import SwiftUI

struct GroupListView: View {
    @Bindable var model: ScanViewModel

    var body: some View {
        List(selection: $model.selectedGroupID) {
            if !model.groups.isEmpty {
                Section {
                    ForEach(model.groups) { group in
                        GroupRow(group: group, markedCount: markedCount(in: group))
                            .tag(group.id)
                    }
                } header: {
                    Text("\(model.groups.count) グループ・重複 \(model.totalDuplicateCount) 枚")
                }
            }
        }
        .listStyle(.sidebar)
        .overlay {
            if model.groups.isEmpty && !model.isScanning {
                sidebarPlaceholder
            }
        }
        .safeAreaInset(edge: .bottom) {
            if !model.groups.isEmpty {
                summaryBar
            }
        }
    }

    private func markedCount(in group: SimilarityGroup) -> Int {
        group.members.filter { model.markedForDeletion.contains($0.id) }.count
    }

    private var sidebarPlaceholder: some View {
        VStack(spacing: 6) {
            if model.folder == nil {
                Text("フォルダが未選択です")
            } else if model.hasScanned {
                Text("似た写真は見つかりませんでした")
            } else {
                Text("スキャンしていません")
            }
        }
        .font(.callout)
        .foregroundStyle(.secondary)
        .padding()
    }

    private var summaryBar: some View {
        VStack(alignment: .leading, spacing: 2) {
            Divider()
            Text("最大 \(model.totalReclaimableText) 削減できます")
                .font(.callout)
            if model.markedCount > 0 {
                Text("\(model.markedCount) 枚を選択中（\(model.markedBytesText)）")
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(.horizontal, 12)
        .padding(.bottom, 8)
        .background(.bar)
    }
}

struct GroupRow: View {
    let group: SimilarityGroup
    let markedCount: Int

    var body: some View {
        HStack(spacing: 10) {
            ThumbnailView(url: group.representativeID, size: 52)

            VStack(alignment: .leading, spacing: 3) {
                Text(group.representative.fileName)
                    .lineLimit(1)
                    .truncationMode(.middle)

                HStack(spacing: 6) {
                    Text(group.kindText)
                        .font(.caption2)
                        .padding(.horizontal, 5)
                        .padding(.vertical, 1)
                        .background(
                            group.isAllExact ? Color.orange.opacity(0.22) : Color.accentColor.opacity(0.18),
                            in: Capsule()
                        )
                    Text("\(group.members.count) 枚")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Text("\(group.reclaimableBytesText) 削減可")
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }

            Spacer(minLength: 0)

            if markedCount > 0 {
                Text("\(markedCount)")
                    .font(.caption.monospacedDigit())
                    .foregroundStyle(.white)
                    .padding(.horizontal, 6)
                    .padding(.vertical, 2)
                    .background(Color.red, in: Capsule())
            }
        }
        .padding(.vertical, 3)
    }
}