defmodule Lazarus do
  @moduledoc """
  Public entrypoint for Lazarus.

  Most applications interact with Lazarus in two layers:

    * `use Lazarus` in a Repo module to inject `Repo.soft_delete*`,
      `Repo.hard_delete*`, read-side filtering, and update behavior that skips
      soft-deleted rows
    * call the functions in this module when you want the same soft-delete
      behavior while passing the Repo module explicitly

  This module is the repo-explicit API for Lazarus's soft-delete helpers.
  Updates use Ecto Repo functions; `use Lazarus` makes `Repo.update*`, loaded
  `Repo.insert_or_update*`, and `Repo.update_all/3` skip soft-deleted rows by
  default.
  `Lazarus.Repo` documents the functions injected into a Repo by `use
  Lazarus`.

  ## Basic usage

      defmodule MyApp.Repo do
        use Ecto.Repo, otp_app: :my_app, adapter: Ecto.Adapters.Postgres
        use Lazarus
      end

  Use `Lazarus.Schema` in schemas that should support soft deletion:

      defmodule MyApp.Post do
        use Ecto.Schema
        use Lazarus.Schema

        schema "posts" do
          soft_deletes()
        end
      end

  Use `Lazarus.Migrations` to add the matching columns:

      defmodule MyApp.Repo.Migrations.AddSoftDeletesToPosts do
        use Ecto.Migration
        use Lazarus.Migrations

        def change do
          alter table(:posts) do
            soft_deletes()
          end
        end
      end

  ## Where to read next

    * `Lazarus.Repo` - injected Repo functions and `use Lazarus` integration
    * `Lazarus.Schema` - schema helpers and schema-level cascade metadata
    * `Lazarus.Migrations` - migration helpers for adding matching columns
    * the HexDocs guides - workflow-oriented explanations of queries,
      cascading, and association replacement
  """

  @doc group: "Soft delete API"
  @doc """
  Soft-deletes a single struct or changeset with an explicit Repo module.

  This is the repo-explicit equivalent of `Repo.soft_delete/2`.

  ## Returns

    * `{:ok, struct}` on success
    * `{:error, :not_found}` when the row was already soft-deleted or no
      longer exists

  ## Options

    * `:reason` - string reason persisted to `deletion_reason` when the schema
      includes that field, or `nil` (default: `nil`)
    * `:cascade` - boolean controlling whether eligible associations are
      cascaded (accepted values: `true`, `false`; default: `false`)
    * `:reload_after_delete` - boolean controlling whether Lazarus reloads the
      soft-deleted struct from the database after deletion (accepted values:
      `true`, `false`; default: repo config `:reload_after_delete`, then
      `false`). The default in-memory return avoids an additional database call
      and is faster, but may be less accurate than a fresh load; associations
      on the returned struct are reset to `Ecto.Association.NotLoaded`. Loading
      after deletion is more accurate, but costs one additional database call.
    * `:skip_associations` - list of association field names to skip during
      cascading, such as `[:comments, :ratings]`
    * `:cascade_depth` - positive integer recursion cap for cascading
      (default: `10`)

  ## Examples

      {:ok, deleted_post} = Lazarus.soft_delete(MyApp.Repo, post)
      {:ok, deleted_post} = Lazarus.soft_delete(MyApp.Repo, post, reason: "Deleted by user")
      {:ok, deleted_post} = Lazarus.soft_delete(MyApp.Repo, post, reload_after_delete: true)
  """
  def soft_delete(repo, struct_or_changeset, opts \\ []) do
    Lazarus.Runtime.soft_delete(repo, struct_or_changeset, opts)
  end

  @doc group: "Soft delete API"
  @doc """
  Soft-deletes a single struct or changeset and raises on failure.

  This is the repo-explicit equivalent of `Repo.soft_delete!/2`.

  ## Returns

    * the deleted struct on success

  ## Options

  Accepts the same options as `soft_delete/3`.

