package privilege

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"github.com/sirupsen/logrus"
	"io"
	"net/http"
	"penahub.gitlab.yandexcloud.net/backend/penahub_common/privilege/config"
)

type Deps struct {
	Logger *logrus.Logger
}

type Handler struct {
	logger *logrus.Logger
}

func NewPrivilegeHandler(deps *Deps) *Handler {
	return &Handler{
		logger: deps.Logger,
	}
}

func (handler *Handler) GetPrivilege(ctx context.Context, url string) ([]config.Privilege, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		handler.logger.Errorf("failed to create GET request: %v", err)
		return nil, err
	}

	return handler.doRequest(req)
}

func (handler *Handler) PostPrivilege(ctx context.Context, data []config.Privilege, url string) ([]config.Privilege, error) {

	payload, err := json.Marshal(data)
	if err != nil {
		handler.logger.Errorf("failed to marshal request body: %v", err)
		return nil, err
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewBuffer(payload))
	if err != nil {
		handler.logger.Errorf("failed to create POST request: %v", err)
		return nil, err
	}
	req.Header.Set("Content-Type", "application/json")

	return handler.doRequest(req)
}

func (handler *Handler) doRequest(req *http.Request) ([]config.Privilege, error) {
	response, err := http.DefaultClient.Do(req)
	if err != nil {
		handler.logger.Errorf("failed to perform HTTP request: %v", err)
		return nil, err
	}
	defer response.Body.Close()

	if response.StatusCode != http.StatusOK {
		return nil, errors.New("unexpected status code")
	}

	var buffer bytes.Buffer
	if _, err := io.Copy(&buffer, response.Body); err != nil {
		handler.logger.Errorf("failed to read response body: %v", err)
		return nil, err
	}

	var privileges []config.Privilege
	if err := json.Unmarshal(buffer.Bytes(), &privileges); err != nil {
		handler.logger.Errorf("failed to unmarshal response body: %v", err)
		return nil, err
	}

	return privileges, nil
}

// return this list must be posted to Hubadmin.
func ComparePrivileges(existing []config.Privilege, incoming []config.Privilege) []config.Privilege {
	existingMap := make(map[string]config.Privilege)
	result := make([]config.Privilege, 0)
	for _, privilege := range existing {
		existingMap[privilege.ID] = privilege
	}

	for _, privilege := range incoming {
		if _, found := existingMap[privilege.ID]; !found {
			result = append(existing, existingMap[privilege.ID])
		}
	}

	return result
}