class ActivityProcessor
  attr_reader :character, :activity, :results

  def initialize(character)
    @character = character
    @activity = character.activity
    @results = []
    process
  end

  def process
    return unless @character.activity_time_remaining <= 0
    if @character.resting?
      @results.replace([{ type: "error", message: "You can't do anything while you're resting." }])
      @character.stop_activity
      return
    end

    unless @character.can_do_activity?(@activity)
      message = "You can't do this right now."
      message += " (requires #{@activity.requirements&.join(", ")})" if @activity.requirements.any?
      message += " (costs #{@activity.costs&.join(", ")})" if @activity.costs.any?
      @results.replace([{ type: "error", message: message }])
      @character.stop_activity
      return
    end

    Character.transaction do
      if @character.rested_duration > 0
        remaining_rested_duration = @character.rested_duration - @character.rested_duration_to_spend_on_activity
        @character.update!(rested_duration: remaining_rested_duration)
      end

      @character.pay_activity_cost

      @activity.whatnot[:results].each do |result|
        type = result[:type]
        case type
        when "xp"
          handle_xp_result(result)
        when "monster"
          raise TooManyWoundsError unless @character.can_fight?
          next if rand > (result[:chance] || 1)

          @results.push({ type: "br" })

          if result[:table].pluck(:gid).include?(@character.trophy_monster_gid)
            monster = Monster.find_by_gid(@character.trophy_monster_gid)
            @results.push({ type: type, monster: monster })
            resolve_combat_with(monster)
            break
          end

          table_roll = rand
          result[:table].sort_by { |t| -t[:score] }.each do |table_entry|
            score = table_entry[:score]
            if table_roll >= score
              monster = Monster.find_by_gid(table_entry[:gid])
              @results.push({ type: type, monster: monster })
              resolve_combat_with(monster)
              break
            end
          end
        when "item"
          handle_item_result(result, with_xp: true)
        when "hearth_amenity"
          bhi = @character.hearth.built_hearth_amenities
                            .find_or_initialize_by(hearth_amenity: HearthAmenity.find_by_gid(result[:gid]))
          bhi.update(level: result[:level])
          @results.push({ type: type, hearth_amenity: bhi.hearth_amenity })
        when "hearth_planting"
          unless @character.hearth.available_planting_spots > 0
            @results.replace([{ type: "error", message: "You're out of space to plant seeds." }])
            @character.stop_activity
            return
          end
          item = Item.find_by_gid(result[:gid])
          hp = @character.hearth.hearth_plantings.create(item: item)
          @results.push({ type: type, hearth_planting: hp })
        when "activity"
          next if rand > (result[:chance] || 1)
          table_roll = rand
          result[:table].sort_by { |t| -t[:score] }.each do |table_entry|
            score = table_entry[:score]
            if table_roll >= score
              new_activity = Activity.find_by_gid(table_entry[:gid])
              unless @character.learned_activities.exists?(activity: new_activity)
                @character.learned_activities.create(activity: new_activity)
                @results.push({ type: type, activity: new_activity })
              end
            end
          end
        else
          raise "Invalid result type (#{type})" # TODO: Improve this.
        end
      end

      if @character.activity && @character.queued_actions
        if @character.queued_actions > 0
          @character.queued_actions -= 1
          @character.activity_started_at = Time.now
          @character.save
        else
          @character.stop_activity
          @results.push({ type: "message", body: "You have finished your work." })
          return
        end
      else
        @character.update(activity_started_at: Time.now)
      end

      unless @results.any?
        @results.push({ type: "message", body: "You come up empty." })
      end

      # HACK: To display any titles that were gained indirectly (not as part of the activity results).
      @character.title_awards.where(created_at: 5.seconds.ago..).each do |title_award|
        @results.push({ type: "title", title: title_award.title })
      end
    end
  rescue ItemQuantityError
    @character.stop_activity
    @results.replace([{ type: "error", message: "You don't have enough items to complete this activity." }])
  rescue HearthPlantingError
    @character.stop_activity
    @results.replace([{ type: "error", message: "You don't have that crop planted." }])
  rescue TooManyWoundsError
    @character.stop_activity
    @results.replace([{ type: "error",
                        message: "You can't fight in your condition. You'll have to heal a wound." }])
  end

