package org.tm.archive.database

import android.content.ContentValues
import android.content.Context
import android.database.sqlite.SQLiteConstraintException
import org.signal.core.util.CursorUtil
import org.signal.core.util.SqlUtil
import org.signal.core.util.delete
import org.signal.core.util.logging.Log
import org.signal.core.util.readToList
import org.signal.core.util.requireBoolean
import org.signal.core.util.requireLong
import org.signal.core.util.toInt
import org.tm.archive.database.model.MessageId
import org.tm.archive.database.model.MessageLogEntry
import org.tm.archive.recipients.Recipient
import org.tm.archive.recipients.RecipientId
import org.tm.archive.util.FeatureFlags
import org.tm.archive.util.RecipientAccessList
import org.whispersystems.signalservice.api.crypto.ContentHint
import org.whispersystems.signalservice.api.messages.SendMessageResult
import org.whispersystems.signalservice.internal.push.Content

/**
 * Stores a rolling buffer of all outgoing messages. Used for the retry logic required for sender key.
 *
 * General note: This class is actually three tables:
 * - one to store the entry
 * - one to store all the devices that were sent it, and
 * - one to store the set of related messages.
 *
 * The general lifecycle of entries in the store goes something like this:
 * - Upon sending a message, put an entry in the 'payload table', an entry for each recipient you sent it to in the 'recipient table', and an entry for each
 *   related message in the 'message table'
 * - Whenever you get a delivery receipt, delete the entries in the 'recipient table'
 * - Whenever there's no more records in the 'recipient table' for a given message, delete the entry in the 'message table'
 * - Whenever you delete a message, delete the relevant entries from the 'payload table'
 * - Whenever you read an entry from the table, first trim off all the entries that are too old
 *
 * Because of all of this, you can be sure that if an entry is in this store, it's safe to resend to someone upon request
 *
 * Worth noting that we use triggers + foreign keys to make sure entries in this table are properly cleaned up. Triggers for when you delete a message, and
 * cascading delete foreign keys between these three tables.
 *
 * Performance considerations:
 * - The most common operations by far are:
 *    - Inserting into the table
 *    - Deleting a recipient (in response to a delivery receipt)
 * - We should also optimize for when we delete messages from the sms/mms tables, since you can delete a bunch at once
 * - We *don't* really need to optimize for retrieval, since that happens very infrequently. In particular, we don't want to slow down inserts in order to
 *   improve retrieval time. That means we shouldn't be adding indexes that optimize for retrieval.
 */
class MessageSendLogTables constructor(context: Context?, databaseHelper: SignalDatabase?) : DatabaseTable(context, databaseHelper), RecipientIdDatabaseReference {

  companion object {
    private val TAG = Log.tag(MessageSendLogTables::class.java)

    @JvmField
    val CREATE_TABLE: Array<String> = arrayOf(MslPayloadTable.CREATE_TABLE, MslRecipientTable.CREATE_TABLE, MslMessageTable.CREATE_TABLE)

    @JvmField
    val CREATE_INDEXES: Array<String> = MslPayloadTable.CREATE_INDEXES + MslRecipientTable.CREATE_INDEXES + MslMessageTable.CREATE_INDEXES

    @JvmField
    val CREATE_TRIGGERS: Array<String> = MslPayloadTable.CREATE_TRIGGERS
  }

  private object MslPayloadTable {
    const val TABLE_NAME = "msl_payload"

    const val ID = "_id"
    const val DATE_SENT = "date_sent"
    const val CONTENT = "content"
    const val CONTENT_HINT = "content_hint"
    const val URGENT = "urgent"

    const val CREATE_TABLE = """
      CREATE TABLE $TABLE_NAME (
        $ID INTEGER PRIMARY KEY,
        $DATE_SENT INTEGER NOT NULL,
        $CONTENT BLOB NOT NULL,
        $CONTENT_HINT INTEGER NOT NULL,
        $URGENT INTEGER NOT NULL DEFAULT 1
      )
    """

