letro-ios/ElementX/Sources/Screens/RoomScreen/RoomScreenModels.swift

//
// Copyright 2024 New Vector Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

import Foundation
import OrderedCollections

enum RoomScreenViewModelAction {
    case focusEvent(eventID: String)
    case displayPinnedEventsTimeline
    case displayRoomDetails
    case displayCall
    case removeComposerFocus
}

enum RoomScreenViewAction {
    case tappedPinnedEventsBanner
    case viewAllPins
    case displayRoomDetails
    case displayCall
}

struct RoomScreenViewState: BindableState {
    var roomTitle = ""
    var roomAvatar: RoomAvatar
    
    var lastScrollDirection: ScrollDirection?
    var isPinningEnabled = false
    // This is used to control the banner
    var pinnedEventsBannerState: PinnedEventsBannerState = .loading(numbersOfEvents: 0)
    var shouldShowPinnedEventsBanner: Bool {
        isPinningEnabled && !pinnedEventsBannerState.isEmpty && lastScrollDirection != .top
    }
    
    var canJoinCall = false
    var hasOngoingCall: Bool
    var shouldShowCallButton = true
    
    var bindings: RoomScreenViewStateBindings
}

struct RoomScreenViewStateBindings { }

enum PinnedEventsBannerState: Equatable {
    case loading(numbersOfEvents: Int)
    case loaded(state: PinnedEventsState)
    
    var isEmpty: Bool {
        switch self {
        case .loaded(let state):
            return state.pinnedEventContents.isEmpty
        case .loading(let numberOfEvents):
            return numberOfEvents == 0
        }
    }
    
    var isLoading: Bool {
        switch self {
        case .loading:
            return true
        default:
            return false
        }
    }
    
    var selectedPinEventID: String? {
        switch self {
        case .loaded(let state):
            return state.selectedPinEventID
        default:
            return nil
        }
    }
    
    var count: Int {
        switch self {
        case .loaded(let state):
            return state.pinnedEventContents.count
        case .loading(let numberOfEvents):
            return numberOfEvents
        }
    }
    
    var selectedPinIndex: Int {
        switch self {
        case .loaded(let state):
            return state.selectedPinIndex
        case .loading(let numbersOfEvents):
            // We always want the index to be the last one when loading, since is the default one.
            return numbersOfEvents - 1
        }
    }
    
    var displayedMessage: AttributedString {
        switch self {
        case .loading:
            return AttributedString(L10n.screenRoomPinnedBannerLoadingDescription)
        case .loaded(let state):
            return state.selectedPinContent
        }
    }
    
    var bannerIndicatorDescription: AttributedString {
        let index = selectedPinIndex + 1
        let boldPlaceholder = "{bold}"
        var finalString = AttributedString(L10n.screenRoomPinnedBannerIndicatorDescription(boldPlaceholder))
        var boldString = AttributedString(L10n.screenRoomPinnedBannerIndicator(index, count))
        boldString.bold()
        finalString.replace(boldPlaceholder, with: boldString)
        return finalString
    }
    
    mutating func previousPin() {
        switch self {
        case .loaded(var state):
            state.previousPin()
            self = .loaded(state: state)
        default:
            break
        }
    }
    
    mutating func setPinnedEventContents(_ pinnedEventContents: OrderedDictionary<String, AttributedString>) {
        switch self {
        case .loading:
            // The default selected event should always be the last one.
            self = .loaded(state: .init(pinnedEventContents: pinnedEventContents, selectedPinEventID: pinnedEventContents.keys.last))
        case .loaded(var state):
            state.pinnedEventContents = pinnedEventContents
            self = .loaded(state: state)
        }
    }
}