// Copyright 2024 Redpanda Data, Inc.
//
// 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.

package jsonpath

import (
	"context"
	"fmt"

	"github.com/PaesslerAG/gval"
	"github.com/PaesslerAG/jsonpath"
	"github.com/generikvault/gvalstrings"

	"github.com/redpanda-data/benthos/v4/public/bloblang"
)

// jsonPathLanguage includes the full gval scripting language and the single quote extension.
var jsonPathLanguage = gval.Full(jsonpath.Language(), gvalstrings.SingleQuoted())

func init() {
	if err := bloblang.RegisterMethodV2("json_path",
		bloblang.NewPluginSpec().
			Experimental().
			Category("Object & Array Manipulation").
			Description("Executes the given JSONPath expression on an object or array and returns the result. The JSONPath expression syntax can be found at https://goessner.net/articles/JsonPath/. For more complex logic, you can use Gval expressions (https://github.com/PaesslerAG/gval).").
			Example("", `root.all_names = this.json_path("$..name")`, [2]string{
				`{"name":"alice","foo":{"name":"bob"}}`,
				`{"all_names":["alice","bob"]}`,
			}, [2]string{
				`{"thing":["this","bar",{"name":"alice"}]}`,
				`{"all_names":["alice"]}`,
			}).
			Example("", `root.text_objects = this.json_path("$.body[?(@.type=='text')]")`, [2]string{
				`{"body":[{"type":"image","id":"foo"},{"type":"text","id":"bar"}]}`,
				`{"text_objects":[{"id":"bar","type":"text"}]}`,
			}).
			Param(bloblang.NewStringParam("expression").Description("The JSONPath expression to execute.")),
		func(args *bloblang.ParsedParams) (bloblang.Method, error) {
			expressionStr, err := args.GetString("expression")
			if err != nil {
				return nil, err
			}
			eval, err := jsonPathLanguage.NewEvaluable(expressionStr)
			if err != nil {
				return nil, fmt.Errorf("failed to evaluate json path expression: %w", err)
			}
			return func(v any) (any, error) {
				return eval(context.Background(), v)
			}, nil
		}); err != nil {
		panic(err)
	}
}