feat: add modpack versions API endpoint

internal/api/modpack_handler.go

@@ -7,7 +7,9 @@ import (
 	"io"
 	"log/slog"
 	"net/http"
+	"net/url"
 	"os"
+	"path"
 
 	"gitea.mrixs.me/minecraft-platform/backend/internal/core"
 	"gitea.mrixs.me/minecraft-platform/backend/internal/core/importer"
@@ -203,3 +205,80 @@ func (h *ModpackHandler) updateJobStatus(ctx context.Context, jobID int, status
 	msg, _ := json.Marshal(update)
 	h.Hub.BroadcastMessage(msg)
 }
+
+// ModpackVersionResponse представляет версию модпака для ответа API
+type ModpackVersionResponse struct {
+	FileID       int      `json:"file_id"`
+	DisplayName  string   `json:"display_name"`
+	FileName     string   `json:"file_name"`
+	FileDate     string   `json:"file_date"`
+	GameVersions []string `json:"game_versions"`
+}
+
+// GetModpackVersions возвращает список доступных версий для модпака по URL
+func (h *ModpackHandler) GetModpackVersions(w http.ResponseWriter, r *http.Request) {
+	pageURL := r.URL.Query().Get("url")
+	if pageURL == "" {
+		http.Error(w, "Missing 'url' query parameter", http.StatusBadRequest)
+		return
+	}
+
+	apiKey := os.Getenv("CURSEFORGE_API_KEY")
+	if apiKey == "" {
+		http.Error(w, "CurseForge API key not configured", http.StatusInternalServerError)
+		return
+	}
+
+	cfImporter := importer.NewCurseForgeImporter("", apiKey)
+
+	// Извлекаем slug из URL
+	parsedURL, err := parseModpackURL(pageURL)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("Invalid URL: %v", err), http.StatusBadRequest)
+		return
+	}
+
+	// Ищем проект по slug
+	projectID, err := cfImporter.FindModpackBySlug(parsedURL)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("Modpack not found: %v", err), http.StatusNotFound)
+		return
+	}
+
+	// Получаем список файлов (версий)
+	files, err := cfImporter.GetModpackFiles(projectID)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("Failed to get versions: %v", err), http.StatusInternalServerError)
+		return
+	}
+
+	// Преобразуем в ответ
+	var versions []ModpackVersionResponse
+	for _, f := range files {
+		versions = append(versions, ModpackVersionResponse{
+			FileID:       f.ID,
+			DisplayName:  f.DisplayName,
+			FileName:     f.FileName,
+			FileDate:     f.FileDate,
+			GameVersions: f.GameVersions,
+		})
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(versions)
+}
+
+// parseModpackURL извлекает slug из URL страницы CurseForge
+func parseModpackURL(rawURL string) (string, error) {
+	parsed, err := url.Parse(rawURL)
+	if err != nil {
+		return "", err
+	}
+	// URL вида https://www.curseforge.com/minecraft/modpacks/all-the-mods-9
+	// path.Base вернет "all-the-mods-9"
+	slug := path.Base(parsed.Path)
+	if slug == "" || slug == "." || slug == "/" {
+		return "", fmt.Errorf("could not extract modpack slug from URL")
+	}
+	return slug, nil
+}