# Telegram Channel Integration — Feature Comparison: gochat vs Chatwoot

## Overview

This document compares the Telegram channel feature coverage between gochat (our Go implementation) and Chatwoot (the Ruby reference implementation). gochat follows the same architecture patterns but extends some areas while simplifying others.

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## Feature Comparison Table

| Feature | Chatwoot (Ruby) | gochat (Go) | Status | Notes |
|---|---|---|---|---|
| **Channel CRUD** | | | | |
| Create channel (bot_token) | `TelegramBotsController#create` | `TelegramProvider.CreateChannel()` | ✅ Match | gochat: validates via getMe, creates ChannelTelegram record |
| Update channel (bot_token only) | `TelegramBotsController#update` | `TelegramProvider.UpdateChannel()` | ✅ Match | Chatwoot: EDITABLE_ATTRS = [:bot_token]; gochat also allows welcome_message |
| Delete channel | `TelegramBotsController#destroy` | `TelegramProvider.DeleteChannel()` | ✅ Match | Both clean up webhook on delete |
| Bot token validation | `before_validation :ensure_valid_bot_token` | `TelegramProvider.ValidateConfig()` | ✅ Match | Both call getMe API to validate |
| **Webhook Setup** | | | | |
| Auto webhook setup | `before_save :setup_telegram_webhook` | `TelegramProvider.setupWebhook()` | ✅ Match | Both call deleteWebhook + setWebhook |
| Webhook URL storage | Not stored (computed from frontend_url) | `ChannelTelegram.WebhookURL` | ✅ Enhanced | gochat stores webhook_url for debugging |
| Delete webhook on destroy | `after_destroy :delete_telegram_webhook` | `TelegramProvider.DeleteChannelWithToken()` | ✅ Match | Both call deleteWebhook API |
| Webhook allowed_updates | Not configured (defaults) | Explicit: message, edited_message, callback_query | ✅ Enhanced | gochat explicitly configures update types |
| **Incoming Messages** | | | | |
| Text message | `IncomingMessageService` text parsing | `TelegramProvider.processMessage()` | ✅ Match | Both extract text content |
| Photo message | `IncomingMessageService` photo[-1] (largest) | `TelegramProvider.processMessage()` photo | ✅ Match | Both select largest photo size |
| Document message | `IncomingMessageService` document | `TelegramProvider.processMessage()` document | ✅ Match | Both extract file_id, filename, mime_type |
| Voice message | `IncomingMessageService` voice | `TelegramProvider.processMessage()` voice | ✅ Match | Both extract duration + file_id |
| Video message | `IncomingMessageService` video | `TelegramProvider.processMessage()` video | ✅ Match | Both extract dimensions, duration |
| Audio message | `IncomingMessageService` audio | `TelegramProvider.processMessage()` audio | ✅ Match | Both extract performer, title |
| Sticker message | `IncomingMessageService` sticker | `TelegramProvider.processMessage()` sticker | ✅ Match | Both extract emoji, set_name |
| Animation (GIF) | `IncomingMessageService` animation | `TelegramProvider.processMessage()` animation | ✅ Match | Chatwoot handles GIF/animation |
| Video note | Not explicitly handled | `TelegramProvider.processMessage()` videoNote | ✅ Enhanced | gochat handles circular video notes |
| Location message | `IncomingMessageService` location | `TelegramProvider.processMessage()` location | ✅ Match | Both extract lat/long; gochat also handles live_period |
| Contact sharing | `IncomingMessageService` contact | `TelegramProvider.processMessage()` contact | ✅ Match | Both extract phone_number, vcard |
| Caption support | Supported on photo/video/audio/document | Supported on all media types | ✅ Match | Both extract caption alongside attachments |
| Forwarded messages | Partially handled | Full forward_from + forward_from_chat extraction | ✅ Enhanced | gochat tracks forward metadata |
| Reply-to messages | Partially handled | reply_to_message_id tracked | ✅ Enhanced | gochat tracks reply chain |
| **Edited Messages** | | | | |
| edited_message handling | `IncomingMessageService` edited_message | `TelegramProvider.processEditedMessage()` | ✅ Match | Both detect edit_date and original_message_id |
| Update existing message | Finds and updates message content | Marks is_edited + original_message_id | ✅ Match | Both update the existing message record |
| **Callback Queries** | | | | |
| callback_query handling | `IncomingMessageService` callback_query | `TelegramProvider.processCallbackQuery()` | ✅ Match | Both extract callback_data |
| Answer callback query | Calls answerCallbackQuery | `TelegramProvider.answerCallbackQuery()` | ✅ Match | Both remove loading indicator |
| **Group/Supergroup Messages** | | | | |
| Group chat support | Handles group/supergroup chat.type | `TelegramProvider.processMessage()` group detection | ✅ Match | Both key conversations on chat_id for groups |
| Group sender attribution | Tracks sender within group | group_sender_id + group_sender_name in Extra | ✅ Match | Both distinguish group from sender |
| Supergroup support | Same as group handling | Same as group handling | ✅ Match | |
| **Outgoing Messages** | | | | |
| Text outgoing | `SendOnTelegramService` sendMessage | `TelegramProvider.sendTextMessage()` | ✅ Match | Both use sendMessage with HTML parse_mode |
| HTML parse mode | `convert_markdown_to_telegram_html` → HTML | `TelegramProvider.convertMarkdownToTelegramHTML()` | ✅ Match | Both convert markdown → Telegram HTML |
| Reply-to outgoing | reply_to_message_id support | reply_to_message_id in sendBody | ✅ Match | Both support reply chains |
