defmodule Explorer.TransactionForm do
  @moduledoc "Format a Block and a Transaction for display."

  import Ecto.Query
  import ExplorerWeb.Gettext

  alias Cldr.Number
  alias Explorer.Block
  alias Explorer.Repo
  alias Explorer.TransactionReceipt

  def build(transaction) do
    block = Ecto.assoc_loaded?(transaction.block) && transaction.block || nil
    receipt = Ecto.assoc_loaded?(transaction.receipt) && transaction.receipt

    Map.merge(transaction, %{
      block_number: block |> block_number,
      age: block |> block_age,
      formatted_age: block |> format_age,
      formatted_timestamp: block |> format_timestamp,
      cumulative_gas_used: block |> cumulative_gas_used,
      to_address_hash: transaction |> to_address_hash,
      from_address_hash: transaction |> from_address_hash,
      confirmations: block |> confirmations,
      status: status(block, receipt || TransactionReceipt.null),
      first_seen: transaction |> first_seen,
      last_seen: transaction |> last_seen,
    })
  end

  def block_number(block) do
    block && block.number || ""
  end

  def block_age(block) do
    block && block.timestamp |> Timex.from_now || "Pending"
  end

  def format_age(block) do
    block && "#{block_age(block)} (#{format_timestamp(block)})" || gettext("Pending")
  end

  def format_timestamp(block) do
    block && block.timestamp |> Timex.format!("%b-%d-%Y %H:%M:%S %p %Z", :strftime) || gettext("Pending")
  end

  def cumulative_gas_used(block) do
    block && block.gas_used |> Number.to_string! || gettext("Pending")
  end

  def to_address_hash(transaction) do
    transaction.to_address && transaction.to_address.hash || nil
  end

  def from_address_hash(transaction) do
    transaction.to_address && transaction.from_address.hash || nil
  end

  def confirmations(block) do
    query = from block in Block, select: max(block.number)
    block && Repo.one(query) - block.number || 0
  end

  def status(block, receipt) do
    statuses = %{0 => gettext("Failure"), 1 => gettext("Success")}
    if is_nil(block) || is_nil(receipt.status) do
      gettext("Pending")
    else
      statuses[receipt.status]
    end
  end

  def first_seen(transaction) do
    transaction.inserted_at |> Timex.from_now
  end

  def last_seen(transaction) do
    transaction.updated_at |> Timex.from_now
  end
end