//
//  PointsRedemptionViewController.swift
//  suixinkan
//

import SnapKit
import UIKit

/// 积分兑现页面，对齐 Android `PointsRedemptionScreen`。
final class PointsRedemptionViewController: BaseViewController, UITableViewDelegate {
    private enum Section {
        case main
    }

    private let viewModel: PointsRedemptionViewModel
    private let walletAPI: any WalletPageServing

    private let scrollView = UIScrollView()
    private let contentStack = UIStackView()
    private let pointsCard = UIView()
    private let pointsValueLabel = UILabel()
    private let summaryLoadingIndicator = UIActivityIndicatorView(style: .large)
    private let inputCard = UIView()
    private let pointsInputField = UITextField()
    private let withdrawablePointsLabel = UILabel()
    private let recordCard = UIView()
    private let tableView = UITableView(frame: .zero, style: .plain)
    private let refreshControl = UIRefreshControl()
    private let bottomBar = UIView()
    private let submitButton = AppButton(title: "立即兑换")

    private var dataSource: UITableViewDiffableDataSource<Section, PointWithdrawItem>!
    private var tableHeightConstraint: Constraint?
    private var lastShownMessage: String?

    /// 初始化积分兑现页面。
    init(
        viewModel: PointsRedemptionViewModel = PointsRedemptionViewModel(),
        walletAPI: any WalletPageServing = NetworkServices.shared.walletAPI
    ) {
        self.viewModel = viewModel
        self.walletAPI = walletAPI
        super.init(nibName: nil, bundle: nil)
    }

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

    override func setupNavigationBar() {
        let titleLabel = UILabel()
        titleLabel.text = "积分兑现"
        titleLabel.textColor = WalletTokens.text333
        titleLabel.font = UIFont.systemFont(ofSize: 18)
        navigationItem.titleView = titleLabel
    }

    override func setupUI() {
        view.backgroundColor = WalletTokens.pageBackground
        contentStack.axis = .vertical
        contentStack.spacing = WalletTokens.cardGap
        bottomBar.backgroundColor = .white

        view.addSubview(scrollView)
        scrollView.addSubview(contentStack)
        view.addSubview(bottomBar)
        bottomBar.addSubview(submitButton)

        contentStack.addArrangedSubview(makeSummaryCard())
        contentStack.addArrangedSubview(makeInputCard())
        contentStack.addArrangedSubview(makeRecordCard())
        configureTable()
    }

    override func setupConstraints() {
        bottomBar.snp.makeConstraints { make in
            make.leading.trailing.bottom.equalToSuperview()
        }
        submitButton.snp.makeConstraints { make in
            make.top.equalToSuperview().offset(WalletTokens.screenInset)
            make.leading.trailing.equalToSuperview().inset(WalletTokens.screenInset)
            make.bottom.equalTo(view.safeAreaLayoutGuide).inset(22)
        }
        submitButton.layer.cornerRadius = WalletTokens.bottomButtonRadius
        scrollView.snp.makeConstraints { make in
            make.top.leading.trailing.equalToSuperview()
            make.bottom.equalTo(bottomBar.snp.top)
        }
        contentStack.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(WalletTokens.screenInset)
            make.width.equalTo(scrollView).offset(-32)
        }
        tableView.snp.makeConstraints { make in
            tableHeightConstraint = make.height.equalTo(200).constraint
        }
    }

    override func bindActions() {
        viewModel.onStateChange = { [weak self] in
            Task { @MainActor in self?.applyState() }
        }
        pointsInputField.addTarget(self, action: #selector(pointsInputChanged), for: .editingChanged)
        refreshControl.addTarget(self, action: #selector(refreshPulled), for: .valueChanged)
        submitButton.addTarget(self, action: #selector(submitTapped), for: .touchUpInside)
        Task { await viewModel.refreshOverview(api: walletAPI) }
        Task { await viewModel.refreshWithdrawList(api: walletAPI) }
    }

    private func configureTable() {
        tableView.backgroundColor = .white
        tableView.separatorStyle = .none
        tableView.delegate = self
        tableView.rowHeight = UITableView.automaticDimension
        tableView.estimatedRowHeight = 120
        scrollView.refreshControl = refreshControl
        tableView.register(PointWithdrawRecordCell.self, forCellReuseIdentifier: PointWithdrawRecordCell.reuseIdentifier)
        dataSource = UITableViewDiffableDataSource<Section, PointWithdrawItem>(tableView: tableView) { tableView, indexPath, item in
            let cell = tableView.dequeueReusableCell(
                withIdentifier: PointWithdrawRecordCell.reuseIdentifier,
                for: indexPath
            ) as? PointWithdrawRecordCell
            cell?.apply(item)
            return cell ?? UITableViewCell()
        }
    }

