book-reader/app/src/main/java/com/aryan/reader/epub/MobiParser.kt

312 lines
No EOL
13 KiB
Kotlin

/*
* Episteme Reader - A native Android document reader.
* Copyright (C) 2026 Episteme Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* Electronic mail: epistemereader@gmail.com
*/
package com.aryan.reader.epub
import android.content.Context
import android.graphics.BitmapFactory
import timber.log.Timber
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext
import org.jsoup.Jsoup
import java.io.File
import java.io.InputStream
import java.util.UUID
class MobiParser(private val context: Context) {
private data class ParsedMobiTocEntry(val title: String, val filePosition: Int) : Comparable<ParsedMobiTocEntry> {
override fun compareTo(other: ParsedMobiTocEntry): Int = this.filePosition.compareTo(other.filePosition)
}
// Updated data class to receive the full raw HTML
private data class ParsedMobiData(
val title: String?,
val author: String?,
val publisher: String?,
val rawHtmlContent: String?, // This is the full HTML of the book
val resources: Array<ParsedMobiResource>,
val toc: Array<ParsedMobiTocEntry>?,
val coverImageResourceUid: Int // Use -1 if not found
) {
override fun equals(other: Any?): Boolean {
if (this === other) return true
if (javaClass != other?.javaClass) return false
other as ParsedMobiData
if (title != other.title) return false
if (author != other.author) return false
if (publisher != other.publisher) return false
if (rawHtmlContent != other.rawHtmlContent) return false
if (!resources.contentEquals(other.resources)) return false
if (toc != null) {
if (other.toc == null) return false
if (!toc.contentEquals(other.toc)) return false
} else if (other.toc != null) return false
if (coverImageResourceUid != other.coverImageResourceUid) return false
return true
}
override fun hashCode(): Int {
var result = title?.hashCode() ?: 0
result = 31 * result + (author?.hashCode() ?: 0)
result = 31 * result + (publisher?.hashCode() ?: 0)
result = 31 * result + (rawHtmlContent?.hashCode() ?: 0)
result = 31 * result + resources.contentHashCode()
result = 31 * result + (toc?.contentHashCode() ?: 0)
result = 31 * result + coverImageResourceUid
return result
}
}
private data class ParsedMobiResource(
val uid: Int,
val path: String,
val data: ByteArray,
val mediaType: String
) {
override fun equals(other: Any?): Boolean {
if (this === other) return true
if (javaClass != other?.javaClass) return false
other as ParsedMobiResource
if (uid != other.uid) return false
if (path != other.path) return false
if (!data.contentEquals(other.data)) return false
if (mediaType != other.mediaType) return false
return true
}
override fun hashCode(): Int {
var result = uid
result = 31 * result + path.hashCode()
result = 31 * result + data.contentHashCode()
result = 31 * result + mediaType.hashCode()
return result
}
}
private external fun parseMobiFile(filePath: String): ParsedMobiData?
companion object {
private const val TAG = "MobiParser"
private const val AZW3_TAG = "AZW3_DEBUG"
const val EXTRACTED_EPUB_DIR_NAME = "extracted_epubs"
init {
System.loadLibrary("mobi")
System.loadLibrary("native-lib")
}
}
private fun getBookExtractionDir(bookIdentifier: String): File {
val parentDir = File(context.cacheDir, EXTRACTED_EPUB_DIR_NAME)
if (!parentDir.exists()) {
parentDir.mkdirs()
}
return File(parentDir, bookIdentifier)
}
suspend fun createMobiBook(inputStream: InputStream, originalBookNameHint: String): EpubBook? = withContext(Dispatchers.IO) {
val tempFile = File.createTempFile("temp_mobi_", ".mobi", context.cacheDir)
try {
tempFile.outputStream().use { output ->
inputStream.copyTo(output)
}
Timber.d("MOBI stream saved to temporary file: ${tempFile.absolutePath}")
} catch (e: Exception) {
Timber.e("Failed to write InputStream to temporary file.", e)
tempFile.delete()
return@withContext null
}
val parsedData = try {
parseMobiFile(tempFile.absolutePath)
} catch (e: UnsatisfiedLinkError) {
Timber.e("JNI call failed. Is the native library loaded correctly?", e)
null
} finally {
tempFile.delete()
}
if (parsedData?.rawHtmlContent == null) {
Timber.e("The native parser returned null or empty HTML content. Check JNI logs.")
return@withContext null
}
Timber.d("Received ${parsedData.resources.size} resources from JNI.")
val bookTitle = parsedData.title ?: originalBookNameHint
val bookAuthor = parsedData.author ?: "Unknown Author"
val bookIdentifier = bookTitle.asFileName() + "_" + UUID.randomUUID().toString().substring(0, 8)
val extractionDir = getBookExtractionDir(bookIdentifier)
extractionDir.mkdirs()
// This map is the key. It maps the 1-based sequential index of an image to its new path.
