Fix parsing of Roman numerals in issue number

proninyaroslav · Jan 17, 2024 · 4378ec3 · 4378ec3
1 parent 79419fd
commit 4378ec3
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Showing 5 changed files with 88 additions and 15 deletions.
diff --git a/app/src/main/java/org/proninyaroslav/opencomicvine/model/Utils.kt b/app/src/main/java/org/proninyaroslav/opencomicvine/model/Utils.kt
@@ -76,17 +76,20 @@ fun issuesCount(firstIssueNumber: String?, lastIssueNumber: String?): Int? {
         return 1
     }
 
-    val firstIssue = if (isSupplement(firstIssueNumber)) {
-        firstIssueNumber?.replace(numberExtractRegex, "")?.toInt()?.plus(1)
-    } else {
-        firstIssueNumber?.toInt()
+    val toInteger = { str: String? ->
+        if (str == null) {
+            null
+        } else if (isSupplement(str)) {
+            str.replace(numberExtractRegex, "").toInt() + 1
+        } else if (str.isRomanNumeral()) {
+            str.romanToArabic()
+        } else {
+            str.toInt()
+        }
     }
 
-    val lastIssue = if (isSupplement(lastIssueNumber)) {
-        lastIssueNumber?.replace(numberExtractRegex, "")?.toInt()?.plus(1)
-    } else {
-        lastIssueNumber?.toInt()
-    }
+    val firstIssue = toInteger(firstIssueNumber?.trim())
+    val lastIssue = toInteger(lastIssueNumber?.trim())
 
     return if (firstIssue != null && lastIssue != null) {
         lastIssue - firstIssue + 1
@@ -96,4 +99,40 @@ fun issuesCount(firstIssueNumber: String?, lastIssueNumber: String?): Int? {
         // At least there are one non-null issue
         1
     }
-}
+}
+
+private val romanCharToValue = mapOf(
+    'I' to 1,
+    'V' to 5,
+    'X' to 10,
+    'L' to 50,
+    'C' to 100,
+    'D' to 500,
+    'M' to 1000,
+)
+private const val romanNumeralRegex = "^M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$"
+
+fun String.romanToArabic(): Int {
+    var arabicValue = 0
+    var lastValue = 0
+
+    uppercase().forEach { char ->
+        val value =
+            romanCharToValue[char] ?: throw IllegalArgumentException("Invalid Roman numeral: $char")
+
+        // If last value is less than current, that means we need to subtract the last value
+        // as it was added previously, then we add the current value minus last value.
+        // For example: IV = 5 - 2*1 = 4 (since I was added previously, we subtract it twice).
+        arabicValue += if (lastValue < value) {
+            value - 2 * lastValue
+        } else {
+            value
+        }
+        lastValue = value
+    }
+
+    return arabicValue
+}
+
+fun String.isRomanNumeral(): Boolean =
+    isNotEmpty() && uppercase().matches(romanNumeralRegex.toRegex())
diff --git a/app/src/main/java/org/proninyaroslav/opencomicvine/types/SearchInfo.kt b/app/src/main/java/org/proninyaroslav/opencomicvine/types/SearchInfo.kt
@@ -22,7 +22,7 @@ package org.proninyaroslav.opencomicvine.types
 import com.squareup.moshi.Json
 import com.squareup.moshi.JsonClass
 import org.proninyaroslav.opencomicvine.model.issuesCount
-import java.util.*
+import java.util.Date
 
 sealed interface SearchInfo {
     val id: Int

diff --git a/app/src/main/java/org/proninyaroslav/opencomicvine/types/VolumeDetails.kt b/app/src/main/java/org/proninyaroslav/opencomicvine/types/VolumeDetails.kt
@@ -23,7 +23,7 @@ import androidx.compose.runtime.Immutable
 import com.squareup.moshi.Json
 import com.squareup.moshi.JsonClass
 import org.proninyaroslav.opencomicvine.model.issuesCount
-import java.util.*
+import java.util.Date
 
 @JsonClass(generateAdapter = true)
 @Immutable

diff --git a/app/src/main/java/org/proninyaroslav/opencomicvine/types/VolumeInfo.kt b/app/src/main/java/org/proninyaroslav/opencomicvine/types/VolumeInfo.kt
@@ -26,7 +26,7 @@ import androidx.room.Ignore
 import com.squareup.moshi.Json
 import com.squareup.moshi.JsonClass
 import org.proninyaroslav.opencomicvine.model.issuesCount
-import java.util.*
+import java.util.Date
 
 @JsonClass(generateAdapter = true)
 @Immutable

diff --git a/app/src/test/java/org/proninyaroslav/opencomicvine/model/UtilsTest.kt b/app/src/test/java/org/proninyaroslav/opencomicvine/model/UtilsTest.kt
@@ -1,7 +1,10 @@
 package org.proninyaroslav.opencomicvine.model
 
-import org.junit.Assert.*
-
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertThrows
+import org.junit.Assert.assertTrue
 import org.junit.Test
 
 class UtilsTest {
@@ -49,5 +52,36 @@ class UtilsTest {
         }
 
         assertEquals(6, issuesCount("1", "5 Suppl."))
+
+        assertEquals(3, issuesCount("1 ", "3 \n"))
+
+        assertEquals(5, issuesCount("I", "V"))
+    }
+
+    @Test
+    fun isRomanNumeral() {
+        val validRoman = "MCMXCIV"
+        val invalidRoman = "MCMZ"
+
+        assertTrue(validRoman.isRomanNumeral())
+
+        assertFalse(invalidRoman.isRomanNumeral())
+
+        assertFalse("".isRomanNumeral())
+
+        assertFalse("ABC".isRomanNumeral())
+
+        assertFalse("123".isRomanNumeral())
+    }
+
+    @Test
+    fun romanToArabic() {
+        assertEquals(1994, "MCMXCIV".romanToArabic())
+
+        assertThrows(IllegalArgumentException::class.java) { "".romanToArabic() }
+
+        assertThrows(IllegalArgumentException::class.java) { "ABC".romanToArabic() }
+
+        assertThrows(IllegalArgumentException::class.java) { "123".romanToArabic() }
     }
 }