feat: current toc item and page information as a stream

.vscode/settings.json

@@ -44,6 +44,7 @@
   "cSpell.words": [
     "acsm",
     "androidx",
+    "animejs",
     "ascii",
     "Ascii",
     "charsets",

bin/install

@@ -12,4 +12,5 @@ if [ "$(uname)" == "Darwin" ]; then
 fi
 
 $PROJECT_ROOT/flutter_readium/bin/build_helper_scripts.sh
+$PROJECT_ROOT/bin/build_js
 $PROJECT_ROOT/bin/update_web_example

flutter_readium/android/src/main/kotlin/dk/nota/flutter_readium/ReadiumExtensions.kt

@@ -18,11 +18,17 @@ import org.readium.r2.shared.publication.Manifest
 import org.readium.r2.shared.publication.Publication
 import org.readium.r2.shared.publication.flatten
 import org.readium.r2.shared.publication.html.cssSelector
+import org.readium.r2.shared.publication.services.content.Content
+import org.readium.r2.shared.publication.services.content.ContentService
 import org.readium.r2.shared.util.Try
+import org.readium.r2.shared.util.Url
 import org.readium.r2.shared.util.mediatype.MediaType
 import org.readium.r2.shared.util.resource.Resource
 import org.readium.r2.shared.util.resource.TransformingResource
 import org.readium.r2.shared.util.resource.filename
+import java.util.Locale
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.seconds
 import org.readium.r2.navigator.preferences.Color as ReadiumColor
 
 private const val TAG = "ReadiumExtensions"
@@ -150,10 +156,10 @@ suspend fun Publication.getMediaOverlays(): List<FlutterMediaOverlay?>? {
     if (!hasMediaOverlays()) return null
 
     // Flatten TOC for title lookup
-    val toc = tableOfContents.flatten().map { Pair(it.href.toString(), it.title) }
+    val toc = tableOfContents.flatten().map { Pair(it.href.toString(), it) }
 
     // Remember last matched TOC item for titles
-    var lastTocMatch: Pair<String, String?>? = null
+    var lastTocMatch: Pair<String, Link>? = null
 
     return this.readingOrder.mapNotNull { r ->
         r.alternates.find { a ->
@@ -163,7 +169,7 @@ suspend fun Publication.getMediaOverlays(): List<FlutterMediaOverlay?>? {
         val jsonString =
             this.get(link)?.read()?.getOrNull()?.let { String(it) } ?: return@mapIndexedNotNull null
         val jsonObject = JSONObject(jsonString)
-        FlutterMediaOverlay.fromJson(jsonObject, index + 1, link.title ?: "")
+        FlutterMediaOverlay.fromJson(jsonObject, index + 1, null, link.title ?: "")
     }
         .map { mo ->
             val items = mo.items.map { item ->
@@ -174,9 +180,15 @@ suspend fun Publication.getMediaOverlays(): List<FlutterMediaOverlay?>? {
 
