dimesheet/backend/internal/services/calendar.go

package services

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"os"
	"time"

	"asterisk.is/dimesheet/models"

	"golang.org/x/oauth2/google"
	"google.golang.org/api/calendar/v3"
	"google.golang.org/api/option"
)

func get_calendar_client() (*http.Client, *context.Context, error) {

	// Load service account credentials from JSON file
	credentialsFile := "credentials.json"
	b, err := os.ReadFile(credentialsFile)
	if err != nil {
		//http.Error(w, "Unable to read service account file", http.StatusInternalServerError)
		return nil, nil, errors.New("Unable to read service account file")
	}

	// Create a Google Calendar service with service account credentials
	ctx := context.Background()
	config, err := google.JWTConfigFromJSON(b, calendar.CalendarReadonlyScope)
	if err != nil {
		//http.Error(w, "Unable to parse service account file to config", http.StatusInternalServerError)
		return nil, nil, errors.New("Unable to parse service account file to config")
	}
	client := config.Client(ctx)
	return client, &ctx, nil
}

func GetEvents() ([]*calendar.Event, error) {

	// Create a new Google Calendar service
	cal_client, ctx, err := get_calendar_client()
	if err != nil {
		return nil, errors.New("Something went wrong:" + err.Error())
	}

	// Create a new Google Calendar service
	srv, err := calendar.NewService(*ctx, option.WithHTTPClient(cal_client))
	if err != nil {
		return nil, errors.New("Unable to retrieve Calendar client")
	}

	// Call the Google Calendar API
	events, err := srv.Events.List("c_9f1bb79a8eaa9761c51ce066f845131ab5c17794c863ba3d58e9124645c6451a@group.calendar.google.com").MaxResults(10).OrderBy("startTime").SingleEvents(true).TimeMin(time.Now().Format(time.RFC3339)).Do()
	if err != nil {
		return nil, errors.New("Unable to retrieve events")
	}

	return events.Items, nil
}

func GetClients() ([]models.Client, error) {

	// Create a new Google Calendar service
	cal_client, ctx, err := get_calendar_client()
	if err != nil {
		return nil, errors.New("Something went wrong:" + err.Error())
	}

	srv, err := calendar.NewService(*ctx, option.WithHTTPClient(cal_client))
	if err != nil {
		return nil, errors.New("Unable to retrieve Calendar client")
	}

	// Call the Google Calendar API

	events, err := srv.CalendarList.List().Do() //srv.Events.List("primary").MaxResults(10).OrderBy("startTime").SingleEvents(true).TimeMin(time.Now().Format(time.RFC3339)).Do()
	if err != nil {
		return nil, errors.New("Unable to retrieve events")
	}

	array := make([]models.Client, 0, len(events.Items))

	for _, calendar_item := range events.Items {
		c := models.Client{}
		s := calendar_item.Description

		err := json.Unmarshal([]byte(s), &c)
		if err != nil {
			panic(err)
		}

		c.CalendarListEntry = calendar_item
		array = append(array, c)
	}
	return array, nil
}