    /** Created for [deleteEntriesForRecipient] */
    val CREATE_INDEXES = arrayOf(
      "CREATE INDEX msl_payload_date_sent_index ON $TABLE_NAME ($DATE_SENT)"
    )

    val CREATE_TRIGGERS = arrayOf(
      """
        CREATE TRIGGER msl_message_delete AFTER DELETE ON ${MessageTable.TABLE_NAME} 
        BEGIN 
          DELETE FROM $TABLE_NAME WHERE $ID IN (SELECT ${MslMessageTable.PAYLOAD_ID} FROM ${MslMessageTable.TABLE_NAME} WHERE ${MslMessageTable.MESSAGE_ID} = old.${MessageTable.ID});
        END
      """,
      """
        CREATE TRIGGER msl_attachment_delete AFTER DELETE ON ${AttachmentTable.TABLE_NAME}
        BEGIN
          DELETE FROM $TABLE_NAME WHERE $ID IN (SELECT ${MslMessageTable.PAYLOAD_ID} FROM ${MslMessageTable.TABLE_NAME} WHERE ${MslMessageTable.TABLE_NAME}.${MslMessageTable.MESSAGE_ID} = old.${AttachmentTable.MESSAGE_ID});
        END
      """
    )
  }

  private object MslRecipientTable {
    const val TABLE_NAME = "msl_recipient"

    const val ID = "_id"
    const val PAYLOAD_ID = "payload_id"
    const val RECIPIENT_ID = "recipient_id"
    const val DEVICE = "device"

    const val CREATE_TABLE = """
      CREATE TABLE $TABLE_NAME (
        $ID INTEGER PRIMARY KEY,
        $PAYLOAD_ID INTEGER NOT NULL REFERENCES ${MslPayloadTable.TABLE_NAME} (${MslPayloadTable.ID}) ON DELETE CASCADE,
        $RECIPIENT_ID INTEGER NOT NULL, 
        $DEVICE INTEGER NOT NULL
      )
    """

    /** Created for [deleteEntriesForRecipient] */
    val CREATE_INDEXES = arrayOf(
      "CREATE INDEX msl_recipient_recipient_index ON $TABLE_NAME ($RECIPIENT_ID, $DEVICE, $PAYLOAD_ID)",
      "CREATE INDEX msl_recipient_payload_index ON $TABLE_NAME ($PAYLOAD_ID)"
    )
  }

  private object MslMessageTable {
    const val TABLE_NAME = "msl_message"

    const val ID = "_id"
    const val PAYLOAD_ID = "payload_id"
    const val MESSAGE_ID = "message_id"

    const val CREATE_TABLE = """
      CREATE TABLE $TABLE_NAME (
        $ID INTEGER PRIMARY KEY,
        $PAYLOAD_ID INTEGER NOT NULL REFERENCES ${MslPayloadTable.TABLE_NAME} (${MslPayloadTable.ID}) ON DELETE CASCADE,
        $MESSAGE_ID INTEGER NOT NULL
      )
    """

    /** Created for [MslPayloadTable.CREATE_TRIGGERS] and [deleteAllRelatedToMessage] */
    val CREATE_INDEXES = arrayOf(
      "CREATE INDEX msl_message_message_index ON $TABLE_NAME ($MESSAGE_ID, $PAYLOAD_ID)",
      "CREATE INDEX msl_message_payload_index ON $TABLE_NAME ($PAYLOAD_ID)"
    )
  }