    private func applyState() {
        pointsValueLabel.text = "\(viewModel.withdrawnPoints)"
        withdrawablePointsLabel.text = "\(viewModel.withdrawnPoints)"
        pointsValueLabel.isHidden = viewModel.overviewLoading
        if viewModel.overviewLoading {
            summaryLoadingIndicator.startAnimating()
        } else {
            summaryLoadingIndicator.stopAnimating()
        }
        pointsInputField.text = viewModel.pointsInput
        submitButton.isEnabled = (Int(viewModel.pointsInput) ?? 0) > 0
        if !viewModel.withdrawRefreshing, !viewModel.overviewLoading {
            refreshControl.endRefreshing()
        }
        var snapshot = NSDiffableDataSourceSnapshot<Section, PointWithdrawItem>()
        snapshot.appendSections([.main])
        snapshot.appendItems(viewModel.withdrawRecords, toSection: .main)
        dataSource.apply(snapshot, animatingDifferences: true) { [weak self] in
            self?.updateTablePresentation()
        }
        showMessageIfNeeded(viewModel.statusMessage)
        showMessageIfNeeded(viewModel.errorMessage)
    }

    private func updateTablePresentation() {
        tableView.layoutIfNeeded()
        let isEmpty = viewModel.withdrawRecords.isEmpty
        updateLoadingFooter()
        guard isEmpty, !viewModel.withdrawLoading else {
            tableView.backgroundView = nil
            let minimumHeight: CGFloat = viewModel.withdrawLoading ? 56 : 44
            let height = max(minimumHeight, min(tableView.contentSize.height, 400))
            tableHeightConstraint?.update(offset: height)
            tableView.isScrollEnabled = tableView.contentSize.height > 400
            return
        }
        let label = UILabel()
        label.text = "暂无提现记录"
        label.font = WalletTokens.bodyFont
        label.textColor = WalletTokens.textDisabled
        label.textAlignment = .center
        tableView.backgroundView = label
        tableHeightConstraint?.update(offset: 200)
        tableView.isScrollEnabled = false
    }

    private func updateLoadingFooter() {
        guard viewModel.withdrawLoading else {
            tableView.tableFooterView = UIView(frame: .zero)
            return
        }
        let footer = UIView(frame: CGRect(x: 0, y: 0, width: tableView.bounds.width, height: 56))
        let indicator = UIActivityIndicatorView(style: .medium)
        indicator.color = WalletTokens.primary
        indicator.startAnimating()
        footer.addSubview(indicator)
        indicator.snp.makeConstraints { make in make.center.equalToSuperview() }
        tableView.tableFooterView = footer
    }

    private func makeSummaryCard() -> UIView {
        pointsCard.backgroundColor = WalletTokens.summaryBackground
        pointsCard.layer.cornerRadius = WalletTokens.contentRadius
        pointsCard.clipsToBounds = true

        let title = UILabel()
        title.text = "可提现积分"
        title.font = WalletTokens.bodyFont
        title.textColor = UIColor.white.withAlphaComponent(0.8)
        title.textAlignment = .center
        pointsValueLabel.font = WalletTokens.displayFont
        pointsValueLabel.textColor = .white
        pointsValueLabel.textAlignment = .center

        pointsCard.addSubview(title)
        pointsCard.addSubview(pointsValueLabel)
        summaryLoadingIndicator.color = .white
        summaryLoadingIndicator.hidesWhenStopped = true
        pointsCard.addSubview(summaryLoadingIndicator)
        title.snp.makeConstraints { make in
            make.top.equalToSuperview().offset(16)
            make.leading.trailing.equalToSuperview().inset(24)
        }
        pointsValueLabel.snp.makeConstraints { make in
            make.top.equalTo(title.snp.bottom).offset(4)
            make.leading.trailing.equalToSuperview().inset(24)
            make.bottom.equalToSuperview().inset(16)
        }
        summaryLoadingIndicator.snp.makeConstraints { make in
            make.center.equalTo(pointsValueLabel)
        }
        return pointsCard
    }

