# frozen_string_literal: true

module Api
  class UsersController < ApiController
    skip_before_action :verify_authenticity_token, only: [:index]

    #
    # Queries the database for a Steam UID, and returns the User's Discord ID if it exists
    #
    # @param uid [String] The Steam UID to query
    #
    def index
      users = []

      if (steam_uids_string = params[:steam_uids])
        users += find_users_by_steam_uid(steam_uids_string)
      end

      if (discord_ids_string = params[:discord_ids])
        users += find_users_by_discord_id(discord_ids_string)
      end

      render json: users
    rescue => e
      render_too_big!(e.message)
    end

    #
    # Returns a user's steam_uid based on their discord ID
    #
    # @param discord_id [String] The Discord ID to query
    #
    def show
      discord_id = params[:discord_id]
      user = User.find_by_discord_id(discord_id)

      render json: {discord_id: user&.discord_id || discord_id, steam_uid: user&.steam_uid}
    end

    private

    def render_too_big!(label) # Lol
      render json: {error: "Exceeded max size of 100 entries for #{label}"}, status: 413
    end

    def find_users_by_steam_uid(steam_uids)
      steam_uids = json_array(steam_uids) if steam_uids.is_a?(String)
      raise "steam_uids" if steam_uids.size > 100

      # No n+1 queries here!
      users = User.where(steam_uid: steam_uids).pluck(:steam_uid, :discord_id).to_h

      # This is formatted so if the provided steam_uid doesn't match, it'll still have an entry in the results
      steam_uids.map { |steam_uid| {discord_id: users[steam_uid], steam_uid: steam_uid} }
    end

    def find_users_by_discord_id(discord_ids)
      discord_ids = json_array(discord_ids) if discord_ids.is_a?(String)
      raise "discord_ids" if discord_ids.size > 100

      # No n+1 queries here!
      users = User.where(discord_id: discord_ids).pluck(:discord_id, :steam_uid).to_h

      # This is formatted so if the provided discord_id doesn't match, it'll still have an entry in the results
      discord_ids.map { |discord_id| {discord_id: discord_id, steam_uid: users[discord_id]} }
    end

    def json_array(string_input)
      JSON.parse(string_input)
    rescue
      []
    end
  end
end