import SwiftUI

/// Typing-Karten-View: User tippt Antwort, drückt Submit → Match-Badge
/// (correct/close/wrong) + User-Eingabe + erwartete Antwort.
///
/// Web-Vorbild: `cards/apps/web/src/lib/components/TypingView.svelte`.
/// Match-Logik in `Typing.check(input:answer:aliases:)` portiert aus
/// `cards/packages/cards-domain/src/typing.ts`.
///
/// Beim Flip vom Parent setzt sich `submitted` synthetisch — falls
/// User nicht selbst tippt und nur "Antwort anzeigen" benutzt, kommen
/// trotzdem korrekte Antwort und manuelle Bewertung über die RatingBar.
struct TypingCardView: View {
    let card: ReviewCard
    let isFlipped: Bool

    @State private var input: String = ""
    @State private var submitted: Bool = false
    @State private var result: TypingMatch?
    @FocusState private var inputFocused: Bool

    private var answer: String {
        card.fields["answer"] ?? ""
    }

    private var aliases: String? {
        card.fields["aliases"]
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 16) {
            text(card.fields["front"] ?? "")
                .font(.title3)
                .foregroundStyle(CardsTheme.foreground)

            if submitted || isFlipped {
                resultView
            } else {
                inputRow
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .onChange(of: isFlipped) { _, flipped in
            // Falls der User über die generische RatingBar auf "Antwort
            // anzeigen" tippt ohne zu raten, springen wir trotzdem in
            // den Result-Modus mit "wrong" als Default-Match (nicht
            // bewertet).
            if flipped, !submitted {
                result = nil
                submitted = true
            }
        }
        .onChange(of: card.id) { _, _ in
            input = ""
            submitted = false
            result = nil
        }
    }

    // MARK: - Input

    private var inputRow: some View {
        HStack(spacing: 8) {
            TextField("Antwort eingeben …", text: $input)
                .textFieldStyle(.plain)
                .focused($inputFocused)
                .padding(.vertical, 10)
                .padding(.horizontal, 12)
                .background(CardsTheme.surface, in: RoundedRectangle(cornerRadius: 8, style: .continuous))
                .overlay(
                    RoundedRectangle(cornerRadius: 8, style: .continuous)
                        .stroke(inputFocused ? CardsTheme.primary : CardsTheme.border, lineWidth: 1)
                )
                .autocorrectionDisabled()
            #if os(iOS)
                .textInputAutocapitalization(.never)
            #endif
                .onSubmit { submit() }

            Button {
                submit()
            } label: {
                Image(systemName: "return")
                    .font(.title3)
                    .frame(width: 44, height: 44)
                    .background(CardsTheme.primary, in: RoundedRectangle(cornerRadius: 8, style: .continuous))
                    .foregroundStyle(CardsTheme.primaryForeground)
            }
            .buttonStyle(.plain)
            .disabled(input.trimmingCharacters(in: .whitespaces).isEmpty)
        }
        .onAppear {
            // SwiftUI's Focus-State braucht einen Tick nach onAppear
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.15) {
                inputFocused = true
            }
        }
    }

    // MARK: - Result

    @ViewBuilder
    private var resultView: some View {
        if let result {
            HStack(spacing: 8) {
                Text(badgeLabel(for: result))
                    .font(.caption.weight(.semibold))
                    .padding(.horizontal, 10)
                    .padding(.vertical, 4)
                    .background(badgeBackground(for: result), in: Capsule())
                    .foregroundStyle(badgeForeground(for: result))
                if !input.isEmpty {
                    Text("„\(input)“")
                        .font(.caption)
                        .foregroundStyle(CardsTheme.mutedForeground)
                        .lineLimit(1)
                }
                Spacer(minLength: 0)
            }
        }

        Divider().background(CardsTheme.border)

        Text(answer)
            .font(.title3.weight(.medium))
            .foregroundStyle(CardsTheme.foreground)

        if result == nil, !submitted {
            // unwahrscheinlich erreicht, aber als Sicherheits-Branch
            EmptyView()
        }
    }

    // MARK: - Logic

    private func submit() {
        guard !submitted else { return }
        let trimmed = input.trimmingCharacters(in: .whitespaces)
        guard !trimmed.isEmpty else { return }
        inputFocused = false
        result = Typing.check(input: trimmed, answer: answer, aliases: aliases)
        submitted = true
        triggerHaptic()
    }

    private func triggerHaptic() {
        #if canImport(UIKit)
            let style: UIImpactFeedbackGenerator.FeedbackStyle =
                result == .correct ? .heavy : .light
            UIImpactFeedbackGenerator(style: style).impactOccurred()
        #endif
    }

    private func badgeLabel(for result: TypingMatch) -> String {
        switch result {
        case .correct: "✓ Richtig"
        case .close: "≈ Fast"
        case .wrong: "✗ Falsch"
        }
    }

    private func badgeBackground(for result: TypingMatch) -> Color {
        switch result {
        case .correct: CardsTheme.success.opacity(0.18)
        case .close: CardsTheme.warning.opacity(0.18)
        case .wrong: CardsTheme.error.opacity(0.18)
        }
    }

    private func badgeForeground(for result: TypingMatch) -> Color {
        switch result {
        case .correct: CardsTheme.success
        case .close: CardsTheme.warning
        case .wrong: CardsTheme.error
        }
    }

    private func text(_ markdown: String) -> some View {
        let attributed = (try? AttributedString(
            markdown: markdown,
            options: AttributedString.MarkdownParsingOptions(
                interpretedSyntax: .inlineOnlyPreservingWhitespace
            )
        )) ?? AttributedString(markdown)
        return Text(attributed)
            .multilineTextAlignment(.leading)
    }
}

#if canImport(UIKit)
    import UIKit
#endif