package eu.kanade.tachiyomi.source

import android.content.Context
import com.github.junrar.Archive
import eu.kanade.tachiyomi.R
import eu.kanade.tachiyomi.source.model.Filter
import eu.kanade.tachiyomi.source.model.FilterList
import eu.kanade.tachiyomi.source.model.MangasPage
import eu.kanade.tachiyomi.source.model.Page
import eu.kanade.tachiyomi.source.model.SChapter
import eu.kanade.tachiyomi.source.model.SManga
import eu.kanade.tachiyomi.util.chapter.ChapterRecognition
import eu.kanade.tachiyomi.util.lang.compareToCaseInsensitiveNaturalOrder
import eu.kanade.tachiyomi.util.storage.DiskUtil
import eu.kanade.tachiyomi.util.storage.EpubFile
import eu.kanade.tachiyomi.util.system.ImageUtil
import eu.kanade.tachiyomi.util.system.logcat
import kotlinx.serialization.json.Json
import kotlinx.serialization.json.JsonObject
import kotlinx.serialization.json.contentOrNull
import kotlinx.serialization.json.decodeFromStream
import kotlinx.serialization.json.intOrNull
import kotlinx.serialization.json.jsonArray
import kotlinx.serialization.json.jsonPrimitive
import logcat.LogPriority
import rx.Observable
import uy.kohesive.injekt.injectLazy
import java.io.File
import java.io.FileInputStream
import java.io.InputStream
import java.util.Locale
import java.util.concurrent.TimeUnit
import java.util.zip.ZipFile

class LocalSource(private val context: Context) : CatalogueSource {
    companion object {
        const val ID = 0L
        const val HELP_URL = "https://tachiyomi.org/help/guides/local-manga/"

        private val SUPPORTED_ARCHIVE_TYPES = setOf("zip", "rar", "cbr", "cbz", "epub")

        private val LATEST_THRESHOLD = TimeUnit.MILLISECONDS.convert(7, TimeUnit.DAYS)

        fun updateCover(context: Context, manga: SManga, input: InputStream): File? {
            val dir = getBaseDirectories(context).firstOrNull()
            if (dir == null) {
                input.close()
                return null
            }
            val cover = getCoverFile(File("${dir.absolutePath}/${manga.url}"))

            if (cover != null && cover.exists()) {
                // It might not exist if using the external SD card
                cover.parentFile?.mkdirs()
                input.use {
                    cover.outputStream().use {
                        input.copyTo(it)
                    }
                }
            }
            return cover
        }

        /**
         * Returns valid cover file inside [parent] directory.
         */
        private fun getCoverFile(parent: File): File? {
            return parent.listFiles()?.find { it.nameWithoutExtension == "cover" }?.takeIf {
                it.isFile && ImageUtil.isImage(it.name) { it.inputStream() }
            }
        }

        private fun getBaseDirectories(context: Context): List<File> {
            val c = context.getString(R.string.app_name) + File.separator + "local"
            return DiskUtil.getExternalStorages(context).map { File(it.absolutePath, c) }
        }
    }

    private val json: Json by injectLazy()

    override val id = ID
    override val name = context.getString(R.string.local_source)
    override val lang = ""
    override val supportsLatest = true

    override fun toString() = context.getString(R.string.local_source)

    override fun fetchPopularManga(page: Int) = fetchSearchManga(page, "", POPULAR_FILTERS)

    override fun fetchSearchManga(page: Int, query: String, filters: FilterList): Observable<MangasPage> {
        val baseDirs = getBaseDirectories(context)

        val time = if (filters === LATEST_FILTERS) System.currentTimeMillis() - LATEST_THRESHOLD else 0L
        var mangaDirs = baseDirs
            .asSequence()
            .mapNotNull { it.listFiles()?.toList() }
            .flatten()
            .filter { it.isDirectory }
            .filterNot { it.name.startsWith('.') }
            .filter { if (time == 0L) it.name.contains(query, ignoreCase = true) else it.lastModified() >= time }
            .distinctBy { it.name }

        val state = ((if (filters.isEmpty()) POPULAR_FILTERS else filters)[0] as OrderBy).state
        when (state?.index) {
            0 -> {
                mangaDirs = if (state.ascending) {
                    mangaDirs.sortedBy { it.name.lowercase(Locale.ENGLISH) }
                } else {
                    mangaDirs.sortedByDescending { it.name.lowercase(Locale.ENGLISH) }
                }
            }
            1 -> {
                mangaDirs = if (state.ascending) {
                    mangaDirs.sortedBy(File::lastModified)
                } else {
                    mangaDirs.sortedByDescending(File::lastModified)
                }
            }
        }

        val mangas = mangaDirs.map { mangaDir ->
            SManga.create().apply {
                title = mangaDir.name
                url = mangaDir.name

