furumi_macos/furumi_macos/SearchViewModel.swift

//
//  SearchViewModel.swift
//  furumi_macos
//

import Foundation
import Observation

@MainActor
@Observable
final class SearchViewModel {
    private var service: CatalogService
    private(set) var results: SearchResult?
    private(set) var isSearching = false
    private(set) var error: String?

    var query: String = "" {
        didSet { debounceSearch() }
    }

    private var pendingTask: Task<Void, Never>?
    private let limit = 20

    init(service: CatalogService) {
        self.service = service
    }

    func reset(service: CatalogService) {
        self.service = service
        self.results = nil
        self.isSearching = false
        self.error = nil
        self.query = ""
        pendingTask?.cancel()
        pendingTask = nil
    }

    private func debounceSearch() {
        pendingTask?.cancel()
        let q = query.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !q.isEmpty else { results = nil; error = nil; return }
        pendingTask = Task { [weak self] in
            do {
                try await Task.sleep(nanoseconds: 300_000_000) // 300ms
            } catch {
                return // cancelled — не вызываем поиск
            }
            await self?.performSearch(q)
        }
    }

    private func performSearch(_ q: String) async {
        guard !q.isEmpty else { return }
        isSearching = true
        error = nil
        defer { isSearching = false }
        do {
            results = try await service.search(query: q, limit: limit)
        } catch {
            self.error = (error as NSError).localizedDescription
            self.results = nil
        }
    }
}