import Foundation
import UIKit
import Display
import SwiftSignalKit
import Postbox
import TelegramCore
import TelegramPresentationData
import TelegramUIPreferences
import ItemListUI
import AccountContext
import AlertUI
import ItemListPeerItem

private final class ChannelMembersControllerArguments {
    let account: Account
    
    let addMember: () -> Void
    let setPeerIdWithRevealedOptions: (PeerId?, PeerId?) -> Void
    let removePeer: (PeerId) -> Void
    let openPeer: (Peer) -> Void
    let inviteViaLink: ()->Void
    init(account: Account, addMember: @escaping () -> Void, setPeerIdWithRevealedOptions: @escaping (PeerId?, PeerId?) -> Void, removePeer: @escaping (PeerId) -> Void, openPeer: @escaping (Peer) -> Void, inviteViaLink: @escaping()->Void) {
        self.account = account
        self.addMember = addMember
        self.setPeerIdWithRevealedOptions = setPeerIdWithRevealedOptions
        self.removePeer = removePeer
        self.openPeer = openPeer
        self.inviteViaLink = inviteViaLink
    }
}

private enum ChannelMembersSection: Int32 {
    case addMembers
    case peers
}

private enum ChannelMembersEntryStableId: Hashable {
    case index(Int32)
    case peer(PeerId)
    
    var hashValue: Int {
        switch self {
            case let .index(index):
                return index.hashValue
            case let .peer(peerId):
                return peerId.hashValue
        }
    }
    
    static func ==(lhs: ChannelMembersEntryStableId, rhs: ChannelMembersEntryStableId) -> Bool {
        switch lhs {
            case let .index(index):
                if case .index(index) = rhs {
                    return true
                } else {
                    return false
                }
            case let .peer(peerId):
                if case .peer(peerId) = rhs {
                    return true
                } else {
                    return false
                }
        }
    }
}

private enum ChannelMembersEntry: ItemListNodeEntry {
    case addMember(PresentationTheme, String)
    case addMemberInfo(PresentationTheme, String)
    case inviteLink(PresentationTheme, String)
    case peerItem(Int32, PresentationTheme, PresentationStrings, PresentationDateTimeFormat, PresentationPersonNameOrder, RenderedChannelParticipant, ItemListPeerItemEditing, Bool)
    
    var section: ItemListSectionId {
        switch self {
            case .addMember, .addMemberInfo, .inviteLink:
                return ChannelMembersSection.addMembers.rawValue
            case .peerItem:
                return ChannelMembersSection.peers.rawValue
        }
    }
    
    var stableId: ChannelMembersEntryStableId {
        switch self {
            case .addMember:
                return .index(0)
            case .addMemberInfo:
                return .index(1)
        case .inviteLink:
            return .index(2)
            case let .peerItem(_, _, _, _, _, participant, _, _):
                return .peer(participant.peer.id)
        }
    }
    
    static func ==(lhs: ChannelMembersEntry, rhs: ChannelMembersEntry) -> Bool {
        switch lhs {
            case let .addMember(lhsTheme, lhsText):
                if case let .addMember(rhsTheme, rhsText) = rhs, lhsTheme === rhsTheme, lhsText == rhsText {
                    return true
                } else {
                    return false
                }
            case let .addMemberInfo(lhsTheme, lhsText):
                if case let .addMemberInfo(rhsTheme, rhsText) = rhs, lhsTheme === rhsTheme, lhsText == rhsText {
                    return true
                } else {
                    return false
                }
        case let .inviteLink(lhsTheme, lhsText):
            if case let .inviteLink(rhsTheme, rhsText) = rhs, lhsTheme === rhsTheme, lhsText == rhsText {
                return true
            } else {
                return false
            }
            case let .peerItem(lhsIndex, lhsTheme, lhsStrings, lhsDateTimeFormat, lhsNameOrder, lhsParticipant, lhsEditing, lhsEnabled):
                if case let .peerItem(rhsIndex, rhsTheme, rhsStrings, rhsDateTimeFormat, rhsNameOrder, rhsParticipant, rhsEditing, rhsEnabled) = rhs {
                    if lhsIndex != rhsIndex {
                        return false
                    }
                    if lhsTheme !== rhsTheme {
                        return false
                    }
                    if lhsStrings !== rhsStrings {
                        return false
                    }
                    if lhsDateTimeFormat != rhsDateTimeFormat {
                        return false
                    }
                    if lhsNameOrder != rhsNameOrder {
                        return false
                    }
                    if lhsParticipant != rhsParticipant {
                        return false
                    }
                    if lhsEditing != rhsEditing {
                        return false
                    }
                    if lhsEnabled != rhsEnabled {
                        return false
                    }
                    return true
                } else {
                    return false
                }
        }
    }
    