                // Try to find the cover
                for (dir in baseDirs) {
                    val cover = getCoverFile(File("${dir.absolutePath}/$url"))
                    if (cover != null && cover.exists()) {
                        thumbnail_url = cover.absolutePath
                        break
                    }
                }

                val chapters = fetchChapterList(this).toBlocking().first()
                if (chapters.isNotEmpty()) {
                    val chapter = chapters.last()
                    val format = getFormat(chapter)
                    if (format is Format.Epub) {
                        EpubFile(format.file).use { epub ->
                            epub.fillMangaMetadata(this)
                        }
                    }

                    // Copy the cover from the first chapter found.
                    if (thumbnail_url == null) {
                        try {
                            val dest = updateCover(chapter, this)
                            thumbnail_url = dest?.absolutePath
                        } catch (e: Exception) {
                            logcat(LogPriority.ERROR, e)
                        }
                    }
                }
            }
        }

        return Observable.just(MangasPage(mangas.toList(), false))
    }

    override fun fetchLatestUpdates(page: Int) = fetchSearchManga(page, "", LATEST_FILTERS)

    override fun fetchMangaDetails(manga: SManga): Observable<SManga> {
        getBaseDirectories(context)
            .asSequence()
            .mapNotNull { File(it, manga.url).listFiles()?.toList() }
            .flatten()
            .firstOrNull { it.extension == "json" }
            ?.apply {
                val obj = json.decodeFromStream<JsonObject>(inputStream())

                manga.title = obj["title"]?.jsonPrimitive?.contentOrNull ?: manga.title
                manga.author = obj["author"]?.jsonPrimitive?.contentOrNull ?: manga.author
                manga.artist = obj["artist"]?.jsonPrimitive?.contentOrNull ?: manga.artist
                manga.description = obj["description"]?.jsonPrimitive?.contentOrNull ?: manga.description
                manga.genre = obj["genre"]?.jsonArray?.joinToString(", ") { it.jsonPrimitive.content }
                    ?: manga.genre
                manga.status = obj["status"]?.jsonPrimitive?.intOrNull ?: manga.status
            }

        return Observable.just(manga)
    }

    override fun fetchChapterList(manga: SManga): Observable<List<SChapter>> {
        val chapters = getBaseDirectories(context)
            .asSequence()
            .mapNotNull { File(it, manga.url).listFiles()?.toList() }
            .flatten()
            .filter { it.isDirectory || isSupportedFile(it.extension) }
            .map { chapterFile ->
                SChapter.create().apply {
                    url = "${manga.url}/${chapterFile.name}"
                    name = if (chapterFile.isDirectory) {
                        chapterFile.name
                    } else {
                        chapterFile.nameWithoutExtension
                    }
                    date_upload = chapterFile.lastModified()

                    val format = getFormat(this)
                    if (format is Format.Epub) {
                        EpubFile(format.file).use { epub ->
                            epub.fillChapterMetadata(this)
                        }
                    }

                    val chapNameCut = stripMangaTitle(name, manga.title)
                    if (chapNameCut.isNotEmpty()) name = chapNameCut
                    ChapterRecognition.parseChapterNumber(this, manga)
                }
            }
            .sortedWith { c1, c2 ->
                val c = c2.chapter_number.compareTo(c1.chapter_number)
                if (c == 0) c2.name.compareToCaseInsensitiveNaturalOrder(c1.name) else c
            }
            .toList()

