Clean up special local folders in database

class StoreSchemaDefinition implements SchemaDefinition {

    static final int DB_VERSION = 75;

    static final int DB_VERSION = 76;

    private final MigrationsHelper migrationsHelper;

package com.fsck.k9.storage.migrations

import android.content.ContentValues

import android.database.sqlite.SQLiteDatabase

import com.fsck.k9.Account

import com.fsck.k9.helper.map

import com.fsck.k9.mailstore.MigrationsHelper

import timber.log.Timber

/**

 * Clean up special local folders

 *

 * In the past local special folders were not always created. For example, when importing settings or when setting up

 * an account, but checking the server settings didn't succeed and the user decided to continue anyway.

 *

 * Clicking "Next" in the incoming server settings screen would check the server settings and, in the case of success,

 * create new special local folders even if they already existed. So it's also possible existing installations have

 * multiple special local folders of one type.

 *

 * Here, we clean up local special folders to have exactly one of each type. Messages in additional folders will be

 * moved to the folder we keep and then the other folders will be deleted. An exception are messages in old Outbox

 * folders. They will be deleted and not be moved to the new/current Outbox folder because this would cause potentially

 * very old messages to be sent. The right thing would be to move them to the Drafts folder. But this is much more

 * complicated. They'd have to be uploaded if the Drafts folder is not a local folder. It's also not clear what should

 * happen if there is no Drafts folder configured.

 */

internal class MigrationTo76(private val db: SQLiteDatabase, private val migrationsHelper: MigrationsHelper) {

    fun cleanUpSpecialLocalFolders() {

        val account = migrationsHelper.account

        Timber.v("Cleaning up Outbox folder")

        val outboxFolderId = account.outboxFolderId ?: createFolder("Outbox", "K9MAIL_INTERNAL_OUTBOX", OUTBOX_FOLDER_TYPE)

        deleteOtherOutboxFolders(outboxFolderId)

        account.outboxFolderId = outboxFolderId

        if (account.isPop3()) {

            Timber.v("Cleaning up Drafts folder")

            val draftsFolderId = account.draftsFolderId ?: createFolder("Drafts", "Drafts", DRAFTS_FOLDER_TYPE)

            moveMessages(DRAFTS_FOLDER_TYPE, draftsFolderId)

            account.draftsFolderId = draftsFolderId

            Timber.v("Cleaning up Sent folder")

            val sentFolderId = account.sentFolderId ?: createFolder("Sent", "Sent", SENT_FOLDER_TYPE)

            moveMessages(SENT_FOLDER_TYPE, sentFolderId)

            account.sentFolderId = sentFolderId

            Timber.v("Cleaning up Trash folder")

            val trashFolderId = account.trashFolderId ?: createFolder("Trash", "Trash", TRASH_FOLDER_TYPE)

            moveMessages(TRASH_FOLDER_TYPE, trashFolderId)

            account.trashFolderId = trashFolderId

        }

        migrationsHelper.saveAccount()

    }

    private fun createFolder(name: String, serverId: String, type: String): Long {

        Timber.v("  Creating new local folder (name=$name, serverId=$serverId, type=$type)…")

        val values = ContentValues().apply {

            put("name", name)

            put("visible_limit", 25)

            put("integrate", 0)

            put("top_group", 0)

            put("poll_class", "NO_CLASS")

            put("push_class", "SECOND_CLASS")

            put("display_class", "NO_CLASS")

            put("server_id", serverId)

            put("local_only", 1)

            put("type", type)

        }

        val folderId = db.insert("folders", null, values)

        Timber.v("    Created folder with ID $folderId")

        return folderId

    }

    private fun deleteOtherOutboxFolders(outboxFolderId: Long) {

        val otherFolderIds = getOtherFolders(OUTBOX_FOLDER_TYPE, outboxFolderId)

        for (folderId in otherFolderIds) {

            deleteFolder(folderId)

        }

    }

    private fun getOtherFolders(folderType: String, excludeFolderId: Long): List<Long> {

        return db.query(

            "folders",

            arrayOf("id"),

            "local_only = 1 AND type = ? AND id != ?",

            arrayOf(folderType, excludeFolderId.toString()),

            null,

            null,

            null

        ).use { cursor ->

            cursor.map { cursor.getLong(0) }

        }

    }

    private fun moveMessages(folderType: String, destinationFolderId: Long) {

        val sourceFolderIds = getOtherFolders(folderType, destinationFolderId)

        for (sourceFolderId in sourceFolderIds) {

            moveMessages(sourceFolderId, destinationFolderId)

            deleteFolder(sourceFolderId)

        }

    }

    private fun moveMessages(sourceFolderId: Long, destinationFolderId: Long) {

        Timber.v("  Moving messages from folder [$sourceFolderId] to folder [$destinationFolderId]…")

        val values = ContentValues().apply {

            put("folder_id", destinationFolderId)

        }

        val rows = db.update("messages", values, "folder_id = ?", arrayOf(sourceFolderId.toString()))

        Timber.v("    $rows messages moved.")

    }

    private fun deleteFolder(folderId: Long) {

        Timber.v("  Deleting folder [$folderId]")

        db.delete("folders", "id = ?", arrayOf(folderId.toString()))

    }

    private fun Account.isPop3() = storeUri.startsWith("pop3")

    companion object {

        private const val OUTBOX_FOLDER_TYPE = "outbox"

        private const val DRAFTS_FOLDER_TYPE = "drafts"

        private const val SENT_FOLDER_TYPE = "sent"

        private const val TRASH_FOLDER_TYPE = "trash"

    }

}

        if (oldVersion < 73) MigrationTo73(db).rewritePendingCommandsToUseFolderIds()

        if (oldVersion < 74) MigrationTo74(db, migrationsHelper.account).removeDeletedMessages()

        if (oldVersion < 75) MigrationTo75(db, migrationsHelper).updateAccountWithSpecialFolderIds()

        if (oldVersion < 76) MigrationTo76(db, migrationsHelper).cleanUpSpecialLocalFolders()

    }

}