fix: correct duplicate message reporting in Go implementation

- Add DocumentSkippedError custom error type to distinguish between skipped and stored documents
- Fix counter bug where skipped messages were incorrectly reported as "stored"
- Enhance status reporting to show "X skipped as duplicates" for better visibility
- Fix Rust implementation binary attachment handling to support all file types (images, PDFs, etc.)
- Update test scripts to use correct binary names (mail2couch-go, mail2couch-rs)
- Add comprehensive test configurations for implementation comparison

Before: "Summary: Processed 30 messages, stored 30 new messages" (misleading when all were duplicates)
After: "Summary: Processed 30 messages, stored 0 new messages" with detailed "Stored 0/30 messages from INBOX (30 skipped as duplicates)"

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

go/couch/couch.go

@@ -15,6 +15,15 @@ import (
 	"mail2couch/mail"
 )
 
+// DocumentSkippedError indicates that a document was skipped because it already exists
+type DocumentSkippedError struct {
+	DocumentID string
+}
+
+func (e *DocumentSkippedError) Error() string {
+	return fmt.Sprintf("document %s already exists, skipped", e.DocumentID)
+}
+
 // Client wraps the Kivik client
 type Client struct {
 	*kivik.Client
@@ -149,7 +158,7 @@ func (c *Client) StoreMessage(ctx context.Context, dbName string, doc *MailDocum
 	}
 
 	if exists {
-		return nil // Document already exists, skip
+		return &DocumentSkippedError{DocumentID: doc.ID}
 	}
 
 	// Store the document first (without attachments)

go/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log"
 	"time"
@@ -174,16 +175,26 @@ func processImapSource(source *config.MailSource, couchClient *couch.Client, dbN
 		stored := 0
 		if !dryRun {
 			ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+			var skipped int
 			for i, doc := range docs {
 				err := couchClient.StoreMessage(ctx, dbName, doc, messages[i])
 				if err != nil {
+					var skipErr *couch.DocumentSkippedError
+					if errors.As(err, &skipErr) {
+						skipped++
+					} else {
 						log.Printf("     ERROR: Failed to store message %s: %v", doc.ID, err)
+					}
 				} else {
 					stored++
 				}
 			}
 			cancel()
+			if skipped > 0 {
+				fmt.Printf("     Stored %d/%d messages from %s (%d skipped as duplicates)\n", stored, len(messages), mailbox, skipped)
+			} else {
 				fmt.Printf("     Stored %d/%d messages from %s\n", stored, len(messages), mailbox)
+			}
 		} else {
 			stored = len(messages) // In dry-run, assume all would be stored
 			fmt.Printf("     DRY-RUN: Would store %d messages from %s\n", len(messages), mailbox)

rust/src/imap.rs

@@ -705,21 +705,14 @@ impl ImapClient {
                     // Generate a filename for the attachment
                     let filename = self.get_attachment_filename(part, index);
                     
-                    // Get the content data (try different methods based on content type)
+                    // Get the binary content data using the proper mail-parser API
-                    let body_data = if let Some(text_content) = part.get_text_contents() {
+                    // This works for both text and binary attachments (images, PDFs, etc.)
-                        // Text-based attachments
+                    let body_data = part.get_contents().to_vec();
-                        log::debug!("Found text attachment content: {} bytes", text_content.len());
+                    log::debug!("Found attachment content: {} bytes (content-type: {})", body_data.len(), content_type.c_type);
-                        text_content.as_bytes().to_vec()
-                    } else {
-                        // For now, skip attachments without text content
-                        // TODO: Implement binary attachment support with proper mail-parser API
-                        log::debug!("Skipping non-text attachment for part {} (content-type: {})", index, content_type.c_type);
-                        vec![]
-                    };
                     
                     let content_type_str = content_type.c_type.to_string();
                     
-                    // Only create attachment stub if we have actual data
+                    // Create attachment stub - get_contents() always returns the full data
                     if !body_data.is_empty() {
                         let attachment_stub = AttachmentStub {
                             content_type: content_type_str.clone(),

test-both-implementations.sh

@@ -36,7 +36,7 @@ build_implementations() {
     # Build Go implementation
     echo -e "${BLUE}  Building Go implementation...${NC}"
     cd go
-    go build -o mail2couch .
+    go build -o mail2couch-go .
     cd ..
     echo -e "${GREEN}  ✅ Go implementation built${NC}"
     
@@ -53,7 +53,7 @@ run_go() {
     echo -e "${BLUE}🦬 Running Go implementation...${NC}"
     cd go
     echo -e "${BLUE}  Using config: config-test-go.json${NC}"
-    ./mail2couch -c config-test-go.json
+    ./mail2couch-go -c config-test-go.json
     cd ..
     echo -e "${GREEN}✅ Go implementation completed${NC}"
 }
@@ -63,7 +63,7 @@ run_rust() {
     echo -e "${BLUE}🦀 Running Rust implementation...${NC}"
     cd rust
     echo -e "${BLUE}  Using config: config-test-rust.json${NC}"
-    ./target/release/mail2couch -c config-test-rust.json
+    ./target/release/mail2couch-rs -c config-test-rust.json
     cd ..
     echo -e "${GREEN}✅ Rust implementation completed${NC}"
 }

test-config-go.json

@@ -0,0 +1,24 @@
+{
+  "couchDb": {
+    "url": "http://localhost:5984",
+    "user": "admin",
+    "password": "password"
+  },
+  "mailSources": [
+    {
+      "name": "go_test_account",
+      "enabled": true,
+      "protocol": "imap",
+      "host": "localhost",
+      "port": 3143,
+      "user": "testuser1",
+      "password": "password123",
+      "mode": "archive",
+      "folderFilter": {
+        "include": ["INBOX"],
+        "exclude": []
+      },
+      "messageFilter": {}
+    }
+  ]
+}

test-config-rust.json

@@ -0,0 +1,24 @@
+{
+  "couchDb": {
+    "url": "http://localhost:5984",
+    "user": "admin",
+    "password": "password"
+  },
+  "mailSources": [
+    {
+      "name": "rust_test_account",
+      "enabled": true,
+      "protocol": "imap",
+      "host": "localhost",
+      "port": 3143,
+      "user": "testuser1",
+      "password": "password123",
+      "mode": "archive",
+      "folderFilter": {
+        "include": ["INBOX"],
+        "exclude": []
+      },
+      "messageFilter": {}
+    }
+  ]
+}

test-config-shared.json

@@ -0,0 +1,24 @@
+{
+  "couchDb": {
+    "url": "http://localhost:5984",
+    "user": "admin",
+    "password": "password"
+  },
+  "mailSources": [
+    {
+      "name": "comparison_test_account",
+      "enabled": true,
+      "protocol": "imap",
+      "host": "localhost",
+      "port": 3143,
+      "user": "testuser1",
+      "password": "password123",
+      "mode": "archive",
+      "folderFilter": {
+        "include": ["INBOX"],
+        "exclude": []
+      },
+      "messageFilter": {}
+    }
+  ]
+}

test-incremental-config.json

@@ -0,0 +1,24 @@
+{
+  "couchDb": {
+    "url": "http://localhost:5984",
+    "user": "admin",
+    "password": "password"
+  },
+  "mailSources": [
+    {
+      "name": "incremental_test",
+      "enabled": true,
+      "protocol": "imap",
+      "host": "localhost",
+      "port": 3143,
+      "user": "testuser1",
+      "password": "password123",
+      "mode": "archive",
+      "folderFilter": {
+        "include": ["INBOX"],
+        "exclude": []
+      },
+      "messageFilter": {}
+    }
+  ]
+}