top-wallpaper/reddit/fetcher.go

package reddit

import (
	"context"
	"io"
	"net/http"
	"net/url"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/labstack/echo/v4"
	"github.com/siteworxpro/top-wallpaper/redis"
	"github.com/siteworxpro/top-wallpaper/resize"
)

func Fetch(ctx context.Context) {
	const defaultImageSize = 1600
	const minImageSize = 100

	rc, err := redis.FromContext(ctx)
	if err != nil {
		panic("Redis client not found in context: " + err.Error())
	}

	l := ctx.Value("logger").(echo.Logger)

	var size int
	if sizeS, ok := os.LookupEnv("MAX_SIZE"); ok {
		size, err = strconv.Atoi(sizeS)
		if err != nil {
			size = defaultImageSize
		}
	} else {
		size = defaultImageSize
	}

	if size < minImageSize {
		size = defaultImageSize
	}

	for {
		select {
		case <-ctx.Done():

			l.Info("Stopping Reddit fetcher...")
			_ = rc.Close()

			return
		default:

			doFetch(rc, l, false, size)

			if os.Getenv("NSFW_MODE") == "true" {
				doFetch(rc, l, true, size)
			}
		}

		time.Sleep(10 * time.Minute)
	}
}

func doFetch(rc *redis.Redis, l echo.Logger, nsfw bool, size int) {
	val, err := rc.Get(rc.GetCacheKey(nsfw))

	l.Info("Checking cache for Reddit image...", " nsfw=", nsfw)

	if err != nil {
		l.Error("Error fetching from Redis: ", err)
		return
	}

	if val != "" {
		l.Info("Reddit image is in cache... skipping...")

		return
	}

	l.Info("Fetching latest image from Reddit...")

	latestImageVal, err := GetLatestImage(func() (*http.Response, error) {

		jsonUrl := wallpaperURL
		if nsfw {
			jsonUrl = nsfwWallpaperURL
		}

		request := &http.Request{
			Method: http.MethodGet,
			Header: http.Header{
				"User-Agent": []string{"Mozilla/5.0 (compatible; RedditBot/1.0; +https://www.reddit.com/wiki/redditauth)"},
			},
			URL: &url.URL{
				Scheme: "https",
				Host:   "www.reddit.com",
				Path:   strings.TrimPrefix(jsonUrl, "https://www.reddit.com"),
			},
		}

		httpClient := &http.Client{
			Timeout: 10 * time.Second,
		}

		response, e := httpClient.Do(request)

		if e != nil {
			l.Error("Error fetching image from Reddit: ", e)
			return nil, e
		}

		if response.StatusCode != http.StatusOK {
			l.Error("Error fetching image from Reddit: ", response.Status)
			return nil, &echo.HTTPError{
				Code:    response.StatusCode,
				Message: "Error fetching image from Reddit",
			}
		}

		return response, nil
	})

	if err != nil {
		l.Error("Error getting latest image URL: ", err)
		return
	}

	response, err := http.Get(latestImageVal)
	if err != nil {
		l.Error("Error fetching image from Reddit: ", err)

		return
	}

	if response.StatusCode != http.StatusOK {
		l.Error("Error fetching image from Reddit: ", response.Status)

		return
	}

	imageDataBytes, err := io.ReadAll(response.Body)
	if err != nil {
		l.Error("Error reading image data: ", err)
		_ = response.Body.Close()
		return
	}

	_ = response.Body.Close()

	imageData := string(imageDataBytes)
	resized, err := resize.Shrink(imageData, uint(size), 70)

	if err != nil {
		l.Error("Error resizing image: ", err)
		return
	}

	err = rc.Set(rc.GetCacheKey(nsfw), resized, 10*time.Minute)
	if err != nil {
		l.Warn("could not cache image")
	}

	l.Info("Reddit image fetched and resized successfully, cached for 10 minutes.")
}