package de.softwareapp_hb.filemanager

import android.app.Application
import android.content.Context
import coil3.ImageLoader
import coil3.SingletonImageLoader
import coil3.video.VideoFrameDecoder
import de.softwareapp_hb.filemanager.data.ApkInspector
import de.softwareapp_hb.filemanager.data.BookmarkStore
import de.softwareapp_hb.filemanager.data.ContentResolverIncomingSource
import de.softwareapp_hb.filemanager.data.DeleteRequestFactory
import de.softwareapp_hb.filemanager.data.IncomingSource
import de.softwareapp_hb.filemanager.data.MediaStoreDeleter
import de.softwareapp_hb.filemanager.data.PackageManagerApkInspector
import de.softwareapp_hb.filemanager.data.SearchIndex
import de.softwareapp_hb.filemanager.data.SqliteBookmarkStore
import de.softwareapp_hb.filemanager.data.SqliteSearchIndex
import de.softwareapp_hb.filemanager.data.SqliteTrashIndex
import de.softwareapp_hb.filemanager.data.StorageProvider
import de.softwareapp_hb.filemanager.data.TrashIndex
import de.softwareapp_hb.filemanager.domain.OperationNotifier
import de.softwareapp_hb.filemanager.service.ServiceOperationNotifier

/**
 * Application entry point and the app's tiny object graph.
 *
 * There is no dependency-injection framework here on purpose: the long-lived collaborators below are
 * built once and handed to the one ViewModel that needs them. Nothing holds a reference to an
 * Activity, so none of this leaks.
 */
class FileManagerApplication : Application(), SingletonImageLoader.Factory {

    /** Where files live and which backend is in effect. */
    lateinit var storage: StorageProvider
        private set

    /** Keeps the foreground service in step with a running operation. */
    lateinit var notifier: OperationNotifier
        private set

    /** Builds the platform's own delete confirmation, when it can. */
    lateinit var deleteRequests: DeleteRequestFactory
        private set

    /** Reads whatever another app shares in. */
    lateinit var incoming: IncomingSource
        private set

    /** Remembers what is in the trash, and where each item came from. */
    lateinit var trashIndex: TrashIndex
        private set

    /** Reads an APK's manifest, so a package can be previewed before it is installed. */
    lateinit var apkInspector: ApkInspector
        private set

    /** Remembers what is on the volumes by name, so a search does not have to walk them. */
    lateinit var searchIndex: SearchIndex
        private set

    /** Remembers the folders the user starred, so the home screen can offer them back. */
    lateinit var bookmarkStore: BookmarkStore
        private set

    override fun onCreate() {
        super.onCreate()
        storage = StorageProvider(this)
        notifier = ServiceOperationNotifier(this)
        deleteRequests = MediaStoreDeleter(this).factory()
        incoming = ContentResolverIncomingSource(contentResolver)
        trashIndex = SqliteTrashIndex(this)
        apkInspector = PackageManagerApkInspector(this)
        searchIndex = SqliteSearchIndex(this)
        bookmarkStore = SqliteBookmarkStore(this)
    }

    /**
     * The image loader every thumbnail and viewer goes through.
     *
     * Built here for one reason: **video frames**. Coil has no idea what to do with an `.mp4` until a
     * decoder is registered for it, and `coil-video` supplies one that understands the platform's own
     * `MediaMetadataRetriever`.
     *
     * The decoder is registered **explicitly** rather than left to `coil-video`'s `META-INF/services`
     * entry, because that entry does not survive a release build: R8 removes both the service file and
     * the class it names, since a class mentioned only from a resource looks unused. Checked against
     * the release APK, where neither was present — which would have left video thumbnails working in
     * debug and silently showing an icon in the build everyone installs.
     *
     * Only the decoder is configured. Coil's own cache sizes are left alone deliberately: they are
     * sized from the device's heap, which a number written here would only be guessing at.
     */
    override fun newImageLoader(context: Context): ImageLoader =
        ImageLoader.Builder(context)
            .components { add(VideoFrameDecoder.Factory()) }
            .build()
}