hugo-medialog/internal/books/api_googlebooks.go

package books

import (
	"encoding/json"
	"fmt"
	"hugo-medialog/utils"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
)

const googleBooksAPIBaseURL = "https://www.googleapis.com/books/v1/volumes?q=intitle:%s&key=%s"

// Function to search for a book by title
func SearchBookByTitle(title string, book *Book) error {
	apiKey := os.Getenv("GOOGLE_BOOKS_API_KEY")
	url := fmt.Sprintf(googleBooksAPIBaseURL, url.QueryEscape(title), apiKey)

	resp, err := http.Get(url)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	var result map[string]interface{}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return err
	}

	items := result["items"].([]interface{})
	if len(items) == 0 {
		return fmt.Errorf("Book %s not found", title)
	}

	// Get the ISBN from any of the results
	isbn, err := extractISBNFromResults(items)
	if err != nil {
		fmt.Printf("ISBN not found\n", isbn)
	} else {
		book.ISBN = isbn
	}

	bookInfo := items[0].(map[string]interface{})["volumeInfo"].(map[string]interface{})

	book.ID = items[0].(map[string]interface{})["id"].(string)
	book.Title = bookInfo["title"].(string)
	book.Author = bookInfo["authors"].([]interface{})[0].(string)
	book.Link = items[0].(map[string]interface{})["selfLink"].(string)
	if pageCount, ok := bookInfo["pageCount"].(float64); ok {
		book.Pages = int(pageCount)
	}
	if publishedDate, ok := bookInfo["publishedDate"].(string); ok {
		if len(publishedDate) >= 4 {
			book.Year, _ = strconv.Atoi(publishedDate[:4])
		}
	}

	book.Image = getBookCoverByTitle(title)
	if err != nil {
		fmt.Printf("Image not found: %s\n", err)
	}

	return nil
}

func extractISBNFromResults(items []interface{}) (string, error) {
	// Loop over all the results and returns first ISBN found (ISBN_13 or
	// ISBN_10)
	for _, item := range items {
		bookInfo := item.(map[string]interface{})["volumeInfo"].(map[string]interface{})
		industryIdentifiers, ok := bookInfo["industryIdentifiers"].([]interface{})
		if !ok {
			continue
		}

		var isbn string
		for _, identifier := range industryIdentifiers {
			id := identifier.(map[string]interface{})
			// Primero intentamos con ISBN_13
			if id["type"] == "ISBN_13" {
				isbn = id["identifier"].(string)
				return isbn, nil
			} else if id["type"] == "ISBN_10" && isbn == "" {
				// Si no hay ISBN_13, intentamos con ISBN_10
				isbn = id["identifier"].(string)
				return isbn, nil
			}
		}
	}

	return "", fmt.Errorf("no ISBN found in any result")
}

func getBookCoverByISBN(isbn string) string {
	openLibraryURL := fmt.Sprintf("https://covers.openlibrary.org/b/isbn/%s-L.jpg", isbn)
	if checkImageExists(openLibraryURL) {
		return openLibraryURL
	}

	amazonURL := fmt.Sprintf("https://images-na.ssl-images-amazon.com/images/P/%s.jpg", isbn)
	if checkImageExists(amazonURL) {
		return amazonURL
	}

	return ""
}

func getBookCoverByTitle(title string) string {
	apiKey := os.Getenv("GOOGLE_CUSTOM_SEARCH_ENGINE_API_KEY")
	cx := os.Getenv("GOOGLE_CX")

	searchURL := fmt.Sprintf("https://www.googleapis.com/customsearch/v1?q=%s+book+cover&key=%s&searchType=image&num=1&cx=%s", url.QueryEscape(title), apiKey, cx)

	resp, err := http.Get(searchURL)
	if err != nil {
		fmt.Printf("Error fetching cover from Google Images API: %s\n", err)
		return "default-cover.jpg"
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		fmt.Printf("Error fetching cover, status code: %d\n", resp.StatusCode)
		return "default-cover.jpg"
	}

	var result map[string]interface{}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		fmt.Printf("Error decoding JSON response: %s\n", err)
		return "default-cover.jpg"
	}

	if items, ok := result["items"].([]interface{}); ok && len(items) > 0 {
		if link, ok := items[0].(map[string]interface{})["link"].(string); ok {
			return link
		}
	}

	return "default-cover.jpg"
}

func checkImageExists(imageURL string) bool {
	resp, err := http.Head(imageURL)
	if err != nil || resp.StatusCode != http.StatusOK {
		return false
	}
	return true
}

func DownloadImage(url, slug string) error {
	imageDir := filepath.Join(os.Getenv("MARKDOWN_OUTPUT_BOOKS_DIR"), os.Getenv("IMAGES_OUTPUT_DIR"))
	if err := utils.CreateDirIfNotExists(imageDir); err != nil {
		return err
	}
	filename := fmt.Sprintf("%s.jpg", slug)
	filePath := filepath.Join(imageDir, filename)

	resp, err := http.Get(url)
	if err != nil {
		return fmt.Errorf("error downloading image: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("non-200 response while downloading image: %d", resp.StatusCode)
	}

	file, err := os.Create(filePath)
	if err != nil {
		return fmt.Errorf("error creating image file: %w", err)
	}
	defer file.Close()

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("error reading image data: %w", err)
	}

	_, err = file.Write(body)
	if err != nil {
		return fmt.Errorf("error writing image data: %w", err)
	}

	fmt.Printf(" - Image saved successfully at: %s\n", filePath)
	return nil
}