# frozen_string_literal: true

require 'ruby_jard/commands/validation_helpers'
require 'ruby_jard/commands/color_helpers'
require 'ruby_jard/commands/continue_command'
require 'ruby_jard/commands/exit_command'
require 'ruby_jard/commands/up_command'
require 'ruby_jard/commands/down_command'
require 'ruby_jard/commands/next_command'
require 'ruby_jard/commands/step_command'
require 'ruby_jard/commands/step_out_command'
require 'ruby_jard/commands/frame_command'
require 'ruby_jard/commands/list_command'
require 'ruby_jard/commands/jard_command'

module RubyJard
  ##
  # Byebug allows customizing processor with a series of hooks (https://github.com/deivid-rodriguez/byebug/blob/e1fb8209d56922f7bafd128af84e61568b6cd6a7/lib/byebug/processors/command_processor.rb)
  #
  # This class is a bridge between REPL library and Byebug. It is inherited from
  # Byebug::CommandProcessor, the processor is triggered. It starts draw the
  # UI, starts a new REPL session, listen for control-flow events threw from
  # repl, and triggers Byebug debugger if needed.
  #
  class ReplProcessor < Byebug::CommandProcessor
    def initialize(context, *args)
      super(context, *args)
      @config = RubyJard.config
      @repl_proxy = RubyJard::ReplProxy.new(
        key_bindings: RubyJard.global_key_bindings
      )
      @previous_flow = RubyJard::ControlFlow.new(:next)
      @output = RubyJard::Console.output
    end

    def at_line
      process_commands_with_lock
    end

    def at_return(_return_value)
      process_commands_with_lock
    end

    def at_end
      process_commands_with_lock
    end

    private

    def process_commands_with_lock
      allowing_other_threads do
        RubyJard::Session.lock do
          RubyJard::Session.sync(@context)
          unless RubyJard::Session.should_stop?
            handle_flow(@previous_flow)
            return
          end

          process_commands
        end
      end
    end

    def process_commands(redraw = true)
      RubyJard::Session.sync(@context)
      RubyJard::ScreenManager.draw_screens if redraw

      return_value = nil

      flow = RubyJard::ControlFlow.listen do
        return_value = @repl_proxy.repl(frame._binding)
      end

      handle_flow(flow)

      return_value
    rescue StandardError => e
      RubyJard::ScreenManager.draw_error(e)
      raise
    end

    def handle_flow(flow)
      return if flow.nil?

      @previous_flow = flow
      command = flow.command
      send("handle_#{command}_command", flow.arguments)
    end

    def handle_next_command(options = {})
      times = options[:times] || 1
      RubyJard::Session.step_over(times)
    end

    def handle_step_command(options = {})
      times = options[:times] || 1
      RubyJard::Session.step_into(times)
    end

    def handle_step_out_command(options = {})
      times = options[:times] || 1

      next_frame = up_n_frames(RubyJard::Session.current_frame.real_pos, times)
      RubyJard::Session.frame = next_frame
      RubyJard::Session.step_over(1)
    end

    def handle_up_command(options = {})
      times = options[:times] || 1

      next_frame = up_n_frames(RubyJard::Session.current_frame.real_pos, times)
      RubyJard::Session.frame = next_frame
      process_commands
    end

    def handle_down_command(options = {})
      times = options[:times] || 1
      next_frame = down_n_frames(RubyJard::Session.current_frame.real_pos, times)
      RubyJard::Session.frame = next_frame
      process_commands
    end

    def handle_frame_command(options)
      next_frame = find_frame(options[:frame].to_i)
      if next_frame.nil?
        # There must be an error in outer validators
        @output.puts 'Error: Frame not found. There should be an error with Jard.'
        process_commands(false)
      elsif next_frame.c_frame?
        @output.puts "Error: Frame #{next_frame} is a c-frame. Not able to inspect c layer!"
        process_commands(false)
      else
        RubyJard::Session.frame = next_frame.real_pos
        process_commands(true)
      end
    end

    def handle_continue_command(_options = {})
      @output.puts '▸▸ Program resumed ▸▸'
      Byebug.stop if Byebug.stoppable?
    end

    def handle_exit_command(_options = {})
      Byebug.stop if Byebug.stoppable?
      Kernel.exit
    end

    def handle_key_binding_command(options = {})
      method_name = "handle_#{options[:action]}_command"
      if respond_to?(method_name, true)
        send(method_name)
      else
        raise RubyJard::Error,
              "Fail to handle key binding `#{options[:action]}`"
      end
    end

    def handle_list_command(_options = {})
      process_commands
    end

    def handle_switch_filter_command(_options = {})
      index = RubyJard::PathFilter::FILTERS.index(@config.filter) || -1
      index = (index + 1) % RubyJard::PathFilter::FILTERS.length
      @config.filter = RubyJard::PathFilter::FILTERS[index]

      process_commands
    end

    def up_n_frames(real_pos, times)
      next_frame = real_pos
      times.times do
        next_frame = [next_frame + 1, RubyJard::Session.current_backtrace.length - 1].min
        while next_frame < RubyJard::Session.current_backtrace.length &&
              (
                RubyJard::Session.current_backtrace[next_frame].c_frame? ||
                RubyJard::Session.current_backtrace[next_frame].hidden?
              )
          next_frame += 1
        end
        return real_pos if next_frame >= RubyJard::Session.current_backtrace.length
      end
      next_frame
    end

    def down_n_frames(real_pos, times)
      next_frame = real_pos
      times.times do
        next_frame = [next_frame - 1, 0].max
        while next_frame >= 0 &&
              (
                RubyJard::Session.current_backtrace[next_frame].c_frame? ||
                RubyJard::Session.current_backtrace[next_frame].hidden?
              )

          next_frame -= 1
        end
        return real_pos if next_frame < 0
      end
      next_frame
    end

    def find_frame(virtual_pos)
      RubyJard::Session.current_backtrace.find { |frame| frame.virtual_pos == virtual_pos }
    end
  end
end