import SwiftUI

/// 比价记录列表(游标分页),对齐安卓 CompareRecordsViewModel。
@MainActor
@Observable
final class CompareRecordsViewModel {
    private(set) var records: [ComparisonRecordDTO] = []
    private(set) var isLoading = false
    private(set) var isLoadingMore = false
    private(set) var hasMore = false
    private(set) var loaded = false
    private(set) var errorMessage: String?

    private var cursor: Int?
    private let service = CompareService()

    func loadFirst() async {
        guard !isLoading else { return }
        isLoading = true
        errorMessage = nil
        defer { isLoading = false; loaded = true }
        do {
            let page = try await service.records(cursor: nil)
            records = page.items
            cursor = page.nextCursor
            hasMore = page.nextCursor != nil
        } catch {
            errorMessage = (error as? LocalizedError)?.errorDescription ?? "加载失败,请下拉重试"
        }
    }

    func loadMore() async {
        guard hasMore, !isLoading, !isLoadingMore, let cursor else { return }
        isLoadingMore = true
        defer { isLoadingMore = false }
        do {
            let page = try await service.records(cursor: cursor)
            records += page.items
            self.cursor = page.nextCursor
            hasMore = page.nextCursor != nil
        } catch {
            // 加载更多失败静默
        }
    }
}