import Foundation
import UIKit
import Display
import SwiftSignalKit
import Postbox
import TelegramCore
import SyncCore
import TelegramPresentationData
import TelegramUIPreferences
import ItemListUI
import PresentationDataUtils
import AccountContext
import ItemListPeerItem
import ItemListPeerActionItem

private final class SelectivePrivacyPeersControllerArguments {
    let context: AccountContext
    
    let setPeerIdWithRevealedOptions: (PeerId?, PeerId?) -> Void
    let removePeer: (PeerId) -> Void
    let addPeer: () -> Void
    let openPeer: (PeerId) -> Void
    
    init(context: AccountContext, setPeerIdWithRevealedOptions: @escaping (PeerId?, PeerId?) -> Void, removePeer: @escaping (PeerId) -> Void, addPeer: @escaping () -> Void, openPeer: @escaping (PeerId) -> Void) {
        self.context = context
        self.setPeerIdWithRevealedOptions = setPeerIdWithRevealedOptions
        self.removePeer = removePeer
        self.addPeer = addPeer
        self.openPeer = openPeer
    }
}

private enum SelectivePrivacyPeersSection: Int32 {
    case add
    case peers
}

private enum SelectivePrivacyPeersEntryStableId: Hashable {
    case add
    case peer(PeerId)
    
    var hashValue: Int {
        switch self {
            case let .peer(peerId):
                return peerId.hashValue
            case .add:
                return 1
        }
    }
    
    static func ==(lhs: SelectivePrivacyPeersEntryStableId, rhs: SelectivePrivacyPeersEntryStableId) -> Bool {
        switch lhs {
            case let .peer(peerId):
                if case .peer(peerId) = rhs {
                    return true
                } else {
                    return false
                }
            case .add:
                if case .add = rhs {
                    return true
                } else {
                    return false
                }
        }
    }
}

private enum SelectivePrivacyPeersEntry: ItemListNodeEntry {
    case peerItem(Int32, PresentationTheme, PresentationStrings, PresentationDateTimeFormat, PresentationPersonNameOrder, SelectivePrivacyPeer, ItemListPeerItemEditing, Bool)
    case addItem(PresentationTheme, String, Bool)
    
    var section: ItemListSectionId {
        switch self {
            case .peerItem:
                return SelectivePrivacyPeersSection.peers.rawValue
            case .addItem:
                return SelectivePrivacyPeersSection.add.rawValue
        }
    }
    
    var stableId: SelectivePrivacyPeersEntryStableId {
        switch self {
            case let .peerItem(_, _, _, _, _, peer, _, _):
                return .peer(peer.peer.id)
            case .addItem:
                return .add
        }
    }
    
    static func ==(lhs: SelectivePrivacyPeersEntry, rhs: SelectivePrivacyPeersEntry) -> Bool {
        switch lhs {
        case let .peerItem(lhsIndex, lhsTheme, lhsStrings, lhsDateTimeFormat, lhsNameOrder, lhsPeer, lhsEditing, lhsEnabled):
                if case let .peerItem(rhsIndex, rhsTheme, rhsStrings, rhsDateTimeFormat, rhsNameOrder, rhsPeer, rhsEditing, rhsEnabled) = rhs {
                    if lhsIndex != rhsIndex {
                        return false
                    }
                    if lhsPeer != rhsPeer {
                        return false
                    }
                    if lhsTheme !== rhsTheme {
                        return false
                    }
                    if lhsStrings !== rhsStrings {
                        return false
                    }
                    if lhsDateTimeFormat != rhsDateTimeFormat {
                        return false
                    }
                    if lhsNameOrder != rhsNameOrder {
                        return false
                    }
                    if lhsEditing != rhsEditing {
                        return false
                    }
                    if lhsEnabled != rhsEnabled {
                        return false
                    }
                    return true
                } else {
                    return false
                }
            case let .addItem(lhsTheme, lhsText, lhsEditing):
                if case let .addItem(rhsTheme, rhsText, rhsEditing) = rhs, lhsTheme === rhsTheme, lhsText == rhsText, lhsEditing == rhsEditing {
                    return true
                } else {
                    return false
                }
        }
    }
    
    static func <(lhs: SelectivePrivacyPeersEntry, rhs: SelectivePrivacyPeersEntry) -> Bool {
        switch lhs {
            case let .peerItem(index, _, _, _, _, _, _, _):
                switch rhs {
                    case let .peerItem(rhsIndex, _, _, _, _, _, _, _):
                        return index < rhsIndex
                    case .addItem:
                        return false
                }
            case .addItem:
                switch rhs {
                    case .peerItem:
                        return true
                    default:
                        return false
                }
        }
    }
    
