), [network, 'multicall3'])
  }

  export async function getTokenData(network: string, token: string): Promise<TokenData> {
    const data = Json.getValue(await Json.load('onchain/tokens.json'), [network, token])
    return {
      network: +network,
      decimals: +data['decimals'],
      address: data['address']
    }
  }

  export function getTokenDataSync(network: string, token: string): TokenData {
    const data = Json.getValue(Json.loadSync('onchain/tokens.json'), [network, token])
    return {
      network: +network,
      decimals: +data['decimals'],
      address: data['address']
    }
  }

  export async function getTokenAddress(network: string, token: string): Promise<string> {
    return (
      await getPathstringBasedContent<string>('onchain/tokenAddresses.json', [
        { network: network, token: token }
      ])
    )[0]
  }

  export function getTokenAddressSync(network: string, token: string): string {
    return getPathstringBasedContentSync<string>('onchain/tokenAddresses.json', [
      { network: network, token: token }
    ])[0]
  }

  export async function getTokenDecimals(network: string, token: string): Promise<number> {
    return (
      await getPathstringBasedContent<number>('onchain/decimals.json', [{ network: network, token: token }])
    )[0]
  }

  export function getTokenDecimalsSync(network: string, token: string): number {
    return getPathstringBasedContentSync<number>('onchain/decimals.json', [
      { network: network, token: token }
    ])[0]
  }
}

export namespace Offchain {
  export async function getUncensoredRpcURL(network: string, name: string = ''): Promise<string> {
    const rpcs = Json.toMap<string>(
      Json.getValue(await Json.load('offchain/infrastructure.json'), ['jrpc-uncensored', network])
    )

    if (name.length !== 0) {
      return rpcs.get(name)!
    }

    let keys = rpcs.keys()
    let randCount = NumberUtils.getRandomFromRange(0, rpcs.size - 1)
    for (let i = 0; i < randCount; i++) keys.next()

    return rpcs.get(keys.next().value)!
  }

  export function getUncensoredRpcURLSync(network: string, name: string = ''): string {
    const rpcs = Json.toMap<string>(
      Json.getValue(Json.loadSync('offchain/infrastructure.json'), ['jrpc-uncensored', network])
    )

    if (name.length !== 0) {
      return rpcs.get(name)!
    }

    let keys = rpcs.keys()
    let randCount = NumberUtils.getRandomFromRange(0, rpcs.size - 1)
    for (let i = 0; i < randCount; i++) keys.next()

    return rpcs.get(keys.next().value)!
  }

  export async function getClassicSubgraphURL(network: string): Promise<string> {
    return Json.getValue(await Json.load('offchain/infrastructure.json'), ['subgraph', network])
  }

  export function getClassicSubgraphURLSync(network: string): string {
    return Json.getValue(Json.loadSync('offchain/infrastructure.json'), ['subgraph', network])
  }
}

export namespace Constants {
  export const MERKLE_TREE_HEIGHT = 20
}

export namespace Docs {
  // TODO: Probably find some easier way to lookup below docs for the end user...

  export class Base {
    _id: string
    _rev?: string

    constructor(id: string) {
      this._id = id
    }
  }

  export class Deposit extends Base {
    blockNumber: number
    leafIndex: number
    commitment: string
    transactionHash: string
    timestamp: string

    constructor(obj: any) {
      const blockNumber = obj['blockNumber']
      const transactionHash = obj['transactionHash']
      const commitment = obj['args']['commitment']
      const leafIndex = obj['args']['leafIndex']
      const timestamp = obj['args']['timestamp']

      // To preserve order because we will need it later
      super(toIndexableString([blockNumber, leafIndex, commitment]))

      this.commitment = commitment
      this.blockNumber = blockNumber
      this.leafIndex = leafIndex
      this.transactionHash = transactionHash
      this.timestamp = timestamp
    }
  }

  export class Withdrawal extends Base {
    blockNumber: number
    to: string
    nullifierHash: string
    transactionHash: string
    fee: string

    constructor(obj: any) {
      const blockNumber = obj['blockNumber']
      const transactionHash = obj['transactionHash']
      const to = obj['args']['to']
      const nullifierHash = obj['args']['nullifierHash']
      const fee = (obj['args']['fee'] as BigNumber).toString()

      super(toIndexableString([blockNumber, to, nullifierHash]))

      this.blockNumber = blockNumber
      this.to = to
      this.nullifierHash = nullifierHash
      this.transactionHash = transactionHash
      this.fee = fee
    }
  }

  export class Note extends Base {
    network: string
    token: string
    denomination: string
    note: string

    constructor(index: number, network: string, token: string, denomination: string, note: string) {
      super(toIndexableString([index, network, denomination, token]))
      this.network = network
      this.token = token
      this.denomination = denomination
      this.note = note
    }
  }

  export class Invoice extends Base {
    network: string
    token: string
    denomination: string
    invoice: string

    constructor(index: number, network: string, token: string, denomination: string, invoice: string) {
      super(toIndexableString([index, network, denomination, token]))
      this.network = network
      this.token = token
      this.denomination = denomination
      this.invoice = invoice
    }
  }

  export class Relayer extends Base {
    address: string
    version: string
    serviceFeePercent: number
    miningFeePercent: number
    status: string
    chainId: number
    prices: Map<string, BigNumber>

    constructor(url: string, properties: RelayerProperties) {
      super(toIndexableString([url]))
      this.address = properties.address
      this.version = properties.version
      this.serviceFeePercent = properties.serviceFeePercent
      this.miningFeePercent = properties.miningFeePercent
      this.status = properties.status
      this.chainId = properties.chainId
      this.prices = properties.prices
    }
  }
}

export namespace Cache {
  export class Base<T extends Docs.Base> {
    private _adapter: string
    private _path: string

    name: string
    db: PouchDB.Database<T>

    constructor(name: string, options?: Options.Cache) {
      this.name = name

      if (options?.persistent === false && options?.adapter !== 'memory' && options?.adapter !== null)
        throw ErrorUtils.getError('Cache.new: if not persistent, cache must use memory adapter.')

