import SwiftUI

struct AIHistoryView: View {
    @Bindable var viewModel: AIHistoryViewModel
    var onOpen: (AIHistoryEntry) -> Void

    private enum Layout {
        static let horizontalPadding: CGFloat = 24
    }

    var body: some View {
        VStack(spacing: 0) {
            header
            filterBar

            if viewModel.isEmpty {
                emptyState
            } else if !viewModel.hasFilteredEntries {
                filteredEmptyState
            } else {
                historyList
            }
        }
        .background(AppTheme.background)
        .alert("Delete this item?", isPresented: deleteBinding) {
            Button("Cancel", role: .cancel) {
                viewModel.cancelDelete()
            }
            Button("Delete", role: .destructive) {
                viewModel.confirmDelete()
            }
        } message: {
            if let entry = viewModel.entryPendingDeletion {
                Text("Remove \"\(entry.displayTitle)\" from history?")
            }
        }
        .alert("Delete all history?", isPresented: $viewModel.showDeleteAllConfirmation) {
            Button("Cancel", role: .cancel) {
                viewModel.cancelDeleteAll()
            }
            Button("Delete All", role: .destructive) {
                viewModel.confirmDeleteAll()
            }
        } message: {
            Text("This permanently removes all saved posts, titles, and comments.")
        }
    }

    private var deleteBinding: Binding<Bool> {
        Binding(
            get: { viewModel.entryPendingDeletion != nil },
            set: { isPresented in
                if !isPresented {
                    viewModel.cancelDelete()
                }
            }
        )
    }

    private var header: some View {
        VStack(spacing: 0) {
            HStack(spacing: 14) {
                ModernSidebarIconView(kind: .history, size: 40)

                VStack(alignment: .leading, spacing: 2) {
                    Text("History")
                        .font(.system(size: 18, weight: .semibold))
                        .foregroundStyle(AppTheme.textPrimary)
                    Text("Saved AI responses from your tools")
                        .font(.system(size: 11))
                        .foregroundStyle(AppTheme.textSecondary)
                }

                Spacer()

                if !viewModel.isEmpty {
                    Button {
                        viewModel.requestDeleteAll()
                    } label: {
                        Label("Delete All", systemImage: "trash")
                            .font(.system(size: 11, weight: .medium))
                    }
                    .buttonStyle(AppDestructiveButtonStyle())
                }
            }
            .padding(.horizontal, Layout.horizontalPadding)
            .padding(.vertical, 16)

            FullWidthDivider()
        }
    }

    private var filterBar: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack(spacing: 6) {
                ForEach(AIHistoryFilter.allCases) { filter in
                    filterChip(filter)
                }
            }
            .padding(.horizontal, Layout.horizontalPadding)
            .padding(.vertical, 12)
        }
    }

    private func filterChip(_ filter: AIHistoryFilter) -> some View {
        let isSelected = viewModel.selectedFilter == filter

        return Button {
            withAnimation(.easeInOut(duration: 0.15)) {
                viewModel.selectedFilter = filter
            }
        } label: {
            Text(filter.title)
                .font(.system(size: 11, weight: isSelected ? .bold : .medium))
                .foregroundStyle(isSelected ? Color(hex: 0xD97706) : AppTheme.textSecondary)
                .padding(.horizontal, 12)
                .padding(.vertical, 7)
                .background(
                    RoundedRectangle(cornerRadius: 8, style: .continuous)
                        .fill(isSelected ? Color(hex: 0xD97706).opacity(0.12) : AppTheme.cardBackground)
                )
                .overlay(
                    RoundedRectangle(cornerRadius: 8, style: .continuous)
                        .stroke(
                            isSelected ? Color(hex: 0xD97706).opacity(0.5) : AppTheme.cardBorder,
                            lineWidth: isSelected ? 1.5 : 1
                        )
                )
        }
        .buttonStyle(.plain)
        .hoverCursor()
    }

