import SwiftUI

struct SavingsView: View {
    @EnvironmentObject var authManager: AuthManager
    @State private var selectedTab = 0
    
    var body: some View {
        ZStack {
            Color(hex: "0a0a1a").ignoresSafeArea()
            VStack(spacing: 0) {
                // Header
                HStack {
                    Text("Накопления").font(.title.bold()).foregroundColor(.white)
                    Spacer()
                }.padding()
                
                // Segment control
                Picker("", selection: $selectedTab) {
                    Text("Обзор").tag(0)
                    Text("Транзакции").tag(1)
                }
                .pickerStyle(.segmented)
                .padding(.horizontal)
                .padding(.bottom, 12)
                
                if selectedTab == 0 {
                    SavingsOverviewTab()
                } else {
                    SavingsTransactionsTab()
                }
            }
        }
    }
}

struct SavingsOverviewTab: View {
    @EnvironmentObject var authManager: AuthManager
    @State private var categories: [SavingsCategory] = []
    @State private var stats: SavingsStats?
    @State private var isLoading = true
    
    var body: some View {
        Group {
            if isLoading {
                ProgressView().tint(Color(hex: "00d4aa")).padding(.top, 40)
                Spacer()
            } else {
                ScrollView {
                    VStack(spacing: 16) {
                        if let s = stats { SavingsTotalCard(stats: s) }
                        VStack(spacing: 10) {
                            ForEach(categories) { cat in SavingsCategoryCard(category: cat) }
                        }.padding(.horizontal)
                    }
                }
            }
        }
        .task { await loadData() }
        .refreshable { await loadData(refresh: true) }
    }
    
    func loadData(refresh: Bool = false) async {
        if !refresh { isLoading = true }
        async let cats = APIService.shared.getSavingsCategories(token: authManager.token)
        async let st = APIService.shared.getSavingsStats(token: authManager.token)
        categories = (try? await cats) ?? []
        stats = try? await st
        isLoading = false
    }
}

struct SavingsTransactionsTab: View {
    @EnvironmentObject var authManager: AuthManager
    @State private var transactions: [SavingsTransaction] = []
    @State private var isLoading = true
    
    var body: some View {
        Group {
            if isLoading {
                ProgressView().tint(Color(hex: "00d4aa")).padding(.top, 40)
                Spacer()
            } else if transactions.isEmpty {
                VStack(spacing: 12) {
                    Text("💸").font(.system(size: 50))
                    Text("Нет транзакций").foregroundColor(Color(hex: "8888aa"))
                }.padding(.top, 60)
                Spacer()
            } else {
                List {
                    ForEach(transactions) { tx in
                        SavingsTransactionRow(transaction: tx)
                            .listRowBackground(Color.clear)
                            .listRowSeparator(.hidden)
                    }
                }
                .listStyle(.plain)
                .scrollContentBackground(.hidden)
            }
        }
        .task { await loadData() }
        .refreshable { await loadData(refresh: true) }
    }
    
    func loadData(refresh: Bool = false) async {
        if !refresh { isLoading = true }
        transactions = (try? await APIService.shared.getSavingsTransactions(token: authManager.token)) ?? []
        isLoading = false
    }
}

struct SavingsTransactionRow: View {
    let transaction: SavingsTransaction
    
    var body: some View {
        HStack(spacing: 12) {
            ZStack {
                Circle()
                    .fill((transaction.isDeposit ? Color(hex: "00d4aa") : Color(hex: "ff4757")).opacity(0.15))
                    .frame(width: 40, height: 40)
                Image(systemName: transaction.isDeposit ? "arrow.down.circle.fill" : "arrow.up.circle.fill")
                    .foregroundColor(transaction.isDeposit ? Color(hex: "00d4aa") : Color(hex: "ff4757"))
            }
            
            VStack(alignment: .leading, spacing: 3) {
                Text(transaction.categoryName ?? "Без категории")
                    .font(.callout).foregroundColor(.white)
                HStack(spacing: 6) {
                    if let userName = transaction.userName {
                        Text(userName).font(.caption).foregroundColor(Color(hex: "8888aa"))
                    }
                    if let date = transaction.date {
                        Text(formatDate(date)).font(.caption2).foregroundColor(Color(hex: "8888aa"))
                    }
                }
            }
            
            Spacer()
            
            Text("\(transaction.isDeposit ? "+" : "-")\(formatAmount(transaction.amount))")
                .font(.callout.bold())
                .foregroundColor(transaction.isDeposit ? Color(hex: "00d4aa") : Color(hex: "ff4757"))
        }
        .padding(12)
        .background(RoundedRectangle(cornerRadius: 12).fill(Color.white.opacity(0.04)))
        .padding(.horizontal)
        .padding(.vertical, 2)
    }
    
    func formatAmount(_ v: Double) -> String {
        if v >= 1_000_000 { return String(format: "%.1f млн ₽", v / 1_000_000) }
        return String(format: "%.0f ₽", v)
    }
    
    func formatDate(_ s: String) -> String {
        let parts = s.prefix(10).split(separator: "-")
        guard parts.count == 3 else { return String(s.prefix(10)) }
        return "\(parts[2]).\(parts[1]).\(parts[0])"
    }
}

