-- API Library
-- (c) Er2 2022 <er2@dismail.de>
-- Zlib License

require 'class'
require 'api.inline'
local tools  = require 'api.tools'
local json   = tools.json

-- parse arguments
local function argp(cid, rmp, pmod, dwp)
  return
    type(cid) == 'table' and cid.chat.id or cid,
    type(rmp) == 'table' and json.encode(rmp) or rmp,
    (type(pmod) == 'boolean' and pmod == true) and 'MarkdownV2' or pmod,
    dwp == nil and true or dwp
end

class 'API' : inherits 'EventsThis' {
  function(this, opts)
    this:super()

    if type(opts) == 'table' then
      if opts.token and type(opts.token) == 'string'
      then this.token = opts.token end
      if opts.norun
      then this.nr = true end
      if not opts.noinl then
        this.inline = new 'APIInline' (this)
      end
    end
  end,

  loop = function(this, limit, offset, timeout, allowed)
    limit = tonumber(limit) or 1
    offset = tonumber(offset) or 0
    timeout = tonumber(timeout) or 0

    this.runs = true
    this:emit 'ready'

    while this.runs do
      offset = this:recvUpdate(limit, offset, timeout, allowed)
    end
  end,

  parseArgs = tools.parseArgs,
  unparseArgs = tools.unparseArgs,

  request = function(this, ...)
    return tools.request(this.token, ...)
  end,

  destroy = function(this) this.runs = false end,

  login = function(this, token, cb)
    this.token = assert(token or this.token, 'Provide token!')

    repeat
      local result, ok = this:getMe()
      if ok and result
      then this.info = result
      end
    until (this.info or {}).result

    this.info = this.info.result
    this.info.name = this.info.first_name

    if type(cb) == 'function'
    then cb(this) end

    if not this.nr
    then this:loop() end
  end,

  recvUpdate = function(this, limit, offset, timeout, allowed)
    local update, ok = this:getUpdates(limit, offset, timeout, allowed)
    if not ok then
      -- See warning below
      return offset + 1
    end
    if ok
    and update
    and update.result
    then for _, upd in pairs(update.result) do
      offset = math.max(upd.update_id + 1, offset)
      this:receiveUpdate(upd)
    end end
    return offset
  end,

  receiveUpdate = function(this, upd)
    this:emit('update', upd)
    if upd.message then
      local msg = upd.message
      local cmd, to = tools.fetchCmd(msg.text or '')
      if cmd then
        -- need @to bot and /cmd@bot in groups
        if to and to ~= this.info.username
        or ((msg.chat.type == 'group' or msg.chat.type == 'supergroup')
          and not to)
        then return end

        -- remove command
        -- 2 = / + @
        msg.text = msg.text:sub(#cmd + #(to or '') + 2 + 1)
        local args = {}
        for v in msg.text:gmatch '%S+'
        do table.insert(args, v) end

        msg.cmd  = cmd
        msg.args = args

        this:emit('command', msg)
        return
      end
      this:emit('message', msg)

    elseif upd.edited_message
    then this:emit('messageEdit', upd.edited_message)

    elseif upd.channel_post
    then this:emit('channelPost', upd.channel_post)

    elseif upd.edited_channel_post
    then this:emit('channelPostEdit', upd.edited_channel_post)

    elseif upd.poll
    then this:emit('poll', upd.poll)
    
    elseif upd.poll_answer
    then this:emit('pollAnswer', upd.poll_answer)

    elseif upd.callback_query
    then this:emit('callbackQuery', upd.callback_query)

    elseif upd.inline_query
    then this:emit('inlineQuery', upd.inline_query)

    elseif upd.shipping_query
    then this:emit('shippingQuery', upd.shipping_query)

    elseif upd.pre_checkout_query
    then this:emit('preCheckoutQuery', upd.pre_checkout_query)

    elseif upd.chosen_inline_result
    then this:emit('inlineResult', upd.chosen_inline_result)
    end
  end,

  -- Getters without params
  getMe = function(this) return this:request 'getMe' end,
  getMyCommands = function(this) return this:request 'getMyCommands' end,