  /** @return The ID of the inserted entry, or -1 if none was inserted. Can be used with [addRecipientToExistingEntryIfPossible] */
  fun insertIfPossible(recipientId: RecipientId, sentTimestamp: Long, sendMessageResult: SendMessageResult, contentHint: ContentHint, messageId: MessageId, urgent: Boolean): Long {
    if (!FeatureFlags.retryReceipts()) return -1

    if (sendMessageResult.isSuccess && sendMessageResult.success.content.isPresent) {
      val recipientDevice = listOf(RecipientDevice(recipientId, sendMessageResult.success.devices))
      return insert(recipientDevice, sentTimestamp, sendMessageResult.success.content.get(), contentHint, listOf(messageId), urgent)
    }

    return -1
  }

  /** @return The ID of the inserted entry, or -1 if none was inserted. Can be used with [addRecipientToExistingEntryIfPossible] */
  fun insertIfPossible(recipientId: RecipientId, sentTimestamp: Long, sendMessageResult: SendMessageResult, contentHint: ContentHint, messageIds: List<MessageId>, urgent: Boolean): Long {
    if (!FeatureFlags.retryReceipts()) return -1

    if (sendMessageResult.isSuccess && sendMessageResult.success.content.isPresent) {
      val recipientDevice = listOf(RecipientDevice(recipientId, sendMessageResult.success.devices))
      return insert(recipientDevice, sentTimestamp, sendMessageResult.success.content.get(), contentHint, messageIds, urgent)
    }

    return -1
  }

  /** @return The ID of the inserted entry, or -1 if none was inserted. Can be used with [addRecipientToExistingEntryIfPossible] */
  fun insertIfPossible(sentTimestamp: Long, possibleRecipients: List<Recipient>, results: List<SendMessageResult>, contentHint: ContentHint, messageId: MessageId, urgent: Boolean): Long {
    if (!FeatureFlags.retryReceipts()) return -1

    val accessList = RecipientAccessList(possibleRecipients)

    val recipientDevices: List<RecipientDevice> = results
      .filter { it.isSuccess && it.success.content.isPresent }
      .map { result ->
        val recipient: Recipient = accessList.requireByAddress(result.address)
        RecipientDevice(recipient.id, result.success.devices)
      }

    if (recipientDevices.isEmpty()) {
      return -1
    }

    val content: Content = results.first { it.isSuccess && it.success.content.isPresent }.success.content.get()

    return insert(recipientDevices, sentTimestamp, content, contentHint, listOf(messageId), urgent)
  }

  fun addRecipientToExistingEntryIfPossible(payloadId: Long, recipientId: RecipientId, sentTimestamp: Long, sendMessageResult: SendMessageResult, contentHint: ContentHint, messageId: MessageId, urgent: Boolean): Long {
    if (!FeatureFlags.retryReceipts()) return payloadId

    if (sendMessageResult.isSuccess && sendMessageResult.success.content.isPresent) {
      val db = databaseHelper.signalWritableDatabase

      db.beginTransaction()
      try {
        sendMessageResult.success.devices.forEach { device ->
          val recipientValues = ContentValues().apply {
            put(MslRecipientTable.PAYLOAD_ID, payloadId)
            put(MslRecipientTable.RECIPIENT_ID, recipientId.serialize())
            put(MslRecipientTable.DEVICE, device)
          }

          db.insert(MslRecipientTable.TABLE_NAME, null, recipientValues)
        }

        db.setTransactionSuccessful()
      } catch (e: SQLiteConstraintException) {
        Log.w(TAG, "Failed to append to existing entry. Creating a new one.")
        val newPayloadId = insertIfPossible(recipientId, sentTimestamp, sendMessageResult, contentHint, messageId, urgent)
        db.setTransactionSuccessful()
        return newPayloadId
      } finally {
        db.endTransaction()
      }
    }

    return payloadId
  }

  private fun insert(recipients: List<RecipientDevice>, dateSent: Long, content: Content, contentHint: ContentHint, messageIds: List<MessageId>, urgent: Boolean): Long {
    val db = databaseHelper.signalWritableDatabase

    db.beginTransaction()
    try {
      val payloadValues = ContentValues().apply {
        put(MslPayloadTable.DATE_SENT, dateSent)
        put(MslPayloadTable.CONTENT, content.encode())
        put(MslPayloadTable.CONTENT_HINT, contentHint.type)
        put(MslPayloadTable.URGENT, urgent.toInt())
      }