        return Observable.just(chapters)
    }

    /**
     * Strips the manga title from a chapter name, matching only based on alphanumeric and whitespace
     * characters.
     */
    private fun stripMangaTitle(chapterName: String, mangaTitle: String): String {
        var chapterNameIndex = 0
        var mangaTitleIndex = 0
        while (chapterNameIndex < chapterName.length && mangaTitleIndex < mangaTitle.length) {
            val chapterChar = chapterName[chapterNameIndex]
            val mangaChar = mangaTitle[mangaTitleIndex]
            if (!chapterChar.equals(mangaChar, true)) {
                val invalidChapterChar = !chapterChar.isLetterOrDigit() && !chapterChar.isWhitespace()
                val invalidMangaChar = !mangaChar.isLetterOrDigit() && !mangaChar.isWhitespace()

                if (!invalidChapterChar && !invalidMangaChar) {
                    return chapterName
                }

                if (invalidChapterChar) {
                    chapterNameIndex++
                }

                if (invalidMangaChar) {
                    mangaTitleIndex++
                }
            } else {
                chapterNameIndex++
                mangaTitleIndex++
            }
        }

        return chapterName.substring(chapterNameIndex).trimStart(' ', '-', '_', ',', ':')
    }

    override fun fetchPageList(chapter: SChapter): Observable<List<Page>> {
        return Observable.error(Exception("Unused"))
    }

    private fun isSupportedFile(extension: String): Boolean {
        return extension.lowercase() in SUPPORTED_ARCHIVE_TYPES
    }

    fun getFormat(chapter: SChapter): Format {
        val baseDirs = getBaseDirectories(context)

        for (dir in baseDirs) {
            val chapFile = File(dir, chapter.url)
            if (!chapFile.exists()) continue

            return getFormat(chapFile)
        }
        throw Exception(context.getString(R.string.chapter_not_found))
    }

    private fun getFormat(file: File) = with(file) {
        when {
            isDirectory -> Format.Directory(this)
            extension.equals("zip", true) || extension.equals("cbz", true) -> Format.Zip(this)
            extension.equals("rar", true) || extension.equals("cbr", true) -> Format.Rar(this)
            extension.equals("epub", true) -> Format.Epub(this)
            else -> throw Exception(context.getString(R.string.local_invalid_format))
        }
    }

    private fun updateCover(chapter: SChapter, manga: SManga): File? {
        return when (val format = getFormat(chapter)) {
            is Format.Directory -> {
                val entry = format.file.listFiles()
                    ?.sortedWith { f1, f2 -> f1.name.compareToCaseInsensitiveNaturalOrder(f2.name) }
                    ?.find { !it.isDirectory && ImageUtil.isImage(it.name) { FileInputStream(it) } }

                entry?.let { updateCover(context, manga, it.inputStream()) }
            }
            is Format.Zip -> {
                ZipFile(format.file).use { zip ->
                    val entry = zip.entries().toList()
                        .sortedWith { f1, f2 -> f1.name.compareToCaseInsensitiveNaturalOrder(f2.name) }
                        .find { !it.isDirectory && ImageUtil.isImage(it.name) { zip.getInputStream(it) } }

                    entry?.let { updateCover(context, manga, zip.getInputStream(it)) }
                }
            }
            is Format.Rar -> {
                Archive(format.file).use { archive ->
                    val entry = archive.fileHeaders
                        .sortedWith { f1, f2 -> f1.fileName.compareToCaseInsensitiveNaturalOrder(f2.fileName) }
                        .find { !it.isDirectory && ImageUtil.isImage(it.fileName) { archive.getInputStream(it) } }

                    entry?.let { updateCover(context, manga, archive.getInputStream(it)) }
                }
            }
            is Format.Epub -> {
                EpubFile(format.file).use { epub ->
                    val entry = epub.getImagesFromPages()
                        .firstOrNull()
                        ?.let { epub.getEntry(it) }

                    entry?.let { updateCover(context, manga, epub.getInputStream(it)) }
                }
            }
        }
    }

    override fun getFilterList() = POPULAR_FILTERS

    private val POPULAR_FILTERS = FilterList(OrderBy(context))
    private val LATEST_FILTERS = FilterList(OrderBy(context).apply { state = Filter.Sort.Selection(1, false) })

    private class OrderBy(context: Context) : Filter.Sort(
        context.getString(R.string.local_filter_order_by),
        arrayOf(context.getString(R.string.title), context.getString(R.string.date)),
        Selection(0, true)
    )

    sealed class Format {
        data class Directory(val file: File) : Format()
        data class Zip(val file: File) : Format()
        data class Rar(val file: File) : Format()
        data class Epub(val file: File) : Format()
    }
}