    static func <(lhs: ChannelMembersEntry, rhs: ChannelMembersEntry) -> Bool {
        switch lhs {
            case .addMember:
                return true
            case .inviteLink:
                switch rhs {
                case .addMember:
                    return false
                default:
                    return true
                }
            case .addMemberInfo:
                switch rhs {
                    case .addMember, .inviteLink:
                        return false
                    default:
                        return true
                }
            
            case let .peerItem(index, _, _, _, _, _, _, _):
                switch rhs {
                    case let .peerItem(rhsIndex, _, _, _, _, _, _, _):
                        return index < rhsIndex
                    case .addMember, .addMemberInfo, .inviteLink:
                        return false
                }
        }
    }
    
    func item(_ arguments: ChannelMembersControllerArguments) -> ListViewItem {
        switch self {
            case let .addMember(theme, text):
                return ItemListActionItem(theme: theme, title: text, kind: .generic, alignment: .natural, sectionId: self.section, style: .blocks, action: {
                    arguments.addMember()
                })
            case let .inviteLink(theme, text):
                return ItemListActionItem(theme: theme, title: text, kind: .generic, alignment: .natural, sectionId: self.section, style: .blocks, action: {
                    arguments.inviteViaLink()
                })
            case let .addMemberInfo(theme, text):
                return ItemListTextItem(theme: theme, text: .plain(text), sectionId: self.section)
            case let .peerItem(_, theme, strings, dateTimeFormat, nameDisplayOrder, participant, editing, enabled):
                let text: ItemListPeerItemText
                if let user = participant.peer as? TelegramUser, let _ = user.botInfo {
                    text = .text(strings.Bot_GenericBotStatus)
                } else {
                    text = .presence
                }
                return ItemListPeerItem(theme: theme, strings: strings, dateTimeFormat: dateTimeFormat, nameDisplayOrder: nameDisplayOrder, account: arguments.account, peer: participant.peer, presence: participant.presences[participant.peer.id], text: text, label: .none, editing: editing, switchValue: nil, enabled: enabled, selectable: true, sectionId: self.section, action: {
                    arguments.openPeer(participant.peer)
                }, setPeerIdWithRevealedOptions: { previousId, id in
                    arguments.setPeerIdWithRevealedOptions(previousId, id)
                }, removePeer: { peerId in
                    arguments.removePeer(peerId)
                })
        }
    }
}

private struct ChannelMembersControllerState: Equatable {
    let editing: Bool
    let peerIdWithRevealedOptions: PeerId?
    let removingPeerId: PeerId?
    let searchingMembers: Bool

    init() {
        self.editing = false
        self.peerIdWithRevealedOptions = nil
        self.removingPeerId = nil
        self.searchingMembers = false
    }
    
    init(editing: Bool, peerIdWithRevealedOptions: PeerId?, removingPeerId: PeerId?, searchingMembers: Bool) {
        self.editing = editing
        self.peerIdWithRevealedOptions = peerIdWithRevealedOptions
        self.removingPeerId = removingPeerId
        self.searchingMembers = searchingMembers
    }
    
    static func ==(lhs: ChannelMembersControllerState, rhs: ChannelMembersControllerState) -> Bool {
        if lhs.editing != rhs.editing {
            return false
        }
        if lhs.peerIdWithRevealedOptions != rhs.peerIdWithRevealedOptions {
            return false
        }
        if lhs.removingPeerId != rhs.removingPeerId {
            return false
        }
        if lhs.searchingMembers != rhs.searchingMembers {
            return false
        }
        return true
    }
    
    func withUpdatedSearchingMembers(_ searchingMembers: Bool) -> ChannelMembersControllerState {
        return ChannelMembersControllerState(editing: self.editing, peerIdWithRevealedOptions: self.peerIdWithRevealedOptions, removingPeerId: self.removingPeerId, searchingMembers: searchingMembers)
    }
    
    func withUpdatedEditing(_ editing: Bool) -> ChannelMembersControllerState {
        return ChannelMembersControllerState(editing: editing, peerIdWithRevealedOptions: self.peerIdWithRevealedOptions, removingPeerId: self.removingPeerId, searchingMembers: self.searchingMembers)
    }
    
