caravela

defmodule <%= inspect @context_module %> do
  @moduledoc """
  Generated by Caravela from <%= inspect @domain_module %>.

  CRUD context with hooks and triple-target policies (row scope +
  field projection + action gates).<%= if @multi_tenant do %>
  Multi-tenant: every read is scoped by `tenant_id` and every write
  stamps `tenant_id` from the caller's `context.tenant`.<% end %>

  Regenerate with `mix caravela.gen.context <%= inspect @domain_module %>`.
  Custom code placed below the `# --- CUSTOM ---` marker is preserved.
  """

<%= if @multi_tenant do %>  import Ecto.Query, only: [where: 3]
<% end %><%= if @any_preloads do %>  import Ecto.Query, only: [preload: 2]
<% end %>
  alias <%= inspect @repo_module %>
<%= for e <- @entities do %>  alias <%= inspect e.module %>
<% end %>
<%= for e <- @entities do %>
  @doc "List `<%= e.plural %>` the caller is allowed to read."
  def <%= e.list_fn %>(context \\ %{}) do
    <%= e.module_short %>
    |> scope_tenant(context)
    |> apply_scope(<%= inspect e.entity_name %>, context)<%= if e.preloads != [] do %>
    |> preload(<%= inspect e.preloads %>)<% end %>
    |> Repo.all()
    |> project_fields(<%= inspect e.entity_name %>, context)
  end

  # --- CUSTOM :<%= e.list_fn %> ---
  # --- END :<%= e.list_fn %> ---

  @doc "Fetch a single `<%= e.singular %>` by id. Returns `nil` if not found or not visible."
  def <%= e.get_fn %>(id, context \\ %{}) do
    <%= e.module_short %>
    |> scope_tenant(context)
    |> apply_scope(<%= inspect e.entity_name %>, context)<%= if e.preloads != [] do %>
    |> preload(<%= inspect e.preloads %>)<% end %>
    |> Repo.get(id)
    |> project_field(<%= inspect e.entity_name %>, context)
  end

  # --- CUSTOM :<%= e.get_fn %> ---
  # --- END :<%= e.get_fn %> ---

  @doc "Fetch a single `<%= e.singular %>` by id. Raises if not found or not visible."
  def <%= e.get_bang_fn %>(id, context \\ %{}) do
    <%= e.module_short %>
    |> scope_tenant(context)
    |> apply_scope(<%= inspect e.entity_name %>, context)<%= if e.preloads != [] do %>
    |> preload(<%= inspect e.preloads %>)<% end %>
    |> Repo.get!(id)
    |> project_field(<%= inspect e.entity_name %>, context)
  end

  @doc "Build an unsaved `<%= e.singular %>` changeset, for use in forms."
  def <%= e.change_fn %>(%<%= e.module_short %>{} = <%= e.singular %>, attrs \\ %{}) do
    <%= e.module_short %>.changeset(<%= e.singular %>, attrs)
  end

  @doc "Create a `<%= e.singular %>`: authorize, apply on_create hook, insert."
  def <%= e.create_fn %>(attrs, context \\ %{}) do
    with :ok <- policy_authorize(<%= inspect e.entity_name %>, :create, context) do
      %<%= e.module_short %>{}
      |> <%= e.module_short %>.changeset(attrs)
      |> inject_tenant_id(context)
      |> apply_changeset_hook(:on_create, <%= inspect e.entity_name %>, context)
      |> Repo.insert()
    end
  end

  # --- CUSTOM :<%= e.create_fn %> ---
  # --- END :<%= e.create_fn %> ---

  @doc "Update a `<%= e.singular %>`: authorize, apply on_update hook, update."
  def <%= e.update_fn %>(%<%= e.module_short %>{} = <%= e.singular %>, attrs, context \\ %{}) do
    with :ok <- policy_authorize(<%= inspect e.entity_name %>, :update, <%= e.singular %>, context) do
      <%= e.singular %>
      |> <%= e.module_short %>.changeset(attrs)
      |> apply_changeset_hook(:on_update, <%= inspect e.entity_name %>, context)
      |> Repo.update()
    end
  end

  # --- CUSTOM :<%= e.update_fn %> ---
  # --- END :<%= e.update_fn %> ---

  @doc """
  Delete a `<%= e.singular %>`: authorize, run on_delete hook, delete.

  Accepts either the loaded struct (skipping the read round-trip) or
  the primary-key id (one `get` + one `delete`). Returns
  `{:error, :not_found}` when called by id and the row is invisible
  or missing.
  """
  def <%= e.delete_fn %>(struct_or_id, context \\ %{})

  def <%= e.delete_fn %>(%<%= e.module_short %>{} = <%= e.singular %>, context) do
    with :ok <- policy_authorize(<%= inspect e.entity_name %>, :delete, <%= e.singular %>, context),
         :ok <- run_delete_hook(<%= inspect e.entity_name %>, <%= e.singular %>, context) do
      Repo.delete(<%= e.singular %>)
    end
  end

  def <%= e.delete_fn %>(id, context) when is_binary(id) or is_integer(id) do
    case <%= e.get_fn %>(id, context) do
      nil -> {:error, :not_found}
      entity -> <%= e.delete_fn %>(entity, context)
    end
  end

  # --- CUSTOM :<%= e.delete_fn %> ---
  # --- END :<%= e.delete_fn %> ---
<% end %>
  # --- Field access metadata -----------------------------------------------
  #
  # Computed once per request and exposed both as JSON projection input
  # (via `project_fields/3`) and as a typed Svelte prop (via
  # `field_access/2`, called from generated LiveViews).

