# Portions of this file are derived from Pleroma:
# Copyright © 2017-2018 Pleroma Authors <https://pleroma.social>
# SPDX-License-Identifier: AGPL-3.0-only
# Upstream: https://git.pleroma.social/pleroma/pleroma/blob/develop/lib/pleroma/formatter.ex

defmodule Mobilizon.Service.Formatter do
  @moduledoc """
  Formats input text to structured data, extracts mentions and hashtags
  """
  alias Mobilizon.Actors.Actor
  alias Mobilizon.Actors

  @tag_regex ~r/\#\w+/u
  def parse_tags(text, data \\ %{}) do
    Regex.scan(@tag_regex, text)
    |> Enum.map(fn ["#" <> tag = full_tag] -> {full_tag, String.downcase(tag)} end)
    |> (fn map ->
          if data["sensitive"] in [true, "True", "true", "1"],
            do: [{"#nsfw", "nsfw"}] ++ map,
            else: map
        end).()
  end

  def parse_mentions(text) do
    # Modified from https://www.w3.org/TR/html5/forms.html#valid-e-mail-address
    regex =
      ~r/@[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]*@?[a-zA-Z0-9_-](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*/u

    Regex.scan(regex, text)
    |> List.flatten()
    |> Enum.uniq()
    |> Enum.map(fn "@" <> match = full_match ->
      {full_match, Actors.get_actor_by_name(match)}
    end)
    |> Enum.filter(fn {_match, user} -> user end)
  end

  # def emojify(text) do
  #   emojify(text, Emoji.get_all())
  # end

  # def emojify(text, nil), do: text

  # def emojify(text, emoji) do
  #   Enum.reduce(emoji, text, fn {emoji, file}, text ->
  #     emoji = HTML.strip_tags(emoji)
  #     file = HTML.strip_tags(file)

  #     String.replace(
  #       text,
  #       ":#{emoji}:",
  #       "<img height='32px' width='32px' alt='#{emoji}' title='#{emoji}' src='#{
  #         MediaProxy.url(file)
  #       }' />"
  #     )
  #     |> HTML.filter_tags()
  #   end)
  # end

  # def get_emoji(text) when is_binary(text) do
  #   Enum.filter(Emoji.get_all(), fn {emoji, _} -> String.contains?(text, ":#{emoji}:") end)
  # end

  # def get_emoji(_), do: []

  @link_regex ~r/[0-9a-z+\-\.]+:[0-9a-z$-_.+!*'(),]+/ui

  @uri_schemes Application.get_env(:pleroma, :uri_schemes, [])
  @valid_schemes Keyword.get(@uri_schemes, :valid_schemes, [])

  # # TODO: make it use something other than @link_regex
  # def html_escape(text, "text/html") do
  #   HTML.filter_tags(text)
  # end

  def html_escape(text, "text/plain") do
    Regex.split(@link_regex, text, include_captures: true)
    |> Enum.map_every(2, fn chunk ->
      {:safe, part} = Phoenix.HTML.html_escape(chunk)
      part
    end)
    |> Enum.join("")
  end

  @doc "changes scheme:... urls to html links"
  def add_links({subs, text}) do
    links =
      text
      |> String.split([" ", "\t", "<br>"])
      |> Enum.filter(fn word -> String.starts_with?(word, @valid_schemes) end)
      |> Enum.filter(fn word -> Regex.match?(@link_regex, word) end)
      |> Enum.map(fn url -> {Ecto.UUID.generate(), url} end)
      |> Enum.sort_by(fn {_, url} -> -String.length(url) end)

    uuid_text =
      links
      |> Enum.reduce(text, fn {uuid, url}, acc -> String.replace(acc, url, uuid) end)

    subs =
      subs ++
        Enum.map(links, fn {uuid, url} ->
          {uuid, "<a href=\"#{url}\">#{url}</a>"}
        end)

    {subs, uuid_text}
  end

  @doc "Adds the links to mentioned actors"
  def add_actor_links({subs, text}, mentions) do
    mentions =
      mentions
      |> Enum.sort_by(fn {name, _} -> -String.length(name) end)
      |> Enum.map(fn {name, actor} -> {name, actor, Ecto.UUID.generate()} end)

    uuid_text =
      mentions
      |> Enum.reduce(text, fn {match, _actor, uuid}, text ->
        String.replace(text, match, uuid)
      end)

    subs =
      subs ++
        Enum.map(mentions, fn {match, %Actor{id: id, url: url}, uuid} ->
          short_match = String.split(match, "@") |> tl() |> hd()

          {uuid,
           "<span><a data-user='#{id}' class='mention' href='#{url}'>@<span>#{short_match}</span></a></span>"}
        end)

    {subs, uuid_text}
  end

  @doc "Adds the hashtag links"
  def add_hashtag_links({subs, text}, tags) do
    tags =
      tags
      |> Enum.sort_by(fn {name, _} -> -String.length(name) end)
      |> Enum.map(fn {name, short} -> {name, short, Ecto.UUID.generate()} end)

    uuid_text =
      tags
      |> Enum.reduce(text, fn {match, _short, uuid}, text ->
        String.replace(text, match, uuid)
      end)

    subs =
      subs ++
        Enum.map(tags, fn {tag_text, tag, uuid} ->
          url =
            "<a data-tag='#{tag}' href='#{MobilizonWeb.Endpoint.url()}/tag/#{tag}' rel='tag'>#{
              tag_text
            }</a>"

          {uuid, url}
        end)

    {subs, uuid_text}
  end

  def finalize({subs, text}) do
    Enum.reduce(subs, text, fn {uuid, replacement}, result_text ->
      String.replace(result_text, uuid, replacement)
    end)
  end
end