-- Fork of the autogroup plugin but only comparing pictures with the same timestamp
local dt = require "darktable"
local du = require "lib/dtutils"
local df = require "lib/dtutils.file"

du.check_min_api_version("7.0.0", "AutoGroupInstant")

local MOD = 'autogroupinstant'

-- return data structure for script_manager

local script_data = {}

script_data.destroy = nil -- function to destory the script
script_data.destroy_method = nil -- set to hide for libs since we can't destroy them commpletely yet, otherwise leave as nil
script_data.restart = nil -- how to restart the (lib) script after it's been hidden - i.e. make it visible again
script_data.show = nil -- only required for libs since the destroy_method only hides them

local gettext = dt.gettext
-- Tell gettext where to find the .mo file translating messages for a particular domain
gettext.bindtextdomain("AutoGroupInstant",dt.configuration.config_dir.."/lua/locale/")

local function _(msgid)
  return gettext.dgettext("AutoGroupInstant", msgid)
end

local Ag = {}
Ag.module_installed = false
Ag.event_registered = false

local GUI = {
  gap =        {},
  selected =   {},
  collection = {}
}


local function InRange(test, low, high) --tests if test value is within range of low and high (inclusive)
  if test >= low and test <= high then
    return true
  else
    return false
  end
end

local function CompTime(first, second) --compares the timestamps and returns true if first was taken before second
  first_time = first.exif_datetime_taken
  if string.match(first_time, '[0-9]') == nil then first_time = '9999:99:99 99:99:99' end
  first_time = tonumber(string.gsub(first_time, '[^0-9]*',''))
  second_time = second.exif_datetime_taken
  if string.match(second_time, '[0-9]') == nil then second_time = '9999:99:99 99:99:99' end
  second_time = tonumber(string.gsub(second_time, '[^0-9]*',''))
  return first_time < second_time
end

local function SeperateTime(str) --seperates the timestamp into individual components for used with OS.time operations
  local cleaned = string.gsub(str, '[^%d]',':')
  cleaned = string.gsub(cleaned, '::*',':')  --YYYY:MM:DD:hh:mm:ss
  local year = string.sub(cleaned,1,4)
  local month = string.sub(cleaned,6,7)
  local day = string.sub(cleaned,9,10)
  local hour = string.sub(cleaned,12,13)
  local min = string.sub(cleaned,15,16)
  local sec = string.sub(cleaned,18,19)
  return {year = year, month = month, day = day, hour = hour, min = min, sec = sec}
end

local function GetTimeDiff(curr_image, prev_image) --returns the time difference (in sec.) from current image and the previous image
  local curr_time = SeperateTime(curr_image.exif_datetime_taken)
  local prev_time = SeperateTime(prev_image.exif_datetime_taken)
  return os.time(curr_time)-os.time(prev_time)
end

local function main(on_collection)
  local images = {}
  if on_collection then 
    local col_images = dt.collection
    for i,image in ipairs(col_images) do --copy images to a standard table, table.sort barfs on type dt_lua_singleton_image_collection
      table.insert(images,i,image)
    end
  else
    images = dt.gui.selection()
  end
  if #images < 2 then 
    dt.print('please select at least 2 images')
    return
  end
  table.sort(images, function(first, second) return CompTime(first,second) end)  --sort images by timestamp
  
  for i, image in ipairs(images) do
    if i == 1 then 
      prev_image = image
    elseif string.match(image.exif_datetime_taken, '[%d]') ~= nil then --make sure current image has a timestamp
      local curr_image = image

      if GetTimeDiff(curr_image, prev_image) == 0 then
        images[i]:group_with(images[i-1])

        for _, member in ipairs(images[i]:get_group_members()) do
          local ext = string.lower(df.get_filetype(member.filename))
          if ext == "rw2" or ext == "arw" then
            member:make_group_leader()
          end
        end
      end
      prev_image = curr_image
    end
  end
end

local function install_module()
  if not Ag.module_installed then
    dt.print_log("installing module")
    dt.register_lib(
      MOD,    -- Module name
      _('Group identical Timestamps'),    -- name
      true,   -- expandable
      true,   -- resetable
      {[dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 99}},   -- containers
      dt.new_widget("box"){
        orientation = "vertical",
        GUI.selected,
        GUI.collection
      }
    )
    Ag.module_installed = true
    dt.print_log("module installed")
    dt.print_log("styles module visibility is " .. tostring(dt.gui.libs["styles"].visible))
  end
end

local function destroy()
  dt.gui.libs[MOD].visible = false
end

local function restart()
  dt.gui.libs[MOD].visible = true
end

-- GUI --
GUI.selected = dt.new_widget("button"){
  label = _('auto group: selected'),
  tooltip =_('auto group selected images'),
  clicked_callback = function() main(false) end
}
GUI.collection = dt.new_widget("button"){
  label = _('auto group: collection'),
  tooltip =_('auto group the entire collection'),
  clicked_callback = function() main(true) end
}

if dt.gui.current_view().id == "lighttable" then
  install_module()
else
  if not Ag.event_registered then
    dt.register_event(
     "AutoGroupInstant", "view-changed",
     function(event, old_view, new_view)
      if new_view.name == "lighttable" and old_view.name == "darkroom" then
        install_module()
       end
    end
  )
  Ag.event_registered = true
  end
end

script_data.destroy = destroy
script_data.destroy_method = "hide"
script_data.restart = restart
script_data.show = restart

return script_data