Update gnosis-algorithm-next-interval

- Use keywords!
- Add argument for initial-interval, successful-reviews,
successful-reviews-c, fails-c, fails-t
- Use initial-interval which is could be different for every note,
instead of gnosis-algorithm-interval value.
- Depending on the value of new arguments for total/consecutive
fails/successful reviews calculate a different interval.

2 files changed, 46 insertions, 18 deletions

diff --git a/gnosis-algorithm.el b/gnosis-algorithm.el
index e6a2b1f..48485eb 100644
--- a/gnosis-algorithm.el
+++ b/gnosis-algorithm.el
@@ -97,23 +97,24 @@ The structure of the given date is (YEAR MONTH DAY)."
     (+ ef (car gnosis-algorithm-ef)))
    (t (error "Invalid quality score passed to gnosis-algorithm-e-factor"))))
 
-;; This should be further tested for notes with last-interval of 0 when success 0
-;; For future versions of this algorithm, we should also calculate
-;; failures in row to have "leech" like notes as well.
-;; TODO: Use initial-interval value instead gnosis-algorithm-interval
-(defun gnosis-algorithm-next-interval (last-interval n ef success ff successful-reviews)
+
+(cl-defun gnosis-algorithm-next-interval (&key last-interval review-num ef success failure-factor successful-reviews successful-reviews-c fails-c fails-t initial-interval)
   "Calculate next interval.
 - LAST-INTERVAL : The number of days since the item was last reviewed.
-- N : Number of times the item has been reviewed.
+-review-num: Number of times the item has been reviewed.
 - EF : Easiness Factor.
 - SUCCESS : Success of the recall, ranges from 0 (unsuccessful) to 1
   (successful).
 - FF: Failure factor
 - SUCCESSFUL-REVIEWS : Number of successful reviews.
+- SUCCESSFULL-REVIEWS-C: Successful reviews in a row.
+- FAILS-C: Failed reviews in a row.
+- FAILS-T: Total failed reviews.
+- INITIAL-INTERVAL: Initial intervals for successful reviews.
 
 Returns a list of: (INTERVAL N EF) where,
 - Next review date in (yyyy mm dd) format.
-- N : Incremented by 1.
+- REVIEW-NUM: Incremented by 1.
 - EF : Modified based on the recall success for the item."
   (cl-assert (and (>= success 0)
 		  (<= success 1)))
@@ -132,23 +133,39 @@ Returns a list of: (INTERVAL N EF) where,
            ;; First successful review -> first interval
            ((and (= successful-reviews 0)
 		 (= success 1)
-		 (< n 10)
+		 (< review-num 10)
 		 (< ef 3.0))
-	    (car gnosis-algorithm-interval))
+	    (car initial-interval))
            ;; Second successful review -> second interval
            ((and (= successful-reviews 1)
-		 (< n 10)
+		 (< review-num 10)
 		 (= success 1)
-		 (< ef 3.0))
-	    (cadr gnosis-algorithm-interval))
+		 (< ef 3.0)
+		 (= fails-c 0)
+	    (cadr initial-interval)))
+	   ;; When successful-reviews-c is above 3, use 150% or 180%
+	   ;; of ef depending on the value of successful-reviews
+	   ((and (= success 1)
+		 (>= successful-reviews-c 3))
+	    (* (* ef (if (>= successful-reviews 10) 1.8 1.5)) last-interval))
+	   ((and (= success 0)
+		 (> fails-c 3))
+	    ;; When fails-c is above 3, use 150% or 180% of
+	    ;; failure-factor depending on the value of total failed
+	    ;; reviews
+	    (* (* failure-factor (if (>= fails-t 10) 1.8 1.5)) last-interval))
 	   ;; For custom review sessions.
+	   ;; When successful-reviews-c is above 0, multiply its value
+	   ;; with ef
 	   ((and (= last-interval 0)
 		 (= success 1))
-	    (* ef 1))
+	    (* ef (if (> successful-reviews-c 0)
+		      successful-reviews-c
+		    1)))
 	   ;; For everything else
            (t (if (= success 1)
                   (* ef last-interval)
-                (* ff last-interval))))))
+                (* failure-factor last-interval))))))
     (list (gnosis-algorithm-date (round interval)) next-ef)))
 
 (provide 'gnosis-algorithm)
diff --git a/gnosis.el b/gnosis.el
index 752d828..a1c356e 100644
--- a/gnosis.el
+++ b/gnosis.el
@@ -861,10 +861,21 @@ SUCCESS is a binary value, 1 = success, 0 = failure.
 Returns a list of the form ((yyyy mm dd) ef)."
   (let ((ff gnosis-algorithm-ff)
 	(ef (nth 2 (gnosis-get 'ef 'review `(= id ,id))))
-	(t-success (gnosis-get 't-success 'review-log `(= id ,id))))
-    (gnosis-algorithm-next-interval (gnosis-review--get-offset id)
-				    (gnosis-get 'n 'review-log `(= id ,id))
-				    ef success ff t-success)))
+	(t-success (gnosis-get 't-success 'review-log `(= id ,id)))
+	(c-success (gnosis-get 'c-success 'review-log `(= id ,id)))
+	(c-fails (gnosis-get 'c-fails 'review-log `(= id ,id)))
+	(t-fails (gnosis-get 't-fails 'review-log `(= id ,id)))
+	(initial-interval (gnosis-get 'interval 'review `(= id ,id))))
+    (gnosis-algorithm-next-interval :last-interval (gnosis-review--get-offset id)
+				    :review-num (gnosis-get 'n 'review-log `(= id ,id))
+				    :ef ef
+				    :success success
+				    :failure-factor ff
+				    :successful-reviews t-success
+				    :successful-reviews-c  c-success
+				    :fails-c c-fails
+				    :fail-t t-fails
+				    :initial-interval initial-interval)))
 
 (defun gnosis-review-due-notes--with-tags ()
   "Return a list of due note tags."