feat: add IndexCommand &cobra.Command{} RunIndexer to internal indexer module in @observerly/skysolve

feat: add IndexCommand &cobra.Command{} RunIndexer to internal indexer module in @observerly/skysolve

Author: michealroberts

indexes/.gitkeep

@@ -0,0 +1,195 @@
+/*****************************************************************************************************************/
+
+//	@author		Michael Roberts <[email protected]>
+//	@package	@observerly/skysolve
+//	@license	Copyright © 2021-2025 observerly
+
+/*****************************************************************************************************************/
+
+package indexer
+
+/*****************************************************************************************************************/
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"syscall"
+
+	"github.com/observerly/skysolve/pkg/catalog"
+	"github.com/observerly/skysolve/pkg/healpix"
+	"github.com/observerly/skysolve/pkg/index"
+	"github.com/spf13/cobra"
+)
+
+/*****************************************************************************************************************/
+
+var (
+	NSide  int
+	Scheme string
+)
+
+/*****************************************************************************************************************/
+
+var IndexCommand = &cobra.Command{
+	Use:   "indexer",
+	Short: "indexer",
+	Long:  "indexer",
+	Run: func(cmd *cobra.Command, args []string) {
+		var scheme healpix.Scheme
+
+		// Extract the scheme from the user input:
+		switch strings.ToUpper(Scheme) {
+		case "NESTED":
+			// Set the scheme to the nested scheme:
+			scheme = healpix.NESTED
+		case "RING":
+			// Set the scheme to the ring scheme:
+			scheme = healpix.RING
+		default:
+			// Set the scheme to the nested scheme by default:
+			scheme = healpix.NESTED
+		}
+
+		params := RunIndexerParams{
+			NSide:  NSide,
+			Scheme: scheme,
+		}
+
+		// Attempt to run the indexer with the given parameters:
+		err := RunIndexer(params)
+		if err != nil {
+			fmt.Printf("Error: %v\n", err)
+			return
+		}
+	},
+}
+
+/*****************************************************************************************************************/
+
+func init() {
+	// Add the nside flag tp the indexer command for the number of sides for the HealPIX scheme:
+	// example usage: --nside 256 or -n 256
+	IndexCommand.Flags().IntVarP(
+		&NSide,
+		"nside",
+		"n",
+		2,
+		"The number of sides for the HealPIX scheme",
+	)
+	IndexCommand.MarkFlagRequired("nside")
+
+	// Add the scheme flag to the indexer command for the HealPIX scheme:
+	// example usage: --scheme NESTED or -s NESTED
+	IndexCommand.Flags().StringVarP(
+		&Scheme,
+		"scheme",
+		"s",
+		"NESTED",
+		"The HealPIX scheme to use",
+	)
+}
+
+/*****************************************************************************************************************/
+
+// Track created files for rollback
+var createdFilePaths []string
+
+/*****************************************************************************************************************/
+
+type RunIndexerParams struct {
+	NSide  int
+	Scheme healpix.Scheme
+}
+
+/*****************************************************************************************************************/
+
+func RunIndexer(params RunIndexerParams) error {
+	// Create a new SIMBAD service client:
+	service := catalog.NewCatalogService(catalog.GAIA, catalog.Params{
+		Limit:     8,  // Limit the number of records to 8
+		Threshold: 16, // Limiting Magntiude, filter out any stars that are magnitude 16 or above (fainter)
+	})
+
+	// Number of sides for the HealPIX:
+	sides := params.NSide
+
+	// Create a new HealPIX instance with the given sides:
+	healPix := healpix.NewHealPIX(sides, params.Scheme)
+
+	// Get the number of pixels for the given sides:
+	pixels := healPix.GetNumberOfPixels()
+
+	// Setup signal handling for cleanup on interrupt:
+	signalChannel := make(chan os.Signal, 1)
+
+	// Listen for interrupt signals on the SIGTERM system call, or os.Interrupt:
+	signal.Notify(signalChannel, os.Interrupt, syscall.SIGTERM)
+
+	// Listen for interrupt signal in a concurrent goroutine, and rollback if received:
+	go func() {
+		<-signalChannel
+		fmt.Println("\nInterrupt received. Rolling back...")
+		rollback(createdFilePaths)
+		os.Exit(1)
+	}()
+
+	// Create a new indexer instance:
+	indexer := index.NewIndexer(*healPix, *service)
+
+	// Generate quads for each pixel in the HealPIX grid for the given sides parameter:
+	for pixel := 0; pixel <= pixels; pixel++ {
+		// Generate quads for the given pixel:
+		quads, err := indexer.GenerateQuadsForPixel(pixel)
+
+		if err != nil {
+			fmt.Printf("failed to generate quads: %v", err)
+			return err
+		}
+
+		quadsMarshalled, err := json.Marshal(quads)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		// Create the directory structure: indexes/<SIDES>
+		directoryPath := filepath.Join("indexes", fmt.Sprint(sides))
+		if err := os.MkdirAll(directoryPath, 0755); err != nil {
+			log.Fatal("Failed to create directory:", err)
+		}
+
+		// File path: indexes/<SIDES>/<PIXEL_INDEX>.json
+		filePath := filepath.Join(directoryPath, fmt.Sprintf("%d.json", pixel))
+
+		// Write the JSON data to the file
+		if err := os.WriteFile(filePath, quadsMarshalled, 0644); err != nil {
+			log.Fatal("Failed to write file:", err)
+		}
+
+		createdFilePaths = append(createdFilePaths, filePath)
+
+		fmt.Printf("Quads saved to %s\n", filePath)
+	}
+
+	// Return nil if the indexer ran successfully:
+	return nil
+}
+
+/*****************************************************************************************************************/
+
+// rollbackFiles deletes created files in case of failure or interruption
+func rollback(filepaths []string) {
+	for _, file := range filepaths {
+		if err := os.Remove(file); err != nil {
+			fmt.Printf("Warning: Failed to remove file %s: %v\n", file, err)
+		} else {
+			fmt.Printf("Rolled back: %s\n", file)
+		}
+	}
+}
+
+/*****************************************************************************************************************/