import SwiftUI

struct AddSourceView: View {
    @Environment(\.dismiss) private var dismiss
    @EnvironmentObject var iapService: IAPService
    @EnvironmentObject var accountStore: AccountStore

    @State private var name = ""
    @State private var selectedCategory: Category?
    @State private var initialValue = ""
    @State private var showingCategoryPicker = false
    @State private var selectedAccountId: UUID?

    @StateObject private var categoryRepository = CategoryRepository()

    var body: some View {
        NavigationStack {
            Form {
                if accountStore.accounts.count > 1 {
                    Section {
                        Picker("Account", selection: $selectedAccountId) {
                            ForEach(accountStore.accounts) { account in
                                Text(account.name).tag(Optional(account.id))
                            }
                        }
                    } header: {
                        Text("Account")
                    }
                }

                // Source Info
                Section {
                    TextField("Source Name", text: $name)
                        .textContentType(.organizationName)

                    Button {
                        showingCategoryPicker = true
                    } label: {
                        HStack {
                            Text("Category")
                                .foregroundColor(.primary)

                            Spacer()

                            if let category = selectedCategory {
                                HStack(spacing: 6) {
                                    Image(systemName: category.icon)
                                        .foregroundColor(category.color)
                                    Text(category.name)
                                        .foregroundColor(.secondary)
                                }
                            } else {
                                Text("Select")
                                    .foregroundColor(.secondary)
                            }

                            Image(systemName: "chevron.right")
                                .font(.caption)
                                .foregroundColor(.secondary)
                        }
                    }
                } header: {
                    Text("Source Information")
                }

                // Initial Value (Optional)
                Section {
                    HStack {
                        Text(currencySymbol)
                            .foregroundColor(.secondary)

                        TextField("0.00", text: $initialValue)
                            .keyboardType(.decimalPad)
                    }
                } header: {
                    Text("Initial Value (Optional)")
                } footer: {
                    Text("You can add snapshots later if you prefer.")
                }
            }
            .navigationTitle("Add Source")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("Cancel") {
                        dismiss()
                    }
                }

                ToolbarItem(placement: .navigationBarTrailing) {
                    Button("Add") {
                        saveSource()
                    }
                    .disabled(!isValid)
                    .fontWeight(.semibold)
                }
            }
            .sheet(isPresented: $showingCategoryPicker) {
                CategoryPickerView(
                    selectedCategory: $selectedCategory,
                    categories: categoryRepository.categories
                )
            }
            .onAppear {
                categoryRepository.createDefaultCategoriesIfNeeded()
                if selectedCategory == nil {
                    selectedCategory = categoryRepository.categories.first
                }
                if selectedAccountId == nil {
                    selectedAccountId = accountStore.selectedAccount?.id ?? accountStore.accounts.first?.id
                }
            }
        }
    }

    // MARK: - Validation

    private var isValid: Bool {
        !name.trimmingCharacters(in: .whitespaces).isEmpty && selectedCategory != nil
    }

    // MARK: - Save

    private func saveSource() {
        guard let category = selectedCategory else { return }

        let repository = InvestmentSourceRepository()
        let source = repository.createSource(
            name: name.trimmingCharacters(in: .whitespaces),
            category: category,
            account: selectedAccount
        )

        // Add initial snapshot if provided
        if let value = parseDecimal(initialValue), value > 0 {
            let snapshotRepository = SnapshotRepository()
            snapshotRepository.createSnapshot(
                for: source,
                date: Date(),
                value: value
            )
        }

        // Schedule notification
        NotificationService.shared.scheduleReminder(for: source)

        // Log analytics
        FirebaseService.shared.logSourceAdded(
            categoryName: category.name,
            sourceCount: repository.sourceCount
        )

        dismiss()
    }

    private func parseDecimal(_ string: String) -> Decimal? {
        let cleaned = string
            .replacingOccurrences(of: currencySymbol, with: "")
            .replacingOccurrences(of: ",", with: ".")
            .trimmingCharacters(in: .whitespaces)

        guard !cleaned.isEmpty else { return nil }

        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        formatter.locale = Locale(identifier: "en_US")

        return formatter.number(from: cleaned)?.decimalValue
    }

    private var currencySymbol: String {
        if let account = selectedAccount, let code = account.currencyCode {
            return CurrencyFormatter.symbol(for: code)
        }
        return AppSettings.getOrCreate(in: CoreDataStack.shared.viewContext).currencySymbol
    }

    private var selectedAccount: Account? {
        guard let id = selectedAccountId else { return nil }
        return accountStore.accounts.first { $0.id == id }
    }
}