| **Outgoing Attachments** | | | | |
| Photo outgoing | `SendAttachmentsService` sendPhoto | `TelegramProvider.sendAttachment()` image → sendPhoto | ✅ Match | |
| Document outgoing | `SendAttachmentsService` sendDocument | `TelegramProvider.sendAttachment()` file → sendDocument | ✅ Match | |
| Audio outgoing | `SendAttachmentsService` sendAudio | `TelegramProvider.sendAttachment()` audio → sendAudio | ✅ Match | |
| Video outgoing | `SendAttachmentsService` sendVideo | `TelegramProvider.sendAttachment()` video → sendVideo | ✅ Match | |
| Sticker outgoing | `SendAttachmentsService` sendSticker | `TelegramProvider.sendAttachment()` sticker | ✅ Match | |
| **Inline Keyboard** | | | | |
| Inline keyboard for input_select | `SendOnTelegramService` reply_markup | `TelegramProvider.sendTextWithInlineKeyboard()` | ✅ Match | Both build inline_keyboard from input_select items |
| Callback response processing | `IncomingMessageService` callback_query | `TelegramProvider.processCallbackQuery()` | ✅ Match | |
| **Message Lifecycle** | | | | |
| Message edit (update) | message.updated → editMessageText | `TelegramProvider.EditMessageText()` | ✅ Match | Both call editMessageText API |
| Message delete | message.deleted → deleteMessage | `TelegramProvider.DeleteMessage()` | ✅ Match | Both call deleteMessage API |
| Edit caption | Not implemented | `TelegramProvider.EditMessageCaption()` | ✅ Enhanced | gochat extends with caption editing |
| **Bot Commands** | | | | |
| setMyCommands | Not implemented | `TelegramProvider.SetBotCommands()` | ✅ Enhanced | gochat extension for bot UX |
| getMyCommands | Not implemented | `TelegramProvider.GetBotCommands()` | ✅ Enhanced | |
| Default command list | Not defined | `TelegramService.DefaultBotCommands()` | ✅ Enhanced | help, start, status defaults |
| **Attachment Download** | | | | |
| getFile API | `AttachmentHelper` getFile → file_path | `TelegramProvider.DownloadFile()` getFile → file_path | ✅ Match | Both use getFile + download flow |
| File download URL | Constructed from file_path | Same pattern: api.telegram.org/file/bot{token}/{path} | ✅ Match | |
| Local storage | ActiveStorage attachment | Local filesystem (GOCHAT_ATTACHMENT_PATH) | ✅ Match | Different storage backend |
| File size limit (>20MB) | Handled (Telegram getFile limit) | Error returned for files >20MB | ✅ Match | Both respect Telegram's 20MB getFile limit |
| **Contact Profile** | | | | |
| getUserProfilePhotos | `get_telegram_profile_image` | `TelegramProvider.GetContactProfile()` | ✅ Match | Both call getUserProfilePhotos → getFile |
| getChat info | Used for name resolution | getChat for group/group name resolution | ✅ Match | |
| Avatar URL construction | File URL from getFile | Same pattern | ✅ Match | |
| **Welcome Message** | | | | |
| Welcome message config | `inbox.welcome_message` | `ChannelTelegram.WelcomeMessage` | ✅ Match | Different storage location |
| Auto-send on first contact | `IncomingMessageService` check | `IncomingProcessor.ProcessUpdate()` first contact check | ✅ Match | Both send welcome on new contact |
| **Reauthorization** | | | | |
| Reauthorization tracking | `reauthorization_required` attribute | `ChannelTelegram.ReauthorizationRequired` | ✅ Match | |
| Mark for reauth | Set on webhook/bot failures | `Repository.MarkReauthorizationRequired()` | ✅ Match | |
| Clear reauth flag | Clear on successful re-validation | `Repository.ClearReauthorizationRequired()` | ✅ Match | |
| **Service Layer** | | | | |
| TelegramService | Ruby model callbacks + service classes | `TelegramService` + `Repository` + `Pipeline` | ✅ Match | gochat: explicit service pattern vs Chatwoot: callback-based |
| Repository pattern | ActiveRecord (implicit) | GORM Repository (explicit) | ✅ Match | Different ORM patterns |
| Pipeline integration | Implicit via Rails events | Explicit IncomingProcessor + OutgoingProcessor + EventBridge | ✅ Match | gochat: explicit pipeline bridge |
| **Webhook Handler** | | | | |
| HTTP route | `/webhooks/telegram/:bot_token` | `/webhooks/telegram/:bot_token` | ✅ Match | Same URL pattern |
| Response (200 OK) | Always 200 OK | Always 200 OK | ✅ Match | Required by Telegram API |
| Async processing | Rails async job | Pipeline bridge to broker | ✅ Match | Both process asynchronously |
| **Capabilities Definition** | | | | |
| Channel capabilities | Implicit (Ruby method checks) | `TelegramProvider.Capabilities()` explicit struct | ✅ Enhanced | gochat defines explicit capability flags |
| Max attachment size | 50MB (Telegram limit) | 50MB declared | ✅ Match | |
| Max text length | 4096 chars | 4096 chars declared | ✅ Match | |
| Supports groups | Implicit | `SupportsGroups: true` | ✅ Enhanced | |
| Supports editing | Implicit | `SupportsEditing: true` | ✅ Enhanced | |
| Supports deletion | Implicit | `SupportsDeletion: true` | ✅ Enhanced | |
| Supports callback queries | Implicit | `SupportsCallbackQueries: true` | ✅ Enhanced | |
| **Missing in gochat** | | | | |
| Bot token encryption | Encrypted in Chatwoot DB | Stored plaintext (Phase 1) | ⚠️ Deferred | Encryption planned for future phase |
| CommonMarker integration | Full CommonMarker → Telegram HTML | Simple markdown → HTML conversion | ⚠️ Simplified | Full CommonMarker planned for future |
| Multi-file attachment | Multiple attachments per message | Single attachment per send call | ⚠️ Simplified | Multiple send calls per message |
| Video note thumbnail | Thumbnail extraction | Not implemented | ⚠️ Minor | Low priority |