    private func makeInputCard() -> UIView {
        inputCard.backgroundColor = .white
        inputCard.layer.cornerRadius = WalletTokens.cardRadius
        inputCard.clipsToBounds = true

        let title = makeTitle("积分提现", size: 18)
        let titleSpacer = UIView()
        titleSpacer.snp.makeConstraints { make in make.height.equalTo(WalletTokens.compactGap) }
        let row = UIStackView()
        row.axis = .horizontal
        row.spacing = 16
        let label = makeBody("可提现积分", color: .black, weight: .medium)
        withdrawablePointsLabel.font = WalletTokens.bodyMediumFont
        withdrawablePointsLabel.textColor = WalletTokens.points
        row.addArrangedSubview(label)
        row.addArrangedSubview(withdrawablePointsLabel)

        let inputContainer = UIView()
        inputContainer.layer.cornerRadius = WalletTokens.chipRadius
        inputContainer.layer.borderWidth = 1
        inputContainer.layer.borderColor = WalletTokens.border.cgColor
        pointsInputField.placeholder = "请输入积分"
        pointsInputField.keyboardType = .numberPad
        pointsInputField.font = WalletTokens.bodyFont
        let allButton = UIButton(type: .system)
        allButton.setTitle("全部提现", for: .normal)
        allButton.setTitleColor(WalletTokens.primary, for: .normal)
        allButton.titleLabel?.font = WalletTokens.bodyFont
        allButton.addTarget(self, action: #selector(withdrawAllTapped), for: .touchUpInside)
        inputContainer.addSubview(pointsInputField)
        inputContainer.addSubview(allButton)
        pointsInputField.snp.makeConstraints { make in
            make.top.bottom.equalToSuperview()
            make.leading.equalToSuperview().offset(12)
            make.trailing.equalTo(allButton.snp.leading).offset(-8)
        }
        allButton.snp.makeConstraints { make in
            make.trailing.equalToSuperview().inset(12)
            make.centerY.equalToSuperview()
        }
        inputContainer.snp.makeConstraints { make in make.height.equalTo(WalletTokens.inputHeight) }

        let ratio = makeBody("积分金额兑换比例12积分=1元人民币", color: WalletTokens.danger)
        ratio.font = WalletTokens.captionFont

        let stack = UIStackView(arrangedSubviews: [title, titleSpacer, row, inputContainer, ratio])
        stack.axis = .vertical
        stack.spacing = WalletTokens.compactGap
        inputCard.addSubview(stack)
        stack.snp.makeConstraints { make in make.edges.equalToSuperview().inset(16) }
        return inputCard
    }

    private func makeRecordCard() -> UIView {
        recordCard.backgroundColor = .white
        recordCard.layer.cornerRadius = WalletTokens.cardRadius
        recordCard.clipsToBounds = true
        let title = makeTitle("积分提现记录", size: 14)
        title.textColor = WalletTokens.primary
        title.font = UIFont.systemFont(ofSize: 14, weight: .bold)
        title.textAlignment = .center
        recordCard.addSubview(title)
        recordCard.addSubview(tableView)
        title.snp.makeConstraints { make in
            make.top.equalToSuperview().offset(WalletTokens.cardPadding)
            make.leading.trailing.equalToSuperview().inset(WalletTokens.cardPadding)
        }
        tableView.snp.makeConstraints { make in
            make.top.equalTo(title.snp.bottom).offset(WalletTokens.rowGap)
            make.leading.trailing.bottom.equalToSuperview().inset(WalletTokens.cardPadding)
        }
        return recordCard
    }

    private func makeTitle(_ text: String, size: CGFloat) -> UILabel {
        let label = UILabel()
        label.text = text
        label.font = .systemFont(ofSize: size, weight: .medium)
        label.textColor = .black
        return label
    }

    private func makeBody(_ text: String, color: UIColor, weight: UIFont.Weight = .regular) -> UILabel {
        let label = UILabel()
        label.text = text
        label.font = .systemFont(ofSize: 14, weight: weight)
        label.textColor = color
        return label
    }

    private func showMessageIfNeeded(_ message: String?) {
        guard let message, !message.isEmpty, message != lastShownMessage else { return }
        lastShownMessage = message
        showToast(message)
    }

    @objc private func pointsInputChanged() {
        viewModel.updatePointsInput(pointsInputField.text ?? "")
    }

