//
//  CommissionRateLogViewController.swift
//  suixinkan
//

import SnapKit
import UIKit

/// 获客员分成比例修改记录页，以时间轴形式展示历史变更。
final class CommissionRateLogViewController: BaseViewController {
    private let viewModel: CommissionRateLogViewModel
    private let orderAPI: OrderAPI
    private let navigationTitle: String

    private let tableView = UITableView(frame: .zero, style: .plain)
    private let emptyLabel = UILabel()
    private let loadingIndicator = UIActivityIndicatorView(style: .medium)
    private let footerLabel = UILabel()
    private var dataSource: UITableViewDiffableDataSource<Int, CommissionRateLogEntity>!

    init(saleUserId: Int, acquirerName: String, orderAPI: OrderAPI? = nil) {
        viewModel = CommissionRateLogViewModel(saleUserId: saleUserId)
        let trimmedName = acquirerName.trimmingCharacters(in: .whitespacesAndNewlines)
        navigationTitle = trimmedName.isEmpty ? "修改记录" : "给\(trimmedName)的分成记录"
        self.orderAPI = orderAPI ?? NetworkServices.shared.orderAPI
        super.init(nibName: nil, bundle: nil)
    }

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

    override func viewDidLoad() {
        super.viewDidLoad()
        Task { await viewModel.refresh(api: orderAPI) }
    }

    override func setupNavigationBar() {
        title = navigationTitle
    }

    override func setupUI() {
        view.backgroundColor = AppColor.pageBackground

        tableView.backgroundColor = AppColor.pageBackground
        tableView.separatorStyle = .none
        tableView.rowHeight = UITableView.automaticDimension
        tableView.estimatedRowHeight = 132
        tableView.delegate = self
        tableView.contentInset.top = AppSpacing.sm
        tableView.register(
            CommissionRateLogTimelineCell.self,
            forCellReuseIdentifier: CommissionRateLogTimelineCell.reuseIdentifier
        )
        tableView.refreshControl = UIRefreshControl()
        tableView.refreshControl?.addTarget(self, action: #selector(refreshPulled), for: .valueChanged)

        dataSource = UITableViewDiffableDataSource<Int, CommissionRateLogEntity>(
            tableView: tableView
        ) { tableView, indexPath, item in
            guard let cell = tableView.dequeueReusableCell(
                withIdentifier: CommissionRateLogTimelineCell.reuseIdentifier,
                for: indexPath
            ) as? CommissionRateLogTimelineCell else {
                return UITableViewCell()
            }
            cell.configure(with: item, isLatest: indexPath.item == 0)
            return cell
        }

        emptyLabel.text = "暂无修改记录"
        emptyLabel.font = .systemFont(ofSize: 14)
        emptyLabel.textColor = AppColor.textTertiary
        emptyLabel.textAlignment = .center
        emptyLabel.isHidden = true

        loadingIndicator.color = AppColor.primary

        footerLabel.font = .systemFont(ofSize: 13)
        footerLabel.textColor = AppColor.textTertiary
        footerLabel.textAlignment = .center

        view.addSubview(tableView)
        view.addSubview(emptyLabel)
        view.addSubview(loadingIndicator)
    }

    override func setupConstraints() {
        tableView.snp.makeConstraints { make in
            make.edges.equalTo(view.safeAreaLayoutGuide)
        }
        emptyLabel.snp.makeConstraints { make in
            make.center.equalTo(tableView)
        }
        loadingIndicator.snp.makeConstraints { make in
            make.center.equalTo(tableView)
        }
    }

    override func bindActions() {
        viewModel.onStateChange = { [weak self] in
            Task { @MainActor in self?.applyState() }
        }
        viewModel.onShowMessage = { [weak self] message in
            Task { @MainActor in self?.showToast(message) }
        }
    }

    private func applyState() {
        if !viewModel.isRefreshing {
            tableView.refreshControl?.endRefreshing()
        }
        if viewModel.initialLoading && viewModel.items.isEmpty {
            loadingIndicator.startAnimating()
        } else {
            loadingIndicator.stopAnimating()
        }
        emptyLabel.isHidden = viewModel.initialLoading || viewModel.isRefreshing || !viewModel.items.isEmpty

        var snapshot = NSDiffableDataSourceSnapshot<Int, CommissionRateLogEntity>()
        snapshot.appendSections([0])
        snapshot.appendItems(viewModel.items)
        dataSource.apply(snapshot, animatingDifferences: true)

        guard !viewModel.items.isEmpty else {
            tableView.tableFooterView = UIView()
            return
        }
        footerLabel.text = viewModel.isLoadingMore ? "加载中…" : (viewModel.canLoadMore ? "" : "没有更多")
        footerLabel.frame = CGRect(x: 0, y: 0, width: view.bounds.width, height: 52)
        tableView.tableFooterView = footerLabel
    }

    @objc private func refreshPulled() {
        Task { await viewModel.refresh(api: orderAPI) }
    }
}

extension CommissionRateLogViewController: UITableViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        guard !viewModel.items.isEmpty,
              scrollView.contentOffset.y > scrollView.contentSize.height - scrollView.bounds.height - 180 else {
            return
        }
        Task { await viewModel.loadMore(api: orderAPI) }
    }
}