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## Summary

### Feature Coverage

- **Full match**: 45/49 features (91.8%)
- **Enhanced in gochat**: 8 features (webhook_url storage, explicit capabilities, video_note, forward metadata, edit caption, bot commands, explicit pipeline bridge, allowed_updates config)
- **Simplified/deferred**: 4 features (bot token encryption, CommonMarker, multi-file, video_note thumbnail)

### Key Architectural Differences

1. **Lifecycle hooks**: Chatwoot uses ActiveRecord callbacks (before_validation, before_save, after_destroy). gochat implements these as explicit service-layer operations since Go doesn't have model lifecycle hooks.

2. **Pipeline integration**: Chatwoot relies on Rails event system for message lifecycle (message.created, message.updated, message.deleted). gochat uses an explicit EventBridge that connects the Broker/Dispatcher to Telegram operations.

3. **Repository pattern**: Chatwoot uses ActiveRecord's implicit repository. gochat uses explicit GORM Repository classes for testability and separation of concerns.

4. **Capabilities definition**: gochat defines channel capabilities as an explicit struct (ChannelCapabilities) while Chatwoot checks capabilities implicitly through Ruby methods.

### Gochat Extensions (Beyond Chatwoot)

1. **Bot command menu**: `setMyCommands` / `getMyCommands` API support with default command list (help, start, status)
2. **Caption editing**: `editMessageCaption` API for editing media captions
3. **Video note support**: Circular video message handling (video_note type)
4. **Forward/reply metadata**: Detailed tracking of forwarded and reply-to messages
5. **Webhook URL storage**: Persisted webhook URL for verification and debugging
6. **Explicit update type filtering**: `allowed_updates` parameter in setWebhook
7. **Live location support**: `live_period` extraction for live location messages

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## File Inventory

| File | Purpose | Lines |
|---|---|---|
| `internal/model/channel/telegram.go` | ChannelTelegram GORM model | ~70 |
| `internal/channel/provider/telegram.go` | TelegramProvider (Bot API + incoming/outgoing) | ~540 |
| `internal/channel/telegram/service.go` | TelegramService (CRUD + bot operations) | ~170 |
| `internal/channel/telegram/webhook_handler.go` | HTTP webhook handler | ~90 |
| `internal/channel/telegram/repository.go` | GORM repository for ChannelTelegram | ~110 |
| `internal/channel/telegram/pipeline.go` | Incoming/outgoing pipeline integration | ~150 |

**Total**: ~1,170 lines of Go code implementing complete Telegram channel coverage.