val sequentialImageMap = parsedData.resources
.filter { it.mediaType.startsWith("image/") }
.sortedBy { it.uid } // Sort by UID to ensure order is correct
.mapIndexed { index, resource -> (index + 1) to resource.path }
.toMap()
parsedData.resources.forEach { resource ->
try {
val file = File(extractionDir, resource.path)
file.parentFile?.mkdirs()
file.writeBytes(resource.data)
Timber.d("Wrote resource to disk -> Path: ${file.absolutePath}, Type: ${resource.mediaType}, Size: ${resource.data.size}")
} catch (e: Exception) {
Timber.e("Parser: FAILED to write resource to disk: ${resource.path}", e)
}
}
val cssFlowMap = parsedData.resources
.filter { it.mediaType == "text/css" && it.path.startsWith("flow_") }
.associate {
val index = it.path.removePrefix("flow_").removeSuffix(".css").toIntOrNull() ?: -1
"kindle:flow:${String.format("%04d", index)}?mime=text/css" to it.path
}
val processChapterHtml: (String) -> String = { html ->
val doc = Jsoup.parse(html)
doc.select("link[href]").forEach { link ->
val originalHref = link.attr("href")
cssFlowMap[originalHref]?.let { newPath ->
link.attr("href", newPath)
Timber.d("Rewrote CSS link from '$originalHref' to '$newPath'")
} ?: Timber.w("Could not find mapping for CSS link: $originalHref")
}
doc.select("img").forEach { img ->
val src = img.attr("src")
if (src.startsWith("kindle:embed:")) {
val embedIndexString = src.substringAfter("embed:").substringBefore("?")
val embedIndex = embedIndexString.toIntOrNull()
if (embedIndex != null) {
// **THE FIX**: Use the sequential map, not a UID map
sequentialImageMap[embedIndex]?.let { newPath ->
img.attr("src", newPath)
Timber.d("Rewrote image src from '$src' to '$newPath' using sequential map")
} ?: Timber.w("No resource found for sequential image index: $embedIndex")
}
} else if (img.hasAttr("recindex")) {
val recIndex = img.attr("recindex").toIntOrNull()
if (recIndex != null) {
sequentialImageMap[recIndex]?.let { newPath ->
img.attr("src", newPath)
img.removeAttr("recindex")
} ?: Timber.w("Kotlin: No matching image found for recindex: $recIndex")
}
}
}
doc.outerHtml()
}
// --- CHAPTER SPLITTING LOGIC ---
val rawHtmlBytes = parsedData.rawHtmlContent.toByteArray(Charsets.UTF_8)
val chapterHtmlParts = mutableListOf<Pair<String, String>>()
val sortedToc = parsedData.toc?.sorted()
if (sortedToc != null && sortedToc.isNotEmpty()) {
Timber.d("Splitting content using TOC (${sortedToc.size} entries).")
for (i in sortedToc.indices) {
val tocEntry = sortedToc[i]
val startByte = tocEntry.filePosition
val endByte = if (i + 1 < sortedToc.size) sortedToc[i + 1].filePosition else rawHtmlBytes.size
if (startByte >= endByte) continue
val chapterBytes = rawHtmlBytes.sliceArray(startByte until endByte)
val chapterHtml = String(chapterBytes, Charsets.UTF_8)
chapterHtmlParts.add(Pair(chapterHtml, tocEntry.title))
}
} else {
Timber.d("No TOC found. Falling back to splitting by <mbp:pagebreak/>.")
val parts = parsedData.rawHtmlContent.split("(?i)<mbp:pagebreak\\s*/>".toRegex())
parts.forEachIndexed { index, html ->
if (html.isNotBlank()) {
chapterHtmlParts.add(Pair(html, "Chapter ${index + 1}"))
}
}
}
Timber.d("Successfully split content into ${chapterHtmlParts.size} chapters.")
val epubChapters = chapterHtmlParts.mapIndexedNotNull { index, (chapterHtml, title) ->
try {
val rewrittenHtml = processChapterHtml(chapterHtml)
val doc = Jsoup.parse(rewrittenHtml)
val chapterFileName = "chapter_$index.html"
val chapterFile = File(extractionDir, chapterFileName)
chapterFile.writeText(rewrittenHtml)
EpubChapter(
chapterId = "mobi_chapter_$index",
title = title,
absPath = chapterFileName,
htmlFilePath = chapterFileName,
htmlContent = rewrittenHtml,
plainTextContent = doc.text()
)
} catch (e: Exception) {
Timber.e("Failed to process split chapter $index", e)
null
}
}
val images = parsedData.resources
.filter { it.mediaType.startsWith("image/") }
.map { EpubImage(absPath = it.path, image = it.data) }
val cssContent = parsedData.resources
.filter { it.mediaType == "text/css" }
.associate { it.path to String(it.data, Charsets.UTF_8) }
Timber.d("Extracted ${cssContent.size} CSS files.")
val coverImageBytes = if (parsedData.coverImageResourceUid != -1) {
parsedData.resources.find { it.uid == parsedData.coverImageResourceUid }?.data
} else {
null
}
val coverImage = coverImageBytes?.let { BitmapFactory.decodeByteArray(it, 0, it.size) }
if (coverImage == null) {
Timber.d("Kotlin: Cover image data not found for UID: ${parsedData.coverImageResourceUid}")
}
val finalBook = EpubBook(
fileName = bookTitle.asFileName(),
title = bookTitle,
author = bookAuthor,
language = "en",
coverImage = coverImage,
chapters = epubChapters,
chaptersForPagination = epubChapters,
images = images,
pageList = emptyList(),
extractionBasePath = extractionDir.absolutePath,
css = cssContent
)
Timber.d("Final EpubBook created. CSS map size: ${finalBook.css.size}, Image count: ${finalBook.images.size}")
return@withContext finalBook
}
}