require 'csv'

class UserAdminController < ApplicationController

  include MailHelperMethods

  before_action :admin_authorization

  def index
    @user_count = User.count
    @users = User.all
    @hidden_columns = ['hashed_password', 'salt', 'created_at', 'updated_at']
    @contests = Contest.enabled
  end

  def active
    sessions = ActiveRecord::SessionStore::Session.where("updated_at >= ?", 60.minutes.ago)
    @users = []
    sessions.each do |session|
      if session.data[:user_id]
        @users << User.find(session.data[:user_id])
      end
    end
  end

  def show
    @user = User.find(params[:id])
  end

  def new
    @user = User.new
  end

  def create
    @user = User.new(user_params)
    @user.activated = true
    if @user.save
      flash[:notice] = 'User was successfully created.'
      redirect_to :action => 'index'
    else
      render :action => 'new'
    end
  end

  def clear_last_ip
    @user = User.find(params[:id])
    @user.last_ip = nil
    @user.save
    redirect_to action: 'index', page: params[:page]
  end

  def create_from_list
    lines = params[:user_list]


    res = User.create_from_list(lines)
    error_logins = res[:error_logins]
    error_msg = res[:first_error]
    ok_user = res[:created_users]


    #add to group
    if params[:add_to_group]
      group = Group.find_by(id: params[:group_id])&.add_users_skip_existing(ok_user)
    end

    # show flash
    if ok_user.count > 0
      flash[:success] = "#{ok_user.count} user(s) was created or updated successfully"
    end
    if error_logins.size > 0
      flash[:error] = "Following user(s) failed to be created: " + error_logins.join(', ') + ". The error of the first failed one are: " + error_msg;
    end
    redirect_to :action => 'index'
  end

  def edit
    @user = User.find(params[:id])
  end

  def update
    @user = User.find(params[:id])
    if @user.update_attributes(user_params)
      flash[:notice] = 'User was successfully updated.'
      redirect_to :action => 'show', :id => @user
    else
      render :action => 'edit'
    end
  end

  def destroy
    User.find(params[:id]).destroy
    redirect_to :action => 'index'
  end

  def user_stat
    if params[:commit] == 'download csv'
      @problems = Problem.all
    else
      @problems = Problem.available_problems
    end
    @users = User.includes(:contests, :contest_stat).where(enabled: true) 
    @scorearray = Array.new
    @users.each do |u|
      ustat = Array.new
      ustat[0] = u
      @problems.each do |p|
        sub = Submission.find_last_by_user_and_problem(u.id,p.id)
        if (sub!=nil) and (sub.points!=nil) and p and p.full_score
          ustat << [(sub.points.to_f*100/p.full_score).round, (sub.points>=p.full_score)]
        else
          ustat << [0,false]
        end
      end
      @scorearray << ustat
    end
    if params[:commit] == 'download csv' then
      csv = gen_csv_from_scorearray(@scorearray,@problems)
      send_data csv, filename: 'last_score.csv'
    else
      render template: 'user_admin/user_stat'
    end
  end

  def user_stat_max
    if params[:commit] == 'download csv'
      @problems = Problem.all
    else
      @problems = Problem.available_problems
    end
    @users = User.includes(:contests).includes(:contest_stat).all
    @scorearray = Array.new
    #set up range from param
    since_id = params.fetch(:since_id, 0).to_i
    until_id = params.fetch(:until_id, 0).to_i
    @users.each do |u|
      ustat = Array.new
      ustat[0] = u
      @problems.each do |p|
        max_points = 0
        Submission.find_in_range_by_user_and_problem(u.id,p.id,since_id,until_id).each do |sub|
          max_points = sub.points if sub and sub.points and (sub.points > max_points)
        end
        ustat << [(max_points.to_f*100/p.full_score).round, (max_points>=p.full_score)]
      end
      @scorearray << ustat
    end

    if params[:commit] == 'download csv' then
      csv = gen_csv_from_scorearray(@scorearray,@problems)
      send_data csv, filename: 'max_score.csv'
    else
      render template: 'user_admin/user_stat'
    end
  end

  def import
    if params[:file]==''
      flash[:notice] = 'Error importing no file'
      redirect_to :action => 'index' and return
    end
    import_from_file(params[:file])
  end

  def random_all_passwords
    users = User.all
    @prefix = params[:prefix] || ''
    @non_admin_users = User.find_non_admin_with_prefix(@prefix)
    @changed = false
    if params[:commit] == 'Go ahead'
      @non_admin_users.each do |user|
        password = random_password
        user.password = password
        user.password_confirmation = password
        user.save
      end
      @changed = true
    end
  end