      val payloadId: Long = db.insert(MslPayloadTable.TABLE_NAME, null, payloadValues)

      val recipientValues: MutableList<ContentValues> = mutableListOf()
      recipients.forEach { recipientDevice ->
        recipientDevice.devices.forEach { device ->
          recipientValues += ContentValues().apply {
            put(MslRecipientTable.PAYLOAD_ID, payloadId)
            put(MslRecipientTable.RECIPIENT_ID, recipientDevice.recipientId.serialize())
            put(MslRecipientTable.DEVICE, device)
          }
        }
      }
      SqlUtil.buildBulkInsert(MslRecipientTable.TABLE_NAME, arrayOf(MslRecipientTable.PAYLOAD_ID, MslRecipientTable.RECIPIENT_ID, MslRecipientTable.DEVICE), recipientValues)
        .forEach { query -> db.execSQL(query.where, query.whereArgs) }

      val messageValues: MutableList<ContentValues> = mutableListOf()
      messageIds.forEach { messageId ->
        messageValues += ContentValues().apply {
          put(MslMessageTable.PAYLOAD_ID, payloadId)
          put(MslMessageTable.MESSAGE_ID, messageId.id)
        }
      }
      SqlUtil.buildBulkInsert(MslMessageTable.TABLE_NAME, arrayOf(MslMessageTable.PAYLOAD_ID, MslMessageTable.MESSAGE_ID), messageValues)
        .forEach { query -> db.execSQL(query.where, query.whereArgs) }

      db.setTransactionSuccessful()
      return payloadId
    } finally {
      db.endTransaction()
    }
  }

  fun getLogEntry(recipientId: RecipientId, device: Int, dateSent: Long): MessageLogEntry? {
    if (!FeatureFlags.retryReceipts()) return null

    trimOldMessages(System.currentTimeMillis(), FeatureFlags.retryRespondMaxAge())

    val db = databaseHelper.signalReadableDatabase
    val table = "${MslPayloadTable.TABLE_NAME} LEFT JOIN ${MslRecipientTable.TABLE_NAME} ON ${MslPayloadTable.TABLE_NAME}.${MslPayloadTable.ID} = ${MslRecipientTable.TABLE_NAME}.${MslRecipientTable.PAYLOAD_ID}"
    val query = "${MslPayloadTable.DATE_SENT} = ? AND ${MslRecipientTable.RECIPIENT_ID} = ? AND ${MslRecipientTable.DEVICE} = ?"
    val args = SqlUtil.buildArgs(dateSent, recipientId, device)

    db.query(table, null, query, args, null, null, null).use { entryCursor ->
      if (entryCursor.moveToFirst()) {
        val payloadId = CursorUtil.requireLong(entryCursor, MslRecipientTable.PAYLOAD_ID)

        db.query(MslMessageTable.TABLE_NAME, null, "${MslMessageTable.PAYLOAD_ID}  = ?", SqlUtil.buildArgs(payloadId), null, null, null).use { messageCursor ->
          val messageIds: MutableList<MessageId> = mutableListOf()

          while (messageCursor.moveToNext()) {
            messageIds.add(
              MessageId(
                id = CursorUtil.requireLong(messageCursor, MslMessageTable.MESSAGE_ID)
              )
            )
          }

          return MessageLogEntry(
            recipientId = RecipientId.from(CursorUtil.requireLong(entryCursor, MslRecipientTable.RECIPIENT_ID)),
            dateSent = CursorUtil.requireLong(entryCursor, MslPayloadTable.DATE_SENT),
            content = Content.ADAPTER.decode(CursorUtil.requireBlob(entryCursor, MslPayloadTable.CONTENT)),
            contentHint = ContentHint.fromType(CursorUtil.requireInt(entryCursor, MslPayloadTable.CONTENT_HINT)),
            urgent = entryCursor.requireBoolean(MslPayloadTable.URGENT),
            relatedMessages = messageIds
          )
        }
      }
    }

