#+TITLE: Channel Slack (channel-slack.org)
#+AUTHOR: Agent
#+FILETAGS: :channel:slack:
#+PROPERTY: header-args:lisp :tangle /home/user/.local/share/passepartout/lisp/channel-slack.lisp

* Channel Slack

Extracted from gateway-messaging in v0.5.0. Isolated platform — Slack-specific poll and send logic.

* Overview

The Slack channel provides bidirectional communication via the Slack Web API
(chat.postMessage for outbound, conversations.history for inbound polling).
Messages from Slack channels are injected into the cognitive pipeline as
~:user-input~ signals with ~:source :slack~. Outbound messages route through
the actuator registry when the pipeline targets ~:slack~.

The channel uses two functions: ~slack-poll~ (inbound sensor) and ~slack-send~
(outbound actuator). Both retrieve the bot token from the credentials vault.
HITL commands are intercepted before injection so approval flows work identically
across all channels.

** Contract

1. (slack-get-token): returns the Slack bot token from the vault
   (via ~vault-get-secret :slack~), or nil if not configured.
2. (slack-poll): polls configured channels via conversations.history,
   injects each non-bot message as a ~:user-input~ stimulus with
   ~:source :slack~. Handles API errors gracefully. HITL commands are
   intercepted before injection.
3. (slack-send action context): sends a message via chat.postMessage.
   Extracts ~:channel-id~ and ~:text~ from the action plist. Uses Bearer
   token authentication. Logs send failures without crashing the pipeline.

* Implementation

#+begin_src lisp
(in-package :passepartout)
(defun slack-get-token ()
  (vault-get-secret :slack))

(defun slack-send (action context)
  "Sends a message via Slack Web API."
  (declare (ignore context))
  (let* ((payload (getf action :payload))
         (meta (getf action :meta))
         (channel (or (getf meta :channel-id) (getf payload :chat-id)))
         (text (or (getf payload :text) (getf action :text)))
         (token (slack-get-token)))
    (when (and token channel text)
      (handler-case
          (dex:post "https://slack.com/api/chat.postMessage"
                    :headers `(("Authorization" . ,(format nil "Bearer ~a" token))
                               ("Content-Type" . "application/json; charset=utf-8"))
                    :content (cl-json:encode-json-to-string
                              `((channel . ,channel) (text . ,text))))
        (error (c) (log-message "SLACK ERROR: ~a" c))))))

(defun slack-poll ()
  "Polls Slack for new messages via conversations.history."
  (let* ((token (slack-get-token)))
    (when token
      (dolist (channel '("general"))  ;; configured channel IDs
        (handler-case
            (let* ((url (format nil "https://slack.com/api/conversations.history?channel=~a&limit=5" channel))
                   (response (dex:get url :headers
                                       `(("Authorization" . ,(format nil "Bearer ~a" token))))))
              (let* ((json (ignore-errors (cl-json:decode-json-from-string response)))
                     (ok (cdr (assoc :ok json)))
                     (messages (cdr (assoc :messages json))))
                (when (and ok messages (listp messages))
                  (dolist (msg messages)
                    (let* ((text (cdr (assoc :text msg)))
                           (user (cdr (assoc :user msg)))
                           (ts (cdr (assoc :ts msg))))
                      (when (and text user (not (string= user "USLACKBOT")))
                        (unless (ignore-errors (hitl-handle-message text :slack))
                          (stimulus-inject
                           (list :type :EVENT
                                 :meta (list :source :slack :chat-id channel)
                                 :payload (list :sensor :user-input :text text))))))))))
          (error (c) (log-message "SLACK POLL ERROR: ~a" c)))))))
#+end_src


#+end_src