import SwiftUI

/// Permanent account deletion. Requires typing the account's email exactly
/// (compared against `appState.currentUser?.email`) plus the password before
/// the destructive action becomes enabled, then a second confirmation
/// dialog before the call actually fires.
struct DeleteAccountView: View {
    @EnvironmentObject private var appState: AppState
    @State private var confirmEmail = ""
    @State private var password = ""
    @State private var isSubmitting = false
    @State private var errorMessage: String?
    @State private var showConfirmDialog = false

    // TODO: `Models/User.swift` doesn't currently expose whether an account
    // is Google-only (i.e. has no password to check).
    // `AccountAPI.deleteAccount(password:confirmEmail:)` accepts `password:
    // nil` specifically for that case, but there's no signal here to detect
    // it, so this screen always shows and requires the password field. Once
    // the `User` model exposes something like `hasPassword`, make this field
    // optional/hidden for Google-only accounts and pass `password: nil`
    // instead of always requiring input here.

    private var emailMatches: Bool {
        guard let accountEmail = appState.currentUser?.email, !accountEmail.isEmpty else { return false }
        return confirmEmail == accountEmail
    }

    private var canSubmit: Bool {
        emailMatches && !password.isEmpty && !isSubmitting
    }

    var body: some View {
        ScrollView {
            VStack(alignment: .leading, spacing: ZenithSpacing.md) {
                Text("Diese Aktion ist unwiderruflich. Dein Konto sowie alle Belege und Ordner werden dauerhaft gelöscht.")
                    .zenithBodyStyle(color: .zenithError)

                ZenithDivider()

                VStack(alignment: .leading, spacing: ZenithSpacing.sm) {
                    Text("Bestätigung").zenithLabelCapsStyle()

                    if let email = appState.currentUser?.email {
                        Text("Gib zur Bestätigung deine E-Mail-Adresse ein: \(email)")
                            .zenithBodySmStyle()
                    }

                    ZenithTextField(
                        label: "E-Mail-Adresse",
                        text: $confirmEmail,
                        placeholder: "E-Mail-Adresse",
                        keyboardType: .emailAddress,
                        textContentType: .emailAddress,
                        autocapitalization: .never,
                        autocorrectionDisabled: true
                    )

                    ZenithTextField(
                        label: "Passwort",
                        text: $password,
                        placeholder: "Passwort",
                        isSecure: true,
                        textContentType: .password
                    )
                }

                if let errorMessage {
                    Text(errorMessage)
                        .zenithBodySmStyle(color: .zenithError)
                }

                Button(role: .destructive) {
                    showConfirmDialog = true
                } label: {
                    if isSubmitting {
                        ProgressView()
                            .tint(.white)
                    } else {
                        Text("Konto endgültig löschen")
                    }
                }
                .buttonStyle(.zenithPrimaryDestructive)
                .disabled(!canSubmit)
                .padding(.top, ZenithSpacing.sm)
            }
            .padding(ZenithSpacing.sm)
        }
        .background(Color.zenithBg)
        .navigationTitle("Konto löschen")
        .navigationBarTitleDisplayMode(.inline)
        .confirmationDialog(
            "Konto wirklich endgültig löschen?",
            isPresented: $showConfirmDialog,
            titleVisibility: .visible
        ) {
            Button("Endgültig löschen", role: .destructive) {
                Task { await deleteAccount() }
            }
            Button("Abbrechen", role: .cancel) {}
        } message: {
            Text("Diese Aktion kann nicht rückgängig gemacht werden.")
        }
    }

    private func deleteAccount() async {
        errorMessage = nil
        isSubmitting = true
        defer { isSubmitting = false }
        do {
            try await AccountAPI.deleteAccount(password: password, confirmEmail: confirmEmail)
            // The account and its session are already gone server-side —
            // this just resets local state. RootView (App/RootView.swift)
            // switches to the login screen automatically once
            // AppState.phase flips to .signedOut.
            await appState.logout()
        } catch {
            errorMessage = error.localizedDescription
        }
    }
}