import SwiftUI
import KeeVaultCore

struct GroupFilterView: View {
    @ObservedObject var vm: GroupFilterViewModel
    let rootGroup: KeeVaultCore.Group

    var body: some View {
        List {
            if !vm.selectedGroupIds.isEmpty {
                Button("Clear Filter", action: vm.clear)
            }
            GroupFilterNode(group: rootGroup, vm: vm)
        }
        .scrollContentBackground(.hidden)
        .background(Color("VaultBackground"))
        .navigationTitle("Groups")
    }
}

private struct GroupFilterNode: View {
    let group: KeeVaultCore.Group
    @ObservedObject var vm: GroupFilterViewModel
    var depth: Int = 0

    var body: some View {
        // A plain SwiftUI.Group (not a container view) flattens its children into
        // separate List rows, so the whole subtree renders always-expanded --
        // no DisclosureGroup, no tap-to-reveal -- active filters are visible at a glance.
        SwiftUI.Group {
            row
            ForEach(group.subgroups) { sub in
                GroupFilterNode(group: sub, vm: vm, depth: depth + 1)
            }
        }
    }

    private var row: some View {
        Button {
            vm.toggle(group)
        } label: {
            HStack {
                Image(systemName: vm.isSelected(group) ? "checkmark.circle.fill" : "circle")
                    .foregroundStyle(vm.isSelected(group) ? Color.accentColor : Color.secondary)
                Label(group.name, systemImage: "folder")
            }
        }
        .buttonStyle(.plain)
        .padding(.leading, CGFloat(depth) * 16)
    }
}