# frozen_string_literal: true

require('faraday')
require('json')

# @author Hernani Rodrigues Vaz
module Etht
  # classe para tratar pedidos etherscan com chave API
  class Etherscan
    attr_reader :key, :url

    # @param [String] :key apikey a juntar aos pedidos HTTP url:
    # @param [String] :url base URL to use as a prefix for all requests
    # @return [Etherscan] API etherscan base
    def initialize(key: ENV['ETHERSCAN_API_KEY'], url: 'https://api.etherscan.io/')
      @key = key
      @url = url
    end

    # @return [<Symbol>] adapter for the connection - default :net_http
    def adapter
      @adapter ||= Faraday.default_adapter
    end

    # manage the default properties and the middleware stack for fulfilling an HTTP request
    #
    # @return [<Faraday::Connection>] connection object with an URL & adapter
    def conn
      @conn ||=
        Faraday.new(url: url) do |c|
          c.request(:url_encoded)
          c.adapter(adapter)
        end
    end

    # @return [<Hash>] resultado json do GET HTTP request
    def get(**ars)
      r =
        conn.get('api') do |o|
          o.headers = { content_type: 'application/json', accept: 'application/json', user_agent: 'etherscan;ruby' }
          o.params = ars.merge({ apikey: key })
        end
      raise(Etht::Erro, r) if r.status != 200

      JSON(r.body)['result']
    end

    # get ether balance for a single address
    #
    # @param [String] add address for balance
    # @return [<String>] devolve saldo
    def address_balance(add)
      raise(Etht::Erro, 'address must be defined') if add.nil?

      get(module: 'account', action: 'balance', address: add, tag: 'latest')
    end

    # get ether balance for multiple addresses
    #
    # @param [String] ads lista de addresses (max 20)
    # @return [Array<Hash>] devolve lista com contas & saldo
    def multi_address_balance(ads)
      raise(Etht::Erro, 'up to 20 accounts in a single batch') if ads.size > 20

      get(module: 'account', action: 'balancemulti', address: ads.join(','), tag: 'latest')
    end

    # get ERC20-token account balance
    #
    # @param add (see address_balance)
    # @param [String] cdd token contract address
    # @return (see address_balance)
    def token_balance(add, cdd)
      raise(Etht::Erro, 'contract or address must be defined') if (cdd || add).nil?

      get(module: 'account', action: 'tokenbalance', address: add, contractaddress: cdd)
    end

    # get a list of normal transactions by address
    #
    # @param [String] add address for transactions
    # @param [Hash] ars opcoes trabalho
    # @option ars [String] :start_block starting blockNo to retrieve results
    # @option ars [String] :end_block ending blockNo to retrieve results
    # @option ars [String] :sort asc -> ascending order, desc -> descending order
    # @option ars [String] :page to get paginated results
    # @option ars [String] :offset max records to return
    # @return [Array<Hash>] devolve ate max 10000 das ultimas transacoes
    def normal_tx(add, **ars)
      raise(Etht::Erro, 'address must be defined') if add.nil?

      transcations('txlist', add, nil, **ars)
    end

    # get a list of ERC20 - token transfer events
    #
    # @param add (see normal_tx)
    # @param [String] cdd token address (nil to get a list of all ERC20 transactions)
    # @param ars (see normal_tx)
    # @option ars (see normal_tx)
    # @return (see normal_tx)
    def token_tx(add, cdd = nil, **ars)
      raise(Etht::Erro, 'contract or address must be defined') if (cdd || add).nil?

      transcations('tokentx', add, cdd, **ars)
    end

    private

    # get a list of transactions
    #
    # @param [String] act accao a executar
    # @param add (see normal_tx)
    # @param cdd (see token_tx)
    # @param ars (see normal_tx)
    # @option ars (see normal_tx)
    # @return (see normal_tx)
    def transcations(act, add, cdd, **ars)
      get(**{ module: 'account', action: act, address: add }.merge({
        contractaddress: cdd,
        startblock: ars[:start_block],
        endblock: ars[:end_block],
        page: ars[:page],
        offset: ars[:offset],
        sort: ars[:sort]
      }.reject { |_, v| v.nil? }))
    end
  end
end