    func withUpdatedPeerIdWithRevealedOptions(_ peerIdWithRevealedOptions: PeerId?) -> ChannelMembersControllerState {
        return ChannelMembersControllerState(editing: self.editing, peerIdWithRevealedOptions: peerIdWithRevealedOptions, removingPeerId: self.removingPeerId, searchingMembers: self.searchingMembers)
    }
    
    func withUpdatedRemovingPeerId(_ removingPeerId: PeerId?) -> ChannelMembersControllerState {
        return ChannelMembersControllerState(editing: self.editing, peerIdWithRevealedOptions: self.peerIdWithRevealedOptions, removingPeerId: removingPeerId, searchingMembers: self.searchingMembers)
    }
}

private func ChannelMembersControllerEntries(context: AccountContext, presentationData: PresentationData, view: PeerView, state: ChannelMembersControllerState, participants: [RenderedChannelParticipant]?) -> [ChannelMembersEntry] {
    if participants == nil || participants?.count == nil {
        return []
    }
    
    var entries: [ChannelMembersEntry] = []
    
    if let participants = participants {
        var canAddMember: Bool = false
        if let peer = view.peers[view.peerId] as? TelegramChannel {
            canAddMember = peer.hasPermission(.inviteMembers)
        }
        
        if canAddMember {
            entries.append(.addMember(presentationData.theme, presentationData.strings.Channel_Members_AddMembers))
            if let peer = view.peers[view.peerId] as? TelegramChannel, peer.addressName == nil {
                entries.append(.inviteLink(presentationData.theme, presentationData.strings.Channel_Members_InviteLink))
            }
            entries.append(.addMemberInfo(presentationData.theme, presentationData.strings.Channel_Members_AddMembersHelp))
        }

        
        var index: Int32 = 0
        let sortedParticipants = participants
        /*
         participants.sorted(by: { lhs, rhs in
         let lhsInvitedAt: Int32
         switch lhs.participant {
         case .creator:
         lhsInvitedAt = Int32.min
         case let .member(_, invitedAt, _, _):
         lhsInvitedAt = invitedAt
         }
         let rhsInvitedAt: Int32
         switch rhs.participant {
         case .creator:
         rhsInvitedAt = Int32.min
         case let .member(_, invitedAt, _, _):
         rhsInvitedAt = invitedAt
         }
         return lhsInvitedAt < rhsInvitedAt
         })
         */
        for participant in sortedParticipants {
            var editable = true
            var canEditMembers = false
            if let peer = view.peers[view.peerId] as? TelegramChannel {
                canEditMembers = peer.hasPermission(.banMembers)
            }
            
            if participant.peer.id == context.account.peerId {
                editable = false
            } else {
                switch participant.participant {
                    case .creator:
                        editable = false
                    case .member:
                        editable = canEditMembers
                }
            }
            entries.append(.peerItem(index, presentationData.theme, presentationData.strings, presentationData.dateTimeFormat, presentationData.nameDisplayOrder, participant, ItemListPeerItemEditing(editable: editable, editing: state.editing, revealed: participant.peer.id == state.peerIdWithRevealedOptions), state.removingPeerId != participant.peer.id))
            index += 1
        }
    }
    
    return entries
}

public func channelMembersController(context: AccountContext, peerId: PeerId) -> ViewController {
    let statePromise = ValuePromise(ChannelMembersControllerState(), ignoreRepeated: true)
    let stateValue = Atomic(value: ChannelMembersControllerState())
    let updateState: ((ChannelMembersControllerState) -> ChannelMembersControllerState) -> Void = { f in
        statePromise.set(stateValue.modify { f($0) })
    }
    
    var presentControllerImpl: ((ViewController, Any?) -> Void)?
    var pushControllerImpl: ((ViewController) -> Void)?
    
    let actionsDisposable = DisposableSet()
    
    let addMembersDisposable = MetaDisposable()
    actionsDisposable.add(addMembersDisposable)
    
    let removePeerDisposable = MetaDisposable()
    actionsDisposable.add(removePeerDisposable)
    
    let peersPromise = Promise<[RenderedChannelParticipant]?>(nil)
    
    let arguments = ChannelMembersControllerArguments(account: context.account, addMember: {
        actionsDisposable.add((peersPromise.get()
        |> take(1)
        |> deliverOnMainQueue).start(next: { members in
            let disabledIds = members?.compactMap({$0.peer.id}) ?? []
            let contactsController = context.sharedContext.makeContactMultiselectionController(ContactMultiselectionControllerParams(context: context, mode: .peerSelection(searchChatList: false, searchGroups: false), options: [], filters: [.excludeSelf, .disable(disabledIds)]))
            
