//
//  CategoryReorderSheet.swift
//  Nextcloud Cookbook iOS Client
//

import SwiftUI

struct CategoryReorderSheet: View {
    @EnvironmentObject var appState: AppState
    @Environment(\.dismiss) private var dismiss

    private static let allRecipesSentinel = "__ALL_RECIPES__"

    @State private var orderedNames: [String] = []

    var body: some View {
        NavigationStack {
            List {
                ForEach(orderedNames, id: \.self) { name in
                    HStack {
                        if name == Self.allRecipesSentinel {
                            Text("All Recipes")
                                .bold()
                        } else {
                            Text(name)
                        }
                        Spacer()
                        if name == Self.allRecipesSentinel {
                            let total = appState.categories.reduce(0) { $0 + $1.recipe_count }
                            Text("\(total)")
                                .foregroundStyle(.secondary)
                                .font(.subheadline)
                        } else if let count = appState.categories.first(where: { $0.name == name })?.recipe_count {
                            Text("\(count)")
                                .foregroundStyle(.secondary)
                                .font(.subheadline)
                        }
                    }
                }
                .onMove { from, to in
                    orderedNames.move(fromOffsets: from, toOffset: to)
                }
            }
            .environment(\.editMode, .constant(.active))
            .navigationTitle(String(localized: "Reorder Categories"))
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button(String(localized: "Cancel")) {
                        dismiss()
                    }
                }
                ToolbarItem(placement: .confirmationAction) {
                    Button(String(localized: "Done")) {
                        appState.updateManualCategoryOrder(orderedNames)
                        dismiss()
                    }
                    .bold()
                }
            }
        }
        .onAppear {
            let currentCategoryNames = appState.categories
                .filter { $0.recipe_count > 0 }
                .map { $0.name }

            let totalCount = appState.categories.reduce(0) { $0 + $1.recipe_count }

            let existing = appState.manualCategoryOrder

            // Keep only names that still exist on the server (or are the sentinel)
            var reconciled = existing.filter {
                $0 == Self.allRecipesSentinel || currentCategoryNames.contains($0)
            }

            // Ensure the All Recipes sentinel is present
            if totalCount > 0 && !reconciled.contains(Self.allRecipesSentinel) {
                reconciled.insert(Self.allRecipesSentinel, at: 0)
            }

            // Append any new categories not yet in the manual order
            for name in currentCategoryNames where !reconciled.contains(name) {
                reconciled.append(name)
            }

            orderedNames = reconciled
        }
    }
}