class ActivityProcessor
  attr_reader :character, :activity, :results

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

  def process
    return unless @character.activity && @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"
          puts "Result: #{result}"
          handle_xp_result(result)
        when "monster_spawn"
          raise TooManyWoundsError unless @character.can_fight?
          next if rand > (result[:chance] || 1)

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

          monster_spawn = MonsterSpawn.where(location: Location.find_by_gid(result[:location])).select(&:alive?).first
          raise MonsterSpawnError unless monster_spawn

          @results.push({ type: type, monster_spawn: monster_spawn })
          resolve_combat_with(monster_spawn)
          break
        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 "condition"
          Character.transaction do
            condition = Condition.find_by_gid(result[:gid])
            @character.states.create!(condition: condition, expires_at: Time.now + result[:duration])
            @results.push({ type: "message", body: result[:message] })
            @results.push({ type: type, condition: condition })
          end
        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])
              raise "Invalid activity gid (#{table_entry[:gid]})" unless new_activity
              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

      # Note: This will result in equipment being checked for breakage twice (after combat, and now) if it provides the
      #   `beastslay_speed` stat. At the time of this writing, that stat doesn't exist.
      #   But just something to keep in mind.
      # Note: This will result in equipment being checked twice if it provides two speed stats.
      #   Fine for now since no equipment gives two skill speed stats, but may want to refine in the future.
      if @activity.whatnot[:requirements].any?
        required_skill_gids = @activity.whatnot[:requirements].select { |r| r[:type] == "skill" }.map { |r| r[:gid] }.uniq
        required_skill_gids.each do |required_skill_gid|
          skill = Skill.find_by_gid(required_skill_gid)
          @character.do_skill_based_equipment_break_checks(skill).each do |broken_item|
            @results.push({ type: "warning", message: "Your #{broken_item.name} was damaged beyond repair!" })
          end
          @character.do_skill_based_item_infix_break_checks(skill).each do |broken_item|
            @results.push({ type: "warning", message: "Your #{broken_item.name} omen faded away." })
          end
        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." }])
  rescue MonsterSpawnError
    @character.stop_activity
    @results.replace([{ type: "error",
                        message: "There are no living leviathans here." }])
  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)
      title = Title.find_by_gid(data[:gid])
      if @character.award_title(title)
        @results.push({ type: "title", title: title })
      end
    end

    def handle_xp_result(data)
      skill = Skill.find_by_gid(data[:gid])
      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, with_xp: with_xp)

            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)

      monster_spawn = nil
      if mon.is_a? MonsterSpawn
        monster_spawn = mon
        mon = monster_spawn.monster
      end

      char = @character
      char_hp = @character.max_hp
      mon_hp = monster_spawn.present? ? monster_spawn.remaining_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)
        if actor == mon
          accuracy_roll += char.total_enemy_stat_change("accuracy")
        end

        evasion_roll = roll(20) + target.evasion(with_combat_style: true)
        if accuracy_roll >= evasion_roll || base_accuracy_roll == 20

          dealt_damage = {}
          actor.damage_ranges.each do |data|
            damage_roll = rand(data[:min]..data[:max])
            dealt_damage[data[:gid]] = damage_roll
          end

          # If you can't do damage any other way, hit 'em with your fists!
          if actor.damage_ranges.none?
            dealt_damage["bash"] = rand(1..2)
            combat_message.call("Lacking any other weapon, #{actor.name} thrashes wildly!")
          end

          if base_accuracy_roll == 20
            combat_message.call("#{actor.name} landed a critical hit!")
            dealt_damage.each do |gid, amount|
              dealt_damage[gid] = amount * 2
            end
          end

          # Apply power to random damages
          actor.power.times do
            dealt_damage[dealt_damage.keys.sample] += 1
          end

          resolved_damage = {}
          dealt_damage.each do |gid, amount|
            effective_resistance = [target.resistance(gid), amount].min
            resolved_damage[gid] = amount - (effective_resistance * rand(0.5..1)).round
          end

          total_damage = resolved_damage.values.sum
          actor == char ? mon_hp -= total_damage : char_hp -= total_damage
          damage_text = "#{total_damage} damage (#{resolved_damage.to_a.map { |gid, amount| "#{amount} #{gid}" }.join(", ")})"
          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

        # HACK: DoT is char-only, and one-damage-type-only for now.
        if actor == char
          actor.dots.each do |data|
            damage_roll = rand(data[:min]..data[:max])
            effective_resistance = [target.resistance(data[:gid]), damage_roll].min
            resolved_damage = damage_roll - (effective_resistance * rand(0.5..1)).round
            mon_hp -= resolved_damage
            combat_message.call("#{data[:message]} (#{resolved_damage} #{data[:gid]})")
          end
        end

        if char_hp < 1 || mon_hp < 1
          @character.do_equipment_break_checks.each do |broken_item|
            @results.push({ type: "warning", message: "Your #{broken_item.name} was damaged beyond repair!" })
          end

          if monster_spawn
            hp_lost = monster_spawn.remaining_hp - mon_hp
            if hp_lost > 0
              monster_spawn.monster_spawn_combats.create(monster_spawn: monster_spawn, character: char,
                                                         hp_lost: monster_spawn.remaining_hp - mon_hp)
            end
          end
          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}." })

            monster_kills = character.monster_kills.find_or_initialize_by(monster: mon)
            monster_kills.quantity ? monster_kills.quantity += 1 : monster_kills.quantity = 1
            monster_kills.save

            if monster_spawn
              char.stop_activity
              return
            else
              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
          end
          break
        end
      end
    end
end