1 files changed, 69 insertions, 0 deletions
diff --git a/src/main/kotlin/features/texturepack/RarityMatcher.kt b/src/main/kotlin/features/texturepack/RarityMatcher.kt
new file mode 100644
index 0000000..634a171
--- /dev/null
+++ b/src/main/kotlin/features/texturepack/RarityMatcher.kt
@@ -0,0 +1,69 @@
+
+package moe.nea.firmament.features.texturepack
+
+import com.google.gson.JsonElement
+import io.github.moulberry.repo.data.Rarity
+import moe.nea.firmament.util.useMatch
+
+abstract class RarityMatcher {
+    abstract fun match(rarity: Rarity): Boolean
+
+    companion object {
+        fun parse(jsonElement: JsonElement): RarityMatcher {
+            val string = jsonElement.asString
+            val range = parseRange(string)
+            if (range != null) return range
+            return Exact(Rarity.valueOf(string))
+        }
+
+        private val allRarities = Rarity.entries.joinToString("|", "(?:", ")")
+        private val intervalSpec =
+            "(?<beginningOpen>[\\[\\(])(?<beginning>$allRarities)?,(?<ending>$allRarities)?(?<endingOpen>[\\]\\)])"
+                .toPattern()
+
+        fun parseRange(string: String): RangeMatcher? {
+            intervalSpec.useMatch<Nothing>(string) {
+                // Open in the set-theory sense, meaning does not include its end.
+                val beginningOpen = group("beginningOpen") == "("
+                val endingOpen = group("endingOpen") == ")"
+                val beginning = group("beginning")?.let(Rarity::valueOf)
+                val ending = group("ending")?.let(Rarity::valueOf)
+                return RangeMatcher(beginning, !beginningOpen, ending, !endingOpen)
+            }
+            return null
+        }
+
+    }
+
+    data class Exact(val expected: Rarity) : RarityMatcher() {
+        override fun match(rarity: Rarity): Boolean {
+            return rarity == expected
+        }
+    }
+
+    data class RangeMatcher(
+        val beginning: Rarity?,
+        val beginningInclusive: Boolean,
+        val ending: Rarity?,
+        val endingInclusive: Boolean,
+    ) : RarityMatcher() {
+        override fun match(rarity: Rarity): Boolean {
+            if (beginning != null) {
+                if (beginningInclusive) {
+                    if (rarity < beginning) return false
+                } else {
+                    if (rarity <= beginning) return false
+                }
+            }
+            if (ending != null) {
+                if (endingInclusive) {
+                    if (rarity > ending) return false
+                } else {
+                    if (rarity >= ending) return false
+                }
+            }
+            return true
+        }
+    }
+
+}