  @doc """
  Returns the `field_access` map for `entity` — keys are field atoms,
  values are `true`, `false`, or `:per_record` (record-dependent rule;
  evaluate per row).
  """
  def field_access(entity, context) do
    actor = actor_from_context(context)
    compute_field_access(entity, actor)
  end

<%= for e <- @entities do %>  defp compute_field_access(<%= inspect e.entity_name %>, actor) do
    %{
<%= for f <- e.field_access_exprs do %>      <%= inspect f.name %> => <%= f.expr %>,
<% end %>    }
  end

<% end %>  defp compute_field_access(_entity, _actor), do: %{}

  # --- Internal: policy + hook dispatch ------------------------------------

  defp apply_scope(query, entity, context) do
    <%= inspect @domain_module %>.__caravela_policy_scope__(entity, query, actor_from_context(context))
  end

  defp apply_changeset_hook(changeset, action, entity, context) do
    <%= inspect @domain_module %>.__caravela_hook__(action, entity, changeset, context)
  end
<%= if @any_on_delete do %>
  defp run_delete_hook(entity, struct, context) do
    case <%= inspect @domain_module %>.__caravela_hook__(:on_delete, entity, struct, context) do
      :ok -> :ok
      {:error, _} = err -> err
      other -> raise "on_delete hook must return :ok or {:error, reason}, got: " <> inspect(other)
    end
  end
<% else %>
  defp run_delete_hook(_entity, _struct, _context), do: :ok
<% end %>
  defp policy_authorize(entity, action, context) do
    if <%= inspect @domain_module %>.__caravela_policy_allow__(
         entity,
         action,
         actor_from_context(context)
       ) == true do
      :ok
    else
      {:error, :unauthorized}
    end
  end

  defp policy_authorize(entity, action, record, context) do
    if <%= inspect @domain_module %>.__caravela_policy_allow__(
         entity,
         action,
         actor_from_context(context),
         record
       ) == true do
      :ok
    else
      {:error, :unauthorized}
    end
  end

  defp actor_from_context(context) do
    context
    |> Map.get(:current_user)
    |> Kernel.||(Map.get(context, "current_user"))
  end

  # List-shaped projection for `list_*`. Strips invisible fields per row.
  defp project_fields(records, entity, context) when is_list(records) do
    field_access = compute_field_access(entity, actor_from_context(context))
    Enum.map(records, &do_project(&1, field_access, entity, context))
  end

  # Single-record projection used by `get_*`. Handles `nil` cleanly.
  defp project_field(nil, _entity, _context), do: nil

  defp project_field(record, entity, context) do
    field_access = compute_field_access(entity, actor_from_context(context))
    do_project(record, field_access, entity, context)
  end

  defp do_project(record, field_access, entity, context) do
    actor = actor_from_context(context)

    Enum.reduce(field_access, record, fn {field, visibility}, acc ->
      case visibility do
        true ->
          acc

        false ->
          redact(acc, field)

        :per_record ->
          if <%= inspect @domain_module %>.__caravela_policy_field_visible__(entity, field, actor, acc) do
            acc
          else
            redact(acc, field)
          end
      end
    end)
  end

  # Works for both Ecto structs and plain maps — the client-bound
  # representation may be either depending on controller/LiveSvelte
  # serialisation. We set the field to `nil` rather than removing it,
  # so the TypeScript shape stays stable for Svelte components.
  defp redact(%_struct{} = record, field) do
    if Map.has_key?(record, field), do: Map.put(record, field, nil), else: record
  end

  defp redact(record, field) when is_map(record) do
    Map.put(record, field, nil)
  end

  defp redact(record, _field), do: record

  # --- Internal: multi-tenant scoping --------------------------------------
<%= if @multi_tenant do %>
  defp scope_tenant(query, %{tenant: %{id: tenant_id}}) when not is_nil(tenant_id) do
    where(query, [q], q.tenant_id == ^tenant_id)
  end

  defp scope_tenant(query, _context), do: query

  defp inject_tenant_id(changeset, %{tenant: %{id: tenant_id}}) when not is_nil(tenant_id) do
    Ecto.Changeset.put_change(changeset, :tenant_id, tenant_id)
  end

  defp inject_tenant_id(changeset, _context), do: changeset
<% else %>
  defp scope_tenant(query, _context), do: query

  defp inject_tenant_id(changeset, _context), do: changeset
<% end %>
  <%= @custom_marker %>