  private
    def roll(sides)
      rand(sides) + 1
    end

    def give_item(data, quantity, with_xp: false)
      item = Item.find_by_gid(data[:gid])
      xp_awards = []
      if with_xp
        xp_awards = data[:xp]&.map { |xpe| { skill: Skill.find_by_gid(xpe[:gid]), amount: xpe[:value] } }
        xp_awards&.each do |award|
          @character.add_skill_xp(award[:skill], (award[:amount] * quantity))
        end
      end
      @character.shift_item(item, quantity)
      @results.push({ type: "item", item: item, quantity: quantity, xp: xp_awards })
    end

    def handle_title_result(data)
      if @character.award_title(data[:gid])
        @results.push({ type: "title", title: title })
      end
    end

    def handle_xp_result(data)
      skill = Skill.find_by_gid(data[:skill])
      amount = data[:base]
      @character.add_skill_xp(skill, amount)
      @results.push({ type: "xp", skill: skill, xp: amount })
    end

    def handle_item_result(data, with_xp: false)
      return if rand > (data[:chance] || 1)

      if data[:table]
        table_roll = rand

        data[:table].sort_by { |t| -t[:score] }.each do |table_entry|
          min_quantity = table_entry[:min_quantity] || table_entry[:quantity] || 1
          max_quantity = table_entry[:max_quantity] || table_entry[:quantity] || 1
          quantity = rand(min_quantity..max_quantity)

          score = table_entry[:score]

          if table_roll >= score
            give_item(table_entry, quantity)

            table_entry[:titles]&.each do |title_data|
              handle_title_result(title_data)
            end
            break
          end
        end
      else
        min_quantity = data[:min_quantity] || data[:quantity] || 1
        max_quantity = data[:max_quantity] || data[:quantity] || 1
        quantity = rand(min_quantity..max_quantity)
        give_item(data, quantity, with_xp: with_xp)
      end
    end

    def resolve_combat_with(mon)
      char = @character
      char_hp = @character.max_hp
      mon_hp = mon.max_hp
      combat_message = ->(msg) { @results.push({ type: "message", body: "[#{char_hp}/#{char.max_hp}] #{msg}" }) }
      char_initiative = roll(20) + char.speed
      mon_initative = roll(20) + mon.speed
      if char_initiative > mon_initative
        turn_order = [[char, mon], [mon, char]]
      elsif mon_initative > char_initiative
        turn_order = [[mon, char], [char, mon]]
      else
        turn_order = [[char, mon], [mon, char]].shuffle
      end
      turn_order.cycle do |actor, target|
        base_accuracy_roll = roll(20)
        accuracy_roll = base_accuracy_roll + actor.accuracy(with_combat_style: true)
        evasion_roll = roll(20) + target.evasion(with_combat_style: true)
        if accuracy_roll >= evasion_roll
          dealt_damage = roll(4) + actor.power(with_combat_style: true) # TODO: Replace d4 with weapon damage
          if base_accuracy_roll == 20
            combat_message.call("#{actor.name} landed a critical hit!")
            dealt_damage = dealt_damage * 2
          end
          blocked_damage = (accuracy_roll >= (roll(20) + target.block(with_combat_style: true))) ? 0 : target.block_value
          blocked_damage = [blocked_damage, (dealt_damage - 1)].min
          resolved_damage = dealt_damage - blocked_damage
          actor == char ? mon_hp -= resolved_damage : char_hp -= resolved_damage
          damage_text = "#{resolved_damage} damage."
          damage_text += " (#{dealt_damage} - #{blocked_damage} blocked)" if blocked_damage > 0
          combat_message.call("#{actor.name} hit for #{damage_text}")
        elsif evasion_roll > accuracy_roll
          combat_message.call("#{target.name} evaded #{actor.name}'s attack.")
        end
        if char_hp < 1 || mon_hp < 1
          if char_hp < 1
            @results.push({ type: "message", body: "You were defeated! You retreat, wounded." })
            char.wounds += 1
            char.save!
            unless char.can_fight?
              @results.push({ type: "error",
                              message: "You can't fight in your condition. You'll have to heal a wound." })
              char.stop_activity
              return
            end
          else
            @results.push({ type: "message", body: "You slew the #{mon.name}." })
            mon.whatnot[:awards]&.each do |award_data|
              case award_data[:type]
              when "title"
                handle_title_result(award_data)
              when "xp"
                handle_xp_result(award_data)
              when "item"
                handle_item_result(award_data)
              else
                raise "Invalid award type string (#{award_data[:type]})"
              end
            end
          end
          @character.do_equipment_break_checks.each do |broken_item|
            @results.push({ type: "warning", message: "Your #{broken_item.name} was damaged beyond repair!" })
          end
          break
        end
      end
    end
end