// MARK: - Category Picker View

struct CategoryPickerView: View {
    @Environment(\.dismiss) private var dismiss
    @Binding var selectedCategory: Category?
    let categories: [Category]

    var body: some View {
        NavigationStack {
            List(categories) { category in
                Button {
                    selectedCategory = category
                    dismiss()
                } label: {
                    HStack(spacing: 12) {
                        ZStack {
                            Circle()
                                .fill(category.color.opacity(0.2))
                                .frame(width: 40, height: 40)

                            Image(systemName: category.icon)
                                .foregroundColor(category.color)
                        }

                        Text(category.name)
                            .foregroundColor(.primary)

                        Spacer()

                        if selectedCategory?.id == category.id {
                            Image(systemName: "checkmark")
                                .foregroundColor(.appPrimary)
                        }
                    }
                }
            }
            .navigationTitle("Select Category")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button("Done") {
                        dismiss()
                    }
                }
            }
        }
    }
}

// MARK: - Edit Source View

struct EditSourceView: View {
    @Environment(\.dismiss) private var dismiss
    @EnvironmentObject var accountStore: AccountStore
    let source: InvestmentSource

    @State private var name: String
    @State private var selectedCategory: Category?
    @State private var showingCategoryPicker = false
    @State private var selectedAccountId: UUID?

    @StateObject private var categoryRepository = CategoryRepository()

    init(source: InvestmentSource) {
        self.source = source
        _name = State(initialValue: source.name)
        _selectedCategory = State(initialValue: source.category)
        _selectedAccountId = State(initialValue: source.account?.id)
    }

    var body: some View {
        NavigationStack {
            Form {
                if accountStore.accounts.count > 1 {
                    Section {
                        Picker("Account", selection: $selectedAccountId) {
                            ForEach(accountStore.accounts) { account in
                                Text(account.name).tag(Optional(account.id))
                            }
                        }
                    } header: {
                        Text("Account")
                    }
                }

                Section {
                    TextField("Source Name", text: $name)

                    Button {
                        showingCategoryPicker = true
                    } label: {
                        HStack {
                            Text("Category")
                                .foregroundColor(.primary)

                            Spacer()

                            if let category = selectedCategory {
                                HStack(spacing: 6) {
                                    Image(systemName: category.icon)
                                        .foregroundColor(category.color)
                                    Text(category.name)
                                        .foregroundColor(.secondary)
                                }
                            }

                            Image(systemName: "chevron.right")
                                .font(.caption)
                                .foregroundColor(.secondary)
                        }
                    }
                }
            }
            .navigationTitle("Edit Source")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("Cancel") {
                        dismiss()
                    }
                }

                ToolbarItem(placement: .navigationBarTrailing) {
                    Button("Save") {
                        saveChanges()
                    }
                    .disabled(!isValid)
                    .fontWeight(.semibold)
                }
            }
            .sheet(isPresented: $showingCategoryPicker) {
                CategoryPickerView(
                    selectedCategory: $selectedCategory,
                    categories: categoryRepository.categories
                )
            }
        }
    }

    private var isValid: Bool {
        !name.trimmingCharacters(in: .whitespaces).isEmpty && selectedCategory != nil
    }

    private func saveChanges() {
        guard let category = selectedCategory else { return }

        let repository = InvestmentSourceRepository()
        repository.updateSource(
            source,
            name: name.trimmingCharacters(in: .whitespaces),
            category: category,
            account: selectedAccount
        )

        // Reschedule notification
        NotificationService.shared.scheduleReminder(for: source)

        dismiss()
    }

    private var selectedAccount: Account? {
        guard let id = selectedAccountId else { return nil }
        return accountStore.accounts.first { $0.id == id }
    }
}

// MARK: - Add Snapshot View

struct AddSnapshotView: View {
    @Environment(\.dismiss) private var dismiss
    let source: InvestmentSource
    let snapshot: Snapshot?

