//
//  FiltersView.swift
//  Tusker
//
//  Created by Shadowfacts on 11/30/22.
//  Copyright © 2022 Shadowfacts. All rights reserved.
//

import SwiftUI
import Pachyderm

struct FiltersView: View {
    let mastodonController: MastodonController
    
    var body: some View {
        FiltersList()
            .environmentObject(mastodonController)
            .environment(\.managedObjectContext, mastodonController.persistentContainer.viewContext)
    }
    
}

struct FiltersList: View {
    @EnvironmentObject private var mastodonController: MastodonController
    @FetchRequest(sortDescriptors: []) private var filters: FetchedResults<FilterMO>
    @Environment(\.dismiss) private var dismiss
    @State private var deletionError: (any Error)?
    @State private var updatingError: (any Error)?
    
    var body: some View {
        if #available(iOS 16.0, *) {
            NavigationStack {
                navigationBody
            }
        } else {
            NavigationView {
                navigationBody
            }
            .navigationViewStyle(.stack)
        }
    }
    
    private var unexpiredFilters: [FilterMO] {
        filters.filter { $0.expiresAt == nil || $0.expiresAt! > Date() }.sorted(using: SemiCaseSensitiveComparator.keyPath(\.titleOrKeyword))
    }
    
    private var expiredFilters: [FilterMO] {
        filters.filter { $0.expiresAt != nil && $0.expiresAt! <= Date() }.sorted(using: SemiCaseSensitiveComparator.keyPath(\.titleOrKeyword))
    }
    
    private var navigationBody: some View {
        List {
            Section {
                NavigationLink {
                    EditFilterView(filter: EditedFilter(), create: true, saveFilter: createFilter)
                } label: {
                    Label("Add Filter", systemImage: "plus")
                        .foregroundColor(.accentColor)
                }
            }
            
            filtersSection(unexpiredFilters)
            filtersSection(expiredFilters)
        }
        .navigationTitle(Text("Filters"))
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .confirmationAction) {
                Button("Done") {
                    dismiss()
                }
            }
        }
        .alertWithData("Error Deleting Filter", data: $deletionError, actions: { _ in
            Button("OK") {
                self.deletionError = nil
            }
        }, message: { error in
            Text(error.localizedDescription)
        })
        .alertWithData("Error Update Filter", data: $updatingError, actions: { _ in
            Button("OK") {
                self.updatingError = nil
            }
        }, message: { error in
            Text(error.localizedDescription)
        })
        .task {
            await mastodonController.loadFilters()
        }
    }
    
    private func filtersSection(_ filters: [FilterMO]) -> some View {
        Section {
            ForEach(filters, id: \.id) { filter in
                NavigationLink {
                    EditFilterView(filter: EditedFilter(filter), create: false, saveFilter: updateFilter)
                } label: {
                    FilterRow(filter: filter)
                }
                .contextMenu {
                    Button(role: .destructive) {
                        deleteFilter(filter)
                    } label: {
                        Text("Delete Filter")
                    }

                }
            }
            .onDelete { indices in
                for filter in indices.map({ filters[$0] }) {
                    deleteFilter(filter)
                }
            }
        }
    }
    
    private func deleteFilter(_ filter: FilterMO) {
        Task { @MainActor in
            let req = FilterV1.delete(filter.id)
            do {
                _ = try await mastodonController.run(req)
                let context = mastodonController.persistentContainer.viewContext
                context.delete(filter)
                mastodonController.persistentContainer.save(context: context)
            } catch {
                self.deletionError = error
            }
        }
    }
    
    private func updateFilter(_ filter: EditedFilter) async throws {
        let mo = filters.first(where: { $0.id == filter.id })!
        
        let updateFrom: AnyFilter
        if mastodonController.instanceFeatures.filtersV2 {
            var updates = filter.keywords.map {
                if let id = $0.id {
                    return FilterV2.KeywordUpdate.update(id: id, keyword: $0.keyword, wholeWord: $0.wholeWord)
                } else {
                    return FilterV2.KeywordUpdate.add(keyword: $0.keyword, wholeWord: $0.wholeWord)
                }
            }
            for existing in mo.keywordMOs where !filter.keywords.contains(where: {  existing.id == $0.id }) {
                if let id = existing.id {
                    updates.append(.destroy(id: id))
                }
            }
            let req = FilterV2.update(filter.id!, title: filter.title ?? "", context: filter.contexts, expiresIn: filter.expiresIn, action: filter.action, keywords: updates)
            let (updated, _) = try await mastodonController.run(req)
            updateFrom = .v2(updated)
        } else {
            let req = FilterV1.update(filter.id!, phrase: filter.keywords.first!.keyword, context: filter.contexts, irreversible: false, wholeWord: filter.keywords.first!.wholeWord, expiresIn: filter.expiresIn)
            let (updated, _) = try await mastodonController.run(req)
            updateFrom = .v1(updated)
        }
        
        let context = mastodonController.persistentContainer.viewContext
        mo.updateFrom(apiFilter: updateFrom, context: context)
        mastodonController.persistentContainer.save(context: context)
    }
    
    private func createFilter(_ filter: EditedFilter) async throws {
        let updateFrom: AnyFilter
        if mastodonController.instanceFeatures.filtersV2 {
            let updates = filter.keywords.map {
                FilterV2.KeywordUpdate.add(keyword: $0.keyword, wholeWord: $0.wholeWord)
            }
            let req = FilterV2.create(title: filter.title!, context: filter.contexts, expiresIn: filter.expiresIn, action: filter.action, keywords: updates)
            let (updated, _) = try await mastodonController.run(req)
            updateFrom = .v2(updated)
        } else {
            let req = Client.createFilterV1(phrase: filter.keywords.first!.keyword, context: filter.contexts, irreversible: nil, wholeWord: filter.keywords.first!.wholeWord, expiresIn: filter.expiresIn)
            let (updated, _) = try await mastodonController.run(req)
            updateFrom = .v1(updated)
        }
        let context = mastodonController.persistentContainer.viewContext
        let mo = FilterMO(context: context)
        mo.updateFrom(apiFilter: updateFrom, context: context)
        mastodonController.persistentContainer.save(context: context)
    }
}

//struct FiltersView_Previews: PreviewProvider {
//    static var previews: some View {
//        FiltersView()
//    }
//}