package jsonpatch

import (
	"encoding/json"

	"gopkg.in/yaml.v2"
)

type Op string

const (
	Add     Op = "add"
	Replace Op = "replace"
	Remove  Op = "remove"
)

type Patch struct {
	Ops []Operation `json:"patch"`
}

func NewPatch(ops ...Operation) *Patch {
	return &Patch{
		Ops: ops,
	}
}

func (p *Patch) AddOperations(ops ...Operation) {
	p.Ops = append(p.Ops, ops...)
}

type Operation struct {
	Op    Op          `json:"op"`
	Path  string      `json:"path"`
	Value interface{} `json:"value,omitempty"`
}

func (op Operation) MarshalYAML() (interface{}, error) {
	m := make(map[string]interface{})
	m["op"] = op.Op
	m["path"] = op.Path
	if op.Value != nil {
		// marshal op.Value to JSON
		valueJSON, err := json.Marshal(op.Value)
		if err != nil {
			return nil, err
		}
		// unmarshal JSON string back to interface{}
		var valueInterface interface{}
		if err := json.Unmarshal(valueJSON, &valueInterface); err != nil {
			return nil, err
		}
		// set value to be the unmarshaled interface{}
		m["value"] = valueInterface
	}
	return m, nil
}

// String converts the Patch to a YAML string
func (p *Patch) String() (string, error) {
	opsYAML, err := yaml.Marshal(p.Ops)
	if err != nil {
		return "", err
	}
	return string(opsYAML), nil
}