    @StateObject private var viewModel: SnapshotFormViewModel

    init(source: InvestmentSource, snapshot: Snapshot? = nil) {
        self.source = source
        self.snapshot = snapshot
        if let snapshot = snapshot {
            _viewModel = StateObject(wrappedValue: SnapshotFormViewModel(source: source, mode: .edit(snapshot)))
        } else {
            _viewModel = StateObject(wrappedValue: SnapshotFormViewModel(source: source))
        }
    }

    var body: some View {
        NavigationStack {
            Form {
                Section {
                    if snapshot == nil && viewModel.previousValue != nil {
                        Button {
                            viewModel.prefillFromPreviousSnapshot()
                        } label: {
                            Label("Duplicate Previous Snapshot", systemImage: "doc.on.doc")
                        }
                    }

                    DatePicker(
                        "Date",
                        selection: $viewModel.date,
                        in: ...Date(),
                        displayedComponents: .date
                    )

                    HStack {
                        Text(viewModel.currencySymbol)
                            .foregroundColor(.secondary)

                        TextField("Value", text: $viewModel.valueString)
                            .keyboardType(.decimalPad)
                    }

                    if viewModel.previousValue != nil {
                        Text(viewModel.previousValueString)
                            .font(.caption)
                            .foregroundColor(.secondary)
                    }
                } header: {
                    Text("Snapshot Details")
                }

                // Change preview
                if let change = viewModel.formattedChange,
                   let percentage = viewModel.formattedChangePercentage {
                    Section {
                        HStack {
                            Text("Change from previous")
                            Spacer()
                            Text("\(change) (\(percentage))")
                                .foregroundColor(
                                    (viewModel.changeFromPrevious ?? 0) >= 0
                                        ? .positiveGreen
                                        : .negativeRed
                                )
                        }
                    }
                }

                if viewModel.inputMode == .detailed {
                    Section {
                        Toggle("Include Contribution", isOn: $viewModel.includeContribution)

                        if viewModel.includeContribution {
                            HStack {
                                Text(viewModel.currencySymbol)
                                    .foregroundColor(.secondary)

                                TextField("New capital added", text: $viewModel.contributionString)
                                    .keyboardType(.decimalPad)
                            }
                        }
                    } header: {
                        Text("Contribution (Optional)")
                    } footer: {
                        Text("Track new capital you've added to separate it from investment growth.")
                    }
                }

                Section {
                    TextField("Notes", text: $viewModel.notes, axis: .vertical)
                        .lineLimit(3...6)
                } header: {
                    Text("Notes (Optional)")
                }
            }
            .navigationTitle(viewModel.title)
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("Cancel") {
                        dismiss()
                    }
                }

                ToolbarItem(placement: .navigationBarTrailing) {
                    Button(viewModel.buttonTitle) {
                        saveSnapshot()
                    }
                    .disabled(!viewModel.isValid)
                    .fontWeight(.semibold)
                }
            }
        }
    }

    private func saveSnapshot() {
        guard let value = viewModel.value else { return }

        let repository = SnapshotRepository()
        if let snapshot = snapshot {
            repository.updateSnapshot(
                snapshot,
                date: viewModel.date,
                value: value,
                contribution: viewModel.contribution,
                notes: viewModel.notes.isEmpty ? nil : viewModel.notes,
                clearContribution: !viewModel.includeContribution,
                clearNotes: viewModel.notes.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
            )
        } else {
            repository.createSnapshot(
                for: source,
                date: viewModel.date,
                value: value,
                contribution: viewModel.contribution,
                notes: viewModel.notes.isEmpty ? nil : viewModel.notes
            )
        }

        // Reschedule notification
        NotificationService.shared.scheduleReminder(for: source)

        // Log analytics
        FirebaseService.shared.logSnapshotAdded(sourceName: source.name, value: value)

        dismiss()
    }
}

#Preview {
    AddSourceView()
        .environmentObject(IAPService())
        .environmentObject(AccountStore(iapService: IAPService()))
}