import MusicAssistantCore
import SwiftUI

struct LanguageBrowserView: View {
    @Binding private var project: SongProject
    private let saveProject: (SongProject) async -> Bool
    private let catalog: LocalLanguageCatalog

    @State private var searchText = ""
    @State private var selectedFamilyCategory: String?
    @State private var hasUnsavedSelectionChanges = false
    @State private var isSaving = false
    @Environment(\.dismiss) private var dismiss

    init(
        project: Binding<SongProject>,
        saveProject: @escaping (SongProject) async -> Bool = { _ in true },
        catalog: LocalLanguageCatalog = LocalLanguageCatalog()
    ) {
        _project = project
        self.saveProject = saveProject
        self.catalog = catalog
    }

    var body: some View {
        NavigationStack {
            List(
                catalog.languages(
                    matching: searchText,
                    familyCategory: selectedFamilyCategory
                ),
                id: \.id
            ) { language in
                Toggle(isOn: selectionBinding(for: language)) {
                    VStack(alignment: .leading, spacing: 4) {
                        Text(language.name)
                            .font(.body.weight(.medium))

                        Text(language.familyCategory)
                            .font(.caption)
                            .foregroundStyle(.secondary)
                    }
                }
                .toggleStyle(.checkbox)
                .padding(.vertical, 2)
            }
            .navigationTitle("Language Catalog")
            .searchable(text: $searchText, prompt: "Search languages")
            .toolbar {
                ToolbarItem(placement: .automatic) {
                    Picker("Region", selection: $selectedFamilyCategory) {
                        Text("All regions").tag(String?.none)

                        ForEach(catalog.familyCategories, id: \.self) { familyCategory in
                            Text(familyCategory).tag(Optional(familyCategory))
                        }
                    }
                    .pickerStyle(.menu)
                }

                ToolbarItem(placement: .cancellationAction) {
                    Button("Done") {
                        Task {
                            await saveSelectionChangesIfNeeded()
                            dismiss()
                        }
                    }
                    .disabled(isSaving)
                }

                if isSaving {
                    ToolbarItem(placement: .status) {
                        ProgressView()
                            .controlSize(.small)
                    }
                }
            }
        }
        .frame(minWidth: 480, minHeight: 560)
        .onDisappear {
            guard hasUnsavedSelectionChanges, !isSaving else { return }

            let projectToSave = project
            hasUnsavedSelectionChanges = false

            Task {
                _ = await saveProject(projectToSave)
            }
        }
    }

    private func selectionBinding(for item: LanguageCatalogItem) -> Binding<Bool> {
        Binding {
            project.language(for: item.id) != nil
        } set: { isSelected in
            if isSelected {
                project.upsertLanguage(item.language)
            } else {
                project.removeLanguage(id: item.id)
            }
            hasUnsavedSelectionChanges = true
        }
    }

    private func saveSelectionChangesIfNeeded() async {
        guard hasUnsavedSelectionChanges else { return }

        isSaving = true
        let didSave = await saveProject(project)
        hasUnsavedSelectionChanges = !didSave
        isSaving = false
    }
}

#Preview {
    LanguageBrowserPreview()
}

private struct LanguageBrowserPreview: View {
    @State private var project = SongProject(
        title: "Language Catalog Preview",
        idea: "Choose song languages."
    )

    var body: some View {
        LanguageBrowserView(project: $project)
    }
}