                 if (match?.second != null) {
                     lastTocMatch = match
-                    item.copy(title = match.second ?: "")
+                    item.copy(
+                        title = match.second.title ?: "",
+                        tocHref = match.second.href.resolve()
+                    )
                 } else if (lastTocMatch?.second != null && lastTocMatch.first.substringBefore("#") == item.textFile) {
-                    item.copy(title = lastTocMatch.second ?: "")
+                    item.copy(
+                        title = lastTocMatch.second.title ?: "",
+                        tocHref = lastTocMatch.second.href.resolve()
+                    )
                 } else {
                     item
                 }
@@ -247,7 +259,127 @@ fun Locator.getTextId(): String? {
 fun Locator.copyWithTimeFragment(time: Double): Locator {
     return copy(
         locations = locations.copy(
-            fragments = listOf("${time}")
+            fragments = listOf("t=${time}")
         )
     )
 }
+
+/**
+ * Helper for getting all cssSelectors for a HTML document.
+ */
+suspend fun Publication.findAllCssSelectors(href: Url): List<String>? {
+    if (!conformsTo(Publication.Profile.EPUB)) {
+        Log.d(TAG, ":findAllCssSelectors - this only works for an EPUB Profile")
+        return null
+    }
+
+    val contentService = findService(ContentService::class) ?: run {
+        Log.d(TAG, ":findAllCssSelectors - no content service found")
+        return null
+    }
+
+    val cleanHref = href.cleanHref()
+
+    val ids = arrayListOf<String>()
+    for (element in contentService.content(
+        Locator(
+            href = cleanHref,
+            mediaType = MediaType.XHTML
+        )
+    )) {
+        if (element !is Content.TextElement) {
+            continue
+        }
+
+        if (element.locator.href.cleanHref().path != cleanHref.path) {
+            // We iterated to the next document, stopping
+            break
+        }
+
+        // We are only interested in #id type of cssSelectors.
+        val cssSelector =
+            element.locator.locations.cssSelector?.takeIf { it.startsWith("#") } ?: continue
+
+        ids.add(cssSelector)
+    }
+
+    return ids
+}
+
+/**
+ * Find the cssSelector for a locator. If it already have one return it, otherwise we need to look it up.
+ */
+suspend fun Publication.findCssSelectorForLocator(locator: Locator): String? {
+    // If our locator already has a cssSelector, use it.
+    locator.locations.cssSelector?.takeIf { it.startsWith("#") }?.let { return it }
+
+    val contentService = findService(ContentService::class) ?: run {
+        Log.d(TAG, ":findCssSelectorForLocator - no content service found")
+        return null
+    }
+
+    val cleanHref = locator.href.cleanHref()
+
+    val locatorProgress = locator.locations.progression ?: 0.0
+    var cssSelector: String? = null
+    for (element in contentService.content(locator)) {
+        if (element !is Content.TextElement) {
+            continue
+        }
+
+        if (element.locator.href.cleanHref().path != cleanHref.path) {
+            // We iterated to the next document, stopping
+            break
+        }
+
+        val eCssSelector = element.locator.locations.cssSelector?.takeIf { it.startsWith("#") }
+        if (eCssSelector == null || !eCssSelector.startsWith("#")) continue
+
+        val progression = element.locator.locations.progression ?: 0.0
+        if (progression > locatorProgress && cssSelector != null) {
+            break
+        }
+
+        cssSelector = eCssSelector
+    }
+
+    return cssSelector?.takeIf { it.isNotEmpty() && it.startsWith("#") }
+}
+
+/**
+ * Remove query and fragment from the Url
+ */
+fun Url.cleanHref() = removeFragment().removeQuery()
+
+val Href.fragmentParameters: Map<String, String>
+    get() = resolve()
+        .fragment
+        // Splits parameters
+        ?.split("&")
+        ?.filter { !it.startsWith("=") }
+        ?.map { it.split("=") }
+        // Only keep named parameters
+        ?.filter { it.size == 2 }
+        ?.associate { it[0].trim().lowercase(Locale.ROOT) to it[1].trim() }
+        ?: mapOf()
+
+
+/**
+ * Media fragment, used for example in audiobooks.
+ *
+ * https://www.w3.org/TR/media-frags/
+ */
+val Href.time: Duration?
+    get() =
+        fragmentParameters["t"]?.toIntOrNull()?.seconds
+
+/**
+ * Returns a list of `Link` after flattening the `children`.
+ */
+fun List<Link>.flattenChildren(): List<Link> {
+    fun Link.flattenChildren(): List<Link> {
+        return listOf(this) + children.flattenChildren()
+    }
+
+    return flatMap { it.flattenChildren() }
+}

flutter_readium/android/src/main/kotlin/dk/nota/flutter_readium/ReadiumReader.kt

@@ -40,6 +40,7 @@ import org.readium.navigator.media.tts.android.AndroidTtsPreferences
 import org.readium.navigator.media.tts.android.AndroidTtsSettings
 import org.readium.r2.navigator.Decoration
 import org.readium.r2.navigator.epub.EpubPreferences
+import org.readium.r2.navigator.extensions.time
 import org.readium.r2.shared.ExperimentalReadiumApi
 import org.readium.r2.shared.InternalReadiumApi
 import org.readium.r2.shared.publication.Link
@@ -176,9 +177,6 @@ object ReadiumReader : TimebasedNavigator.TimebasedListener, EpubNavigator.Visua
 
     private var epubNavigator: EpubNavigator? = null
 
-    val epubCurrentLocator: Locator?
-        get() = epubNavigator?.currentLocator?.value
-
     private var _audioPreferences: FlutterAudioPreferences = FlutterAudioPreferences()
 
     /** Current audio preferences (defaults if audio hasn't been enabled yet). */
@@ -398,6 +396,13 @@ object ReadiumReader : TimebasedNavigator.TimebasedListener, EpubNavigator.Visua
             state[currentPublicationUrlKey] = value
         }
 
+    /***
+     * For EPUB profile, maps document [Url] to a list of all the cssSelectors in the document.
+     *
+     * This is used to find the current toc item.
+     */
+    private var currentPublicationCssSelectorMap: MutableMap<Url, List<String>>? = null
+
     /**
      * Sets the headers used in the HTTP requests for fetching publication resources, including
      * resources in already created `Publication` objects.
@@ -579,6 +584,7 @@ object ReadiumReader : TimebasedNavigator.TimebasedListener, EpubNavigator.Visua
         mainScope.async {
             _currentPublication?.close()
             _currentPublication = null
+            currentPublicationCssSelectorMap = null
 
             ttsNavigator?.dispose()
             ttsNavigator = null
@@ -608,12 +614,13 @@ object ReadiumReader : TimebasedNavigator.TimebasedListener, EpubNavigator.Visua
         // TODO: Notify client
     }
 
