Fix case-insensitive search excerpt handling

android/build.gradle

@@ -73,6 +73,8 @@ dependencies {
     implementation 'com.github.MikeOrtiz:TouchImageView:3.6'
 
 // Testing
+    testImplementation "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
+    testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'androidx.test.ext:junit:1.2.1'
     androidTestImplementation 'androidx.test.espresso:espresso-contrib:3.6.1'
     androidTestImplementation "androidx.test:core:1.6.1"

android/src/main/kotlin/org/ligi/survivalmanual/functions/Search.kt

@@ -9,9 +9,22 @@ private const val EXCERPT_SIZE = 100
 
 @VisibleForTesting
 fun getExcerpt(text: String, term: String): String {
-    val index = text.indexOf(term)
-    val rough = text.substring(max(index - EXCERPT_SIZE, 0)..(index + EXCERPT_SIZE).coerceAtMost(text.lastIndex))
-    return rough.substring(rough.indexOf(" ")..rough.lastIndexOf(" "))
+    val index = text.indexOf(term, ignoreCase = true)
+    if (index == -1) {
+        return text.take(EXCERPT_SIZE * 2).trim()
+    }
+
+    val startBound = max(index - EXCERPT_SIZE, 0)
+    val endBound = (index + term.length + EXCERPT_SIZE).coerceAtMost(text.length)
+
+    val excerptStart = text.lastIndexOf(' ', startBound).takeIf { it >= 0 }?.plus(1) ?: startBound
+    val excerptEnd = text.indexOf(' ', endBound).takeIf { it >= 0 } ?: endBound
+
+    if (excerptEnd > excerptStart) {
+        return text.substring(excerptStart, excerptEnd).trim()
+    }
+
+    return text.substring(startBound, endBound).trim()
 }
 
 interface Search {

android/src/test/java/org/ligi/survivalmanual/functions/SearchTest.kt

@@ -0,0 +1,27 @@
+package org.ligi.survivalmanual.functions
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class SearchTest {
+    @Test
+    fun `excerpt uses case insensitive matches`() {
+        val text = "This is a Sample text about survival readiness."
+        val term = "sample"
+
+        val excerpt = getExcerpt(text, term)
+
+        assertTrue(excerpt.contains("Sample", ignoreCase = false), "Excerpt should contain the original casing of the match")
+    }
+
+    @Test
+    fun `excerpt handles text without spaces`() {
+        val text = "SurvivalManual"
+        val term = "manual"
+
+        val excerpt = getExcerpt(text, term)
+
+        assertEquals(text, excerpt, "Excerpt should fall back to the available text when no spaces are present")
+    }
+}