    @objc private func withdrawAllTapped() {
        viewModel.withdrawAll()
    }

    @objc private func refreshPulled() {
        Task { await viewModel.refreshOverview(api: walletAPI) }
        Task { await viewModel.refreshWithdrawList(api: walletAPI) }
    }

    @objc private func submitTapped() {
        Task {
            showLoading()
            await viewModel.applyWithdraw(api: walletAPI)
            hideLoading()
        }
    }

    func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        Task { await viewModel.loadMoreWithdrawListIfNeeded(currentIndex: indexPath.row, api: walletAPI) }
    }
}

/// 积分提现记录 Cell。
private final class PointWithdrawRecordCell: UITableViewCell {
    static let reuseIdentifier = "PointWithdrawRecordCell"

    private let cardView = UIView()
    private let pointsLabel = UILabel()
    private let amountLabel = UILabel()
    private let timeLabel = UILabel()
    private let progressView = UIProgressView(progressViewStyle: .bar)
    private let percentLabel = UILabel()
    private let stepsStack = UIStackView()
    private let infoLabel = UILabel()
    private let statusLabel = UILabel()
    private let remarkLabel = UILabel()

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        setupUI()
    }

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

    /// 配置积分提现记录。
    func apply(_ record: PointWithdrawItem) {
        pointsLabel.text = "-\(record.points)积分"
        amountLabel.text = record.amount != nil && record.status == 2 ? "+\(formatAmount(record.amount))" : ""
        amountLabel.isHidden = amountLabel.text?.isEmpty ?? true
        timeLabel.text = record.createdAt.isEmpty ? "----" : record.createdAt
        let display = PointWithdrawStatusDisplay(status: record.status)
        let style = statusStyle(for: display.tone)
        statusLabel.text = display.title
        statusLabel.textColor = style.text
        statusLabel.backgroundColor = style.background
        let progress = display.progress
        progressView.progress = Float(progress) / 100.0
        progressView.progressTintColor = style.progress
        progressView.isHidden = progress == 0
        percentLabel.isHidden = progress == 0
        stepsStack.isHidden = progress == 0
        percentLabel.text = "\(progress)%"
        configureSteps(progress: progress, tint: style.progress)
        infoLabel.text = infoText(for: record)
        remarkLabel.text = record.rejectReason.isEmpty ? "" : "备注信息：\(record.rejectReason)"
        remarkLabel.isHidden = record.rejectReason.isEmpty
        updateDynamicConstraints(progress: progress, showsRemark: !record.rejectReason.isEmpty)
    }

    private func setupUI() {
        selectionStyle = .none
        backgroundColor = .white
        cardView.backgroundColor = .white
        cardView.layer.cornerRadius = WalletTokens.contentRadius
        cardView.layer.borderWidth = 1
        cardView.layer.borderColor = WalletTokens.cardBorder.cgColor
        cardView.clipsToBounds = true
        pointsLabel.font = WalletTokens.metricMediumFont
        pointsLabel.textColor = WalletTokens.textPrimary
        amountLabel.font = WalletTokens.metricMediumFont
        amountLabel.textColor = WalletTokens.danger
        amountLabel.textAlignment = .right
        timeLabel.font = WalletTokens.bodyFont
        timeLabel.textColor = WalletTokens.textMuted
        progressView.trackTintColor = WalletTokens.progressTrack
        progressView.layer.cornerRadius = 3
        progressView.clipsToBounds = true
        percentLabel.font = WalletTokens.bodyMediumFont
        percentLabel.textColor = WalletTokens.textTertiary
        percentLabel.textAlignment = .right
        stepsStack.axis = .horizontal
        stepsStack.distribution = .equalSpacing
        statusLabel.font = WalletTokens.captionFont
        statusLabel.textAlignment = .center
        statusLabel.layer.cornerRadius = WalletTokens.chipRadius
        statusLabel.clipsToBounds = true
        infoLabel.font = WalletTokens.bodyFont
        infoLabel.textColor = WalletTokens.textSecondary
        infoLabel.numberOfLines = 0
        remarkLabel.font = WalletTokens.bodyFont
        remarkLabel.textColor = WalletTokens.danger
        remarkLabel.numberOfLines = 0

        contentView.addSubview(cardView)
        [pointsLabel, amountLabel, timeLabel, progressView, percentLabel, stepsStack, infoLabel, statusLabel, remarkLabel].forEach(cardView.addSubview)

