package com.keylesspalace.tusky.components.account

import android.util.Log
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import at.connyduck.calladapter.networkresult.fold
import com.keylesspalace.tusky.appstore.BlockEvent
import com.keylesspalace.tusky.appstore.DomainMuteEvent
import com.keylesspalace.tusky.appstore.EventHub
import com.keylesspalace.tusky.appstore.MuteEvent
import com.keylesspalace.tusky.appstore.ProfileEditedEvent
import com.keylesspalace.tusky.appstore.UnfollowEvent
import com.keylesspalace.tusky.db.AccountManager
import com.keylesspalace.tusky.entity.Account
import com.keylesspalace.tusky.entity.Relationship
import com.keylesspalace.tusky.network.MastodonApi
import com.keylesspalace.tusky.util.Error
import com.keylesspalace.tusky.util.Loading
import com.keylesspalace.tusky.util.Resource
import com.keylesspalace.tusky.util.Success
import kotlinx.coroutines.Job
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
import javax.inject.Inject

class AccountViewModel @Inject constructor(
    private val mastodonApi: MastodonApi,
    private val eventHub: EventHub,
    private val accountManager: AccountManager
) : ViewModel() {

    val accountData = MutableLiveData<Resource<Account>>()
    val relationshipData = MutableLiveData<Resource<Relationship>>()

    val noteSaved = MutableLiveData<Boolean>()

    val isRefreshing = MutableLiveData<Boolean>().apply { value = false }
    private var isDataLoading = false

    lateinit var accountId: String
    var isSelf = false

    private var noteUpdateJob: Job? = null

    init {
        viewModelScope.launch {
            eventHub.events.collect { event ->
                if (event is ProfileEditedEvent && event.newProfileData.id == accountData.value?.data?.id) {
                    accountData.postValue(Success(event.newProfileData))
                }
            }
        }
    }

    private fun obtainAccount(reload: Boolean = false) {
        if (accountData.value == null || reload) {
            isDataLoading = true
            accountData.postValue(Loading())

            viewModelScope.launch {
                mastodonApi.account(accountId)
                    .fold(
                        { account ->
                            accountData.postValue(Success(account))
                            isDataLoading = false
                            isRefreshing.postValue(false)
                        },
                        { t ->
                            Log.w(TAG, "failed obtaining account", t)
                            accountData.postValue(Error(cause = t))
                            isDataLoading = false
                            isRefreshing.postValue(false)
                        }
                    )
            }
        }
    }

    private fun obtainRelationship(reload: Boolean = false) {
        if (relationshipData.value == null || reload) {
            relationshipData.postValue(Loading())

            viewModelScope.launch {
                mastodonApi.relationships(listOf(accountId))
                    .fold(
                        { relationships ->
                            relationshipData.postValue(if (relationships.isNotEmpty()) Success(relationships[0]) else Error())
                        },
                        { t ->
                            Log.w(TAG, "failed obtaining relationships", t)
                            relationshipData.postValue(Error(cause = t))
                        }
                    )
            }
        }
    }

    fun changeFollowState() {
        val relationship = relationshipData.value?.data
        if (relationship?.following == true || relationship?.requested == true) {
            changeRelationship(RelationShipAction.UNFOLLOW)
        } else {
            changeRelationship(RelationShipAction.FOLLOW)
        }
    }

    fun changeBlockState() {
        if (relationshipData.value?.data?.blocking == true) {
            changeRelationship(RelationShipAction.UNBLOCK)
        } else {
            changeRelationship(RelationShipAction.BLOCK)
        }
    }

    fun muteAccount(notifications: Boolean, duration: Int?) {
        changeRelationship(RelationShipAction.MUTE, notifications, duration)
    }

    fun unmuteAccount() {
        changeRelationship(RelationShipAction.UNMUTE)
    }

    fun changeSubscribingState() {
        val relationship = relationshipData.value?.data
        if (relationship?.notifying == true || /* Mastodon 3.3.0rc1 */
            relationship?.subscribing == true /* Pleroma */
        ) {
            changeRelationship(RelationShipAction.UNSUBSCRIBE)
        } else {
            changeRelationship(RelationShipAction.SUBSCRIBE)
        }
    }

    fun blockDomain(instance: String) {
        viewModelScope.launch {
            mastodonApi.blockDomain(instance).fold({
                eventHub.dispatch(DomainMuteEvent(instance))
                val relation = relationshipData.value?.data
                if (relation != null) {
                    relationshipData.postValue(Success(relation.copy(blockingDomain = true)))
                }
            }, { e ->
                Log.e(TAG, "Error muting $instance", e)
            })
        }
    }

    fun unblockDomain(instance: String) {
        viewModelScope.launch {
            mastodonApi.unblockDomain(instance).fold({
                val relation = relationshipData.value?.data
                if (relation != null) {
                    relationshipData.postValue(Success(relation.copy(blockingDomain = false)))
                }
            }, { e ->
                Log.e(TAG, "Error unmuting $instance", e)
            })
        }
    }

    fun changeShowReblogsState() {
        if (relationshipData.value?.data?.showingReblogs == true) {
            changeRelationship(RelationShipAction.FOLLOW, false)
        } else {
            changeRelationship(RelationShipAction.FOLLOW, true)
        }
    }

