import SwiftUI
import SwiftData

struct DishFormView: View {
    @Environment(\.modelContext) private var context
    @Environment(\.dismiss) private var dismiss
    @Query private var tags: [Tag]
    @Query private var dishes: [Dish]
    @Query private var allSettings: [AppSettings]
    @StateObject private var viewModel = DishViewModel()
    @State private var showPremium = false
    @State private var showDishLimitUpsell = false

    var dish: Dish?

    private var language: AppLanguage {
        (allSettings.first?.languageEnum ?? .system).resolved()
    }

    private var reachedFreeDishLimit: Bool {
        guard let settings = allSettings.first else { return false }
        if viewModel.isEditing { return false }
        return PremiumAccess.hasReachedFreeDishLimit(dishCount: dishes.count, isPremium: settings.isPremium)
    }

    var body: some View {
        NavigationStack {
            ZStack {
                Color.mealMoodBackground.ignoresSafeArea()

                ScrollView {
                    VStack(spacing: 20) {
                        // Name field
                        VStack(alignment: .leading, spacing: 8) {
                            Text("dish_name_label")
                                .font(.mealMoodSmall)
                                .foregroundColor(.mealMoodTextSecondary)

                            TextField(
                                text: $viewModel.name,
                                prompt: Text("dish_name_placeholder").foregroundColor(.mealMoodTextSecondary.opacity(0.6))
                            ) {
                                EmptyView()
                            }
                                .font(.mealMoodBody)
                                .foregroundColor(.mealMoodTextPrimary)
                                .tint(.mealMoodCoral)
                                .padding(14)
                                .background(Color.mealMoodSurface)
                                .cornerRadius(12)
                                .overlay(
                                    RoundedRectangle(cornerRadius: 12)
                                        .stroke(Color(hex: "#F0F0F0"), lineWidth: 1)
                                )
                        }

                        // Description field
                        VStack(alignment: .leading, spacing: 8) {
                            Text("dish_description_label")
                                .font(.mealMoodSmall)
                                .foregroundColor(.mealMoodTextSecondary)

                            TextField(
                                text: $viewModel.descriptionText,
                                prompt: Text("dish_description_placeholder").foregroundColor(.mealMoodTextSecondary.opacity(0.6)),
                                axis: .vertical
                            ) {
                                EmptyView()
                            }
                                .font(.mealMoodBody)
                                .foregroundColor(.mealMoodTextPrimary)
                                .tint(.mealMoodCoral)
                                .lineLimit(2...4)
                                .padding(14)
                                .background(Color.mealMoodSurface)
                                .cornerRadius(12)
                                .overlay(
                                    RoundedRectangle(cornerRadius: 12)
                                        .stroke(Color(hex: "#F0F0F0"), lineWidth: 1)
                                )
                        }

                        // Tags section
                        VStack(alignment: .leading, spacing: 8) {
                            Text("dish_tags_label")
                                .font(.mealMoodSmall)
                                .foregroundColor(.mealMoodTextSecondary)

                            if !viewModel.selectedTagIds.isEmpty {
                                FlowLayout(spacing: 6) {
                                    ForEach(tags.filter { viewModel.selectedTagIds.contains($0.id) }) { tag in
                                        HStack(spacing: 4) {
                                            TagPill(name: tag.localizedName(language: language), color: tag.color)
                                            Button {
                                                viewModel.selectedTagIds.remove(tag.id)
                                            } label: {
                                                Image(systemName: "xmark.circle.fill")
                                                    .font(.system(size: 14))
                                                    .foregroundColor(.mealMoodTextSecondary)
                                            }
                                        }
                                    }
                                }
                            }

                            Button {
                                viewModel.showTagSelector = true
                            } label: {
                                HStack {
                                    Image(systemName: "plus.circle")
                                    Text("dish_add_tag")
                                }
                                .font(.mealMoodSmall)
                                .foregroundColor(.mealMoodCoral)
                            }
                        }