    func item(presentationData: ItemListPresentationData, arguments: Any) -> ListViewItem {
        let arguments = arguments as! SelectivePrivacyPeersControllerArguments
        switch self {
            case let .peerItem(_, theme, strings, dateTimeFormat, nameDisplayOrder, peer, editing, enabled):
                var text: ItemListPeerItemText = .none
                if let group = peer.peer as? TelegramGroup {
                    text = .text(strings.Conversation_StatusMembers(Int32(group.participantCount)))
                } else if let channel = peer.peer as? TelegramChannel {
                    if let participantCount = peer.participantCount {
                        text = .text(strings.Conversation_StatusMembers(Int32(participantCount)))
                    } else {
                        switch channel.info {
                            case .group:
                                text = .text(strings.Group_Status)
                            case .broadcast:
                                text = .text(strings.Channel_Status)
                        }
                    }
                }
                return ItemListPeerItem(presentationData: presentationData, dateTimeFormat: dateTimeFormat, nameDisplayOrder: nameDisplayOrder, context: arguments.context, peer: peer.peer, presence: nil, text: text, label: .none, editing: editing, switchValue: nil, enabled: enabled, selectable: true, sectionId: self.section, action: {
                    arguments.openPeer(peer.peer.id)
                }, setPeerIdWithRevealedOptions: { previousId, id in
                    arguments.setPeerIdWithRevealedOptions(previousId, id)
                }, removePeer: { peerId in
                    arguments.removePeer(peerId)
                })
            case let .addItem(theme, text, editing):
                return ItemListPeerActionItem(presentationData: presentationData, icon: PresentationResourcesItemList.plusIconImage(theme), title: text, sectionId: self.section, editing: editing, action: {
                    arguments.addPeer()
                })
        }
    }
}

private struct SelectivePrivacyPeersControllerState: Equatable {
    let editing: Bool
    let peerIdWithRevealedOptions: PeerId?
    
    init() {
        self.editing = false
        self.peerIdWithRevealedOptions = nil
    }
    
    init(editing: Bool, peerIdWithRevealedOptions: PeerId?) {
        self.editing = editing
        self.peerIdWithRevealedOptions = peerIdWithRevealedOptions
    }
    
    static func ==(lhs: SelectivePrivacyPeersControllerState, rhs: SelectivePrivacyPeersControllerState) -> Bool {
        if lhs.editing != rhs.editing {
            return false
        }
        if lhs.peerIdWithRevealedOptions != rhs.peerIdWithRevealedOptions {
            return false
        }
        return true
    }
    
    func withUpdatedEditing(_ editing: Bool) -> SelectivePrivacyPeersControllerState {
        return SelectivePrivacyPeersControllerState(editing: editing, peerIdWithRevealedOptions: self.peerIdWithRevealedOptions)
    }
    
    func withUpdatedPeerIdWithRevealedOptions(_ peerIdWithRevealedOptions: PeerId?) -> SelectivePrivacyPeersControllerState {
        return SelectivePrivacyPeersControllerState(editing: self.editing, peerIdWithRevealedOptions: peerIdWithRevealedOptions)
    }
}

private func selectivePrivacyPeersControllerEntries(presentationData: PresentationData, state: SelectivePrivacyPeersControllerState, peers: [SelectivePrivacyPeer]) -> [SelectivePrivacyPeersEntry] {
    var entries: [SelectivePrivacyPeersEntry] = []
    
    entries.append(.addItem(presentationData.theme, presentationData.strings.Privacy_AddNewPeer, state.editing))
    
    var index: Int32 = 0
    for peer in peers {
        entries.append(.peerItem(index, presentationData.theme, presentationData.strings, presentationData.dateTimeFormat, presentationData.nameDisplayOrder, peer, ItemListPeerItemEditing(editable: true, editing: state.editing, revealed: peer.peer.id == state.peerIdWithRevealedOptions), true))
        index += 1
    }
    
    return entries
}

public func selectivePrivacyPeersController(context: AccountContext, title: String, initialPeers: [PeerId: SelectivePrivacyPeer], updated: @escaping ([PeerId: SelectivePrivacyPeer]) -> Void) -> ViewController {
    let statePromise = ValuePromise(SelectivePrivacyPeersControllerState(), ignoreRepeated: true)
    let stateValue = Atomic(value: SelectivePrivacyPeersControllerState())
    let updateState: ((SelectivePrivacyPeersControllerState) -> SelectivePrivacyPeersControllerState) -> Void = { f in
        statePromise.set(stateValue.modify { f($0) })
    }
    
    var dismissImpl: (() -> Void)?
    var presentControllerImpl: ((ViewController, ViewControllerPresentationArguments?) -> Void)?
    var pushControllerImpl: ((ViewController) -> Void)?
    