    /**
     * @param parameter showReblogs if RelationShipAction.FOLLOW, notifications if MUTE
     */
    private fun changeRelationship(
        relationshipAction: RelationShipAction,
        parameter: Boolean? = null,
        duration: Int? = null
    ) = viewModelScope.launch {
        val relation = relationshipData.value?.data
        val account = accountData.value?.data
        val isMastodon = relationshipData.value?.data?.notifying != null

        if (relation != null && account != null) {
            // optimistically post new state for faster response

            val newRelation = when (relationshipAction) {
                RelationShipAction.FOLLOW -> {
                    if (account.locked) {
                        relation.copy(requested = true)
                    } else {
                        relation.copy(following = true)
                    }
                }
                RelationShipAction.UNFOLLOW -> relation.copy(following = false)
                RelationShipAction.BLOCK -> relation.copy(blocking = true)
                RelationShipAction.UNBLOCK -> relation.copy(blocking = false)
                RelationShipAction.MUTE -> relation.copy(muting = true)
                RelationShipAction.UNMUTE -> relation.copy(muting = false)
                RelationShipAction.SUBSCRIBE -> {
                    if (isMastodon) {
                        relation.copy(notifying = true)
                    } else {
                        relation.copy(subscribing = true)
                    }
                }
                RelationShipAction.UNSUBSCRIBE -> {
                    if (isMastodon) {
                        relation.copy(notifying = false)
                    } else {
                        relation.copy(subscribing = false)
                    }
                }
            }
            relationshipData.postValue(Loading(newRelation))
        }

        val relationshipCall = when (relationshipAction) {
            RelationShipAction.FOLLOW -> mastodonApi.followAccount(
                accountId,
                showReblogs = parameter ?: true
            )
            RelationShipAction.UNFOLLOW -> mastodonApi.unfollowAccount(accountId)
            RelationShipAction.BLOCK -> mastodonApi.blockAccount(accountId)
            RelationShipAction.UNBLOCK -> mastodonApi.unblockAccount(accountId)
            RelationShipAction.MUTE -> mastodonApi.muteAccount(
                accountId,
                parameter ?: true,
                duration
            )
            RelationShipAction.UNMUTE -> mastodonApi.unmuteAccount(accountId)
            RelationShipAction.SUBSCRIBE -> {
                if (isMastodon) {
                    mastodonApi.followAccount(accountId, notify = true)
                } else {
                    mastodonApi.subscribeAccount(accountId)
                }
            }
            RelationShipAction.UNSUBSCRIBE -> {
                if (isMastodon) {
                    mastodonApi.followAccount(accountId, notify = false)
                } else {
                    mastodonApi.unsubscribeAccount(accountId)
                }
            }
        }

        relationshipCall.fold(
            { relationship ->
                relationshipData.postValue(Success(relationship))

                when (relationshipAction) {
                    RelationShipAction.UNFOLLOW -> eventHub.dispatch(UnfollowEvent(accountId))
                    RelationShipAction.BLOCK -> eventHub.dispatch(BlockEvent(accountId))
                    RelationShipAction.MUTE -> eventHub.dispatch(MuteEvent(accountId))
                    else -> { }
                }
            },
            { t ->
                Log.w(TAG, "failed loading relationship", t)
                relationshipData.postValue(Error(relation, cause = t))
            }
        )
    }

    fun noteChanged(newNote: String) {
        noteSaved.postValue(false)
        noteUpdateJob?.cancel()
        noteUpdateJob = viewModelScope.launch {
            delay(1500)
            mastodonApi.updateAccountNote(accountId, newNote)
                .fold(
                    {
                        noteSaved.postValue(true)
                        delay(4000)
                        noteSaved.postValue(false)
                    },
                    { t ->
                        Log.w(TAG, "Error updating note", t)
                    }
                )
        }
    }

    fun refresh() {
        reload(true)
    }

    private fun reload(isReload: Boolean = false) {
        if (isDataLoading) {
            return
        }
        accountId.let {
            obtainAccount(isReload)
            if (!isSelf) {
                obtainRelationship(isReload)
            }
        }
    }

    fun setAccountInfo(accountId: String) {
        this.accountId = accountId
        this.isSelf = accountManager.activeAccount?.accountId == accountId
        reload(false)
    }

    enum class RelationShipAction {
        FOLLOW, UNFOLLOW, BLOCK, UNBLOCK, MUTE, UNMUTE, SUBSCRIBE, UNSUBSCRIBE
    }

    companion object {
        const val TAG = "AccountViewModel"
    }
}