+    @OptIn(InternalReadiumApi::class)
     override fun onTimebasedCurrentLocatorChanges(
         locator: Locator, currentReadingOrderLink: Link?
     ) {
         val duration = currentReadingOrderLink?.duration
         val timeOffset =
-            locator.locations.fragments.find { it.startsWith("t=") }?.substring(2)?.toDoubleOrNull()
+            locator.locations.time?.inWholeSeconds?.toDouble()
                 ?: (duration?.let { duration ->
                     locator.locations.progression?.let { prog -> duration * prog }
                 })
@@ -631,6 +638,63 @@ object ReadiumReader : TimebasedNavigator.TimebasedListener, EpubNavigator.Visua
         currentReaderWidget?.go(locator, true)
     }
 
+    /**
+     * Find the current table of content item from a locator.
+     */
+    suspend fun epubFindCurrentToc(locator: Locator): Locator {
+        val publication = currentPublication ?: run {
+            Log.e(TAG, ":epubFindCurrentToc - no currentPublication")
+            return locator
+        }
+
+        if (!publication.conformsTo(Publication.Profile.EPUB)) {
+            Log.d(TAG, ":epubFindCurrentToc - not an EPUB profile")
+            return locator
+        }
+
+        val cssSelector = publication.findCssSelectorForLocator(locator) ?: run {
+            Log.e(TAG, ":epubFindCurrentToc - missing cssSelector in locator")
+            return locator
+        }
+
+        val resultLocator =
+            locator.copyWithLocations(
+                otherLocations = locator.locations.otherLocations +
+                    ("cssSelector" to cssSelector)
+            )
+
+        val cleanHref = resultLocator.href.cleanHref()
+        val tocLinks = publication.tableOfContents.flattenChildren().filter {
+            it.href.resolve().cleanHref().path == cleanHref.path
+        }
+
+        val documentCssSelectors = epubGetAllDocumentCssSelectors(resultLocator.href)
+        val idx = documentCssSelectors.indexOf(cssSelector).takeIf { it > -1 } ?: run {
+            // cssSelector wasn't found in the list of document cssSelectors, best effort is to assume first
+            Log.d(
+                TAG,
+                ":epubFindCurrentToc cssSelector:${cssSelector} not found in contentIds, assume idx = 0"
+            )
+            0
+        }
+
+        val toc =
+            tocLinks.associateBy { documentCssSelectors.indexOf("#${it.href.resolve().fragment}") }
+
+        val tocItem = toc.entries.lastOrNull { it.key <= idx }?.value
+            ?: toc.entries.firstOrNull()?.value ?: run {
+                Log.d(TAG, ":epubFindCurrentToc - no tocItem found")
+                return resultLocator
+            }
+
+        return resultLocator.copy(
+            title = tocItem.title
+        ).copyWithLocations(
+            otherLocations = resultLocator.locations.otherLocations +
+                ("toc" to tocItem.href.resolve().toString())
+        )
+    }
+
     @OptIn(InternalReadiumApi::class)
     suspend fun epubEnable(
         initialLocator: Locator?,
@@ -716,7 +780,8 @@ object ReadiumReader : TimebasedNavigator.TimebasedListener, EpubNavigator.Visua
                 )
             },
             { language, availableVoices -> null },
-            AndroidTtsPreferences())?.voices ?: setOf()
+            AndroidTtsPreferences()
+        )?.voices ?: setOf()
     }
 
     fun ttsGetPreferences(): FlutterTtsPreferences? {
@@ -929,10 +994,26 @@ object ReadiumReader : TimebasedNavigator.TimebasedListener, EpubNavigator.Visua
     }
 
     /**
-     * Get locator fragments from EPUB navigator.
+     * Get first visible locator from the EPUB navigator.
+     */
+    suspend fun firstVisibleElementLocator(): Locator? {
+        return epubNavigator?.firstVisibleElementLocator()
+    }
+
+    /**
+     * Get all cssSelectors for an EPUB file.
+     * Note: These only includes text elements, so body, page breaks etc are not included.
      */
-    suspend fun epubGetLocatorFragments(locator: Locator): Locator? {
-        return epubNavigator?.getLocatorFragments(locator)
+    suspend fun epubGetAllDocumentCssSelectors(href: Url): List<String> {
+        val cssSelectorMap = currentPublicationCssSelectorMap ?: mutableMapOf()
+        currentPublicationCssSelectorMap = cssSelectorMap
+
+        val cleanHref = href.cleanHref()
+        return cssSelectorMap.getOrPut(cleanHref) {
+            currentPublication?.findAllCssSelectors(
+                cleanHref
+            ) ?: listOf()
+        }
     }
 
     /**