  # contest management

  def contests
    @contest, @users = find_contest_and_user_from_contest_id(params[:id])
    @contests = Contest.enabled
  end

  def assign_from_list
    contest_id = params[:users_contest_id]
    org_contest, users = find_contest_and_user_from_contest_id(contest_id)
    contest = Contest.find(params[:new_contest][:id])
    if !contest
      flash[:notice] = 'Error: no contest'
      redirect_to :action => 'contests', :id =>contest_id
    end

    note = []
    users.each do |u|
      u.contests = [contest]
      note << u.login
    end
    flash[:notice] = 'User(s) ' + note.join(', ') + 
      " were successfully reassigned to #{contest.title}." 
    redirect_to :action => 'contests', :id =>contest.id
  end

  def add_to_contest
    user = User.find(params[:id])
    contest = Contest.find(params[:contest_id])
    if user and contest
      user.contests << contest
    end
    redirect_to :action => 'index'
  end

  def remove_from_contest
    user = User.find(params[:id])
    contest = Contest.find(params[:contest_id])
    if user and contest
      user.contests.delete(contest)
    end
    redirect_to :action => 'index'
  end

  def contest_management
  end

  def manage_contest
    contest = Contest.find(params[:contest][:id])
    if !contest
      flash[:notice] = 'You did not choose the contest.'
      redirect_to :action => 'contest_management' and return
    end

    operation = params[:operation]

    if not ['add','remove','assign'].include? operation
      flash[:notice] = 'You did not choose the operation to perform.'
      redirect_to :action => 'contest_management' and return
    end

    lines = params[:login_list]
    if !lines or lines.blank?
      flash[:notice] = 'You entered an empty list.'
      redirect_to :action => 'contest_management' and return
    end

    note = []
    users = []
    lines.split("\n").each do |line|
      user = User.find_by_login(line.chomp)
      if user
        if operation=='add'
          if ! user.contests.include? contest
            user.contests << contest
          end
        elsif operation=='remove'
          user.contests.delete(contest)
        else
          user.contests = [contest]
        end

        if params[:reset_timer]
          user.contest_stat.forced_logout = true
          user.contest_stat.reset_timer_and_save
        end

        if params[:notification_emails]
          send_contest_update_notification_email(user, contest) 
        end

        note << user.login
        users << user
      end
    end

    if params[:reset_timer]
      logout_users(users)
    end

    flash[:notice] = 'User(s) ' + note.join(', ') + 
      ' were successfully modified.  ' 
    redirect_to :action => 'contest_management'    
  end

  # admin management

  def admin
    @admins = Role.where(name: 'admin').take.users
    @tas = Role.where(name: 'ta').take.users
  end

  def modify_role
    user = User.find_by_login(params[:login])
    role = Role.find_by_name(params[:role])
    unless user && role
      flash[:error] = 'Unknown user or role'
      redirect_to admin_user_admin_index_path
      return
    end
    if params[:commit] == 'Grant'
      #grant role
      user.roles << role
      flash[:notice] = "User '#{user.login}' has been granted the role '#{role.name}'"
    else
      #revoke role
      if user.login == 'root' && role.name == 'admin'
        flash[:error] = 'You cannot revoke admisnistrator permission from root.'
        redirect_to admin_user_admin_index_path
        return
      end
      user.roles.delete(role)
      flash[:notice] = "The role '#{role.name}' has been revoked from User '#{user.login}'"
    end
    redirect_to admin_user_admin_index_path
  end

  # mass mailing

  def mass_mailing
  end

  def bulk_mail
    lines = params[:login_list]
    if !lines or lines.blank?
      flash[:notice] = 'You entered an empty list.'
      redirect_to :action => 'mass_mailing' and return
    end

    mail_subject = params[:subject]
    if !mail_subject or mail_subject.blank?
      flash[:notice] = 'You entered an empty mail subject.'
      redirect_to :action => 'mass_mailing' and return
    end

    mail_body = params[:email_body]
    if !mail_body or mail_body.blank?
      flash[:notice] = 'You entered an empty mail body.'
      redirect_to :action => 'mass_mailing' and return
    end

    note = []
    users = []
    lines.split("\n").each do |line|
      user = User.find_by_login(line.chomp)
      if user
        send_mail(user.email, mail_subject, mail_body)
        note << user.login
      end
    end

    flash[:notice] = 'User(s) ' + note.join(', ') + 
      ' were successfully modified.  ' 
    redirect_to :action => 'mass_mailing'
  end