    return null
  }

  fun deleteAllRelatedToMessage(messageId: Long) {
    val db = databaseHelper.signalWritableDatabase
    val query = "${MslPayloadTable.ID} IN (SELECT ${MslMessageTable.PAYLOAD_ID} FROM ${MslMessageTable.TABLE_NAME} WHERE ${MslMessageTable.MESSAGE_ID} = ?)"
    val args = SqlUtil.buildArgs(messageId)

    db.delete(MslPayloadTable.TABLE_NAME, query, args)
  }

  fun deleteEntryForRecipient(dateSent: Long, recipientId: RecipientId, device: Int) {
    deleteEntriesForRecipient(listOf(dateSent), recipientId, device)
  }

  fun deleteEntriesForRecipient(dateSent: List<Long>, recipientId: RecipientId, device: Int) {
    val db = databaseHelper.signalWritableDatabase
    db.beginTransaction()
    try {
      val query = """
        DELETE FROM ${MslRecipientTable.TABLE_NAME} WHERE
        ${MslRecipientTable.RECIPIENT_ID} = ? AND
        ${MslRecipientTable.DEVICE} = ? AND
        ${MslRecipientTable.PAYLOAD_ID} IN (
          SELECT ${MslPayloadTable.ID} 
          FROM ${MslPayloadTable.TABLE_NAME} 
          WHERE ${MslPayloadTable.DATE_SENT} IN (${dateSent.joinToString(",")}) 
        )
        RETURNING ${MslRecipientTable.PAYLOAD_ID}"""
      val args = SqlUtil.buildArgs(recipientId, device)

      val payloadIds = db.rawQuery(query, args).readToList {
        it.requireLong(MslRecipientTable.PAYLOAD_ID)
      }

      val queries = SqlUtil.buildCollectionQuery(MslPayloadTable.ID, payloadIds)
      queries.forEach {
        db.delete(MslPayloadTable.TABLE_NAME, "${it.where} AND ${MslPayloadTable.ID} NOT IN (SELECT ${MslRecipientTable.PAYLOAD_ID} FROM ${MslRecipientTable.TABLE_NAME})", it.whereArgs)
      }
      db.setTransactionSuccessful()
    } finally {
      db.endTransaction()
    }
  }

  fun deleteAllForRecipient(recipientId: RecipientId) {
    if (!FeatureFlags.retryReceipts()) return

    writableDatabase
      .delete(MslRecipientTable.TABLE_NAME)
      .where("${MslRecipientTable.RECIPIENT_ID} = ?", recipientId)
      .run()

    writableDatabase
      .delete(MslPayloadTable.TABLE_NAME)
      .where("${MslPayloadTable.ID} NOT IN (SELECT ${MslRecipientTable.PAYLOAD_ID} FROM ${MslRecipientTable.TABLE_NAME})")
      .run()
  }

  fun deleteAll() {
    databaseHelper.signalWritableDatabase.delete(MslPayloadTable.TABLE_NAME, null, null)
  }

  fun trimOldMessages(currentTime: Long, maxAge: Long) {
    val db = databaseHelper.signalWritableDatabase
    val query = "${MslPayloadTable.DATE_SENT} < ?"
    val args = SqlUtil.buildArgs(currentTime - maxAge)

    db.delete(MslPayloadTable.TABLE_NAME, query, args)
  }

  override fun remapRecipient(oldRecipientId: RecipientId, newRecipientId: RecipientId) {
    val values = ContentValues().apply {
      put(MslRecipientTable.RECIPIENT_ID, newRecipientId.serialize())
    }

    val db = databaseHelper.signalWritableDatabase
    val query = "${MslRecipientTable.RECIPIENT_ID} = ?"
    val args = SqlUtil.buildArgs(oldRecipientId.serialize())

    db.update(MslRecipientTable.TABLE_NAME, values, query, args)
  }

  private data class RecipientDevice(val recipientId: RecipientId, val devices: List<Int>)
}