Skip to content

refactor(ai): extract session lifecycle service #93

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
turinglambdaai merged 1 commit into from
Oct 25, 2026
Merged

refactor(ai): extract session lifecycle service #93

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
154 changes: 51 additions & 103 deletions app/backend.rkt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
(prefix-in rivet-info: rivet/app-info)
rivet/backend
"core/ai.rkt"
"core/ai-session.rkt"
"core/apps.rkt"
"core/bindings.rkt"
"core/clipboard.rkt"
Expand Down Expand Up @@ -398,63 +399,51 @@
(define (ai-row id title subtitle arg badge)
(list id title subtitle "AI" arg "sparkles" "" badge))

;; Conversation memory and the last answer. Module-level boxes, NOT
;; parameters: every RVT1 request runs on its own worker thread, and a
;; parameter written in one worker is invisible to the next (this is also
;; why the old parameter-based chat memory never actually survived a
;; round-trip in production, while single-threaded tests stayed green).
;; The streaming thread and later RPCs share these; one semaphore guards
;; the pair against a concurrent reset.
(define ai-memory-lock (make-semaphore 1))
(define ai-history-box (box '()))
(define ai-last-answer-box (box ""))
;; The product-owned service owns shared memory and worker lifecycle. It is
;; intentionally outside request parameters: every RVT1 request runs on its
;; own worker, while the conversation and an in-flight provider call belong to
;; the application process.
(define ai-service
(make-ai-session-service
#:memory-path ai-memory-path
#:on-start
(lambda ()
(state-set! ai-stream (AiStream "running" "" (void))))
#:on-delta
(lambda (partial)
(state-set! ai-stream (AiStream "running" partial (void))))
#:on-terminal
(lambda (terminal)
(case (ai-session-terminal-phase terminal)
[(done)
(define answer (ai-session-terminal-text terminal))
(state-set! ai-stream (AiStream "done" answer (void)))
(ai-finished answer)]
[(error)
(define message (ai-session-terminal-error terminal))
(state-set! ai-stream (AiStream "error" "" message))
(notify message)]
[(cancelled)
(state-set! ai-stream (AiStream "idle" "" (void)))]))))

(define (ai-history)
(unbox ai-history-box))
(ai-session-history ai-service))

(define (ai-last-answer)
(unbox ai-last-answer-box))
(ai-session-last-answer ai-service))

;; Persistent memory (Raycast-2.0 "Memory" parity): the transcript and the
;; last answer survive restarts. The file is local-only by construction —
;; the same never-synced policy as ai-keys.json, because a transcript is
;; sensitive.
(define (ai-restore-memory!)
(with-handlers ([exn:fail? void])
(define raw (read-json-file (ai-memory-path) (hash)))
(when (hash? raw)
(define hist (hash-ref raw 'history '()))
;; JSON arrays come back as lists; memory stores pairs.
(when (and (list? hist)
(andmap (lambda (e)
(and (list? e) (= (length e) 2)
(string? (list-ref e 0))
(string? (list-ref e 1))))
hist))
(set-box! ai-history-box
(for/list ([e (in-list hist)])
(cons (list-ref e 0) (list-ref e 1)))))
(define last (hash-ref raw 'last-answer #f))
(when (string? last) (set-box! ai-last-answer-box last)))))

(define (ai-persist-memory!)
;; Memory stores pairs; JSON needs lists. (The swallow-on-failure here
;; once hid exactly this: pairs are not jsexpr, so nothing was ever
;; written and the "persistence" silently saved nothing.)
(with-handlers ([exn:fail? void])
(write-json-atomic!
(ai-memory-path)
(hasheq 'history (for/list ([e (in-list (ai-history))])
(list (car e) (cdr e)))
'last-answer (ai-last-answer)))))
(ai-session-restore! ai-service))

(define (ai-set-history! h)
(set-box! ai-history-box h)
(ai-persist-memory!))
(ai-session-set-history! ai-service h))

(define (ai-set-last-answer! a)
(set-box! ai-last-answer-box a)
(ai-persist-memory!))
(ai-session-set-last-answer! ai-service a))

(define (ai-copy-last-answer)
(define answer (ai-last-answer))
Expand Down Expand Up @@ -606,53 +595,20 @@
(if (pair? items) (clipboard-item-text (car items)) ""))
""))