                        if showDishLimitUpsell && reachedFreeDishLimit {
                            PremiumUpsellBanner(
                                messageKey: "premium_limit_dishes",
                                actionTitleKey: "premium_subscribe"
                            ) {
                                showPremium = true
                            }
                        }

                        // Delete button (edit mode only)
                        if viewModel.isEditing {
                            Button {
                                viewModel.showDeleteAlert = true
                            } label: {
                                HStack {
                                    Image(systemName: "trash")
                                    Text("dish_delete")
                                }
                                .font(.mealMoodBodyBold)
                                .foregroundColor(.mealMoodError)
                                .padding(.vertical, 14)
                                .frame(maxWidth: .infinity)
                                .background(Color.mealMoodError.opacity(0.1))
                                .cornerRadius(14)
                            }
                            .padding(.top, 20)
                        }
                    }
                    .padding(24)
                }
            }
            .navigationTitle(viewModel.isEditing ? String(localized: "dish_edit_title") : String(localized: "dish_new_title"))
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("dish_cancel") { dismiss() }
                        .foregroundColor(.mealMoodTextSecondary)
                }
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button {
                        guard !reachedFreeDishLimit else {
                            withAnimation(.easeInOut(duration: 0.2)) {
                                showDishLimitUpsell = true
                            }
                            showPremium = true
                            HapticManager.shared.notification(type: .warning)
                            return
                        }
                        viewModel.save(context: context)
                        dismiss()
                    } label: {
                        Image(systemName: "checkmark")
                            .fontWeight(.semibold)
                            .foregroundColor(viewModel.isValid ? .mealMoodCoral : .gray)
                    }
                    .disabled(!viewModel.isValid)
                }
            }
            .sheet(isPresented: $viewModel.showTagSelector) {
                TagSelectorSheet(tags: tags, selectedTagIds: $viewModel.selectedTagIds)
            }
            .sheet(isPresented: $showPremium) {
                if let settings = allSettings.first {
                    NavigationStack { PremiumView(settings: settings) }
                }
            }
            .alert("dish_delete_title", isPresented: $viewModel.showDeleteAlert) {
                Button("dish_cancel", role: .cancel) {}
                Button("dish_delete", role: .destructive) {
                    let deleted = viewModel.deleteDish(context: context)
                    if deleted {
                        dismiss()
                    }
                }
            } message: {
                Text("dish_delete_message")
            }
            .alert("dish_delete_blocked_title", isPresented: $viewModel.showAssignedDeleteAlert) {
                Button("dish_delete_blocked_ok", role: .cancel) {}
            } message: {
                Text("dish_delete_blocked_message")
            }
            .onAppear {
                if let dish = dish {
                    viewModel.loadDish(dish)
                }
            }
        }
    }
}

// Simple flow layout for tags
struct FlowLayout: Layout {
    var spacing: CGFloat = 8

    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
        let result = arrange(proposal: proposal, subviews: subviews)
        return result.size
    }

    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) {
        let result = arrange(proposal: proposal, subviews: subviews)
        for (index, position) in result.positions.enumerated() {
            subviews[index].place(at: CGPoint(x: bounds.minX + position.x, y: bounds.minY + position.y), proposal: .unspecified)
        }
    }

    private func arrange(proposal: ProposedViewSize, subviews: Subviews) -> (size: CGSize, positions: [CGPoint]) {
        let maxWidth = proposal.width ?? .infinity
        var positions: [CGPoint] = []
        var x: CGFloat = 0
        var y: CGFloat = 0
        var maxHeight: CGFloat = 0
        var rowHeight: CGFloat = 0

        for subview in subviews {
            let size = subview.sizeThatFits(.unspecified)
            if x + size.width > maxWidth && x > 0 {
                x = 0
                y += rowHeight + spacing
                rowHeight = 0
            }
            positions.append(CGPoint(x: x, y: y))
            rowHeight = max(rowHeight, size.height)
            x += size.width + spacing
            maxHeight = max(maxHeight, y + rowHeight)
        }

        return (CGSize(width: maxWidth, height: maxHeight), positions)
    }
}