package org.thoughtcrime.securesms.conversation.v2

import android.content.ContentResolver
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.viewModelScope
import app.cash.copper.flow.observeQuery
import com.goterl.lazysodium.utils.KeyPair
import dagger.assisted.Assisted
import dagger.assisted.AssistedInject
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.update
import kotlinx.coroutines.launch
import org.session.libsession.messaging.open_groups.OpenGroup
import org.session.libsession.messaging.open_groups.OpenGroupApi
import org.session.libsession.messaging.utilities.SessionId
import org.session.libsession.messaging.utilities.SodiumUtilities
import org.session.libsession.utilities.recipients.Recipient
import org.session.libsignal.utilities.IdPrefix
import org.session.libsignal.utilities.Log
import org.thoughtcrime.securesms.database.DatabaseContentProviders
import org.thoughtcrime.securesms.database.Storage
import org.thoughtcrime.securesms.database.model.MessageRecord
import org.thoughtcrime.securesms.repository.ConversationRepository
import java.util.UUID

class ConversationViewModel(
    val threadId: Long,
    val edKeyPair: KeyPair?,
    private val contentResolver: ContentResolver,
    private val repository: ConversationRepository,
    private val storage: Storage
) : ViewModel() {

    val showSendAfterApprovalText: Boolean
        get() = recipient?.run { isContactRecipient && !isLocalNumber && !hasApprovedMe() } ?: false

    private val _uiState = MutableStateFlow(ConversationUiState(conversationExists = true))
    val uiState: StateFlow<ConversationUiState> = _uiState

    private var _recipient: RetrieveOnce<Recipient> = RetrieveOnce {
        repository.maybeGetRecipientForThreadId(threadId)
    }
    val recipient: Recipient?
        get() = _recipient.value

    private var _openGroup: RetrieveOnce<OpenGroup> = RetrieveOnce {
        storage.getOpenGroup(threadId)
    }
    val openGroup: OpenGroup?
        get() = _openGroup.value

    val serverCapabilities: List<String>
        get() = openGroup?.let { storage.getServerCapabilities(it.server) } ?: listOf()

    val blindedPublicKey: String?
        get() = if (openGroup == null || edKeyPair == null || !serverCapabilities.contains(OpenGroupApi.Capability.BLIND.name.lowercase())) null else {
            SodiumUtilities.blindedKeyPair(openGroup!!.publicKey, edKeyPair)?.publicKey?.asBytes
                ?.let { SessionId(IdPrefix.BLINDED, it) }?.hexString
        }

    init {
        viewModelScope.launch(Dispatchers.IO) {
            contentResolver.observeQuery(DatabaseContentProviders.Conversation.getUriForThread(threadId))
                .collect {
                    val recipientExists = storage.getRecipientForThread(threadId) != null
                    if (!recipientExists && _uiState.value.conversationExists) {
                        _uiState.update { it.copy(conversationExists = false) }
                    }
                }
        }
    }

    fun saveDraft(text: String) {
        GlobalScope.launch(Dispatchers.IO) {
            repository.saveDraft(threadId, text)
        }
    }

    fun getDraft(): String? {
        val draft: String? = repository.getDraft(threadId)

        viewModelScope.launch(Dispatchers.IO) {
            repository.clearDrafts(threadId)
        }

        return draft
    }

    fun inviteContacts(contacts: List<Recipient>) {
        repository.inviteContacts(threadId, contacts)
    }

    fun block() {
        val recipient = recipient ?: return Log.w("Loki", "Recipient was null for block action")
        if (recipient.isContactRecipient) {
            repository.setBlocked(recipient, true)
        }
    }

    fun unblock() {
        val recipient = recipient ?: return Log.w("Loki", "Recipient was null for unblock action")
        if (recipient.isContactRecipient) {
            repository.setBlocked(recipient, false)
        }
    }

    fun deleteThread() = viewModelScope.launch {
        repository.deleteThread(threadId)
    }