            addMembersDisposable.set((contactsController.result
            |> deliverOnMainQueue
            |> introduceError(AddChannelMemberError.self)
            |> mapToSignal { [weak contactsController] contacts -> Signal<Never, AddChannelMemberError> in
                contactsController?.displayProgress = true
                
                let signal = context.peerChannelMemberCategoriesContextsManager.addMembers(account: context.account, peerId: peerId, memberIds: contacts.compactMap({ contact -> PeerId? in
                    switch contact {
                        case let .peer(contactId):
                            return contactId
                        default:
                            return nil
                    }
                }))
                
                return signal
                |> ignoreValues
                |> deliverOnMainQueue
                |> afterCompleted {
                    contactsController?.dismiss()
                }
            }).start(error: { [weak contactsController] error in
                let presentationData = context.sharedContext.currentPresentationData.with { $0 }
                let text: String
                switch error {
                    case .limitExceeded:
                        text = presentationData.strings.Channel_ErrorAddTooMuch
                    case .tooMuchJoined:
                        text = presentationData.strings.Invite_ChannelsTooMuch
                    case .generic:
                        text = presentationData.strings.Login_UnknownError
                    case .restricted:
                        text = presentationData.strings.Channel_ErrorAddBlocked
                    case let .bot(memberId):
                        let _ = (context.account.postbox.transaction { transaction in
                            return transaction.getPeer(peerId)
                        }
                        |> deliverOnMainQueue).start(next: { peer in
                            guard let peer = peer as? TelegramChannel else {
                                presentControllerImpl?(textAlertController(context: context, title: nil, text: presentationData.strings.Login_UnknownError, actions: [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]), nil)
                                contactsController?.dismiss()
                                
                                return
                            }
                            
                            if peer.hasPermission(.addAdmins) {
                                contactsController?.displayProgress = false
                                presentControllerImpl?(textAlertController(context: context, title: nil, text: presentationData.strings.Channel_AddBotErrorHaveRights, actions: [TextAlertAction(type: .genericAction, title: presentationData.strings.Common_Cancel, action: {}), TextAlertAction(type: .defaultAction, title: presentationData.strings.Channel_AddBotAsAdmin, action: {
                                    contactsController?.dismiss()
                                    
                                    pushControllerImpl?(channelAdminController(context: context, peerId: peerId, adminId: memberId, initialParticipant: nil, updated: { _ in
                                    }, upgradedToSupergroup: { _, f in f () }, transferedOwnership: { _ in }))
                                })]), nil)
                            } else {
                                presentControllerImpl?(textAlertController(context: context, title: nil, text: presentationData.strings.Channel_AddBotErrorHaveRights, actions: [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]), nil)
                            }
                            
                            contactsController?.dismiss()
                        })
                        return
                    case .botDoesntSupportGroups:
                        text = presentationData.strings.Channel_BotDoesntSupportGroups
                    case .tooMuchBots:
                        text = presentationData.strings.Channel_TooMuchBots
                }
                presentControllerImpl?(textAlertController(context: context, title: nil, text: text, actions: [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]), nil)
                contactsController?.dismiss()
            }))
            
            presentControllerImpl?(contactsController, ViewControllerPresentationArguments(presentationAnimation: .modalSheet))
        }))
        
    }, setPeerIdWithRevealedOptions: { peerId, fromPeerId in
        updateState { state in
            if (peerId == nil && fromPeerId == state.peerIdWithRevealedOptions) || (peerId != nil && fromPeerId == nil) {
                return state.withUpdatedPeerIdWithRevealedOptions(peerId)
            } else {
                return state
            }
        }
    }, removePeer: { memberId in
        updateState {
            return $0.withUpdatedRemovingPeerId(memberId)
        }
        
        removePeerDisposable.set((context.peerChannelMemberCategoriesContextsManager.updateMemberBannedRights(account: context.account, peerId: peerId, memberId: memberId, bannedRights: TelegramChatBannedRights(flags: [.banReadMessages], untilDate: Int32.max))
        |> deliverOnMainQueue).start(completed: {
            updateState {
                return $0.withUpdatedRemovingPeerId(nil)
            }
        }))
    }, openPeer: { peer in
        if let controller = context.sharedContext.makePeerInfoController(context: context, peer: peer, mode: .generic) {
            pushControllerImpl?(controller)
        }
    }, inviteViaLink: {
        presentControllerImpl?(channelVisibilityController(context: context, peerId: peerId, mode: .privateLink, upgradedToSupergroup: { _, f in f() }), ViewControllerPresentationArguments(presentationAnimation: .modalSheet))
    })
    
