Initial commit

app/src/main/java/com/aryan/reader/paginatedreader/PaginatedReaderViewModel.kt

@@ -0,0 +1,149 @@
+// PaginatedReaderViewModel.kt
+package com.aryan.reader.paginatedreader
+
+import android.content.Context
+import android.os.Build
+import androidx.annotation.RequiresApi
+import androidx.annotation.VisibleForTesting
+import androidx.compose.runtime.snapshotFlow
+import androidx.compose.ui.text.TextMeasurer
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.unit.Constraints
+import androidx.compose.ui.unit.Density
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.aryan.reader.epub.EpubBook
+import com.aryan.reader.paginatedreader.data.BookCacheDatabase
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.protobuf.ProtoBuf
+
+data class PaginatedReaderUiState(
+    val isLoading: Boolean = true,
+    val totalPageCount: Int = 0,
+    val generation: Int = 0
+)
+
+@OptIn(ExperimentalSerializationApi::class)
+@RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
+class PaginatedReaderViewModel : ViewModel() {
+    @VisibleForTesting
+    internal var paginator: IPaginator? = null
+        private set
+
+    private val _uiState = MutableStateFlow(PaginatedReaderUiState())
+    val uiState: StateFlow<PaginatedReaderUiState> = _uiState.asStateFlow()
+
+    @VisibleForTesting
+    internal fun setPaginatorForTest(testPaginator: IPaginator) {
+        paginator = testPaginator
+        observePaginatorState()
+    }
+
+    companion object {
+        val proto = ProtoBuf { serializersModule = semanticBlockModule }
+    }
+
+    fun initialize(
+        book: EpubBook,
+        textMeasurer: TextMeasurer,
+        textConstraints: Constraints,
+        textStyle: TextStyle,
+        density: Density,
+        isDarkTheme: Boolean,
+        context: Context,
+        initialChapterToPaginate: Int?,
+        mathMLRenderer: MathMLRenderer
+    ) {
+        if (paginator != null) return
+
+        viewModelScope.launch {
+            _uiState.value = _uiState.value.copy(isLoading = true)
+
+            // CSS Parsing and Font Loading
+            val userAgentStylesheet = UserAgentStylesheet.default
+            var allRules = OptimizedCssRules() // CHANGED from: mutableListOf<CssRule>()
+            val allFontFaces = mutableListOf<FontFaceInfo>()
+
+            val uaResult = CssParser.parse(
+                cssContent = userAgentStylesheet,
+                cssPath = null,
+                baseFontSizeSp = textStyle.fontSize.value,
+                density = density.density,
+                constraints = textConstraints,
+                isDarkTheme = isDarkTheme
+            )
+            allRules = allRules.merge(uaResult.rules) // CHANGED
+            allFontFaces.addAll(uaResult.fontFaces)
+
+            book.css.forEach { (path, content) ->
+                val bookCssResult = CssParser.parse(
+                    cssContent = content,
+                    cssPath = path,
+                    baseFontSizeSp = textStyle.fontSize.value,
+                    density = density.density,
+                    constraints = textConstraints,
+                    isDarkTheme = isDarkTheme
+                )
+                allRules = allRules.merge(bookCssResult.rules) // CHANGED
+                allFontFaces.addAll(bookCssResult.fontFaces)
+            }
+            val fontFamilyMap = loadFontFamilies(
+                fontFaces = allFontFaces,
+                extractionPath = book.extractionBasePath
+            )
+            val bookId = book.title
+            val bookCacheDao = BookCacheDatabase.getDatabase(context.applicationContext).bookCacheDao()
+            val newPaginator = BookPaginator(
+                coroutineScope = viewModelScope,
+                chapters = book.chaptersForPagination,
+                textMeasurer = textMeasurer,
+                constraints = textConstraints,
+                textStyle = textStyle,
+                extractionBasePath = book.extractionBasePath,
+                density = density,
+                fontFamilyMap = fontFamilyMap,
+                isDarkTheme = isDarkTheme,
+                bookId = bookId,
+                bookCacheDao = bookCacheDao,
+                proto = proto,
+                initialChapterToPaginate = initialChapterToPaginate ?: 0,
+                bookCss = book.css,
+                userAgentStylesheet = userAgentStylesheet,
+                allFontFaces = allFontFaces,
+                context = context.applicationContext,
+                mathMLRenderer = mathMLRenderer,
+                userTextAlign = null
+            )
+            paginator = newPaginator
+
+            observePaginatorState()
+        }
+    }
+
+    private fun observePaginatorState() {
+        val p = paginator ?: return
+        viewModelScope.launch {
+            snapshotFlow { p.isLoading }.collect {
+                _uiState.value = _uiState.value.copy(isLoading = it)
+            }
+        }
+        viewModelScope.launch {
+            snapshotFlow { p.totalPageCount }.collect {
+                _uiState.value = _uiState.value.copy(totalPageCount = it)
+            }
+        }
+        viewModelScope.launch {
+            snapshotFlow { p.generation }.collect {
+                _uiState.value = _uiState.value.copy(generation = it)
+            }
+        }
+    }
+
+    fun onLinkClick(currentChapterPath: String, href: String, onNavigationComplete: (Int) -> Unit) {
+        paginator?.navigateToHref(currentChapterPath, href, onNavigationComplete)
+    }
+}