Your personal Reddit trend analyst, right in your Discord server.

SubTrends is a Discord bot that turns the latest posts and comments from any subreddit into a concise, engaging trend brief using OpenAI GPT models.

• Subreddit analysis: Summarizes themes, sentiment, and hot takes across recent top posts and comments.
• OpenAI-powered summaries: Uses OpenAI Chat Completions (e.g., gpt-5-mini, gpt-5).
• Top post links: Includes direct links to the posts referenced.
• Model selection: Change the model on the fly with a slash command.
• History & autocomplete: Personal per-user history, used to autocomplete subreddit when typing /trend.
• Long message splitting: Automatically splits long results to fit Discord limits.
• Persistent sessions: Stores user model choices and history on disk.
• Rate-limited & resilient: Built-in rate limiting, OAuth token caching, and timeouts for Reddit/OpenAI.
• Docker support: Container build for easy deployment.

1. A user invokes /trend <subreddit>.
2. The bot fetches top posts and their top comments via the Reddit API (with OAuth).
3. Content is summarized by OpenAI using a structured prompt.
4. The bot returns a formatted brief with a header and top post links.

graph TD
    A[User on Discord] -- /trend subreddit --> B(SubTrends Bot)
    B -- Fetch top posts/comments --> C(Reddit API)
    C -- Returns data --> B
    B -- Send data for summary --> D(OpenAI API)
    D -- Returns summary --> B
    B -- Post summary --> A

• /trend <subreddit>: Analyze a subreddit (type without r/). Autocomplete pulls from your history.
• /model <model>: Change the summary model.
  • Available choices are provided in Discord. Current options:
    • gpt-5-mini — fast and efficient (default)
    • gpt-5 — most capable
• /history: Show your last N analyzed subreddits (configurable; default 25).
• /clear: Clear your history.

Legacy text command is also supported by default: type !trend <subreddit>.

• Go 1.23+
• Docker (optional)
• A Reddit app (client ID/secret)
• A Discord bot (token)
• An OpenAI API key

git clone https://github.com/your-username/subtrends.git
cd subtrends

Create .env in the project root:

# .env
# Discord
DISCORD_BOT_TOKEN=your_discord_bot_token

# Reddit (https://www.reddit.com/prefs/apps)
REDDIT_CLIENT_ID=your_reddit_client_id
REDDIT_CLIENT_SECRET=your_reddit_client_secret

# OpenAI
OPENAI_API_KEY=your_openai_api_key

# --- Optional settings (override defaults from config.go) ---
REDDIT_POST_LIMIT=7
REDDIT_COMMENT_LIMIT=7
REDDIT_TIMEFRAME=day  # day, week, month, year, all

You can also generate a starter file with make init-env.

Using Go:

go mod tidy
go run .

Using Makefile helpers:

make run    # run locally, respects .env if present

Using Docker:

docker build -t subtrends .
# Mount local data/ into container for persistence across restarts
docker run --env-file .env --name subtrends-bot -d -v $(pwd)/data:/app/data subtrends

The bot is configured via environment variables. Important settings:

• DISCORD_BOT_TOKEN: Discord bot token
• REDDIT_CLIENT_ID, REDDIT_CLIENT_SECRET: Reddit OAuth credentials
• OPENAI_API_KEY: OpenAI API key

• OPENAI_API_ENDPOINT (default https://api.openai.com/v1/chat/completions)
• OPENAI_REQUEST_TIMEOUT (default 45s)
• OPENAI_REQUESTS_PER_MINUTE (default 10)
• OPENAI_BURST_SIZE (default 3)
• SUMMARY_HEADER (default 📱 *REDDIT PULSE* 📱\n\n)

• REDDIT_BASE_URL (default https://oauth.reddit.com)
• REDDIT_AUTH_URL (default https://www.reddit.com/api/v1/access_token)
• REDDIT_POST_LIMIT (default 7)
• REDDIT_COMMENT_LIMIT (default 7)
• REDDIT_TIMEFRAME (default day; one of day, week, month, year, all)
• REDDIT_REQUESTS_PER_SECOND (default 1)
• REDDIT_BURST_SIZE (default 5)
• REDDIT_TOKEN_EXPIRY_BUFFER (default 5m)
• REDDIT_TOKEN_FILE_PATH (default data/reddit_token.json)
• REDDIT_REQUEST_TIMEOUT (default 10s)
• REDDIT_CONCURRENT_REQUESTS (default 3)
• REDDIT_USER_AGENT (default SubTrends/1.0)
• REDDIT_PUBLIC_URL (default https://reddit.com)

• SESSION_FILE_PATH (default data/sessions.json)
• HISTORY_INIT_CAPACITY (default 50)
• HISTORY_DISPLAY_LIMIT (default 25)
• DISCORD_MESSAGE_SPLIT_LENGTH (default 1900)
• LEGACY_COMMAND_PREFIX (default !trend )
• SHUTDOWN_TIMEOUT (default 5s)

The current model options are presented as Discord choices:

• gpt-5-mini — fast and efficient (default)
• gpt-5 — most capable

Choose with /model. Your selection is saved per-user.

• make help — list tasks
• make run — run locally
• make build — build binary to bin/subtrends-bot
• make tidy — go mod tidy
• make test / make coverage — run tests and generate report
• make docker-build / make docker-run — build/run container

• User sessions (history, chosen model): data/sessions.json
• Reddit OAuth token cache: data/reddit_token.json

Both files are created automatically. They are written with file mode 0600. When using Docker, they persist if you bind mount data/.

• Go + discordgo
• OpenAI Chat Completions API
• Reddit API (OAuth)
• Docker