package ezhandler

import (
	"bytes"
	"encoding/json"
	"io"
	"net/http"
)

// ResponseHelper is a simpler way to return a response.
type ResponseHelper interface {
	// Body returns the body of the response. It is written to an [http.ResponseWriter].
	Body() (io.Reader, error)
	// Status should be a valid HTTP status.
	Status() int
	// Headers returns headers that should be added to the response.
	Headers() http.Header
}

type jsonResponse struct {
	value  any
	status int
}

var _ ResponseHelper = new(jsonResponse)

func (j *jsonResponse) Body() (io.Reader, error) {
	b, err := json.Marshal(j.value)
	if err != nil {
		return nil, err
	}
	return bytes.NewReader(b), nil
}

func (j *jsonResponse) Status() int {
	return j.status
}

func (j *jsonResponse) Headers() http.Header {
	header := make(http.Header)
	header.Set("Content-Type", "application/json")
	return header
}

// JSONResponse returns a [ResponseHelper] that JSON encodes value with a 200 response.
func JSONResponse(value any) ResponseHelper {
	return JSONResponseWithStatus(value, http.StatusOK)
}

// JSONResponseWithStatus returns a [ResponseHelper] that JSON encodes value with the provided status.
func JSONResponseWithStatus(value any, status int) ResponseHelper {
	return &jsonResponse{
		value:  value,
		status: status,
	}
}