feat(merge): add support for merging from a list of source files

cmd/relspec/convert.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"git.warky.dev/wdevs/relspecgo/pkg/merge"
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/bun"
@@ -45,6 +46,7 @@ var (
 	convertSourceType    string
 	convertSourcePath    string
 	convertSourceConn    string
+	convertFromList      []string
 	convertTargetType    string
 	convertTargetPath    string
 	convertPackageName   string
@@ -166,6 +168,7 @@ func init() {
 	convertCmd.Flags().StringVar(&convertSourceType, "from", "", "Source format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql, sqlite)")
 	convertCmd.Flags().StringVar(&convertSourcePath, "from-path", "", "Source file path (for file-based formats)")
 	convertCmd.Flags().StringVar(&convertSourceConn, "from-conn", "", "Source connection string (for pgsql) or file path (for sqlite)")
+	convertCmd.Flags().StringSliceVar(&convertFromList, "from-list", nil, "Comma-separated list of source file paths to read and merge (mutually exclusive with --from-path)")
 
 	convertCmd.Flags().StringVar(&convertTargetType, "to", "", "Target format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql)")
 	convertCmd.Flags().StringVar(&convertTargetPath, "to-path", "", "Target output path (file or directory)")
@@ -191,17 +194,29 @@ func runConvert(cmd *cobra.Command, args []string) error {
 	fmt.Fprintf(os.Stderr, "\n=== RelSpec Schema Converter ===\n")
 	fmt.Fprintf(os.Stderr, "Started at: %s\n\n", getCurrentTimestamp())
 
+	// Validate mutually exclusive flags
+	if convertSourcePath != "" && len(convertFromList) > 0 {
+		return fmt.Errorf("--from-path and --from-list are mutually exclusive")
+	}
+
 	// Read source database
 	fmt.Fprintf(os.Stderr, "[1/2] Reading source schema...\n")
 	fmt.Fprintf(os.Stderr, "      Format: %s\n", convertSourceType)
-	if convertSourcePath != "" {
-		fmt.Fprintf(os.Stderr, "      Path:   %s\n", convertSourcePath)
-	}
-	if convertSourceConn != "" {
-		fmt.Fprintf(os.Stderr, "      Conn:   %s\n", maskPassword(convertSourceConn))
-	}
 
-	db, err := readDatabaseForConvert(convertSourceType, convertSourcePath, convertSourceConn)
+	var db *models.Database
+	var err error
+
+	if len(convertFromList) > 0 {
+		db, err = readDatabaseListForConvert(convertSourceType, convertFromList)
+	} else {
+		if convertSourcePath != "" {
+			fmt.Fprintf(os.Stderr, "      Path:   %s\n", convertSourcePath)
+		}
+		if convertSourceConn != "" {
+			fmt.Fprintf(os.Stderr, "      Conn:   %s\n", maskPassword(convertSourceConn))
+		}
+		db, err = readDatabaseForConvert(convertSourceType, convertSourcePath, convertSourceConn)
+	}
 	if err != nil {
 		return fmt.Errorf("failed to read source: %w", err)
 	}
@@ -237,6 +252,30 @@ func runConvert(cmd *cobra.Command, args []string) error {
 	return nil
 }
 
+func readDatabaseListForConvert(dbType string, files []string) (*models.Database, error) {
+	if len(files) == 0 {
+		return nil, fmt.Errorf("file list is empty")
+	}
+
+	fmt.Fprintf(os.Stderr, "      Files:  %d file(s)\n", len(files))
+
+	var base *models.Database
+	for i, filePath := range files {
+		fmt.Fprintf(os.Stderr, "      [%d/%d] %s\n", i+1, len(files), filePath)
+		db, err := readDatabaseForConvert(dbType, filePath, "")
+		if err != nil {
+			return nil, fmt.Errorf("failed to read %s: %w", filePath, err)
+		}
+		if base == nil {
+			base = db
+		} else {
+			merge.MergeDatabases(base, db, &merge.MergeOptions{})
+		}
+	}
+
+	return base, nil
+}
+
 func readDatabaseForConvert(dbType, filePath, connString string) (*models.Database, error) {
 	var reader readers.Reader