;; The AI run action: validate, then hand the provider call to a backend
;; thread (ai-request-streaming) and return "started" immediately — the
;; The AI run action: validate, then hand the provider call to the session
;; service and return "started" immediately — the
;; answer streams to hosts through the ai-stream State and lands on the
;; clipboard via ai-finished when complete. run-action therefore never
;; blocks on a model.
(define ai-streaming? (box #f))

(define (start-ai-stream! chat? raw-arg prompt)
(set-box! ai-streaming? #t)
(state-set! ai-stream (AiStream "running" "" (void)))
(define provider (ai-effective-provider))
(define key (ai-get-key (ai-keys-path) provider))
(define model (ai-effective-model))
(define base-url (ai-effective-base-url))
(define history (if chat? (ai-history) '()))
;; Delta pushes are State frames; throttle so a fast model cannot flood
;; the wire (150 ms is well under human reading latency).
(define last-push (box 0.0))
(thread
(lambda ()
(define answer
(ai-request-streaming provider base-url key model prompt
#:history history
#:on-delta
(lambda (partial)
(define now (current-inexact-milliseconds))
(when (> (- now (unbox last-push)) 150)
(set-box! last-push now)
(with-handlers ([exn:fail? void])
(state-set! ai-stream
(AiStream "running" partial
(void))))))))
(set-box! ai-streaming? #f)
(cond
;; Error strings from ai-request-streaming all start with "AI ".
[(string-prefix? answer "AI ")
(with-handlers ([exn:fail? void])
(state-set! ai-stream (AiStream "error" "" answer)))
(notify answer)]
[else
(ai-set-last-answer! answer)
(when chat?
(ai-set-history!
(ai-history-append history (string-trim (substring raw-arg 4)) answer)))
(with-handlers ([exn:fail? void])
(state-set! ai-stream (AiStream "done" answer (void))))
(ai-finished answer)]))))
(ai-session-start!
ai-service
(ai-session-request provider base-url key model prompt
(and chat? (string-trim (substring raw-arg 4))))))

(define (ai-run! engine arg)
(define provider (ai-effective-provider))
Expand All @@ -666,32 +622,24 @@
(string-prefix? arg v))
(string=? (string-trim (ai-newest-clipboard-text engine)) ""))
(cons "nothing on the clipboard to work on" '())]
[(unbox ai-streaming?)
(cons "AI is already answering — wait for it or ask something new later" '())]
[else
(define chat? (string-prefix? arg "chat"))
(define prompt
(if chat?
(string-trim (substring arg 4))
(build-ai-prompt arg (ai-newest-clipboard-text engine))))
(start-ai-stream! chat? arg prompt)
(cons "started" '())]))
(case (start-ai-stream! chat? arg prompt)
[(started) (cons "started" '())]
[(busy)
(cons "AI is already answering — wait for it or ask something new later" '())]
[(closed) (cons "AI service is closed" '())])]))

;; Drop the last chat exchange — the minimal branching primitive: roll
;; the conversation back to try a different direction.
(define (ai-undo-exchange!)
(define hist (ai-history))
(cond
[(null? hist) (cons "nothing to undo" '())]
[else
(define kept
(let loop ([h hist])
(if (<= (length h) 2)
'()
(cons (car h) (loop (cdr h))))))
(ai-set-history! kept)
(ai-set-last-answer! "")
(cons "ok" (list (cons 'notify "Undone: dropped the last exchange")))]))
(if (ai-session-undo! ai-service)
(cons "ok" (list (cons 'notify "Undone: dropped the last exchange")))
(cons "nothing to undo" '())))

(define (ai-act! engine id arg)
(case (string->symbol id)
Expand Down Expand Up @@ -736,10 +684,7 @@
(cons "copied" (list (cons 'paste-to-frontmost answer)))
(cons "no AI answer yet" '()))]
[(ai.reset)
(call-with-semaphore ai-memory-lock
(lambda ()
(ai-set-history! '())
(ai-set-last-answer! "")))
(ai-session-reset! ai-service)
(cons "ok" (list (cons 'notify "AI conversation reset")))]
[else (cons (format "unknown ai action: ~a" id) '())]))

Expand Down Expand Up @@ -1773,4 +1718,7 @@
(state-set! hotkey (settings-get manager 'hotkey))
(state-set! language (settings-get manager 'language))
(void engine)
(serve-fds in-fd out-fd))
(dynamic-wind
void
(lambda () (serve-fds in-fd out-fd))
(lambda () (ai-session-close! ai-service))))
Loading
Loading