76 lines
2.2 KiB
Elixir
76 lines
2.2 KiB
Elixir
defmodule Wiki.Content.Renderer do
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alias Wiki.Repo
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alias Wiki.Content.Page
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alias WikiWeb.Router.Helpers, as: Routes
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alias WikiWeb.Endpoint
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import Ecto.Query
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@spec render(String.t(), integer()) :: String.t()
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def render(content, user_id) do
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{content, _linked_pages} = replace_page_links(content, user_id)
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content
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|> render_markdown()
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end
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@spec get_linked_pages(page :: Page.t()) :: [integer()]
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def get_linked_pages(%Page{content: content, user_id: user_id}) do
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{_content, linked_pages} = replace_page_links(content, user_id)
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Enum.uniq(linked_pages)
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end
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@page_link_regex ~r/\[\[.*?\]\]/
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@spec replace_page_links(content :: String.t(), user_id :: integer()) ::
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{String.t(), [integer()]}
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defp replace_page_links(content, user_id) do
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results = Regex.scan(@page_link_regex, content, return: :index)
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results
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|> Enum.reverse()
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|> Enum.reduce({content, []}, fn [{start, length}], {str, acc} ->
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# can't use String.slice here, because the indicies produced by Regex.scan are character indices, and slice operates on graphemes
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match = :erlang.binary_part(str, start, length)
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title = String.slice(match, 2..-3)
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lower_title = String.downcase(title)
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str_before = :erlang.binary_part(str, 0, start)
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str_after = :erlang.binary_part(str, start + length, byte_size(str) - start - length)
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{path, acc} =
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from(p in Page)
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|> where([p], p.user_id == ^user_id)
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|> where([p], fragment("lower(?)", p.title) == ^lower_title)
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|> select([p], p.id)
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|> Repo.one()
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|> case do
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nil ->
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{
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Routes.page_path(Endpoint, :new, title: title),
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acc
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}
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linked_page_id ->
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{
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Routes.page_path(Endpoint, :show, linked_page_id),
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[linked_page_id | acc]
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}
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end
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page_link = "[#{title}](#{path})"
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{
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str_before <> page_link <> str_after,
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acc
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}
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end)
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end
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@spec render_markdown(content :: String.t()) :: String.t()
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defp render_markdown(content) do
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{:ok, html, _errors} = Earmark.as_html(content)
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html
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end
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end
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