    fun deleteLocally(message: MessageRecord) {
        val recipient = recipient ?: return Log.w("Loki", "Recipient was null for delete locally action")
        repository.deleteLocally(recipient, message)
    }

    fun setRecipientApproved() {
        val recipient = recipient ?: return Log.w("Loki", "Recipient was null for set approved action")
        repository.setApproved(recipient, true)
    }

    fun deleteForEveryone(message: MessageRecord) = viewModelScope.launch {
        val recipient = recipient ?: return@launch
        repository.deleteForEveryone(threadId, recipient, message)
            .onFailure {
                showMessage("Couldn't delete message due to error: $it")
            }
    }

    fun deleteMessagesWithoutUnsendRequest(messages: Set<MessageRecord>) = viewModelScope.launch {
        repository.deleteMessageWithoutUnsendRequest(threadId, messages)
            .onFailure {
                showMessage("Couldn't delete message due to error: $it")
            }
    }

    fun banUser(recipient: Recipient) = viewModelScope.launch {
        repository.banUser(threadId, recipient)
            .onSuccess {
                showMessage("Successfully banned user")
            }
            .onFailure {
                showMessage("Couldn't ban user due to error: $it")
            }
    }

    fun banAndDeleteAll(recipient: Recipient) = viewModelScope.launch {
        repository.banAndDeleteAll(threadId, recipient)
            .onSuccess {
                showMessage("Successfully banned user and deleted all their messages")
            }
            .onFailure {
                showMessage("Couldn't execute request due to error: $it")
            }
    }

    fun acceptMessageRequest() = viewModelScope.launch {
        val recipient = recipient ?: return@launch Log.w("Loki", "Recipient was null for accept message request action")
        repository.acceptMessageRequest(threadId, recipient)
            .onSuccess {
                _uiState.update {
                    it.copy(isMessageRequestAccepted = true)
                }
            }
            .onFailure {
                showMessage("Couldn't accept message request due to error: $it")
            }
    }

    fun declineMessageRequest() {
        repository.declineMessageRequest(threadId)
    }

    private fun showMessage(message: String) {
        _uiState.update { currentUiState ->
            val messages = currentUiState.uiMessages + UiMessage(
                id = UUID.randomUUID().mostSignificantBits,
                message = message
            )
            currentUiState.copy(uiMessages = messages)
        }
    }
    
    fun messageShown(messageId: Long) {
        _uiState.update { currentUiState ->
            val messages = currentUiState.uiMessages.filterNot { it.id == messageId }
            currentUiState.copy(uiMessages = messages)
        }
    }

    fun hasReceived(): Boolean {
        return repository.hasReceived(threadId)
    }

    fun updateRecipient() {
        _recipient.updateTo(repository.maybeGetRecipientForThreadId(threadId))
    }

    @dagger.assisted.AssistedFactory
    interface AssistedFactory {
        fun create(threadId: Long, edKeyPair: KeyPair?, contentResolver: ContentResolver): Factory
    }

    @Suppress("UNCHECKED_CAST")
    class Factory @AssistedInject constructor(
        @Assisted private val threadId: Long,
        @Assisted private val edKeyPair: KeyPair?,
        @Assisted private val contentResolver: ContentResolver,
        private val repository: ConversationRepository,
        private val storage: Storage
    ) : ViewModelProvider.Factory {

        override fun <T : ViewModel> create(modelClass: Class<T>): T {
            return ConversationViewModel(threadId, edKeyPair, contentResolver, repository, storage) as T
        }
    }
}

data class UiMessage(val id: Long, val message: String)

data class ConversationUiState(
    val uiMessages: List<UiMessage> = emptyList(),
    val isMessageRequestAccepted: Boolean? = null,
    val conversationExists: Boolean
)

data class RetrieveOnce<T>(val retrieval: () -> T?) {
    private var triedToRetrieve: Boolean = false
    private var _value: T? = null

    val value: T?
        get() {
            if (triedToRetrieve) { return _value }

            triedToRetrieve = true
            _value = retrieval()
            return _value
        }

    fun updateTo(value: T?) { _value = value }
}