Introduce group posts

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/mobilizon/posts/posts.ex

@@ -0,0 +1,135 @@
+defmodule Mobilizon.Posts do
+  @moduledoc """
+  The Posts context.
+  """
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Events.Tag
+  alias Mobilizon.Posts.Post
+  alias Mobilizon.Storage.{Page, Repo}
+
+  import Ecto.Query
+  require Logger
+
+  @post_preloads [:author, :attributed_to, :picture]
+
+  import EctoEnum
+
+  defenum(PostVisibility, :post_visibility, [
+    :public,
+    :unlisted,
+    :restricted,
+    :private
+  ])
+
+  @doc """
+  Returns the list of recent posts for a group
+  """
+  @spec get_posts_for_group(Actor.t(), integer | nil, integer | nil) :: Page.t()
+  def get_posts_for_group(%Actor{id: group_id}, page \\ nil, limit \\ nil) do
+    group_id
+    |> do_get_posts_for_group()
+    |> Page.build_page(page, limit)
+  end
+
+  @spec get_public_posts_for_group(Actor.t(), integer | nil, integer | nil) :: Page.t()
+  def get_public_posts_for_group(%Actor{id: group_id}, page \\ nil, limit \\ nil) do
+    group_id
+    |> do_get_posts_for_group()
+    |> where([p], p.visibility == ^:public and not p.draft)
+    |> Page.build_page(page, limit)
+  end
+
+  def do_get_posts_for_group(group_id) do
+    Post
+    |> where(attributed_to_id: ^group_id)
+    |> order_by(desc: :inserted_at)
+    |> preload([p], [:author, :attributed_to, :picture])
+  end
+
+  @doc """
+  Get a post by it's ID
+  """
+  @spec get_post(integer | String.t()) :: Post.t() | nil
+  def get_post(nil), do: nil
+  def get_post(id), do: Repo.get(Post, id)
+
+  @spec get_post_with_preloads(integer | String.t()) :: Post.t() | nil
+  def get_post_with_preloads(id) do
+    Post
+    |> Repo.get(id)
+    |> Repo.preload(@post_preloads)
+  end
+
+  @spec get_post_by_slug(String.t()) :: Post.t() | nil
+  def get_post_by_slug(nil), do: nil
+  def get_post_by_slug(slug), do: Repo.get_by(Post, slug: slug)
+
+  @spec get_post_by_slug_with_preloads(String.t()) :: Post.t() | nil
+  def get_post_by_slug_with_preloads(slug) do
+    Post
+    |> Repo.get_by(slug: slug)
+    |> Repo.preload(@post_preloads)
+  end
+
+  @doc """
+  Get a post by it's URL
+  """
+  @spec get_post_by_url(String.t()) :: Post.t() | nil
+  def get_post_by_url(url), do: Repo.get_by(Post, url: url)
+
+  @spec get_post_by_url_with_preloads(String.t()) :: Post.t() | nil
+  def get_post_by_url_with_preloads(url) do
+    Post
+    |> Repo.get_by(url: url)
+    |> Repo.preload(@post_preloads)
+  end
+
+  @doc """
+  Creates a post.
+  """
+  @spec create_post(map) :: {:ok, Post.t()} | {:error, Ecto.Changeset.t()}
+  def create_post(attrs \\ %{}) do
+    %Post{}
+    |> Post.changeset(attrs)
+    |> Repo.insert()
+  end
+
+  @doc """
+  Updates a post.
+  """
+  @spec update_post(Post.t(), map) :: {:ok, Post.t()} | {:error, Ecto.Changeset.t()}
+  def update_post(%Post{} = post, attrs) do
+    post
+    |> Repo.preload(:tags)
+    |> Post.changeset(attrs)
+    |> Repo.update()
+  end
+
+  @doc """
+  Deletes a post
+  """
+  @spec delete_post(Post.t()) :: {:ok, Post.t()} | {:error, Ecto.Changeset.t()}
+  def delete_post(%Post{} = post), do: Repo.delete(post)
+
+  @doc """
+  Returns the list of tags for the post.
+  """
+  @spec list_tags_for_post(integer | String.t()) :: [Tag.t()]
+  def list_tags_for_post(post_id) do
+    {:ok, uuid} = Ecto.UUID.dump(post_id)
+
+    uuid
+    |> tags_for_post_query()
+    |> Repo.all()
+  end
+
+  @spec tags_for_post_query(integer) :: Ecto.Query.t()
+  defp tags_for_post_query(post_id) do
+    from(
+      t in Tag,
+      join: p in "posts_tags",
+      on: t.id == p.tag_id,
+      where: p.post_id == ^post_id
+    )
+  end
+end