      if (options?.adapter === 'memory' && options?.persistent === true)
        throw ErrorUtils.getError("Cache.new: can't specify memory adapter if persistent.")

      const dbAdapter = options?.adapter ?? (options?.persistent === false ? 'memory' : 'leveldb')

      if (options?.cachePath)
        if (options.cachePath.charAt(options.cachePath.length - 1) != '/') options.cachePath += '/'

      if (!Files.cacheDirExists(options?.cachePath)) Files.makeCacheDir()

      this._path = Files.getCachePath(name, options?.cachePath)

      this._adapter = dbAdapter

      this.db = new PouchDB<T>(this._path, { adapter: dbAdapter })
    }

    async exportAsArchive(outDirPath?: string, debug: boolean = false): Promise<void> {
      await this.close()

      if (outDirPath) outDirPath = outDirPath[outDirPath.length - 1] != '/' ? outDirPath + '/' : outDirPath

      const outStream = createWriteStream((outDirPath ?? Files.getCachePath('')) + this.name + '.zip')

      const archive = archiver('zip', {
        zlib: {
          level: 9
        }
      })

      // listen for all archive data to be written
      // 'close' event is fired only when a file descriptor is involved
      if (debug)
        outStream.on('close', function () {
          console.debug('Cache.exportAsArchive: ' + archive.pointer() + ' total bytes written.')
          console.debug('Cache.exportAsArchive: fo closed.')
        })

      // This event is fired when the data source is drained no matter what was the data source.
      // It is not part of this library but rather from the NodeJS Stream API.
      // @see: https://nodejs.org/api/stream.html#stream_event_end
      if (debug)
        outStream.on('end', function () {
          console.log('Cache.exportAsArchive: drained.')
        })

      archive.on('warning', (err) => {
        if (err.code != 'ENOENT') throw ErrorUtils.ensureError(err)
      })

      archive.on('error', (err) => {
        throw ErrorUtils.ensureError(err)
      })

      archive.pipe(outStream)

      archive.directory(this._path, this.name)

      await archive.finalize()

      outStream.close()

      this.db = new PouchDB<T>(this._path, { adapter: this._adapter })
    }

    async get(keys: Array<any>): Promise<T> {
      return await this.db.get(toIndexableString(keys)).catch((err) => {
        throw ErrorUtils.ensureError(err)
      })
    }

    async close(): Promise<void> {
      await this.db.close().catch((err) => {
        throw ErrorUtils.ensureError(err)
      })
    }

    async clear(): Promise<void> {
      await this.db.destroy().catch((err) => {
        throw ErrorUtils.ensureError(err)
      })
    }
  }

  export abstract class Syncable<T extends Docs.Base> extends Base<T> {
    pooler?: AsyncUtils.PromisePooler

    constructor(name: string, options?: Options.Cache) {
      super(name, options)
    }

    abstract buildDoc(response: any): Docs.Base

    abstract getCallbacks(...args: Array<any>): Array<AsyncUtils.Callback>

    abstract getErrorHandlers(...args: Array<any>): Array<AsyncUtils.ErrorHandler>

    initializePooler(
      callbacks: Array<AsyncUtils.Callback>,
      errorHandlers: Array<AsyncUtils.ErrorHandler>,
      concurrencyLimit: number
    ): void {
      if (this.pooler) this.pooler.reset()
      this.pooler = new AsyncUtils.PromisePooler(callbacks, errorHandlers, concurrencyLimit)
    }

    async close(): Promise<void> {
      if (this.pooler && this.pooler.pending)
        throw ErrorUtils.getError("Syncable.close: can't clear while pooler still has pending promises.")
      await super.close()
    }

    async clear(): Promise<void> {
      if (this.pooler && this.pooler.pending)
        throw ErrorUtils.getError("Syncable.clear: can't clear while pooler still has pending promises.")
      await super.clear()
    }
  }

  type DocsArray<T extends Docs.Base> = Array<{
    doc?: T
    id: string
    key: string
    value: {
      rev: string
      deleted?: boolean
    }
  }>

  export async function loadContents<T extends Docs.Base>(
    nameOfContent: string,
    full: boolean = true,
    emptyError: Error = ErrorUtils.getError(
      `Core.loadCacheContents: there is no cache entry for ${nameOfContent}`
    )
  ): Promise<DocsArray<T>> {
    const cache = new Cache.Base<T>(nameOfContent)

    const docs = await cache.db.allDocs({ include_docs: full }).catch((err) => {
      throw ErrorUtils.ensureError(err)
    })

    if (docs.total_rows === 0) {
      await cache.clear()
      throw emptyError
    }

    return docs.rows as DocsArray<T>
  }
}