import SwiftUI

/// CSV-Import-Form für den `.csv`-Sub-Modus in `DeckEditorView`. Zeigt
/// File-Picker-Button, Deck-Namens-Feld und eine Preview-Liste der
/// erkannten Karten.
///
/// State (Datei-Picker-Bool, geparste Rows, Deck-Name) lebt im Parent —
/// dieser View arbeitet nur über `@Binding`.
struct CSVImportFormSections: View {
    @Binding var rows: [CSVRow]
    @Binding var deckName: String
    @Binding var showImporter: Bool

    var body: some View {
        Section {
            Button {
                showImporter = true
            } label: {
                Label(rows.isEmpty ? "CSV-Datei wählen" : "Andere Datei wählen", systemImage: "doc.text")
            }
        } header: {
            Text("Datei")
        } footer: {
            Text("Format pro Zeile: vorne,hinten,typ. Typ-Spalte optional (Default basic).")
        }

        if !rows.isEmpty {
            Section("Deck-Name") {
                TextField("Deck-Name", text: $deckName)
                    .textInputAutocapitalization(.sentences)
            }

            Section {
                preview
            } header: {
                Text("Vorschau (\(rows.count) Karten)")
            } footer: {
                Text("Image-Occlusion und Audio-Cards werden im CSV-Import übersprungen — die brauchen Datei-Uploads.")
            }
        }
    }

    @ViewBuilder
    private var preview: some View {
        let visible = rows.prefix(8)
        ForEach(Array(visible.enumerated()), id: \.offset) { _, row in
            VStack(alignment: .leading, spacing: 4) {
                Text(row.front)
                    .font(.subheadline)
                    .lineLimit(2)
                    .foregroundStyle(CardsTheme.foreground)
                Text(row.back)
                    .font(.caption)
                    .lineLimit(2)
                    .foregroundStyle(CardsTheme.mutedForeground)
                if row.type != .basic {
                    Text(typeLabel(row.type))
                        .font(.caption2)
                        .foregroundStyle(CardsTheme.primary)
                }
            }
            .padding(.vertical, 2)
        }
        if rows.count > visible.count {
            Text("… und \(rows.count - visible.count) weitere")
                .font(.caption)
                .foregroundStyle(CardsTheme.mutedForeground)
        }
    }

    private func typeLabel(_ type: CardType) -> String {
        switch type {
        case .basic: "Einfach"
        case .basicReverse: "Beidseitig"
        case .cloze: "Lückentext"
        case .typing: "Eintippen"
        case .multipleChoice: "Multiple Choice"
        case .imageOcclusion: "Bild-Verdeckung (übersprungen)"
        case .audioFront: "Audio (übersprungen)"
        }
    }
}