package api

import (
	"context"
	"fmt"
	"time"

	"task-dashboard/internal/models"

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

type GoogleCalendarClient struct {
	srv        *calendar.Service
	calendarID string
}

func NewGoogleCalendarClient(ctx context.Context, credentialsFile, calendarID string) (*GoogleCalendarClient, error) {
	srv, err := calendar.NewService(ctx, option.WithCredentialsFile(credentialsFile))
	if err != nil {
		return nil, fmt.Errorf("unable to retrieve Calendar client: %v", err)
	}

	return &GoogleCalendarClient{
		srv:        srv,
		calendarID: calendarID,
	}, nil
}

func (c *GoogleCalendarClient) GetUpcomingEvents(ctx context.Context, maxResults int) ([]models.CalendarEvent, error) {
	t := time.Now().Format(time.RFC3339)
	events, err := c.srv.Events.List(c.calendarID).ShowDeleted(false).
		SingleEvents(true).TimeMin(t).MaxResults(int64(maxResults)).OrderBy("startTime").Do()
	if err != nil {
		return nil, fmt.Errorf("unable to retrieve events: %v", err)
	}

	var calendarEvents []models.CalendarEvent
	for _, item := range events.Items {
		var start, end time.Time
		if item.Start.DateTime == "" {
			// All-day event
			start, _ = time.Parse("2006-01-02", item.Start.Date)
			end, _ = time.Parse("2006-01-02", item.End.Date)
		} else {
			start, _ = time.Parse(time.RFC3339, item.Start.DateTime)
			end, _ = time.Parse(time.RFC3339, item.End.DateTime)
		}

		calendarEvents = append(calendarEvents, models.CalendarEvent{
			ID:          item.Id,
			Summary:     item.Summary,
			Description: item.Description,
			Start:       start,
			End:         end,
			HTMLLink:    item.HtmlLink,
		})
	}

	return calendarEvents, nil
}