feat(pkg): preserve PostgreSQL types in mapDataType function

* Add support for known PostgreSQL types and modifiers
* Implement canonicalization for PostgreSQL types
* Introduce unit tests for PostgreSQL type handling

pkg/readers/dctx/reader.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers"
 )
 
@@ -232,7 +233,19 @@ func (r *Reader) convertField(dctxField *models.DCTXField, tableName string) ([]
 
 // mapDataType maps Clarion data types to SQL types
 func (r *Reader) mapDataType(clarionType string, size int) (sqlType string, precision int) {
-	switch strings.ToUpper(clarionType) {
+	trimmedType := strings.TrimSpace(clarionType)
+
+	// Preserve known PostgreSQL types (including arrays and extension types)
+	// from DCTX input instead of coercing them to generic text.
+	if pgsql.IsKnownPostgresType(trimmedType) {
+		pgType := canonicalizePostgresType(trimmedType)
+		if !pgsql.HasExplicitTypeModifier(pgType) && size > 0 && pgsql.SupportsLength(pgType) {
+			return pgType, size
+		}
+		return pgType, 0
+	}
+
+	switch strings.ToUpper(trimmedType) {
 	case "LONG":
 		if size == 8 {
 			return "bigint", 0
@@ -306,6 +319,32 @@ func (r *Reader) mapDataType(clarionType string, size int) (sqlType string, prec
 	}
 }
 
+func canonicalizePostgresType(typeStr string) string {
+	t := strings.ToLower(strings.Join(strings.Fields(strings.TrimSpace(typeStr)), " "))
+	if t == "" {
+		return ""
+	}
+
+	// Handle array suffixes
+	arrayCount := 0
+	for strings.HasSuffix(t, "[]") {
+		arrayCount++
+		t = strings.TrimSpace(strings.TrimSuffix(t, "[]"))
+	}
+
+	// Handle optional type modifier
+	modifier := ""
+	if idx := strings.Index(t, "("); idx > 0 {
+		if end := strings.LastIndex(t, ")"); end > idx {
+			modifier = t[idx : end+1]
+			t = strings.TrimSpace(t[:idx])
+		}
+	}
+
+	base := pgsql.CanonicalizeBaseType(t)
+	return base + modifier + strings.Repeat("[]", arrayCount)
+}
+
 // processKeys processes DCTX keys and converts them to indexes and primary keys
 func (r *Reader) processKeys(dctxTable *models.DCTXTable, table *models.Table, fieldGuidMap map[string]string) error {
 	for _, dctxKey := range dctxTable.Keys {