import SwiftUI

struct AddPackView: View {
	@State private var urlText = ""
	@State private var isLoading = false
	@State private var errorMessage: String?
	@State private var packs: [SavedPack]

	var onPacksChanged: () -> Void

	init(onPacksChanged: @escaping () -> Void) {
		self.onPacksChanged = onPacksChanged
		_packs = State(initialValue: StickerStore.shared.savedPacks)
	}

	var body: some View {
		NavigationView {
			List {
				Section {
					HStack {
						TextField("t.me/addstickers/PackName", text: $urlText)
							.textContentType(.URL)
							.autocorrectionDisabled()
							.textInputAutocapitalization(.never)

						Button {
							addPack()
						} label: {
							if isLoading {
								ProgressView()
							} else {
								Text("Add")
							}
						}
						.disabled(urlText.isEmpty || isLoading)
					}

					if let errorMessage {
						Text(errorMessage)
							.foregroundStyle(.red)
							.font(.caption)
					}
				} header: {
					Text("Add Sticker Pack")
				} footer: {
					Text("Paste a Telegram sticker link or pack name.")
				}

				if !packs.isEmpty {
					Section("Saved Packs") {
						ForEach(packs, id: \.name) { pack in
							HStack {
								VStack(alignment: .leading) {
									Text(pack.title)
									Text("\(pack.stickerCount) stickers")
										.font(.caption)
										.foregroundStyle(.secondary)
								}
								Spacer()
							}
						}
						.onDelete(perform: deletePacks)
					}
				}
			}
			.navigationTitle("Sticker Packs")
			.navigationBarTitleDisplayMode(.inline)
		}
	}

	// MARK: - Actions

	private func addPack() {
		let name = extractPackName(from: urlText)
		guard !name.isEmpty else {
			errorMessage = "Could not parse pack name from input."
			return
		}

		isLoading = true
		errorMessage = nil

		Task {
			do {
				let response = try await StickerClonerAPI.fetchStickerSet(name: name)
				try await StickerStore.shared.addPack(response: response)
				packs = StickerStore.shared.savedPacks
				urlText = ""
				onPacksChanged()
			} catch {
				errorMessage = error.localizedDescription
			}
			isLoading = false
		}
	}

	private func deletePacks(at offsets: IndexSet) {
		for index in offsets {
			StickerStore.shared.removePack(name: packs[index].name)
		}
		packs = StickerStore.shared.savedPacks
		onPacksChanged()
	}

	private func extractPackName(from input: String) -> String {
		let trimmed = input.trimmingCharacters(in: .whitespacesAndNewlines)

		// Handle full URL: https://t.me/addstickers/PackName
		if let url = URL(string: trimmed),
		   let host = url.host,
		   host.hasSuffix("t.me") {
			let components = url.pathComponents
			if let addstickersIndex = components.firstIndex(of: "addstickers"),
			   addstickersIndex + 1 < components.count {
				return components[addstickersIndex + 1]
			}
			return url.lastPathComponent
		}

		// Handle bare URL without scheme
		if trimmed.contains("t.me/addstickers/") {
			return trimmed.components(separatedBy: "t.me/addstickers/").last ?? ""
		}

		// Treat as bare pack name
		return trimmed
	}
}