feat(settings): enter multiple dictionary source URLs in one sheet

Allow adding and removing URL fields in the Add Source sheet,
validate the whole form at once, and sanitize entered URLs.

app/src/main/java/com/example/research/ui/settings/components/DictionaryUrlInputContent.kt

@@ -3,6 +3,9 @@ package com.example.research.ui.settings.components
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.text.input.InputTransformation
+import androidx.compose.foundation.text.input.TextFieldLineLimits
+import androidx.compose.foundation.text.input.TextFieldState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.ui.res.painterResource
 import androidx.compose.material3.*
@@ -16,7 +19,6 @@ import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.semantics.testTagsAsResourceId
 import androidx.compose.ui.text.input.ImeAction
 import androidx.compose.ui.text.input.KeyboardType
-import androidx.compose.ui.text.input.TextFieldValue
 import androidx.compose.ui.unit.dp
 import com.example.research.R
 import com.example.research.core.domain.model.DictionarySource
@@ -64,6 +66,20 @@ private fun validateDictionaryUrl(context: UrlValidationContext): String? {
     }
 }
 
+private val urlInputTransformation = InputTransformation {
+    val text = toString()
+    val filtered = text
+        .take(2048)
+        .filter { char ->
+            !char.isISOControl() &&
+                char != '\u0000' &&
+                char.code !in 128..<160
+        }
+    if (filtered != text) {
+        replace(0, length, filtered)
+    }
+}
+
 @Composable
 fun DictionaryUrlInputContent(
     existingSources: List<DictionarySource>,
@@ -71,7 +87,7 @@ fun DictionaryUrlInputContent(
     onCancel: () -> Unit,
     modifier: Modifier = Modifier
 ) {
-    val urls = remember { mutableStateListOf(TextFieldValue("")) }
+    val urls = remember { mutableStateListOf(TextFieldState("")) }
     val validationErrors = remember { mutableStateMapOf<Int, String>() }
     val scrollState = rememberScrollState()
     val focusManager = LocalFocusManager.current
@@ -96,8 +112,8 @@ fun DictionaryUrlInputContent(
     // Cache prefixes for all input URLs to avoid repeated extraction during recomposition
     val inputUrlPrefixes = remember {
         derivedStateOf {
-            urls.associate { urlValue ->
+            urls.associate { urlState ->
-                val urlString = urlValue.text.trim()
+                val urlString = urlState.trimmedText()
                 urlString to if (urlString.isNotEmpty()) {
                     DictionarySource.extractPrefix(urlString)
                 } else null
@@ -119,10 +135,10 @@ fun DictionaryUrlInputContent(
             style = MaterialTheme.typography.headlineSmall
         )
 
-        urls.forEachIndexed { index, urlValue ->
+        urls.forEachIndexed { index, urlState ->
             val isLastItem = index == urls.lastIndex
-            
+
-            val urlString = urlValue.text.trim()
+            val urlString = urlState.trimmedText()
             val cachedPrefix = inputUrlPrefixes.value[urlString]
             val realtimeError = remember(urlString, existingPrefixes, urls.size, cachedPrefix) {
                 validateDictionaryUrl(
@@ -130,7 +146,7 @@ fun DictionaryUrlInputContent(
                         url = urlString,
                         existingSources = existingSources,
                         existingPrefixes = existingPrefixes,
-                        urlsInForm = urls.map { it.text.trim() },
+                        urlsInForm = urls.map { it.trimmedText() },
                         urlPrefix = cachedPrefix,
                         errorMessages = errorMessages
                     )
@@ -140,20 +156,8 @@ fun DictionaryUrlInputContent(
             val displayError = validationErrors[index] ?: realtimeError
 
             OutlinedTextField(
-                value = urlValue,
+                state = urlState,
-                onValueChange = { newValue ->
+                inputTransformation = urlInputTransformation,
-                    val filtered = newValue.copy(
-                        text = newValue.text
-                            .take(2048)
-                            .filter { char -> 
-                                !char.isISOControl() && 
-                                char != '\u0000' &&
-                                        char.code !in 128..<160
-                            }
-                    )
-                    urls[index] = filtered
-                    validationErrors.remove(index)
-                },
                 label = { Text(if (index == 0) stringResource(R.string.dictionary_source_url_hint) else "URL ${index + 1}") },
                 isError = displayError != null,
                 supportingText = displayError?.let { { Text(it) } },
@@ -168,7 +172,7 @@ fun DictionaryUrlInputContent(
                             Modifier
                         }
                     ),
-                singleLine = true,
+                lineLimits = TextFieldLineLimits.SingleLine,
                 keyboardOptions = KeyboardOptions(
                     keyboardType = KeyboardType.Uri,
                     imeAction = if (isLastItem) ImeAction.Done else ImeAction.Next
@@ -188,7 +192,7 @@ fun DictionaryUrlInputContent(
 
         TextButton(
             onClick = {
-                urls.add(TextFieldValue(""))
+                urls.add(TextFieldState(""))
             },
             modifier = Modifier
                 .align(Alignment.Start)
@@ -224,8 +228,8 @@ fun DictionaryUrlInputContent(
                     val validUrls = mutableListOf<String>()
                     val seenUrls = mutableSetOf<String>()
 
-                    urls.forEachIndexed { index, urlValue ->
+                    urls.forEachIndexed { index, urlState ->
-                        val urlString = urlValue.text.trim()
+                        val urlString = urlState.trimmedText()
                         if (urlString.isBlank()) {
                             if (urls.size == 1) {
                                 validationErrors[index] = errorMessages.empty
@@ -263,9 +267,9 @@ fun DictionaryUrlInputContent(
                     .weight(1f)
                     .testTag("add_confirm_button")
                     .semantics { testTagsAsResourceId = true },
-                enabled = urls.any { it.text.trim().isNotBlank() } &&
+                enabled = urls.any { it.trimmedText().isNotBlank() } &&
-                         urls.none { urlValue ->
+                         urls.none { urlState ->
-                             val urlString = urlValue.text.trim()
+                             val urlString = urlState.trimmedText()
                              if (urlString.isEmpty()) {
                                  false
                              } else {
@@ -275,7 +279,7 @@ fun DictionaryUrlInputContent(
                                          url = urlString,
                                          existingSources = existingSources,
                                          existingPrefixes = existingPrefixes,
-                                         urlsInForm = urls.map { it.text.trim() },
+                                         urlsInForm = urls.map { it.trimmedText() },
                                          urlPrefix = urlPrefix,
                                          errorMessages = errorMessages
                                      )
@@ -289,3 +293,5 @@ fun DictionaryUrlInputContent(
         Spacer(modifier = Modifier.height(8.dp))
     }
 }
+
+private fun TextFieldState.trimmedText(): String = text.trim().toString()