/// 分成比例修改记录的时间轴 Cell。
final class CommissionRateLogTimelineCell: UITableViewCell {
    static let reuseIdentifier = "CommissionRateLogTimelineCell"

    private let railView = UIView()
    private let dotView = UIView()
    private let cardView = UIView()
    private let metadataLabel = UILabel()
    private let latestBadgeLabel = UILabel()
    private let beforeRateLabel = UILabel()
    private let arrowImageView = UIImageView(image: UIImage(systemName: "arrow.right"))
    private let afterRateLabel = UILabel()
    private let remarkLabel = UILabel()
    private let contentStack = UIStackView()

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        selectionStyle = .none
        backgroundColor = AppColor.pageBackground
        contentView.backgroundColor = AppColor.pageBackground

        railView.backgroundColor = AppColor.primary.withAlphaComponent(0.16)
        dotView.backgroundColor = AppColor.primary
        dotView.layer.cornerRadius = 4

        cardView.backgroundColor = .white
        cardView.layer.cornerRadius = AppRadius.md
        cardView.layer.shadowColor = UIColor.black.cgColor
        cardView.layer.shadowOpacity = 0.04
        cardView.layer.shadowOffset = CGSize(width: 0, height: 1)
        cardView.layer.shadowRadius = 2

        metadataLabel.font = .systemFont(ofSize: 12)
        metadataLabel.textColor = AppColor.textSecondary
        metadataLabel.numberOfLines = 2

        latestBadgeLabel.text = "最新"
        latestBadgeLabel.font = .systemFont(ofSize: 11, weight: .semibold)
        latestBadgeLabel.textColor = AppColor.primary
        latestBadgeLabel.textAlignment = .center
        latestBadgeLabel.backgroundColor = AppColor.primary.withAlphaComponent(0.10)
        latestBadgeLabel.layer.cornerRadius = 9
        latestBadgeLabel.clipsToBounds = true
        latestBadgeLabel.isHidden = true
        latestBadgeLabel.setContentHuggingPriority(.required, for: .horizontal)
        latestBadgeLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
        latestBadgeLabel.snp.makeConstraints { make in
            make.width.equalTo(38)
            make.height.equalTo(18)
        }

        let headerStack = UIStackView(arrangedSubviews: [metadataLabel, latestBadgeLabel])
        headerStack.axis = .horizontal
        headerStack.alignment = .top
        headerStack.spacing = AppSpacing.sm

        [beforeRateLabel, afterRateLabel].forEach { label in
            label.font = .systemFont(ofSize: 17, weight: .semibold)
            label.textColor = AppColor.textPrimary
            label.setContentCompressionResistancePriority(.required, for: .horizontal)
        }
        afterRateLabel.textColor = AppColor.primary
        arrowImageView.tintColor = AppColor.textTertiary
        arrowImageView.contentMode = .scaleAspectFit

        let rateStack = UIStackView(arrangedSubviews: [beforeRateLabel, arrowImageView, afterRateLabel, UIView()])
        rateStack.axis = .horizontal
        rateStack.alignment = .center
        rateStack.spacing = AppSpacing.sm
        arrowImageView.snp.makeConstraints { make in
            make.size.equalTo(16)
        }

        remarkLabel.font = .systemFont(ofSize: 13)
        remarkLabel.textColor = AppColor.textSecondary
        remarkLabel.numberOfLines = 0

        contentStack.axis = .vertical
        contentStack.spacing = AppSpacing.sm
        contentStack.addArrangedSubview(headerStack)
        contentStack.addArrangedSubview(rateStack)
        contentStack.addArrangedSubview(remarkLabel)

        contentView.addSubview(railView)
        contentView.addSubview(dotView)
        contentView.addSubview(cardView)
        cardView.addSubview(contentStack)

        railView.snp.makeConstraints { make in
            make.leading.equalToSuperview().offset(24)
            make.top.bottom.equalToSuperview()
            make.width.equalTo(1.5)
        }
        dotView.snp.makeConstraints { make in
            make.centerX.equalTo(railView)
            make.top.equalToSuperview().offset(20)
            make.size.equalTo(8)
        }
        cardView.snp.makeConstraints { make in
            make.leading.equalTo(railView.snp.trailing).offset(16)
            make.trailing.equalToSuperview().inset(14)
            make.top.equalToSuperview().offset(4)
            make.bottom.equalToSuperview().inset(8)
        }
        contentStack.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(15)
        }
    }

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

    /// 绑定比例变化、时间及可选备注。
    func configure(with item: CommissionRateLogEntity, isLatest: Bool) {
        metadataLabel.text = item.metadataLine
        latestBadgeLabel.isHidden = !isLatest
        beforeRateLabel.text = item.displayBeforeRate
        afterRateLabel.text = item.displayAfterRate
        if let remark = item.displayRemark {
            remarkLabel.text = "备注：\(remark)"
            remarkLabel.isHidden = false
        } else {
            remarkLabel.text = nil
            remarkLabel.isHidden = true
        }
        accessibilityLabel = [
            isLatest ? "最新记录" : nil,
            item.metadataLine,
            "\(item.displayBeforeRate)修改为\(item.displayAfterRate)",
            item.displayRemark.map { "备注\($0)" },
        ].compactMap { $0 }.joined(separator: "，")
    }
}