// MARK: - SavingsTotalCard

struct SavingsTotalCard: View {
    let stats: SavingsStats
    
    var body: some View {
        VStack(spacing: 20) {
            VStack(spacing: 6) {
                Text("Общий баланс").font(.subheadline).foregroundColor(Color(hex: "8888aa"))
                Text(formatAmount(stats.totalBalance ?? 0))
                    .font(.system(size: 36, weight: .bold))
                    .foregroundColor(.white)
            }
            
            HStack(spacing: 0) {
                VStack(spacing: 4) {
                    Text("Пополнения").font(.caption).foregroundColor(Color(hex: "8888aa"))
                    Text("+\(formatAmount(stats.totalDeposits ?? 0))").font(.callout.bold()).foregroundColor(Color(hex: "00d4aa"))
                }
                Spacer()
                VStack(spacing: 4) {
                    Text("Снятия").font(.caption).foregroundColor(Color(hex: "8888aa"))
                    Text("-\(formatAmount(stats.totalWithdrawals ?? 0))").font(.callout.bold()).foregroundColor(Color(hex: "ff4757"))
                }
                Spacer()
                VStack(spacing: 4) {
                    Text("Категорий").font(.caption).foregroundColor(Color(hex: "8888aa"))
                    Text("\(stats.categoriesCount ?? 0)").font(.callout.bold()).foregroundColor(.white)
                }
            }
        }
        .padding(20)
        .background(
            LinearGradient(colors: [Color(hex: "1a1a3e"), Color(hex: "12122a")], startPoint: .topLeading, endPoint: .bottomTrailing)
        )
        .cornerRadius(20)
        .overlay(RoundedRectangle(cornerRadius: 20).stroke(Color(hex: "00d4aa").opacity(0.3), lineWidth: 1))
        .padding(.horizontal)
    }
    
    func formatAmount(_ v: Double) -> String {
        if v >= 1_000_000 {
            return String(format: "%.2f млн ₽", v / 1_000_000)
        } else if v >= 1000 {
            return String(format: "%.0f ₽", v)
        }
        return String(format: "%.0f ₽", v)
    }
}

// MARK: - SavingsCategoryCard

struct SavingsCategoryCard: View {
    let category: SavingsCategory
    @State private var appeared = false
    
    var body: some View {
        VStack(spacing: 12) {
            HStack(spacing: 12) {
                ZStack {
                    Circle()
                        .fill(Color(hex: category.color).opacity(0.2))
                        .frame(width: 46, height: 46)
                    Image(systemName: category.icon)
                        .foregroundColor(Color(hex: category.color))
                        .font(.title3)
                }
                
                VStack(alignment: .leading, spacing: 4) {
                    Text(category.name).font(.callout.bold()).foregroundColor(.white)
                    Text(category.typeLabel).font(.caption).foregroundColor(Color(hex: "8888aa"))
                }
                
                Spacer()
                
                VStack(alignment: .trailing, spacing: 2) {
                    Text(formatAmount(category.currentAmount ?? 0))
                        .font(.callout.bold())
                        .foregroundColor(Color(hex: category.color))
                    if let end = category.depositEndDate {
                        Text("до \(formatDate(end))")
                            .font(.caption2)
                            .foregroundColor(Color(hex: "8888aa"))
                    }
                }
            }
            
            if category.isDeposit == true, let target = category.depositAmount, target > 0 {
                let progress = min((category.currentAmount ?? 0) / target, 1.0)
                VStack(spacing: 4) {
                    GeometryReader { geo in
                        ZStack(alignment: .leading) {
                            RoundedRectangle(cornerRadius: 4).fill(Color.white.opacity(0.08))
                            RoundedRectangle(cornerRadius: 4)
                                .fill(LinearGradient(colors: [Color(hex: "ffa502"), Color(hex: "ff6b35")], startPoint: .leading, endPoint: .trailing))
                                .frame(width: geo.size.width * CGFloat(appeared ? progress : 0))
                                .animation(.easeInOut(duration: 0.8), value: appeared)
                        }
                    }
                    .frame(height: 6)
                    HStack {
                        Text("\(Int(progress * 100))%")
                            .font(.caption2).foregroundColor(Color(hex: "ffa502"))
                        Spacer()
                        Text("цель: \(formatAmount(target))")
                            .font(.caption2).foregroundColor(Color(hex: "8888aa"))
                    }
                }
            }
        }
        .padding(16)
        .background(
            RoundedRectangle(cornerRadius: 16)
                .fill(Color.white.opacity(0.04))
                .overlay(RoundedRectangle(cornerRadius: 16).stroke(Color(hex: category.color).opacity(0.15), lineWidth: 1))
        )
        .opacity(appeared ? 1 : 0)
        .offset(y: appeared ? 0 : 20)
        .onAppear {
            withAnimation(.easeOut(duration: 0.4)) { appeared = true }
        }
    }
    
    func formatAmount(_ v: Double) -> String {
        if v >= 1_000_000 { return String(format: "%.2f млн ₽", v / 1_000_000) }
        return String(format: "%.0f ₽", v)
    }
    
    func formatDate(_ s: String) -> String {
        let parts = s.prefix(10).split(separator: "-")
        guard parts.count == 3 else { return s }
        return "\(parts[2]).\(parts[1]).\(parts[0])"
    }
}