  ## Raises

    * `ArgumentError` when the row was already soft-deleted or no longer
      exists

  ## Examples

      deleted_post = Lazarus.soft_delete!(MyApp.Repo, post)
      deleted_post = Lazarus.soft_delete!(MyApp.Repo, post, reason: "Moderator action")
      deleted_post = Lazarus.soft_delete!(MyApp.Repo, post, reload_after_delete: true)
  """
  def soft_delete!(repo, struct_or_changeset, opts \\ []) do
    Lazarus.Runtime.soft_delete!(repo, struct_or_changeset, opts)
  end

  @doc group: "Soft delete API"
  @doc """
  Soft-deletes all rows matched by a schema-aware queryable.

  This is the repo-explicit equivalent of `Repo.soft_delete_all/2`.

  ## Returns

    * `{count, nil}` when the query does not include a `select`
    * `{count, returned}` when the query includes a `select`, matching the
      usual Ecto bulk-update return shape

  ## Options

    * `:reason` - string reason persisted to `deletion_reason` when the schema
      includes that field, or `nil` (default: `nil`)
    * `:cascade` - boolean controlling whether eligible associations are
      cascaded (accepted values: `true`, `false`; default: `false`)
    * `:skip_associations` - list of association field names to skip during
      cascading, such as `[:comments, :ratings]`
    * `:cascade_depth` - positive integer recursion cap for cascading
      (default: `10`)
    * `:allow_raw_sql` - boolean controlling whether fragments are allowed in
      the bulk soft-delete query (accepted values: `true`, `false`; default:
      `false`)
    * `:allow_schema_less_sources` - boolean controlling whether schema-less
      joins and nested sources are allowed in the bulk soft-delete query
      (accepted values: `true`, `false`; default: `false`). The root source
      must still be schema-aware.

  ## Query Requirements

    * the query root must be schema-aware, such as `Post` or `{"posts", Post}`
    * schema-less roots such as `from(row in "posts")` are not supported
    * subquery roots such as `from(row in subquery(...))` are not supported
    * schema-less joins and nested schema-less sources require
      `allow_schema_less_sources: true`

  See the "Query Support" guide for the full set of supported query shapes.

  ## Examples

      Lazarus.soft_delete_all(MyApp.Repo, Post)

      Lazarus.soft_delete_all(
        MyApp.Repo,
        from(post in Post, where: post.author_id == ^author_id),
        reason: "Bulk cleanup"
      )
  """
  def soft_delete_all(repo, queryable, opts \\ []) do
    Lazarus.Runtime.soft_delete_all(repo, queryable, opts)
  end

  @doc group: "Query helpers"
  @doc """
  Recursively applies Lazarus's read-side soft-delete filtering to an Ecto
  query.

  This is the same query-rewriting step injected into Repos that `use
  Lazarus` for reads. `Repo.update_all/3` uses the same recursive filtering
  internally.

  ## Returns

    * a rewritten query when filtering is applied
    * the original query unchanged when `with_deleted: true` is passed
      and the query shape is safe or explicitly allowed
    * non-query values unchanged

  ## Options

    * `:with_deleted` - boolean controlling whether soft-delete filtering is
      bypassed for the whole query (accepted values: `true`, `false`; default:
      `false`)
    * `:allow_raw_sql` - boolean controlling whether raw SQL fragments are
      allowed (accepted values: `true`, `false`; default: `false`)
    * `:allow_schema_less_sources` - boolean controlling whether schema-less
      string table sources are allowed (accepted values: `true`, `false`;
      default: `false`)

  ## Raises

    * `ArgumentError` when the query contains raw SQL fragments unless
      `allow_raw_sql: true` is passed
    * `ArgumentError` when the query contains schema-less root or join sources
      unless `allow_schema_less_sources: true` is passed

  ## Examples

      query =
        from(post in Post, select: post.id)

      Lazarus.deep_filter_soft_deleted(query, [])
      Lazarus.deep_filter_soft_deleted(query, with_deleted: true)
      Lazarus.deep_filter_soft_deleted(query, allow_raw_sql: true)
      Lazarus.deep_filter_soft_deleted(query, allow_schema_less_sources: true)

  See the "Query Support" guide for the precise root, join, subquery, and CTE
  behaviors.
  """
  def deep_filter_soft_deleted(query, opts) do
    Lazarus.Query.deep_filter_soft_deleted(query, opts)
  end

  @doc false
  defmacro __using__(opts \\ []) do
    quote do
      use Lazarus.Repo, unquote(opts)
    end
  end
end