package exh.ui.migration

import eu.kanade.tachiyomi.data.database.DatabaseHelper
import eu.kanade.tachiyomi.data.database.models.Manga
import eu.kanade.tachiyomi.data.preference.PreferencesHelper
import eu.kanade.tachiyomi.data.preference.getOrDefault
import exh.isExSource
import exh.isLewdSource
import exh.metadata.MetadataHelper
import uy.kohesive.injekt.injectLazy

class UrlMigrator {
    private val db: DatabaseHelper by injectLazy()

    private val prefs: PreferencesHelper by injectLazy()

    private val metadataHelper: MetadataHelper by lazy { MetadataHelper() }

    fun perform() {
        db.inTransaction {
            val dbMangas = db.getMangas()
                    .executeAsBlocking()

            //Find all EX mangas
            val qualifyingMangas = dbMangas.asSequence().filter {
                isLewdSource(it.source)
            }

            val possibleDups = mutableListOf<Manga>()
            val badMangas = mutableListOf<Manga>()

            qualifyingMangas.forEach {
                if(it.url.startsWith("g/")) //Missing slash at front so we are bad
                    badMangas.add(it)
                else
                    possibleDups.add(it)
            }

            //Sort possible dups so we can use binary search on it
            possibleDups.sortBy { it.url }

            badMangas.forEach { manga ->
                //Build fixed URL
                val urlWithSlash = "/" + manga.url
                //Fix metadata if required
                val metadata = metadataHelper.fetchEhMetadata(manga.url, isExSource(manga.source))
                metadata?.url?.let {
                    if(it.startsWith("g/")) { //Check if metadata URL has no slash
                        metadata.url = urlWithSlash //Fix it
                        metadataHelper.writeGallery(metadata, manga.source) //Write new metadata to disk
                    }
                }
                //If we have a dup (with the fixed url), use the dup instead
                val possibleDup = possibleDups.binarySearchBy(urlWithSlash, selector = { it.url })
                if(possibleDup >= 0) {
                    //Make sure it is favorited if we are
                    if(manga.favorite) {
                        val dup = possibleDups[possibleDup]
                        dup.favorite = true
                        db.insertManga(dup).executeAsBlocking() //Update DB with changes
                    }
                    //Delete ourself (but the dup is still there)
                    db.deleteManga(manga).executeAsBlocking()
                    return@forEach
                }
                //No dup, correct URL and reinsert ourselves
                manga.url = urlWithSlash
                db.insertManga(manga).executeAsBlocking()
            }
        }
    }

    fun tryMigration() {
        if(!prefs.hasPerformedURLMigration().getOrDefault()) {
            perform()
            prefs.hasPerformedURLMigration().set(true)
        }
    }
}