# frozen_string_literal: true

module Reducer
  def self.call(state, action)
    case action
    when Actions::LoadFriends
      state.merge(
        active_friend_index: action.friends.empty? ? nil : 0,
        friends: action.friends.map do |friend|
          [
            friend.number,
            public_key:     friend.public_key.to_hex.freeze,
            name:           friend.name.freeze,
            status:         friend.status,
            status_message: friend.status_message.freeze,
            history:        [].freeze,
            new_message: {
              text: '',
              cursor_pos: 0,
            }.freeze,
          ]
        end.to_h.freeze,
      ).freeze
    when Actions::FriendRequest
      friend = action.tox_client.friend_add_norequest action.public_key

      state.merge(
        active_friend_index: state[:active_friend_index] || state[:friends].count,

        friends: state[:friends].merge(
          friend.number => {
            public_key:     friend.public_key.to_hex.freeze,
            name:           friend.name.freeze,
            status:         friend.status,
            status_message: friend.status_message.freeze,
            history:        [].freeze,
            new_message: {
              text: '',
              cursor_pos: 0,
            }.freeze,
          }.freeze,
        ).freeze,
      ).freeze
    when Actions::FriendMessage
      state.merge(
        friends: state[:friends].merge(
          action.friend.number => state[:friends][action.friend.number].merge(
            history: (state[:friends][action.friend.number][:history] + [
              out:  false,
              time: Time.now.utc.freeze,
              name: action.friend.name.freeze,
              text: action.text.freeze,
            ]).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::ChangeFriendName
      state.merge(
        friends: state[:friends].merge(
          action.friend.number => state[:friends][action.friend.number].merge(
            name: action.new_name.freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::ChangeFriendStatusMessage
      state.merge(
        friends: state[:friends].merge(
          action.friend.number => state[:friends][action.friend.number].merge(
            status_message: action.new_status_message.freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::ChangeFriendStatus
      state.merge(
        friends: state[:friends].merge(
          action.friend.number => state[:friends][action.friend.number].merge(
            status: action.new_status,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::WindowLeft
      state.merge(
        focus: :sidebar,

        sidebar: state[:sidebar].merge(
          focused: true,

          logo: state[:sidebar][:logo].merge(focused: state[:sidebar][:focus] == :logo).freeze,
          menu: state[:sidebar][:menu].merge(focused: state[:sidebar][:focus] == :menu).freeze,
        ).freeze,

        chat: state[:chat].merge(
          focused: false,

          info:               state[:chat][:info].merge(focused: false).freeze,
          new_message: state[:chat][:new_message].merge(focused: false).freeze,
          history:         state[:chat][:history].merge(focused: false).freeze,
        ).freeze,
      ).freeze
    when Actions::WindowRight
      state.merge(
        focus: :chat,

        sidebar: state[:sidebar].merge(
          focused: true,

          logo: state[:sidebar][:logo].merge(focused: false).freeze,
          menu: state[:sidebar][:menu].merge(focused: false).freeze,
        ).freeze,

        chat: state[:chat].merge(
          focused: false,

          info:               state[:chat][:info].merge(focused: state[:chat][:focus] == :info).freeze,
          new_message: state[:chat][:new_message].merge(focused: state[:chat][:focus] == :new_message).freeze,
          history:         state[:chat][:history].merge(focused: state[:chat][:focus] == :history).freeze,
        ).freeze,
      ).freeze
    when Actions::MenuUp
      return state if state[:active_friend_index].nil?

      active_friend_index = state[:active_friend_index] + 1
      top = state[:sidebar][:menu][:top]

      if active_friend_index.negative?
        active_friend_index = state[:friends].count - 1
      elsif active_friend_index >= state[:friends].count
        active_friend_index = 0
      end

      if active_friend_index < top
        top = active_friend_index
      elsif active_friend_index >= top + state[:height]
        top = active_friend_index - state[:height] + 1
      end

      state.merge(
        active_friend_index: active_friend_index,

        sidebar: state[:sidebar].merge(
          menu: state[:sidebar][:menu].merge(
            top: top,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::MenuDown
      return state if state[:active_friend_index].nil?