        cardView.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(UIEdgeInsets(top: 6, left: 0, bottom: 6, right: 0))
        }
        pointsLabel.snp.makeConstraints { make in
            make.top.leading.equalToSuperview().offset(16)
        }
        amountLabel.snp.makeConstraints { make in
            make.centerY.equalTo(pointsLabel)
            make.leading.greaterThanOrEqualTo(pointsLabel.snp.trailing).offset(12)
            make.trailing.equalToSuperview().inset(16)
        }
        timeLabel.snp.makeConstraints { make in
            make.top.equalTo(pointsLabel.snp.bottom).offset(8)
            make.leading.trailing.equalToSuperview().inset(16)
        }
        progressView.snp.makeConstraints { make in
            make.top.equalTo(timeLabel.snp.bottom).offset(12)
            make.leading.equalToSuperview().offset(WalletTokens.cardPadding)
            make.trailing.equalTo(percentLabel.snp.leading).offset(-WalletTokens.rowGap)
            make.height.equalTo(WalletTokens.progressHeight)
        }
        percentLabel.snp.makeConstraints { make in
            make.centerY.equalTo(progressView)
            make.trailing.equalToSuperview().inset(WalletTokens.cardPadding)
        }
        stepsStack.snp.makeConstraints { make in
            make.top.equalTo(progressView.snp.bottom).offset(8)
            make.leading.trailing.equalToSuperview().inset(16)
        }
        statusLabel.snp.makeConstraints { make in
            make.centerY.equalTo(infoLabel)
            make.trailing.equalToSuperview().inset(16)
            make.height.equalTo(22)
            make.width.greaterThanOrEqualTo(70)
        }
        updateDynamicConstraints(progress: 0, showsRemark: false)
    }

    private func updateDynamicConstraints(progress: Int, showsRemark: Bool) {
        infoLabel.snp.remakeConstraints { make in
            if progress > 0 {
                make.top.equalTo(stepsStack.snp.bottom).offset(WalletTokens.compactGap)
            } else {
                make.top.equalTo(timeLabel.snp.bottom).offset(WalletTokens.compactGap)
            }
            make.leading.equalToSuperview().offset(WalletTokens.cardPadding)
            make.trailing.lessThanOrEqualTo(statusLabel.snp.leading).offset(-WalletTokens.compactGap)
            if !showsRemark {
                make.bottom.equalToSuperview().inset(14)
            }
        }
        remarkLabel.snp.remakeConstraints { make in
            make.top.equalTo(infoLabel.snp.bottom).offset(WalletTokens.tinyGap)
            make.leading.trailing.equalToSuperview().inset(WalletTokens.cardPadding)
            if showsRemark {
                make.bottom.equalToSuperview().inset(14)
            }
        }
    }

    private func configureSteps(progress: Int, tint: UIColor) {
        stepsStack.arrangedSubviews.forEach { $0.removeFromSuperview() }
        ["提交申请", "审核中", "打款中", "已完成"].enumerated().forEach { index, title in
            let label = UILabel()
            label.text = title
            label.font = WalletTokens.stepFont
            label.textColor = progress >= Int((Float(index) / 3.0) * 100) ? tint : WalletTokens.textMuted
            stepsStack.addArrangedSubview(label)
        }
    }

    private func statusStyle(for tone: WalletStatusTone) -> (background: UIColor, text: UIColor, progress: UIColor) {
        switch tone {
        case .success:
            (WalletTokens.successBackground, WalletTokens.success, WalletTokens.summaryBackground)
        case .warning:
            (WalletTokens.pointsPendingBackground, WalletTokens.points, WalletTokens.summaryBackground)
        case .danger:
            (WalletTokens.dangerBackground, WalletTokens.danger, WalletTokens.progressDanger)
        case .info:
            (WalletTokens.infoBackground, WalletTokens.summaryBackground, WalletTokens.summaryBackground)
        }
    }

    private func infoText(for record: PointWithdrawItem) -> String {
        let display = PointWithdrawStatusDisplay(status: record.status)
        let value: String
        switch record.status {
        case 3: value = record.reviewedAt
        case 2: value = record.paymentTime
        default: value = record.estimatedReceiptTime
        }
        return "\(display.timeTitle)\(value.isEmpty ? "暂无" : value)"
    }

    private func formatAmount(_ value: Double?) -> String {
        guard let value else { return "¥0.00" }
        return String(format: "¥%.2f", value)
    }
}