%%%=============================================================================
%% Copyright 2012- Klarna AB
%% Copyright 2015- AUTHORS
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% @doc JESSE (JSon Schema Erlang)
%%
%% This is an interface module which provides an access to the main
%% functionality of jesse, such as 1) updating of the schema definitions cache;
%% 2) validation json data against a schema.
%% @end
%%%=============================================================================

%%%_* Module declaration =======================================================
-module(jesse_cli).

%%%_* Exports ==================================================================
%% API
-export([main/1]).

%%%_* API ======================================================================

-include("jesse_schema_validator.hrl").

main([]) ->
  main(["--help"]);
main(["-h"]) ->
  main(["--help"]);
main(["--help"]) ->
  io:fwrite( "Usage: ~s [--json] [path_to_json_schema] path_to_json_schema -- "
             "path_to_json_instance [path_to_json_instance] ~n"
           , [escript:script_name()]
           );
main(Options) ->
  main(Options, [], [], []).

main(["--json"|Rest], Options, [], []) ->
  main(Rest, Options ++ [{json, true}], [], []);

main(["--"|JsonInstances], Options, Schemata, []) ->
  run(Options, Schemata, JsonInstances);
main([Schema|Rest], Options, Schemata, []) ->
  main(Rest, Options, [Schema|Schemata], []).

%%%_* Internal =================================================================

run(_Options, _Schemata, []) ->
  ok;
run(Options, [Schema|_] = Schemata, [JsonInstance|JsonInstances]) ->
  JesseResult = jesse_run(JsonInstance, Schema, Schemata),
  Result = case JesseResult of
             {ok, _} ->
               [ {filename, list_to_binary(JsonInstance)}
               , {result, ok}
               ];
             {error, Reasons} ->
               JsxReasons = lists:map(fun jesse_error:reason_to_jsx/1, Reasons),
               [ {filename, list_to_binary(JsonInstance)}
               , {result, error}
               , {errors, JsxReasons}
               ]
           end,
  case proplists:get_value(json, Options) of
    undefined ->
      io:fwrite("~p\n\n", [Result]);
    true ->
      io:fwrite("~s\n\n", [jesse_lib:json_encode(Result)])
  end,
  case JesseResult of
    {ok, _} ->
      run(Options, Schemata, JsonInstances);
    _ ->
      %% init:stop not setting status code correctly
      %% init:stop(1)
      halt(1)
  end.


jesse_run(JsonInstance, Schema, Schemata) ->
  {ok, _} = application:ensure_all_started(jesse),
  ok = add_schemata(Schemata),
  {ok, JsonInstanceBinary} = file:read_file(JsonInstance),
  JsonInstanceJsx = jesse_lib:json_decode(JsonInstanceBinary),
  jesse:validate( Schema
                , JsonInstanceJsx
                ).

add_schemata([]) ->
  ok;
add_schemata([SchemaFile|Rest]) ->
  {ok, SchemaBin} = file:read_file(SchemaFile),
  Schema0 = jesse_lib:json_decode(SchemaBin),
  Schema = maybe_fill_schema_id(SchemaFile, Schema0),
  ok = jesse:add_schema(SchemaFile, Schema),
  add_schemata(Rest).

maybe_fill_schema_id(SchemaFile, Schema) ->
  SchemaFqdn = "file://" ++ filename:absname(SchemaFile),
  Version = jesse_json_path:value(<<"$schema">>, Schema, ?json_schema_draft6),
  Id = jesse_lib:get_schema_id(Schema),
  case {Version, Id} of
    {?json_schema_draft6, undefined} ->
      [ {?ID, unicode:characters_to_binary(SchemaFqdn)}
        | Schema
      ];
    {_, undefined} ->
      [ {?ID_OLD, unicode:characters_to_binary(SchemaFqdn)}
        | Schema
      ];
    _ ->
      Schema
  end.