      active_friend_index = state[:active_friend_index] + 1
      top = state[:sidebar][:menu][:top]

      if active_friend_index.negative?
        active_friend_index = state[:friends].count - 1
      elsif active_friend_index >= state[:friends].count
        active_friend_index = 0
      end

      if active_friend_index < top
        top = active_friend_index
      elsif active_friend_index >= top + state[:height]
        top = active_friend_index - state[:height] + 1
      end

      state.merge(
        active_friend_index: active_friend_index,

        sidebar: state[:sidebar].merge(
          menu: state[:sidebar][:menu].merge(
            top: top,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessageEnter
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      text = state[:friends][friend_number][:new_message][:text].strip.freeze

      return state if text.empty?

      error = false

      begin
        action.tox_client.friend(friend_number).send_message text
      rescue
        error = true
      end

      state.merge(
        friends: state[:friends].merge(
          friend_number => state[:friends][friend_number].merge(
            new_message: state[:friends][friend_number][:new_message].merge(
              text: '',
              cursor_pos: 0,
            ),

            history: (state[:friends][friend_number][:history] + [
              error:    error,
              out:      true,
              received: false,
              time:     Time.now.utc.freeze,
              name:     action.tox_client.name.freeze,
              text:     text,
            ]).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessagePutc
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      friend = state[:friends][friend_number]
      new_message = friend[:new_message]

      text       = new_message[:text]
      cursor_pos = new_message[:cursor_pos]

      text = "#{text[0...cursor_pos]}#{action.char}#{text[cursor_pos..-1]}"
      cursor_pos += 1

      state.merge(
        friends: state[:friends].merge(
          friend_number => friend.merge(
            new_message: new_message.merge(
              text: text,
              cursor_pos: cursor_pos,
            ).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessageLeft
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      friend = state[:friends][friend_number]
      new_message = friend[:new_message]

      cursor_pos = new_message[:cursor_pos]

      cursor_pos -= 1

      cursor_pos = 0 if cursor_pos.negative?

      state.merge(
        friends: state[:friends].merge(
          friend_number => friend.merge(
            new_message: new_message.merge(
              cursor_pos: cursor_pos,
            ).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessageRight
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      friend = state[:friends][friend_number]
      new_message = friend[:new_message]

      text       = new_message[:text]
      cursor_pos = new_message[:cursor_pos]

      cursor_pos += 1

      cursor_pos = text.length if cursor_pos > text.length

      state.merge(
        friends: state[:friends].merge(
          friend_number => friend.merge(
            new_message: new_message.merge(
              cursor_pos: cursor_pos,
            ).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessageHome
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      friend = state[:friends][friend_number]
      new_message = friend[:new_message]

      state.merge(
        friends: state[:friends].merge(
          friend_number => friend.merge(
            new_message: new_message.merge(
              cursor_pos: 0,
            ).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessageEnd
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      friend = state[:friends][friend_number]
      new_message = friend[:new_message]

      state.merge(
        friends: state[:friends].merge(
          friend_number => friend.merge(
            new_message: new_message.merge(
              cursor_pos: new_message[:text].length,
            ).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessageBackspace
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      friend = state[:friends][friend_number]
      new_message = friend[:new_message]

      text       = new_message[:text]
      cursor_pos = new_message[:cursor_pos]

      return state unless cursor_pos.positive?

      text = "#{text[0...(cursor_pos - 1)]}#{text[cursor_pos..-1]}"
      cursor_pos -= 1

      state.merge(
        friends: state[:friends].merge(
          friend_number => friend.merge(
            new_message: new_message.merge(
              text:       text,
              cursor_pos: cursor_pos,
            ).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    when Actions::NewMessageDelete
      return state if state[:active_friend_index].nil?

      friend_number = state[:friends].keys[state[:active_friend_index]]

      return state if friend_number.nil?

      friend = state[:friends][friend_number]
      new_message = friend[:new_message]

      text       = new_message[:text]
      cursor_pos = new_message[:cursor_pos]

      return state if cursor_pos > text.length

      text = "#{text[0...cursor_pos]}#{text[(cursor_pos + 1)..-1]}"

      state.merge(
        friends: state[:friends].merge(
          friend_number => friend.merge(
            new_message: new_message.merge(
              text:       text,
              cursor_pos: cursor_pos,
            ).freeze,
          ).freeze,
        ).freeze,
      ).freeze
    else
      state
    end
  end
end