    let peerView = context.account.viewTracker.peerView(peerId)
    
    let (disposable, loadMoreControl) = context.peerChannelMemberCategoriesContextsManager.recent(postbox: context.account.postbox, network: context.account.network, accountPeerId: context.account.peerId, peerId: peerId, updated: { state in
        peersPromise.set(.single(state.list))
    })
    actionsDisposable.add(disposable)
    
    var previousPeers: [RenderedChannelParticipant]?
    
    let signal = combineLatest(queue: .mainQueue(), context.sharedContext.presentationData, statePromise.get(), peerView, peersPromise.get())
    |> deliverOnMainQueue
    |> map { presentationData, state, view, peers -> (ItemListControllerState, (ItemListNodeState<ChannelMembersEntry>, ChannelMembersEntry.ItemGenerationArguments)) in
        var rightNavigationButton: ItemListNavigationButton?
        var secondaryRightNavigationButton: ItemListNavigationButton?
        if let peers = peers, !peers.isEmpty {
            if state.editing {
                rightNavigationButton = ItemListNavigationButton(content: .text(presentationData.strings.Common_Done), style: .bold, enabled: true, action: {
                    updateState { state in
                        return state.withUpdatedEditing(false)
                    }
                })
            } else {
                rightNavigationButton = ItemListNavigationButton(content: .text(presentationData.strings.Common_Edit), style: .regular, enabled: true, action: {
                    updateState { state in
                        return state.withUpdatedEditing(true)
                    }
                })
                if let cachedData = view.cachedData as? CachedChannelData, cachedData.participantsSummary.memberCount ?? 0 >= 200 {
                    secondaryRightNavigationButton = ItemListNavigationButton(content: .icon(.search), style: .regular, enabled: true, action: {
                        updateState { state in
                            return state.withUpdatedSearchingMembers(true)
                        }
                    })
                }
                
            }
        }
        
        var searchItem: ItemListControllerSearch?
        if state.searchingMembers {
            searchItem = ChannelMembersSearchItem(context: context, peerId: peerId, searchContext: nil, cancel: {
                updateState { state in
                    return state.withUpdatedSearchingMembers(false)
                }
            }, openPeer: { peer, _ in
                if let infoController = context.sharedContext.makePeerInfoController(context: context, peer: peer, mode: .generic) {
                    pushControllerImpl?(infoController)
                }
            }, pushController: { c in
                pushControllerImpl?(c)
            })
        }
        
        var emptyStateItem: ItemListControllerEmptyStateItem?
        if peers == nil || peers?.count == 0 {
            emptyStateItem = ItemListLoadingIndicatorEmptyStateItem(theme: presentationData.theme)
        }
        
        let previous = previousPeers
        previousPeers = peers
        
        let controllerState = ItemListControllerState(theme: presentationData.theme, title: .text(presentationData.strings.Channel_Subscribers_Title), leftNavigationButton: nil, rightNavigationButton: rightNavigationButton, secondaryRightNavigationButton: secondaryRightNavigationButton, backNavigationButton: ItemListBackButton(title: presentationData.strings.Common_Back), animateChanges: true)
        let listState = ItemListNodeState(entries: ChannelMembersControllerEntries(context: context, presentationData: presentationData, view: view, state: state, participants: peers), style: .blocks, emptyStateItem: emptyStateItem, searchItem: searchItem, animateChanges: previous != nil && peers != nil && previous!.count >= peers!.count)
        
        return (controllerState, (listState, arguments))
    }
    |> afterDisposed {
        actionsDisposable.dispose()
    }
    
    let controller = ItemListController(context: context, state: signal)
    presentControllerImpl = { [weak controller] c, p in
        if let controller = controller {
            controller.present(c, in: .window(.root), with: p)
        }
    }
    pushControllerImpl = { [weak controller] c in
        if let controller = controller {
            (controller.navigationController as? NavigationController)?.pushViewController(c)
        }
    }
    controller.visibleBottomContentOffsetChanged = { offset in
        if let loadMoreControl = loadMoreControl, case let .known(value) = offset, value < 40.0 {
            context.peerChannelMemberCategoriesContextsManager.loadMore(peerId: peerId, control: loadMoreControl)
        }
    }
    return controller
}