#! /usr/bin/env nix-shell
#! nix-shell -i ruby -p ruby

require 'json'

PROTOCOL_VERSION = 0

WINDOW_ID_NONE = -1
WINDOW_ID_CURRENT = -2
TAB_ID_NONE = -1

module WebExtension
  class <<self
    def read()
      length = $stdin.read(4).unpack1('L')
      json = $stdin.read(length)
      JSON.parse(json)
    end

    def write(obj)
      json = JSON.generate(obj)
      raise "tried to send object larger than maximum allowed 1 MiB, was #{json.length/1024/1024} MiB" if json.length > 1024*1024
      $stdout.write([ json.length ].pack('L'))
      $stdout.write(json)
      $stdout.flush()
    end
  end
end

module API
  class <<self
    def call(command, *args)
      WebExtension::write([ command, args ])
    end

    def console_log(*args)
      call('console:log', *args)
    end

    def console_error(*args)
      call('console:error', *args)
    end
  end
end

# alwaysOnTop: false
# focused: true
# height: 1080
# id: 18
# incognito: false
# left: 0
# state: "fullscreen"
# title: "Toolbox - Extension / Help, I'm drowning in tabs! — Mozilla Firefox"
# top: 0
# type: "normal"
# width: 1920
# Window = Struct(
#   :id,
#   :type,
#   :state,

#   :title,

#   :always_on_top?,
#   :focused?,
#   :incognito?,

#   :width,
#   :height,
#   :top,
#   :left,
# )

# active: true
# attention: false
# audible: false
# cookieStoreId: "firefox-default"
# discarded: false
# favIconUrl: "chrome://branding/content/icon32.png"
# height: 1006
# hidden: false
# highlighted: true
# id: 2834
# incognito: false
# index: 1228
# isArticle: false
# isInReaderMode: false
# lastAccessed: 1625021510454
# mutedInfo: Object { muted: false }
# pinned: false
# sharingState: Object { camera: false, microphone: false }
# status: "complete"
# successorTabId: -1
# title: "New Tab"
# url: "about:newtab"
# width: 1599
# windowId: 18
# Tab = Struct(
#   :id,
#   :window_id,
#   :index,
#   :successor_tab_id,
#   :last_accessed,

#   :status,
#   :url,
#   :icon_url,
#   :title,
  
#   :active?,
#   :attention?,
#   :audible?,
#   :pinned?,
#   :hidden?,
#   :discarded?,
#   :incognito?,
#   :selected?,

#   :width,
#   :height,

#   :cookie_store_id,
#   :article?,
#   :in_reader_mode?,

#   :muted_info,
#   :sharing_state,
# )

# class State
#   attr_reader :windows, :tabs

#   def initialize(raw)
#     @tabs = raw.concat_map
#   end
# end

if $stdin.tty?
  $stderr.puts 'TODO'
  exit 1
end

WebExtension::write(PROTOCOL_VERSION)
version = WebExtension::read()
if version != PROTOCOL_VERSION
  $stderr.puts "Extension protocol has an incompatible version! Wanted #{PROTOCOL_VERSION}, got #{version}"
  exit 1
end

API::console_log('Native application successfully loaded.')

loop do
  command, data = WebExtension::read()

  case command
  when 'init:windows' then API::console_log("Initialised #{data.length} windows.")
  when 'init:tabs' then API::console_log("Initialised #{data.length} tabs.")
  when 'init:contexts' then API::console_log("Initialised #{data.length} contexts.")
  
  when 'window:create' then API::console_log('Window created', data)
  when 'window:destroy' then API::console_log("Window #{data} destroyed")
  when 'window:focus'
    if data == WINDOW_ID_NONE
      then API::console_log('Browser lost focus')
      else API::console_log("Window #{data} focused")
    end

  when 'tab:create' then API::console_log('Tab created', data)
  when 'tab:destroy' then API::console_log("Tab #{data[0]} destroyed in window #{data[1]}#{", due to the window closing" if data[2]}")
  when 'tab:update' then API::console_log("Tab #{data[0]} updated", data[1])
  when 'tab:activate' then API::console_log("Tab #{data[1]} in window #{data[0]} activated#{", previous tab was #{data[2]}" if not data[2].nil?}")
  when 'tab:select' then API::console_log("Tabs #{data[1]} in window #{data[0]} selected")
  when 'tab:detach' then API::console_log("Tab #{data[0]} detached from window #{data[1]} at position #{data[2]}")
  when 'tab:attach' then API::console_log("Tab #{data[0]} attached to window #{data[1]} at position #{data[2]}")

  when 'context:create' then API::console_error('context:create NYI')
  when 'context:destroy' then API::console_error('context:destroy NYI')
  when 'context:update' then API::console_error('context:update NYI')

  else API::console_error("Unknown native command #{command}")
  end
end