session-ios/Session/Settings/ConversationSettingsViewModel.swift

// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import Foundation
import GRDB
import DifferenceKit
import SessionUIKit
import SessionMessagingKit
import SessionUtilitiesKit

class ConversationSettingsViewModel: SessionTableViewModel<NoNav, ConversationSettingsViewModel.Section, ConversationSettingsViewModel.Section> {
    // MARK: - Section
    
    public enum Section: SessionTableSection {
        case messageTrimming
        case audioMessages
        case blockedContacts
        
        var title: String? {
            switch self {
                case .messageTrimming: return "CONVERSATION_SETTINGS_SECTION_MESSAGE_TRIMMING".localized()
                case .audioMessages: return "CONVERSATION_SETTINGS_SECTION_AUDIO_MESSAGES".localized()
                case .blockedContacts: return nil
            }
        }
        
        var style: SessionTableSectionStyle {
            switch self {
                case .blockedContacts: return .padding
                default: return .titleRoundedContent
            }
        }
    }
    
    // MARK: - Content
    
    private struct State: Equatable {
        let trimOpenGroupMessagesOlderThanSixMonths: Bool
        let shouldAutoPlayConsecutiveAudioMessages: Bool
    }
    
    override var title: String { "CONVERSATION_SETTINGS_TITLE".localized() }
    
    public override var observableTableData: ObservableData { _observableTableData }
    
    /// This is all the data the screen needs to populate itself, please see the following link for tips to help optimise
    /// performance https://github.com/groue/GRDB.swift#valueobservation-performance
    ///
    /// **Note:** This observation will be triggered twice immediately (and be de-duped by the `removeDuplicates`)
    /// this is due to the behaviour of `ValueConcurrentObserver.asyncStartObservation` which triggers it's own
    /// fetch (after the ones in `ValueConcurrentObserver.asyncStart`/`ValueConcurrentObserver.syncStart`)
    /// just in case the database has changed between the two reads - unfortunately it doesn't look like there is a way to prevent this
    private lazy var _observableTableData: ObservableData = ValueObservation
        .trackingConstantRegion { [weak self] db -> State in
            State(
                trimOpenGroupMessagesOlderThanSixMonths: db[.trimOpenGroupMessagesOlderThanSixMonths],
                shouldAutoPlayConsecutiveAudioMessages: db[.shouldAutoPlayConsecutiveAudioMessages]
            )
        }
        .removeDuplicates()
        .handleEvents(didFail: { SNLog("[ConversationSettingsViewModel] Observation failed with error: \($0)") })
        .publisher(in: Storage.shared)
        .withPrevious()
        .map { (previous: State?, current: State) -> [SectionModel] in
            return [
                SectionModel(
                    model: .messageTrimming,
                    elements: [
                        SessionCell.Info(
                            id: .messageTrimming,
                            title: "CONVERSATION_SETTINGS_MESSAGE_TRIMMING_TITLE".localized(),
                            subtitle: "CONVERSATION_SETTINGS_MESSAGE_TRIMMING_DESCRIPTION".localized(),
                            rightAccessory: .toggle(
                                .boolValue(
                                    key: .trimOpenGroupMessagesOlderThanSixMonths,
                                    value: current.trimOpenGroupMessagesOlderThanSixMonths,
                                    oldValue: (previous ?? current).trimOpenGroupMessagesOlderThanSixMonths
                                )
                            ),
                            onTap: {
                                Storage.shared.write { db in
                                    db[.trimOpenGroupMessagesOlderThanSixMonths] = !db[.trimOpenGroupMessagesOlderThanSixMonths]
                                }
                            }
                        )
                    ]
                ),
                SectionModel(
                    model: .audioMessages,
                    elements: [
                        SessionCell.Info(
                            id: .audioMessages,
                            title: "CONVERSATION_SETTINGS_AUDIO_MESSAGES_AUTOPLAY_TITLE".localized(),
                            subtitle: "CONVERSATION_SETTINGS_AUDIO_MESSAGES_AUTOPLAY_DESCRIPTION".localized(),
                            rightAccessory: .toggle(
                                .boolValue(
                                    key: .shouldAutoPlayConsecutiveAudioMessages,
                                    value: current.shouldAutoPlayConsecutiveAudioMessages,
                                    oldValue: (previous ?? current).shouldAutoPlayConsecutiveAudioMessages
                                )
                            ),
                            onTap: {
                                Storage.shared.write { db in
                                    db[.shouldAutoPlayConsecutiveAudioMessages] = !db[.shouldAutoPlayConsecutiveAudioMessages]
                                }
                            }
                        )
                    ]
                ),
                SectionModel(
                    model: .blockedContacts,
                    elements: [
                        SessionCell.Info(
                            id: .blockedContacts,
                            title: "CONVERSATION_SETTINGS_BLOCKED_CONTACTS_TITLE".localized(),
                            styling: SessionCell.StyleInfo(
                                tintColor: .danger,
                                backgroundStyle: .noBackground
                            ),
                            onTap: { [weak self] in
                                self?.transitionToScreen(
                                    SessionTableViewController(viewModel: BlockedContactsViewModel())
                                )
                            }
                        )
                    ]
                )
            ]
        }
        .mapToSessionTableViewData(for: self)
}