import SwiftUI

struct AccountsView: View {
  @EnvironmentObject private var model: AppModel
  @EnvironmentObject private var drawers: DrawerCoordinator
  @Binding var route: Route

  @State private var error: String?
  @State private var busy = false
  @State private var showAccountPrompt = false
  @State private var showSubaddressPrompt = false
  @State private var pendingLabel = ""
  @State private var subaddressAccount = 0

  var body: some View {
    VStack(alignment: .leading, spacing: 18) {
      ScreenHeader(title: "Accounts & addresses",
                   subtitle: "Each address gets its own QR code",
                   onBack: { route = .home })

      PrimaryButton(title: busy ? "Working…" : "New account", disabled: busy) {
        showAccountPrompt = true
      }

      if let error {
        MessageBanner(message: error, isError: true)
      }

      ForEach(model.moneroAccounts) { account in
        accountCard(account)
      }

      if model.moneroAccounts.isEmpty {
        Text("No accounts yet. Accounts and addresses appear after the wallet opens.")
          .font(.system(size: 12))
          .foregroundStyle(Theme.muted)
      }
    }
    .task(id: model.moneroReady) { await model.loadAccounts() }
    .alert("Account name", isPresented: $showAccountPrompt) {
      TextField("e.g. Savings", text: $pendingLabel)
      Button("Create") { createAccount() }
      Button("Cancel", role: .cancel) { pendingLabel = "" }
    }
    .alert("Address label", isPresented: $showSubaddressPrompt) {
      TextField("e.g. From Alice", text: $pendingLabel)
      Button("Create") { createSubaddress() }
      Button("Cancel", role: .cancel) { pendingLabel = "" }
    }
  }

  private func accountCard(_ account: MoneroAccount) -> some View {
    Card {
      VStack(alignment: .leading, spacing: 10) {
        HStack {
          VStack(alignment: .leading, spacing: 3) {
            Text(account.title)
              .font(.system(size: 15, weight: .semibold))
              .foregroundStyle(Theme.text)
            Text("\(account.balance) XMR")
              .font(.system(size: 12))
              .foregroundStyle(Theme.muted)
          }
          Spacer()
        }

        addressRow(title: "Primary address",
                   address: account.address,
                   isUsed: true)

        if !account.subaddresses.isEmpty {
          Divider().overlay(Theme.border)
          ForEach(account.subaddresses.filter { $0.index != 0 }) { subaddress in
            addressRow(title: subaddress.label.isEmpty ? "Address \(subaddress.index)" : subaddress.label,
                       address: subaddress.address,
                       isUsed: subaddress.isUsed,
                       balance: subaddress.balance)
          }
        }

        SecondaryButton(title: "New address in this account") {
          subaddressAccount = account.index
          pendingLabel = ""
          showSubaddressPrompt = true
        }
      }
    }
  }

  private func addressRow(title: String, address: String, isUsed: Bool, balance: String? = nil) -> some View {
    Button {
      drawers.qr = AddressQR(title: title, address: address)
    } label: {
      HStack(spacing: 8) {
        VStack(alignment: .leading, spacing: 2) {
          Text(title)
            .font(.system(size: 12, weight: .medium))
            .foregroundStyle(Theme.muted)
          Text(address.isEmpty ? "—" : address)
            .font(.system(size: 11, design: .monospaced))
            .foregroundStyle(Theme.text)
            .lineLimit(1)
            .truncationMode(.middle)
          if let balance {
            Text("\(balance) XMR\(isUsed ? "" : " · unused")")
              .font(.system(size: 11))
              .foregroundStyle(Theme.muted)
          }
        }
        Spacer(minLength: 6)
        Image(systemName: "qrcode")
          .font(.system(size: 14, weight: .semibold))
          .foregroundStyle(Theme.accent)
          .frame(width: 32, height: 32)
          .background(Theme.surfaceAlt)
          .clipShape(RoundedRectangle(cornerRadius: 10, style: .continuous))
      }
      .contentShape(Rectangle())
    }
    .buttonStyle(.plain)
    .disabled(address.isEmpty)
  }

  private func createAccount() {
    busy = true
    error = nil
    Task {
      defer { busy = false }
      do {
        try await model.addAccount(label: pendingLabel)
        pendingLabel = ""
      } catch {
        self.error = error.localizedDescription
      }
    }
  }

  private func createSubaddress() {
    busy = true
    error = nil
    Task {
      defer { busy = false }
      do {
        try await model.addSubaddress(accountIndex: subaddressAccount, label: pendingLabel)
        pendingLabel = ""
      } catch {
        self.error = error.localizedDescription
      }
    }
  }
}