    let actionsDisposable = DisposableSet()
    
    let addPeerDisposable = MetaDisposable()
    actionsDisposable.add(addPeerDisposable)
    
    let removePeerDisposable = MetaDisposable()
    actionsDisposable.add(removePeerDisposable)
    
    let peersPromise = Promise<[SelectivePrivacyPeer]>()
    peersPromise.set(context.account.postbox.transaction { transaction -> [SelectivePrivacyPeer] in
        return Array(initialPeers.values)
    })
    
    let arguments = SelectivePrivacyPeersControllerArguments(context: context, 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
        let applyPeers: Signal<Void, NoError> = peersPromise.get()
        |> take(1)
        |> deliverOnMainQueue
        |> mapToSignal { peers -> Signal<Void, NoError> in
            var updatedPeers = peers
            for i in 0 ..< updatedPeers.count {
                if updatedPeers[i].peer.id == memberId {
                    updatedPeers.remove(at: i)
                    break
                }
            }
            peersPromise.set(.single(updatedPeers))
            
            var updatedPeerDict: [PeerId: SelectivePrivacyPeer] = [:]
            for peer in updatedPeers {
                updatedPeerDict[peer.peer.id] = peer
            }
            updated(updatedPeerDict)
            
            if updatedPeerDict.isEmpty {
                dismissImpl?()
            }
            
            return .complete()
        }
        
        removePeerDisposable.set(applyPeers.start())
    }, addPeer: {
        let controller = context.sharedContext.makeContactMultiselectionController(ContactMultiselectionControllerParams(context: context, mode: .peerSelection(searchChatList: true, searchGroups: true), options: []))
        addPeerDisposable.set((controller.result
        |> take(1)
        |> deliverOnMainQueue).start(next: { [weak controller] peerIds in
            let applyPeers: Signal<Void, NoError> = peersPromise.get()
            |> take(1)
            |> mapToSignal { peers -> Signal<[SelectivePrivacyPeer], NoError> in
                return context.account.postbox.transaction { transaction -> [SelectivePrivacyPeer] in
                    var updatedPeers = peers
                    var existingIds = Set(updatedPeers.map { $0.peer.id })
                    for peerId in peerIds {
                        guard case let .peer(peerId) = peerId else {
                            continue
                        }
                        if let peer = transaction.getPeer(peerId), !existingIds.contains(peerId) {
                            existingIds.insert(peerId)
                            var participantCount: Int32?
                            if let channel = peer as? TelegramChannel, case .group = channel.info {
                                if let cachedData = transaction.getPeerCachedData(peerId: peerId) as? CachedChannelData {
                                    participantCount = cachedData.participantsSummary.memberCount
                                }
                            }
                            
                            updatedPeers.append(SelectivePrivacyPeer(peer: peer, participantCount: participantCount))
                        }
                    }
                    return updatedPeers
                }
            }
            |> deliverOnMainQueue
            |> mapToSignal { updatedPeers -> Signal<Void, NoError> in
                peersPromise.set(.single(updatedPeers))
                
                var updatedPeerDict: [PeerId: SelectivePrivacyPeer] = [:]
                for peer in updatedPeers {
                    updatedPeerDict[peer.peer.id] = peer
                }
                updated(updatedPeerDict)
                
                return .complete()
            }
            
            removePeerDisposable.set(applyPeers.start())
            controller?.dismiss()
        }))
        presentControllerImpl?(controller, ViewControllerPresentationArguments(presentationAnimation: .modalSheet))
    }, openPeer: { peerId in
        let _ = (context.account.postbox.transaction { transaction -> Peer? in
            return transaction.getPeer(peerId)
        }
        |> deliverOnMainQueue).start(next: { peer in
            guard let peer = peer, let controller = context.sharedContext.makePeerInfoController(context: context, peer: peer, mode: .generic, avatarInitiallyExpanded: false, fromChat: false) else {
                return
            }
            pushControllerImpl?(controller)
        })
    })
    
    var previousPeers: [SelectivePrivacyPeer]?
    
    let signal = combineLatest(context.sharedContext.presentationData, statePromise.get(), peersPromise.get())
    |> deliverOnMainQueue
    |> map { presentationData, state, peers -> (ItemListControllerState, (ItemListNodeState, Any)) in
        var rightNavigationButton: ItemListNavigationButton?
        if !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)
                    }
                })
            }
        }
        
        let previous = previousPeers
        previousPeers = peers
        
        let controllerState = ItemListControllerState(presentationData: ItemListPresentationData(presentationData), title: .text(title), leftNavigationButton: nil, rightNavigationButton: rightNavigationButton, backNavigationButton: ItemListBackButton(title: presentationData.strings.Common_Back), animateChanges: true)
        let listState = ItemListNodeState(presentationData: ItemListPresentationData(presentationData), entries: selectivePrivacyPeersControllerEntries(presentationData: presentationData, state: state, peers: peers), style: .blocks, emptyStateItem: nil, animateChanges: previous != nil && previous!.count >= peers.count)
        
        return (controllerState, (listState, arguments))
    }
    |> afterDisposed {
        actionsDisposable.dispose()
    }
    
    let controller = ItemListController(context: context, state: signal)
    dismissImpl = { [weak controller] in
        if let controller = controller, let navigationController = controller.navigationController as? NavigationController {
            navigationController.filterController(controller, animated: true)
        }
    }
    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 navigationController = controller?.navigationController as? NavigationController {
            navigationController.pushViewController(c)
        }
    }
    return controller
}