//
//  OrderListView.swift
//  suixinkan
//

import SnapKit
import UIKit

/// 订单列表容器，含下拉刷新、空态与分页，对齐 Android LazyColumn。
final class OrderListView: UIView {

    var onRefresh: (() -> Void)?
    var onLoadMore: ((Int) -> Void)?

    let tableView = UITableView(frame: .zero, style: .plain)
    private let refreshControl = UIRefreshControl()
    private let loadingIndicator = UIActivityIndicatorView(style: .medium)
    private let emptyLabel = UILabel()
    private let footerLabel = UILabel()
    private let footerSpinner = UIActivityIndicatorView(style: .medium)

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = AppColor.pageBackground
        tableView.backgroundColor = .clear
        tableView.separatorStyle = .none
        tableView.keyboardDismissMode = .onDrag
        tableView.contentInset = UIEdgeInsets(top: OrderTokens.cardGap, left: 0, bottom: OrderTokens.cardGap, right: 0)
        tableView.refreshControl = refreshControl
        refreshControl.addTarget(self, action: #selector(refreshTriggered), for: .valueChanged)

        loadingIndicator.hidesWhenStopped = true
        loadingIndicator.color = AppColor.primary

        emptyLabel.font = .app(.body)
        emptyLabel.textColor = OrderTokens.label563
        emptyLabel.text = "暂无订单"
        emptyLabel.textAlignment = .center

        footerLabel.font = .app(.body)
        footerLabel.textColor = OrderTokens.label563
        footerLabel.textAlignment = .center
        footerLabel.text = "没有更多"

        footerSpinner.hidesWhenStopped = true
        footerSpinner.color = AppColor.primary

        addSubview(tableView)
        addSubview(loadingIndicator)
        tableView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
        loadingIndicator.snp.makeConstraints { make in
            make.center.equalToSuperview()
        }
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func apply(
        isRefreshing: Bool,
        canLoadMore: Bool,
        isEmpty: Bool,
        isLoading: Bool = false,
        isLoadingMore: Bool = false
    ) {
        if isRefreshing {
            if !refreshControl.isRefreshing { refreshControl.beginRefreshing() }
        } else {
            refreshControl.endRefreshing()
        }

        if isLoading, isEmpty {
            loadingIndicator.startAnimating()
            tableView.backgroundView = nil
            tableView.tableFooterView = nil
        } else {
            loadingIndicator.stopAnimating()
            if isEmpty {
                tableView.backgroundView = emptyBackgroundView()
            } else {
                tableView.backgroundView = nil
            }
            tableView.tableFooterView = footerView(canLoadMore: canLoadMore, isLoadingMore: isLoadingMore, isEmpty: isEmpty)
        }
    }

    private func emptyBackgroundView() -> UIView {
        let container = UIView(frame: tableView.bounds)
        emptyLabel.frame = container.bounds
        emptyLabel.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        container.addSubview(emptyLabel)
        return container
    }

    private func footerView(canLoadMore: Bool, isLoadingMore: Bool, isEmpty: Bool) -> UIView? {
        guard !isEmpty else { return nil }
        if isLoadingMore {
            let container = UIView(frame: CGRect(x: 0, y: 0, width: bounds.width, height: 44))
            footerSpinner.center = CGPoint(x: container.bounds.midX, y: container.bounds.midY)
            footerSpinner.autoresizingMask = [.flexibleLeftMargin, .flexibleRightMargin]
            container.addSubview(footerSpinner)
            footerSpinner.startAnimating()
            return container
        }
        footerSpinner.stopAnimating()
        guard !canLoadMore else { return nil }
        footerLabel.frame = CGRect(x: 0, y: 0, width: bounds.width, height: 44)
        return footerLabel
    }

    @objc private func refreshTriggered() {
        onRefresh?()
    }

    func notifyLoadMoreIfNeeded(at index: Int, shouldLoad: Bool) {
        guard shouldLoad else { return }
        onLoadMore?(index)
    }
}