From 307f5824fa0064280ec8697e682fc3a7d523743d Mon Sep 17 00:00:00 2001
From: Noah Holm <32292420+noppaz@users.noreply.github.com>
Date: Sun, 29 Mar 2026 20:14:54 +0200
Subject: [PATCH] refactor: open files in command function consistently

---
 internal/commands/commands.go          | 33 +++++++++++++++++++++-----
 internal/parse/rowgroup_values.go      |  8 +------
 internal/parse/rowgroup_values_test.go | 10 +++++++-
 3 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/internal/commands/commands.go b/internal/commands/commands.go
index 739554a..c775a70 100644
--- a/internal/commands/commands.go
+++ b/internal/commands/commands.go
@@ -10,9 +10,9 @@ import (
 )
 
 func MetaCommand(filename string) error {
-	reader, err := file.OpenParquetFile(filename, true)
+	reader, err := openParquetFile(filename)
 	if err != nil {
-		return fmt.Errorf("error opening parquet file: %w", err)
+		return err
 	}
 	defer reader.Close()
 
@@ -25,9 +25,9 @@ func MetaCommand(filename string) error {
 }
 
 func RowGroupsCommand(filename string, perPage int) error {
-	reader, err := file.OpenParquetFile(filename, true)
+	reader, err := openParquetFile(filename)
 	if err != nil {
-		return fmt.Errorf("error opening parquet file: %w", err)
+		return err
 	}
 	defer reader.Close()
 
@@ -45,7 +45,13 @@ func RowGroupsCommand(filename string, perPage int) error {
 }
 
 func HeadCommand(filename string, amount int) error {
-	headers, rows, err := parse.ReadRows(filename, amount)
+	reader, err := openParquetFile(filename)
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+
+	headers, rows, err := parse.ReadRows(reader, amount)
 	if err != nil {
 		return err
 	}
@@ -57,7 +63,13 @@ func HeadCommand(filename string, amount int) error {
 }
 
 func LessCommand(filename string, amount int) error {
-	headers, rows, err := parse.ReadRows(filename, amount)
+	reader, err := openParquetFile(filename)
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+
+	headers, rows, err := parse.ReadRows(reader, amount)
 	if err != nil {
 		return err
 	}
@@ -68,3 +80,12 @@ func LessCommand(filename string, amount int) error {
 
 	return visualize.ViewportCreator(header, content)
 }
+
+func openParquetFile(filename string) (*file.Reader, error) {
+	reader, err := file.OpenParquetFile(filename, true)
+	if err != nil {
+		return nil, fmt.Errorf("error opening parquet file: %w", err)
+	}
+
+	return reader, nil
+}
diff --git a/internal/parse/rowgroup_values.go b/internal/parse/rowgroup_values.go
index afda5b3..2e5d6a7 100644
--- a/internal/parse/rowgroup_values.go
+++ b/internal/parse/rowgroup_values.go
@@ -9,13 +9,7 @@ import (
 	"golang.org/x/sync/errgroup"
 )
 
-func ReadRows(filename string, amount int) ([]string, [][]string, error) {
-	reader, err := file.OpenParquetFile(filename, true)
-	if err != nil {
-		return nil, nil, fmt.Errorf("error opening parquet file: %w", err)
-	}
-	defer reader.Close()
-
+func ReadRows(reader *file.Reader, amount int) ([]string, [][]string, error) {
 	const rowGroupIndex = 0
 	firstRowGroup := reader.RowGroup(rowGroupIndex)
 
diff --git a/internal/parse/rowgroup_values_test.go b/internal/parse/rowgroup_values_test.go
index ad144fb..aae9969 100644
--- a/internal/parse/rowgroup_values_test.go
+++ b/internal/parse/rowgroup_values_test.go
@@ -3,6 +3,8 @@ package parse
 import (
 	"slices"
 	"testing"
+
+	"github.com/apache/arrow-go/v18/parquet/file"
 )
 
 func Test_ReadRows(t *testing.T) {
@@ -40,7 +42,13 @@ func Test_ReadRows(t *testing.T) {
 
 	for _, tt := range testCases {
 		t.Run(tt.name, func(t *testing.T) {
-			headers, rows, err := ReadRows(tt.input.filename, tt.input.amount)
+			reader, err := file.OpenParquetFile(tt.input.filename, true)
+			if err != nil {
+				t.Fatalf("OpenParquetFile returned err: %v", err)
+			}
+			defer reader.Close()
+
+			headers, rows, err := ReadRows(reader, tt.input.amount)
 			if err != nil {
 				t.Errorf("ReadRows returned err: %v", err)
 			}