  -- Getters with params
  getChat = function(this, chatId)
    return this:request('getChat', {
      chat_id = chatId,
    })
  end,

  getUpdates = function(this, limit, offset, timeout, allowed)
    -- WARNING: Due to LuaSec body limit, this function can return nil
    allowed = type(allowed) == 'table' and json.decode(allowed) or allowed
    return this:request('getUpdates', {
      timeout = timeout,
      offset = offset,
      limit = limit,
      allowed_updates = allowed,
    })
  end,

  -- Setters
  send = function(this, chatId, text, parseMode, disableWeb, notNotify, replyTo, markup)
    chatId, markup, parseMode, disableWeb = argp(chatId, markup, parseMode, disableWeb)

    return this:request('sendMessage', {
      chat_id = chatId,
      text = tostring(text),
      parse_mode = parseMode,
      disable_web_page_preview = disableWeb,
      disable_notification = notNotify,
      reply_to_message_id = replyTo,
      reply_markup = markup,
    })
  end,

  reply = function(this, message, text, parseMode, disableWeb, markup, notNotify)
    local _, markup, parseMode, disableWeb = argp(message, markup, parseMode, disableWeb)
    return this:request('sendMessage', {
      chat_id = message.chat.id,
      text = text,
      parse_mode = parseMode,
      disable_web_page_preview = disableWeb,
      disable_notification = notNotify,
      reply_to_message_id = message.message_id,
      reply_markup = markup,
    })
  end,

  forward = function(this, message, to, notNotify)
    to = argp(to)
    return this:request('forwardMessage', {
      chat_id = to,
      from_chat_id = message.chat.id,
      disable_notification = notNotify,
      message_id = message.message_id,
    })
  end,

  sendSticker = function(this, message, sticker, notNotify, markup, protect, replyTo, sendWreply)
    message, markup = argp(message, markup)
    return this:request('sendSticker', {
      chat_id = message,
      sticker = sticker,
      disable_notification = notNotify,
      protect_content = protect,
      reply_to_message_id = replyTo,
      allow_sending_without_reply = sendWreply,
      reply_markup = markup,
    })
  end,
  sendPhoto = function(this, message, file, caption, parseMode, notNotify, replyTo, markup)
    message, markup, parseMode = argp(message, markup, parseMode)
    return this:request('sendPhoto', {
      chat_id = message,
      caption = caption,
      parse_mode = parseMode,
      disable_notification = notNotify,
      reply_to_message_id = replyTo,
      reply_markup = markup,
    }, {photo = file})
  end,
  sendDocument = function(this, message, file, caption, parseMode, notNotify, replyTo, markup)
    message, markup, parseMode = argp(message, markup, parseMode)
    return this:request('sendDocument', {
      chat_id = message,
      caption = caption,
      parse_mode = parseMode,
      disable_notification = notNotify,
      reply_to_message_id = replyTo,
      reply_markup = markup,
    }, {document = file})
  end,
  sendPoll = function(this, message, question, options, anon, type, manyAnswers, correct, explanation, parseMode, period, closes, notNotify, replyTo, markup)
    message, markup, parseMode = argp(message, markup, parseMode)
    options = type(opt) == 'string' and options or json.decode(options)
    anon = type(anon) == 'boolean' and anon or false
    manyAnswers = type(manyAnswers) == 'boolean' and manyAnswers or false
    return this:request('sendPoll', {
      chat_id = message,
      question = question,
      options = options,
      is_anonymous = anon,
      type = type,
      allows_multiple_answers = manyAnswers,
      correct_option_id = correct,
      explanation = explanation,
      explanation_parse_mode = parseMode,
      open_period = period,
      close_date = closes,
      disable_notification = notNotify,
      reply_to_message_id = replyTo,
      reply_markup = markup,
    })
  end,

  answerCallback = function(this, id, text, alert, url, caches)
    return this:request('answerCallbackQuery', {
      callback_query_id = id,
      text = text,
      show_alert = alert,
      url = url,
      cache_time = caches,
    })
  end,

  setMyCommands = function(this, commands, language, scope)
    return this:request('setMyCommands', {
      commands = json.encode(commands),
      language_code = tostring(language),
      scope = scope,
    })
  end,
}