defmodule Reblog.Engine.Builder do
  @moduledoc """
  Builds particular file associations.
  """
  require Logger

  @doc """
  Build a page provided page details.
  """
  def build(:page, vinyl, context) do
    build_context = Map.put(context, :title, vinyl.basename)
    content_rendered = EEx.eval_string(vinyl.contents, assigns: Map.to_list(build_context))

    build_context = Map.put(build_context, :body, content_rendered)
    page_rendered = EEx.eval_string(build_context.base_layout, assigns: Map.to_list(build_context))
    {page_rendered, build_context}
  end

  @doc """
  Build a post provided post details.
  """
  def build(:post, vinyl, context) do
    [post_date, _] = String.split(vinyl.basename, "_")
    {post_body, front_matter} = build(:post_body, vinyl)

    build_context = %{
      title: context.name,
      body: post_body,
      url: Path.join(["/", context.blog, "#{vinyl.stem}.html"]),
      date: Date.from_iso8601!(post_date),
      excerpt: ""
    }

    build_context = Map.merge(context, build_context)
    build_context = Map.merge(build_context, front_matter)

    post_rendered = EEx.eval_string(build_context.base_layout, assigns: Map.to_list(build_context))
    {post_rendered, build_context}
  end
  def build(:post_body, vinyl) do
    Logger.debug(fn -> ["Contents: ", vinyl.contents] end)
    # required: description, author, email
    {front_matter, body} = YamlFrontMatter.parse!(vinyl.contents)

    front_matter = for {k, v} <- front_matter, into: %{}, do: {String.to_atom(k), v}

    {Earmark.as_html!(body), front_matter}
  end
end