    private var historyList: some View {
        ScrollView {
            LazyVStack(spacing: 8) {
                ForEach(viewModel.filteredEntries) { entry in
                    AIHistoryRowView(
                        entry: entry,
                        onOpen: { onOpen(entry) },
                        onDelete: { viewModel.requestDelete(entry) }
                    )
                }
            }
            .padding(.horizontal, Layout.horizontalPadding)
            .padding(.bottom, 24)
        }
    }

    private var emptyState: some View {
        VStack(spacing: 12) {
            Image(systemName: "clock.arrow.circlepath")
                .font(.system(size: 32))
                .foregroundStyle(Color(hex: 0xD97706).opacity(0.7))

            Text("No history yet")
                .font(.system(size: 15, weight: .semibold))
                .foregroundStyle(AppTheme.textPrimary)

            Text("Generated posts, optimized titles, and comments\nwill appear here automatically.")
                .font(.system(size: 12))
                .foregroundStyle(AppTheme.textSecondary)
                .multilineTextAlignment(.center)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }

    private var filteredEmptyState: some View {
        VStack(spacing: 12) {
            Image(systemName: "line.3.horizontal.decrease.circle")
                .font(.system(size: 28))
                .foregroundStyle(AppTheme.textTertiary)

            Text("No \(viewModel.selectedFilter.title.lowercased()) in history")
                .font(.system(size: 14, weight: .semibold))
                .foregroundStyle(AppTheme.textPrimary)

            Text("Try another filter or generate content with the AI tools.")
                .font(.system(size: 12))
                .foregroundStyle(AppTheme.textSecondary)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

private struct AIHistoryRowView: View {
    let entry: AIHistoryEntry
    var onOpen: () -> Void
    var onDelete: () -> Void

    var body: some View {
        HStack(alignment: .top, spacing: 12) {
            ModernSidebarIconView(kind: entry.toolKind.iconKind, size: 36)

            VStack(alignment: .leading, spacing: 4) {
                HStack(spacing: 6) {
                    Text(entry.toolKind.title)
                        .font(.system(size: 9, weight: .semibold))
                        .foregroundStyle(AppTheme.textTertiary)
                        .textCase(.uppercase)
                        .tracking(0.3)

                    Text("·")
                        .foregroundStyle(AppTheme.textTertiary)

                    Text(entry.createdAt, style: .relative)
                        .font(.system(size: 9))
                        .foregroundStyle(AppTheme.textTertiary)
                }

                Text(entry.displayTitle)
                    .font(.system(size: 13, weight: .semibold))
                    .foregroundStyle(AppTheme.textPrimary)
                    .lineLimit(2)
                    .multilineTextAlignment(.leading)

                Text(entry.displaySubtitle)
                    .font(.system(size: 11))
                    .foregroundStyle(AppTheme.textSecondary)
            }

            Spacer(minLength: 8)

            HStack(spacing: 6) {
                Button(action: onOpen) {
                    Label("Open", systemImage: "arrow.up.right.square")
                        .font(.system(size: 10, weight: .medium))
                        .labelStyle(.titleAndIcon)
                }
                .buttonStyle(AppSecondaryButtonStyle())

                Button(action: onDelete) {
                    Image(systemName: "trash")
                        .font(.system(size: 10, weight: .medium))
                }
                .buttonStyle(AppDestructiveButtonStyle())
            }
        }
        .padding(14)
        .background(
            RoundedRectangle(cornerRadius: AppTheme.cornerRadiusSmall)
                .fill(AppTheme.cardBackground)
                .overlay(
                    RoundedRectangle(cornerRadius: AppTheme.cornerRadiusSmall)
                        .stroke(AppTheme.cardBorder, lineWidth: 1)
                )
        )
        .hoverCard(cornerRadius: AppTheme.cornerRadiusSmall)
    }
}

#Preview {
    AIHistoryView(viewModel: AIHistoryViewModel()) { _ in }
        .frame(width: 880, height: 720)
}