  #bulk manage
  def bulk_manage

    begin
      if params[:filter_group]
        @users = Group.find_by(id: params[:filter_group_id]).users
      else
        @users = User.all
      end
      @users = @users.where('(login REGEXP ?) OR (remark REGEXP ?)',params[:regex],params[:regex]) unless params[:regex].blank?
      @users.count if @users #test the sql
    rescue Exception
      flash[:error] = 'Regular Expression is malformed'
      @users = nil
    end

    if params[:commit]
      @action = {}
      @action[:set_enable] = params[:enabled]
      @action[:enabled] = params[:enable] == "1"
      @action[:gen_password] = params[:gen_password]
      @action[:add_group] = params[:add_group]
      @action[:group_name] = params[:group_name]
    end

    if params[:commit] == "Perform"
      if @action[:set_enable]
        @users.update_all(enabled: @action[:enabled])
      end
      if @action[:gen_password]
        @users.each do |u|
          password = random_password
          u.password = password
          u.password_confirmation = password
          u.save
        end
      end
      if @action[:add_group] and @action[:group_name]
        @group = Group.find(@action[:group_name])
        ok = []
        failed = []
        @users.each do |user|  
          begin
            @group.users << user
            ok << user.login
          rescue => e
            failed << user.login
          end
        end
        flash[:success] = "The following users are added to the 'group #{@group.name}': " + ok.join(', ') if ok.count > 0
        flash[:alert] = "The following users are already in the 'group #{@group.name}': " + failed.join(', ') if failed.count > 0
      end
    end
  end

  protected

  def random_password(length=5)
    chars = 'abcdefghijkmnopqrstuvwxyz23456789'
    newpass = ""
    length.times { newpass << chars[rand(chars.size-1)] }
    return newpass
  end

  def import_from_file(f)
    data_hash = YAML.load(f)
    @import_log = ""

    country_data = data_hash[:countries]
    site_data = data_hash[:sites]
    user_data = data_hash[:users]

    # import country
    countries = {}
    country_data.each_pair do |id,country|
      c = Country.find_by_name(country[:name])
      if c!=nil
        countries[id] = c
        @import_log << "Found #{country[:name]}\n"
      else
        countries[id] = Country.new(:name => country[:name])
        countries[id].save
        @import_log << "Created #{country[:name]}\n"
      end
    end

    # import sites
    sites = {}
    site_data.each_pair do |id,site|
      s = Site.find_by_name(site[:name])
      if s!=nil
        @import_log << "Found #{site[:name]}\n"
      else
        s = Site.new(:name => site[:name])
        @import_log << "Created #{site[:name]}\n"
      end
      s.password = site[:password]
      s.country = countries[site[:country_id]]
      s.save
      sites[id] = s
    end

    # import users
    user_data.each_pair do |id,user|
      u = User.find_by_login(user[:login])
      if u!=nil
        @import_log << "Found #{user[:login]}\n"
      else
        u = User.new(:login => user[:login])
        @import_log << "Created #{user[:login]}\n"
      end
      u.full_name = user[:name]
      u.password = user[:password]
      u.country = countries[user[:country_id]]
      u.site = sites[user[:site_id]]
      u.activated = true
      u.email = "empty-#{u.login}@none.com"
      if not u.save
        @import_log << "Errors\n"
        u.errors.each { |attr,msg|  @import_log << "#{attr} - #{msg}\n" } 
      end
    end

  end

  def logout_users(users)
    users.each do |user|
      contest_stat = user.contest_stat(true)
      if contest_stat and !contest_stat.forced_logout
        contest_stat.forced_logout = true
        contest_stat.save
      end
    end
  end

  def send_contest_update_notification_email(user, contest)
    contest_title_name = GraderConfiguration['contest.name']
    contest_name = contest.name
    mail_subject = t('contest.notification.email_subject', {
                       :contest_title_name => contest_title_name,
                       :contest_name => contest_name })
    mail_body = t('contest.notification.email_body', {
                    :full_name => user.full_name,
                    :contest_title_name => contest_title_name,
                    :contest_name => contest.name,
                  })

    logger.info mail_body
    send_mail(user.email, mail_subject, mail_body)
  end

  def find_contest_and_user_from_contest_id(id)
    if id!='none'
      @contest = Contest.find(id)
    else
      @contest = nil
    end
    if @contest
      @users = @contest.users
    else
      @users = User.find_users_with_no_contest
    end
    return [@contest, @users]
  end

  def gen_csv_from_scorearray(scorearray,problem)
    CSV.generate do |csv|
      #add header
      header = ['User','Name', 'Activated?', 'Logged in', 'Contest']
      problem.each { |p| header << p.name }
      header += ['Total','Passed']
      csv << header
      #add data
      scorearray.each do |sc|
        total = num_passed = 0
        row = Array.new
        sc.each_index do |i|
          if i == 0
            row << sc[i].login
            row << sc[i].full_name
            row << sc[i].activated
            row << (sc[i].try(:contest_stat).try(:started_at).nil? ? 'no' : 'yes')
            row << sc[i].contests.collect {|c| c.name}.join(', ')
          else
            row << sc[i][0]
            total += sc[i][0]
            num_passed += 1 if sc[i][1]
          end
        end
        row << total 
        row << num_passed
        csv << row
      end
    end
  end

  private
    def user_params
      params.require(:user).permit(:login,:password,:password_confirmation,:email, :alias, :full_name,:remark)
    end
end