(**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

open Flow_ast_differ
open Utils_js

let layout_of_node comments node =
  let old = !Js_layout_generator.with_attached_comments in
  Js_layout_generator.with_attached_comments := comments;
  let layout = match node with
  | Raw str -> Layout.Atom str
  | Literal lit -> Js_layout_generator.literal lit
  | Statement stmt -> Js_layout_generator.statement stmt
  | Program ast -> Js_layout_generator.program ~preserve_docblock:true ~checksum:None ast
  | Expression expr ->
    (* Wrap the expression in parentheses because we don't know what context we are in. *)
    (* TODO keep track of the expression context for printing, which will only insert parens when
     * actually needed. *)
    Layout.fuse [
      Layout.Atom "(";
      Js_layout_generator.expression expr;
      Layout.Atom ")";
    ]
  | Identifier id -> Js_layout_generator.identifier id
  | Pattern pat -> Js_layout_generator.pattern pat
  | Params params -> Js_layout_generator.arrow_function_params params
  | Variance var -> Js_layout_generator.variance var
  | Type typ -> Js_layout_generator.type_ typ
  | TypeParam t_param -> Js_layout_generator.type_param t_param
  | TypeAnnotation annot -> Js_layout_generator.type_annotation ~parens:false annot
  | FunctionTypeAnnotation annot -> Js_layout_generator.type_annotation ~parens:true annot
  | ClassProperty prop -> Js_layout_generator.class_property prop
  | ObjectProperty prop -> Js_layout_generator.object_property prop
  | TemplateLiteral t_lit -> Js_layout_generator.template_literal t_lit
  | JSXChild child ->
    begin match Js_layout_generator.jsx_child child with
    | Some (_, layout_node) -> layout_node
    (* This case shouldn't happen, so return Empty *)
    | None -> Layout.Empty end
  | JSXIdentifier id -> Js_layout_generator.jsx_identifier id in
  Js_layout_generator.with_attached_comments := old;
  layout

let text_of_node comments =
  layout_of_node comments
  (* TODO if we are reprinting the entire program we probably want this to be
   * false. Add some tests and make sure we get it right. *)
  %> Pretty_printer.print ~source_maps:None ~skip_endline:true
  %> Source.contents

let text_of_nodes break =
  let sep = match break with | Some str -> str | None -> "\n" in
  text_of_node %> ListUtils.to_string sep

let edit_of_change comments = function
  | loc, Replace (_, new_node) -> (loc, text_of_node comments new_node)
  | loc, Insert (break, new_nodes) -> (loc, text_of_nodes break comments new_nodes)
  | loc, Delete _ -> (loc, "")

let edits_of_changes comments changes =
  List.map (edit_of_change comments) changes
