//
// Copyright 2026 Novaloop AG
//
// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
// Please see LICENSE files in the repository root for full details.
//

import Combine
import SwiftUI

typealias HealthChatProfileEditScreenViewModelType = StateStoreViewModelV2<HealthChatProfileEditScreenViewState, HealthChatProfileEditScreenViewAction>

class HealthChatProfileEditScreenViewModel: HealthChatProfileEditScreenViewModelType, HealthChatProfileEditScreenViewModelProtocol {
    private let clientProxy: ClientProxyProtocol
    private let apiService: HealthChatAPIServiceProtocol
    private let mediaUploadingPreprocessor: MediaUploadingPreprocessor
    private let userIndicatorController: UserIndicatorControllerProtocol
    
    private let actionsSubject: PassthroughSubject<HealthChatProfileEditScreenViewModelAction, Never> = .init()
    var actionsPublisher: AnyPublisher<HealthChatProfileEditScreenViewModelAction, Never> {
        actionsSubject.eraseToAnyPublisher()
    }
    
    init(userSession: UserSessionProtocol,
         apiService: HealthChatAPIServiceProtocol,
         mediaUploadingPreprocessor: MediaUploadingPreprocessor,
         userIndicatorController: UserIndicatorControllerProtocol) {
        clientProxy = userSession.clientProxy
        self.apiService = apiService
        self.mediaUploadingPreprocessor = mediaUploadingPreprocessor
        self.userIndicatorController = userIndicatorController
        
        super.init(initialViewState: HealthChatProfileEditScreenViewState(), mediaProvider: userSession.mediaProvider)
        
        Task { await loadProfile() }
    }
    
    // MARK: - Public
    
    override func process(viewAction: HealthChatProfileEditScreenViewAction) {
        switch viewAction {
        case .cancel:
            showUnsavedChangesAlert() // The cancel button is only shown when there are unsaved changes.
        case .save:
            Task { await saveProfile() }
        case .retry:
            Task { await loadProfile() }
        case .presentMediaSource:
            state.bindings.showMediaSheet = true
        case .displayCameraPicker:
            actionsSubject.send(.displayCameraPicker)
        case .displayMediaPicker:
            actionsSubject.send(.displayMediaPicker)
        case .displayFilePicker:
            actionsSubject.send(.displayFilePicker)
        case .removeImage:
            state.localMedia = nil
            state.selectedAvatarURL = nil
        }
    }
    
    func didSelectMediaURL(url: URL) {
        Task {
            let userIndicatorID = UUID().uuidString
            defer { userIndicatorController.retractIndicatorWithId(userIndicatorID) }
            userIndicatorController.submitIndicator(UserIndicator(id: userIndicatorID,
                                                                  type: .modal(progress: .indeterminate, interactiveDismissDisabled: true, allowsInteraction: false),
                                                                  title: L10n.commonLoading,
                                                                  persistent: true))
            
            guard case let .success(maxUploadSize) = await clientProxy.maxMediaUploadSize else {
                MXLog.error("Failed to get max upload size")
                state.bindings.alertInfo = .init(id: .unknown)
                return
            }
            let mediaResult = await mediaUploadingPreprocessor.processMedia(at: url, maxUploadSize: maxUploadSize)
            
            switch mediaResult {
            case .success(.image):
                state.localMedia = try? mediaResult.get()
            case .failure, .success:
                state.bindings.alertInfo = .init(id: .failedProcessingMedia)
            }
        }
    }
    
    // MARK: - Private
    
    private func loadProfile() async {
        state.loadFailed = false
        
        state.canEditAvatar = await clientProxy.capabilities.canChangeAvatar()
        
        switch await apiService.ownProfile() {
        case .success(let profile):
            state.selectedAvatarURL = profile.avatarURL
            state.bindings.title = profile.title ?? ""
            state.bindings.firstName = profile.firstName ?? ""
            state.bindings.lastName = profile.lastName ?? ""
            state.bindings.specialty = profile.specialty ?? ""
            state.bindings.practiceName = profile.practiceName ?? ""
            state.bindings.businessCity = profile.businessCity ?? ""
            state.bindings.businessEmail = profile.businessEmail ?? ""
            state.bindings.businessTel = profile.businessTel ?? ""
            state.bindings.furtherInfo = profile.furtherInfo ?? ""
            state.bindings.street = profile.street ?? ""
            state.bindings.houseNumber = profile.houseNumber ?? ""
            state.bindings.postalCode = profile.postalCode ?? ""
            state.bindings.website = profile.website ?? ""
            state.initialProfile = profile
        case .failure:
            state.loadFailed = true
        }
    }
    
    private func showUnsavedChangesAlert() {
        state.bindings.alertInfo = .init(id: .unsavedChanges,
                                         title: L10n.dialogUnsavedChangesTitle,
                                         message: L10n.dialogUnsavedChangesDescription,
                                         primaryButton: .init(title: L10n.actionSave) { Task { await self.saveProfile() } },
                                         secondaryButton: .init(title: L10n.actionDiscard, role: .cancel) { self.actionsSubject.send(.dismiss) })
    }
    
    private func saveProfile() async {
        let userIndicatorID = UUID().uuidString
        defer { userIndicatorController.retractIndicatorWithId(userIndicatorID) }
        userIndicatorController.submitIndicator(UserIndicator(id: userIndicatorID,
                                                              type: .modal(progress: .indeterminate, interactiveDismissDisabled: true, allowsInteraction: false),
                                                              title: L10n.screenEditProfileUpdatingDetails,
                                                              persistent: true))
        
        do {
            if state.avatarDidChange {
                try await saveAvatar()
            }
            
            // The fields go second so the derived display name reflects the latest names.
            if let update = state.fieldsUpdate {
                try await apiService.updateOwnProfile(update).get()
            }
            
            actionsSubject.send(.dismiss)
        } catch {
            MXLog.error("Failed saving the HealthChat profile with error: \(error)")
            state.bindings.alertInfo = .init(id: .saveError,
                                             title: L10n.screenEditProfileErrorTitle,
                                             message: L10n.screenEditProfileError)
        }
    }
    
    private func saveAvatar() async throws {
        if let localMedia = state.localMedia {
            try await clientProxy.setUserAvatar(media: localMedia).get()
        } else if state.selectedAvatarURL == nil {
            try await clientProxy.removeUserAvatar().get()
        }
    }
}