/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.fenix.home.sessioncontrol

import android.content.Context
import android.graphics.Bitmap
import android.os.Parcelable
import android.view.View
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import io.reactivex.Observer
import kotlinx.android.parcel.Parcelize
import mozilla.components.browser.session.Session
import org.mozilla.fenix.ext.components
import org.mozilla.fenix.mvi.ViewState
import org.mozilla.fenix.mvi.Change
import mozilla.components.feature.tab.collections.TabCollection as ACTabCollection
import mozilla.components.feature.tab.collections.Tab as ComponentTab
import org.mozilla.fenix.mvi.Action
import org.mozilla.fenix.mvi.ActionBusFactory
import org.mozilla.fenix.mvi.UIComponent
import org.mozilla.fenix.mvi.UIComponentViewModelBase
import org.mozilla.fenix.mvi.UIComponentViewModelProvider

class SessionControlComponent(
    private val container: ViewGroup,
    bus: ActionBusFactory,
    viewModelProvider: UIComponentViewModelProvider<SessionControlState, SessionControlChange>
) :
    UIComponent<SessionControlState, SessionControlAction, SessionControlChange>(
        bus.getManagedEmitter(SessionControlAction::class.java),
        bus.getSafeManagedObservable(SessionControlChange::class.java),
        viewModelProvider
    ) {

    override fun initView() = SessionControlUIView(container, actionEmitter, changesObservable)

    val view: RecyclerView
        get() = uiView.view as RecyclerView

    init {
        bind()
    }
}

@Parcelize
data class Tab(
    val sessionId: String,
    val url: String,
    val hostname: String,
    val title: String,
    val selected: Boolean? = null,
    val thumbnail: Bitmap? = null
) : Parcelable

fun List<Tab>.toSessionBundle(context: Context): MutableList<Session> {
    val sessionBundle = mutableListOf<Session>()
    this.forEach {
        context.components.core.sessionManager.findSessionById(it.sessionId)?.let { session ->
            sessionBundle.add(session)
        }
    }

    return sessionBundle
}

/**
 * Describes various onboarding states.
 */
enum class OnboardingState {
    // Signed out, no account carried over from Fennec.
    SignedOut,
    // Auto-signed in, via a Fennec account.
    AutoSignedIn,
    // Manually signed in while in onboarding.
    ManuallySignedIn
}

sealed class Mode {
    object Normal : Mode()
    object Private : Mode()
    data class Onboarding(val state: OnboardingState) : Mode()
}

data class SessionControlState(
    val tabs: List<Tab>,
    val expandedCollections: Set<Long>,
    val collections: List<TabCollection>,
    val mode: Mode
) : ViewState

typealias TabCollection = ACTabCollection

sealed class TabAction : Action {
    data class SaveTabGroup(val selectedTabSessionId: String?) : TabAction()
    object Add : TabAction()
    object ShareTabs : TabAction()
    data class CloseAll(val private: Boolean) : TabAction()
    data class Select(val tabView: View, val sessionId: String) : TabAction()
    data class Close(val sessionId: String) : TabAction()
    data class Share(val sessionId: String) : TabAction()
    object PrivateBrowsingLearnMore : TabAction()
}

sealed class CollectionAction : Action {
    data class Expand(val collection: TabCollection) : CollectionAction()
    data class Collapse(val collection: TabCollection) : CollectionAction()
    data class Delete(val collection: TabCollection) : CollectionAction()
    data class AddTab(val collection: TabCollection) : CollectionAction()
    data class Rename(val collection: TabCollection) : CollectionAction()
    data class OpenTab(val tab: ComponentTab) : CollectionAction()
    data class OpenTabs(val collection: TabCollection) : CollectionAction()
    data class ShareTabs(val collection: TabCollection) : CollectionAction()
    data class RemoveTab(val collection: TabCollection, val tab: ComponentTab) : CollectionAction()
}

sealed class OnboardingAction : Action {
    object Finish : OnboardingAction()
}

sealed class SessionControlAction : Action {
    data class Tab(val action: TabAction) : SessionControlAction()
    data class Collection(val action: CollectionAction) : SessionControlAction()
    data class Onboarding(val action: OnboardingAction) : SessionControlAction()
}

fun Observer<SessionControlAction>.onNext(tabAction: TabAction) {
    onNext(SessionControlAction.Tab(tabAction))
}

fun Observer<SessionControlAction>.onNext(collectionAction: CollectionAction) {
    onNext(SessionControlAction.Collection(collectionAction))
}

fun Observer<SessionControlAction>.onNext(onboardingAction: OnboardingAction) {
    onNext(SessionControlAction.Onboarding(onboardingAction))
}

sealed class SessionControlChange : Change {
    data class Change(val tabs: List<Tab>, val mode: Mode, val collections: List<TabCollection>) :
        SessionControlChange()
    data class TabsChange(val tabs: List<Tab>) : SessionControlChange()
    data class ModeChange(val mode: Mode) : SessionControlChange()
    data class CollectionsChange(val collections: List<TabCollection>) : SessionControlChange()
    data class ExpansionChange(val collection: TabCollection, val expand: Boolean) : SessionControlChange()
}

class SessionControlViewModel(
    initialState: SessionControlState
) : UIComponentViewModelBase<SessionControlState, SessionControlChange>(initialState, reducer) {
    companion object {
        val reducer: (SessionControlState, SessionControlChange) -> SessionControlState = { state, change ->
            when (change) {
                is SessionControlChange.CollectionsChange -> state.copy(collections = change.collections)
                is SessionControlChange.TabsChange -> state.copy(tabs = change.tabs)
                is SessionControlChange.ModeChange -> state.copy(mode = change.mode)
                is SessionControlChange.ExpansionChange -> {
                    val newExpandedCollection = state.expandedCollections.toMutableSet()

                    if (change.expand) {
                        newExpandedCollection.add(change.collection.id)
                    } else {
                        newExpandedCollection.remove(change.collection.id)
                    }

                    state.copy(expandedCollections = newExpandedCollection)
                }
                is SessionControlChange.Change -> state.copy(
                    tabs = change.tabs,
                    mode = change.mode,
                    collections = change.collections
                )
            }
        }
    }
}