From c28dbf40debd25786276e6b5601236730f010997 Mon Sep 17 00:00:00 2001
From: Ekaitz Zarraga <ekaitz@elenq.tech>
Date: Wed, 18 Dec 2024 14:30:13 +0100
Subject: simulation: gateways: get radio events

---
 simulation.scm | 49 +++++++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/simulation.scm b/simulation.scm
index a710fa0..ee71d10 100644
--- a/simulation.scm
+++ b/simulation.scm
@@ -1,6 +1,7 @@
 (define-module (simulation)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-69)
   #:use-module (ice-9 atomic)
   #:use-module (ice-9 match)
@@ -46,6 +47,7 @@
 ;; type can be:
 ;; '[up/down]link-start
 ;; '[up/down]link-end
+;; 'interference
 (define-record-type <radio-event>
   (make-radio-event type channel-n frame)
   radio-event?
@@ -156,31 +158,27 @@
 
 (define (make-gateway id upstream downstream)
   (define time-on-air 0.01) ;s (TODO)
+  (define radio-interference-queue '())
 
-  (define (ack-confirmed-data to channel seq-number)
-    (spawn-fiber
-      ;; TODO: answer in the second window??
-      (lambda ()
-        (sleep RECEIVE_DELAY1)
-        (let ((frame (make-frame seq-number to '() 'ack)))
-          (put-message downstream (make-radio-event 'downlink-start channel frame))
-          (sleep time-on-air) ;; TODO: size / data-rate
-          (put-message downstream (make-radio-event 'downlink-end channel frame))))))
+  (define (forward-frame x)
+    (ll "forwarding ~a" x))
 
   ;; Upstream: listen, and answer in new fibers
   (lambda ()
     (forever
-      (let* ((msg (get-message upstream))) ;; TODO: make this get events instead
-        (ll "Gateway ~a: Data #~a got from ~a"
-            id
-            (frame-FCnt msg)
-            (frame-DeviceAddr msg))
-        (match (frame-body msg)
-          ('confirmed-data
-           (ack-confirmed-data (frame-DeviceAddr msg)
-                               1
-                               (frame-FCnt msg))) ;; TODO: wrong!
-          ('unconfirmed-data #f))))))
+      (let* ((ev (get-message upstream)))
+        (match ev
+          (($ <radio-event> 'uplink-start channel-n frame) #f)
+          (($ <radio-event> 'interference channel-n frame)
+           (set! radio-interference-queue (cons ev radio-interference-queue)))
+          (($ <radio-event> 'uplink-end channel-n frame)
+           (let-values (((mine not-mine)
+                         (partition (lambda (x) (eq? (radio-event-frame x)
+                                                     (radio-event-frame ev)))
+                                    radio-interference-queue)))
+             (set! radio-interference-queue not-mine)
+             (when (null? mine) ;; TODO
+               (forward-frame frame)))))))))
 
 
 (define (make-radio in end-devices gateways)
@@ -214,6 +212,9 @@
                (frame-FCnt frame)
                channel-n)
            (use-lorawan-channel! channel-n ev)
+           (hash-table-walk gateways
+                            (lambda (k gateway)
+                              (put-message (device-channel gateway) ev)))
            (when (interference? channel-n)
              ;; TODO: send an 'interference event to the device
              (ll "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")))
@@ -224,6 +225,10 @@
                (frame-FCnt frame)
                channel-n)
            (use-lorawan-channel! channel-n ev)
+           (put-message
+             (device-channel (hash-table-ref end-devices
+                                             (frame-DeviceAddr frame)))
+             ev)
            (when (interference? channel-n)
              ;; TODO: send an 'interference event to the device
              (ll "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")))
@@ -236,7 +241,7 @@
            (release-lorawan-channel! channel-n ev)
            (hash-table-walk gateways
                             (lambda (k gateway)
-                              (put-message (device-channel gateway) frame))))
+                              (put-message (device-channel gateway) ev))))
 
           (($ <radio-event> 'downlink-end channel-n frame)
            (ll "Device ~a ended uplink-frame #~a on channel ~a"
@@ -247,7 +252,7 @@
            (put-message
              (device-channel (hash-table-ref end-devices
                                              (frame-DeviceAddr frame)))
-             frame)))))))
+             ev)))))))
 
 
 (define (make-network-server upstream gateways end-devices)
-- 
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