import SwiftUI

struct BrowseView: View {
    let connection: NASConnection
    @Binding var selectedPath: String
    @Environment(\.dismiss) private var dismiss

    @State private var currentPath: String = "/"
    @State private var items: [NASItem] = []
    @State private var isLoading = false
    @State private var error: String? = nil
    @State private var showCreateFolder = false
    @State private var newFolderName = ""

    var body: some View {
        NavigationStack {
            ZStack {
                AppTheme.background.ignoresSafeArea()

                VStack(spacing: 0) {
                    // Path bar
                    HStack(spacing: 8) {
                        Image(systemName: "externaldrive")
                            .font(.system(size: 12, weight: .medium))
                            .foregroundStyle(AppTheme.inkTertiary)
                        Text(currentPath)
                            .font(AppTheme.caption())
                            .foregroundStyle(AppTheme.inkSecondary)
                            .lineLimit(1)
                            .truncationMode(.middle)
                        Spacer()
                    }
                    .padding(.horizontal, AppTheme.cardPad)
                    .padding(.vertical, 10)
                    .background(AppTheme.surfaceSunken)

                    Rectangle()
                        .fill(AppTheme.separator)
                        .frame(height: 0.5)

                    if isLoading {
                        Spacer()
                        VStack(spacing: 10) {
                            ProgressView()
                                .tint(AppTheme.inkTertiary)
                            Text("Loading…")
                                .font(AppTheme.caption())
                                .foregroundStyle(AppTheme.inkTertiary)
                        }
                        Spacer()
                    } else if let error {
                        Spacer()
                        VStack(spacing: 12) {
                            Image(systemName: "exclamationmark.triangle")
                                .font(.system(size: 28, weight: .ultraLight))
                                .foregroundStyle(AppTheme.inkQuaternary)
                            VStack(spacing: 4) {
                                Text("Could not load folder")
                                    .font(.system(size: 14, weight: .medium))
                                    .foregroundStyle(AppTheme.inkSecondary)
                                Text(error)
                                    .font(AppTheme.caption())
                                    .foregroundStyle(AppTheme.inkTertiary)
                                    .multilineTextAlignment(.center)
                            }
                        }
                        .padding(.horizontal, 32)
                        Spacer()
                    } else {
                        List {
                            if currentPath != "/" {
                                Button(action: navigateUp) {
                                    HStack(spacing: 10) {
                                        Image(systemName: "arrow.up")
                                            .font(.system(size: 13, weight: .medium))
                                            .foregroundStyle(AppTheme.inkSecondary)
                                            .frame(width: 22)
                                        Text("Parent folder")
                                            .font(AppTheme.body())
                                            .foregroundStyle(AppTheme.inkSecondary)
                                        Spacer()
                                    }
                                    .padding(.horizontal, 16)
                                    .padding(.vertical, 12)
                                }
                                .buttonStyle(PlainButtonStyle())
                                .listRowInsets(EdgeInsets())
                                .listRowSeparator(.hidden)
                            }

                            ForEach(items) { item in
                                FolderRow(
                                    item: item,
                                    isSelected: selectedPath == item.path
                                ) {
                                    if item.isDirectory {
                                        navigate(to: item.path)
                                    } else {
                                        selectedPath = item.path
                                    }
                                }
                                .listRowInsets(EdgeInsets())
                                .listRowSeparator(.hidden)
                            }
                        }
                        .listStyle(.plain)
                    }
                }
            }
            .navigationTitle("Choose folder")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("Cancel") { dismiss() }
                        .font(AppTheme.body())
                        .foregroundStyle(AppTheme.inkSecondary)
                }
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button {
                        newFolderName = ""
                        showCreateFolder = true
                    } label: {
                        Image(systemName: "folder.badge.plus")
                            .foregroundStyle(AppTheme.inkSecondary)
                    }
                }
                ToolbarItem(placement: .bottomBar) {
                    Button("Select this folder") {
                        selectedPath = currentPath
                        dismiss()
                    }
                    .font(.system(size: 15, weight: .semibold))
                    .foregroundStyle(AppTheme.ink)
                }
            }
            .alert("New folder", isPresented: $showCreateFolder) {
                TextField("Folder name", text: $newFolderName)
                Button("Create") { Task { await createFolder() } }
                Button("Cancel", role: .cancel) {}
            }
        }
        .task { await loadDirectory(path: currentPath) }
    }

    private func loadDirectory(path: String) async {
        isLoading = true
        error = nil
        do {
            let s: any NASTransferProtocol = connection.nasProtocol == .smb ? SMBService() : SFTPService()
            try await s.connect(to: connection.host, port: connection.port,
                                username: connection.username, password: connection.password)
            items = try await s.listDirectory(at: path).filter { $0.isDirectory }
            s.disconnect()
        } catch let e as BackupError {
            self.error = e.errorDescription
        } catch {
            self.error = error.localizedDescription
        }
        isLoading = false
    }

    private func navigate(to path: String) {
        currentPath = path
        Task { await loadDirectory(path: path) }
    }

    private func navigateUp() {
        let parent = (currentPath as NSString).deletingLastPathComponent
        navigate(to: parent.isEmpty ? "/" : parent)
    }

    private func createFolder() async {
        guard !newFolderName.isEmpty else { return }
        let newPath = "\(currentPath)/\(newFolderName)"
        do {
            let s: any NASTransferProtocol = connection.nasProtocol == .smb ? SMBService() : SFTPService()
            try await s.connect(to: connection.host, port: connection.port,
                                username: connection.username, password: connection.password)
            try await s.createDirectory(at: newPath)
            s.disconnect()
            await loadDirectory(path: currentPath)
        } catch {}
    }
}