import SwiftUI

/// 金币流水(游标分页)。
@MainActor
@Observable
final class CoinHistoryViewModel {
    private(set) var items: [CoinTransactionDTO] = []
    private(set) var isLoading = false
    private(set) var isLoadingMore = false
    private(set) var hasMore = false
    private(set) var loaded = false

    private var cursor: Int?
    private let wallet = WalletService()

    func loadFirst() async {
        guard !isLoading else { return }
        isLoading = true
        defer { isLoading = false; loaded = true }
        if let page = try? await wallet.coinTransactions(cursor: nil) {
            items = page.items
            cursor = page.nextCursor
            hasMore = page.nextCursor != nil
        } else {
            hasMore = false
        }
    }

    func loadMore() async {
        guard hasMore, !isLoading, !isLoadingMore, let cursor else { return }
        isLoadingMore = true
        defer { isLoadingMore = false }
        if let page = try? await wallet.coinTransactions(cursor: cursor) {
            items += page.items
            self.cursor = page.nextCursor
            hasMore = page.nextCursor != nil
        }
    }
}