import {IChain, IBridge, BridgeJSON, IBridgePair, IToken, Option} from './types'
import {sha256} from '@ethersproject/solidity'

export class BridgePair implements IBridgePair {
  token0: IToken
  token1: IToken

  constructor(token0: IToken, token1: IToken) {
    this.token0 = token0
    this.token1 = token1
  }

  id(): string {
    const concatId: string =
      this.token0.id.toLowerCase() < this.token1.id.toLowerCase()
        ? this.token0.id + this.token1.id
        : this.token1.id + this.token0.id

    return sha256(['string'], [concatId])
  }

  getToken0Capcity(): Option<string> {
    // TODO: calculate by price oracle and onchain data
    return '10000'
  }

  getToken1Capcity(): Option<string> {
    // TODO: calculate by price oracle and onchain data
    return '20000'
  }
}

export class Bridge implements IBridge {
  chain0: IChain
  chain1: IChain
  pairs: IBridgePair[]
  pairBounding: Map<string, boolean>

  constructor(chain0: IChain, chain1: IChain) {
    this.chain0 = chain0
    this.chain1 = chain1
    this.pairs = []
    this.pairBounding = new Map<string, boolean>()
  }

  addBridgePair(pair: IBridgePair) {
    const id = pair.id()
    if (this.pairBounding.get(id)) {
      throw new Error('Bridge pair already exist')
    }
    this.pairs.push(pair)
    // Two way bouding
    // FIXME: not working
    this.pairBounding.set(id, true)
    console.log(`Adding new bridge pair with id: ${id}`)
  }

  // Return corresponding bridged asset for a given asset
  getBridgedAsset(token: IToken): Option<[IChain, IToken]> {
    // let pair: keyof IBridgePair
    for (let i = 0; i < this.pairs.length; i++) {
      const pair: IBridgePair = this.pairs[i]
      if (pair.token0.id.toLowerCase() === token.id.toLowerCase())
        return [this.chain1, pair.token1]
      if (pair.token1.id.toLowerCase() === token.id.toLowerCase())
        return [this.chain0, pair.token0]
    }
    return null
  }

  toJSON(): BridgeJSON {
    const tokens: string[] = []
    for (const pair of this.pairs) {
      // By default we treat token0 as reserved asset, token1 as as corresponding peg asset
      tokens.push(pair.token0.symbol)
    }
    return {
      chain0: this.chain0.name,
      chain1: this.chain1.name,
      tokens: tokens,
    }
  }
}