From 222d4375ee9c5728b028fe5bde27249aa9912c3a Mon Sep 17 00:00:00 2001
From: Kistaro Windrider <kistaro@gmail.com>
Date: Sat, 1 Apr 2023 19:31:50 -0700
Subject: [PATCH] deck.Strip -- remove cards

Given a function that identifies cards to remove, remove them from the deck. This can be used to find and strip out cards that are only conditionally appropriate (and aren't appropriate anymore).
---
 cardsim/deck.go | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/cardsim/deck.go b/cardsim/deck.go
index 28214a6..b888150 100644
--- a/cardsim/deck.go
+++ b/cardsim/deck.go
@@ -264,9 +264,33 @@ func (d *Deck[C]) ShuffleTop(frac float64) error {
 	return d.ShuffleRange(0.0, frac)
 }
 
-// Shufflebottom uses ShuffleRange to shuffle the bottom frac (between 0.0 and
+// ShuffleBottom uses ShuffleRange to shuffle the bottom frac (between 0.0 and
 // 1.0) of the deck. See ShuffleRange and ShufflePart for information on
 // rounding and warnings.
 func (d *Deck[C]) ShuffleBottom(frac float64) error {
 	return d.ShuffleRange(frac, 1.0)
 }
+
+// Strip removes all cards from the deck where shouldRemove returns true.
+// shouldRemove is provided with each card in the deck and its index.
+// It returns how many cards were stripped from the deck.
+func (d *Deck[C]) Strip(shouldRemove func(idx int, c Card[C]) bool) int {
+	stripped := 0
+	startStripRange := -1
+	for i := 0; i < len(d.cards); i++ {
+		if shouldRemove(i, d.cards[i]) {
+			stripped++
+			if startStripRange < 0 {
+				startStripRange = i
+			}
+		} else if startStripRange >= 0 {
+			d.cards = DeleteNFrom(d.cards, startStripRange, i-startStripRange)
+			i = startStripRange
+			startStripRange = -1
+		}
+	}
+	if startStripRange >= 0 {
+		d.cards = d.cards[:startStripRange]
+	}
+	return stripped
+}