local EventListener = require("ui/widget/eventlistener")
local Event = require("ui/event")
local ReaderZooming = require("apps/reader/modules/readerzooming")
local util = require("util")

local ReaderKoptListener = EventListener:new{}

function ReaderKoptListener:setZoomMode(zoom_mode)
    if self.document.configurable.text_wrap == 1 then
        -- in reflow mode only "page" zoom mode is valid so override any other zoom mode
        self.ui:handleEvent(Event:new("SetZoomMode", "page", "koptlistener"))
    else
        self.ui:handleEvent(Event:new("SetZoomMode", zoom_mode, "koptlistener"))
    end
end

function ReaderKoptListener:onReadSettings(config)
    -- normal zoom mode is zoom mode used in non-reflow mode.
    local normal_zoom_mode = config:readSetting("normal_zoom_mode")
                          or G_reader_settings:readSetting("zoom_mode")
                          or "page"
    normal_zoom_mode = util.arrayContains(ReaderZooming.available_zoom_modes, normal_zoom_mode)
                   and normal_zoom_mode
                    or "page"
    self.normal_zoom_mode = normal_zoom_mode
    self:setZoomMode(normal_zoom_mode)
    self.document.configurable.contrast = config:readSetting("kopt_contrast")
                                       or G_reader_settings:readSetting("kopt_contrast")
                                       or 1.0
    self.ui:handleEvent(Event:new("GammaUpdate", 1/self.document.configurable.contrast))
    -- since K2pdfopt v2.21 negative value of word spacing is also used, for config
    -- compatability we should manually change previous -1 to a more reasonable -0.2
    if self.document.configurable.word_spacing == -1 then
        self.document.configurable.word_spacing = -0.2
    end
end

function ReaderKoptListener:onSaveSettings()
    self.ui.doc_settings:saveSetting("normal_zoom_mode", self.normal_zoom_mode)
end

function ReaderKoptListener:onRestoreZoomMode()
    -- "RestoreZoomMode" event is sent when reflow mode on/off is toggled
    self:setZoomMode(self.normal_zoom_mode)
    return true
end

function ReaderKoptListener:onSetZoomMode(zoom_mode, orig)
    if orig == "koptlistener" then return end
    -- capture zoom mode set outside of koptlistener which should always be normal zoom mode
    self.normal_zoom_mode = zoom_mode
    self:setZoomMode(self.normal_zoom_mode)
end

function ReaderKoptListener:onFineTuningFontSize(delta)
    self.document.configurable.font_size = self.document.configurable.font_size + delta
end

function ReaderKoptListener:onZoomUpdate(zoom)
    -- an exceptional case is reflow mode
    if self.document.configurable.text_wrap == 1 then
        self.view.state.zoom = 1.0
    end
end

-- misc koptoption handler
function ReaderKoptListener:onDocLangUpdate(lang)
    if lang == "chi_sim" or lang == "chi_tra" or
        lang == "jpn" or lang == "kor" then
        self.document.configurable.word_spacing = DKOPTREADER_CONFIG_WORD_SPACINGS[1]
    else
        self.document.configurable.word_spacing = DKOPTREADER_CONFIG_WORD_SPACINGS[3]
    end
end

return ReaderKoptListener