//
//  DepositOrderViewControllers.swift
//  suixinkan
//

import SnapKit
import UIKit

// MARK: - Deposit List Diffable 标识

private typealias DepositListSection = Int
private typealias DepositListItem = String

/// 押金列表空态 / 加载态标识。
private enum DepositListItemID {
    static let placeholder = "depositList:placeholder"
}

// MARK: - Deposit Detail Diffable 标识

private typealias DepositDetailSection = Int
private typealias DepositDetailRow = String

/// 押金详情行标识。
private enum DepositDetailRowID {
    static let placeholder = "depositDetail:placeholder"
    static func field(_ index: Int) -> String { "depositDetail:field:\(index)" }
}

// MARK: - Deposit Shooting Diffable 标识

private typealias DepositShootingSection = Int
private typealias DepositShootingRow = String

/// 押金拍摄信息 section 索引。
private enum DepositShootingSectionID {
    static let summary = 0
    static let material = 1
    static let complete = 2
}

/// 押金拍摄信息行标识。
private enum DepositShootingRowID {
    static let placeholder = "depositShooting:placeholder"
    static let scenicSpot = "depositShooting:scenicSpot"
    static let rating = "depositShooting:rating"
    static func material(_ index: Int) -> String { "depositShooting:material:\(index)" }
    static func complete(_ index: Int) -> String { "depositShooting:complete:\(index)" }
}

/// 押金订单列表页，支持查询、分页、核销和退款。
final class DepositOrderListViewController: UIViewController, UITableViewDelegate {

    private let viewModel = DepositOrderListViewModel()
    private var orderNumberField = UITextField()

    private lazy var tableView: UITableView = {
        let table = UITableView(frame: .zero, style: .insetGrouped)
        table.delegate = self
        table.register(DepositOrderCell.self, forCellReuseIdentifier: DepositOrderCell.reuseID)
        return table
    }()

    /// Diffable 数据源，驱动押金订单列表与分页刷新。
    private var tableDataSource: UITableViewDiffableDataSource<DepositListSection, DepositListItem>!

    /// 视图加载完成后的 UI 初始化与数据绑定。
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "押金订单"
        view.backgroundColor = AppDesignUIKit.pageBackground
        configureTableDataSource()
        view.addSubview(tableView)
        tableView.snp.makeConstraints { make in make.edges.equalToSuperview() }

        viewModel.onChange = { [weak self] in self?.applyTableSnapshot(reconfigure: true) }
        setupHeader()
        Task { await reload(showLoading: true) }
    }

    /// 配置 Diffable 数据源。
    private func configureTableDataSource() {
        tableDataSource = UITableViewDiffableDataSource<DepositListSection, DepositListItem>(
            tableView: tableView
        ) { [weak self] (tableView: UITableView, indexPath: IndexPath, item: DepositListItem) -> UITableViewCell? in
            guard let self else { return UITableViewCell() }
            if item == DepositListItemID.placeholder {
                let cell = UITableViewCell()
                cell.textLabel?.text = self.viewModel.loading ? "加载中..." : "暂无押金订单"
                cell.selectionStyle = .none
                return cell
            }
            guard let orderItem = self.viewModel.orders.first(where: { $0.orderNumber == item }) else {
                return UITableViewCell()
            }
            let cell = tableView.dequeueReusableCell(withIdentifier: DepositOrderCell.reuseID, for: indexPath) as! DepositOrderCell
            cell.configure(item: orderItem, isOperating: self.viewModel.operatingOrderNumber == orderItem.orderNumber)
            cell.onDetail = { [weak self] in
                self.flatMap { $0.appServices.appNavigator.push(.orders(.depositDetail(orderNumber: orderItem.orderNumber)), from: $0) }
            }
            cell.onWriteOff = { [weak self] in self?.writeOff(orderItem) }
            cell.onRefund = { [weak self] in self?.refund(orderItem) }
            return cell
        }
        applyTableSnapshot(animated: false)
    }

    /// 构建 Diffable snapshot。
    private func buildTableSnapshot() -> NSDiffableDataSourceSnapshot<DepositListSection, DepositListItem> {
        var snapshot = NSDiffableDataSourceSnapshot<DepositListSection, DepositListItem>()
        snapshot.appendSections([0])
        if viewModel.orders.isEmpty {
            snapshot.appendItems([DepositListItemID.placeholder], toSection: 0)
        } else {
            snapshot.appendItems(viewModel.orders.map(\.orderNumber), toSection: 0)
        }
        return snapshot
    }

    /// 应用 snapshot 刷新列表。
    private func applyTableSnapshot(animated: Bool = true, reconfigure: Bool = false) {
        var snapshot = buildTableSnapshot()
        if reconfigure, !snapshot.itemIdentifiers.isEmpty {
            snapshot.reconfigureItems(snapshot.itemIdentifiers)
        }
        tableDataSource.apply(snapshot, animatingDifferences: animated)
    }

    /// 初始化Header相关 UI 或状态。
    private func setupHeader() {
        let header = UIView(frame: CGRect(x: 0, y: 0, width: view.bounds.width, height: 120))
        orderNumberField.placeholder = "请输入押金订单号"
        orderNumberField.borderStyle = .roundedRect
        orderNumberField.autocorrectionType = .no
        orderNumberField.autocapitalizationType = .none

        let detailButton = makePrimaryButton(title: "查看订单详情")
        detailButton.addTarget(self, action: #selector(openDetail), for: .touchUpInside)

        header.addSubview(orderNumberField)
        header.addSubview(detailButton)
        orderNumberField.snp.makeConstraints { make in
            make.top.leading.trailing.equalToSuperview().inset(16)
            make.height.equalTo(44)
        }
        detailButton.snp.makeConstraints { make in
            make.top.equalTo(orderNumberField.snp.bottom).offset(12)
            make.leading.trailing.equalToSuperview().inset(16)
        }
        tableView.tableHeaderView = header
    }

    /// open详情相关逻辑。
    @objc private func openDetail() {
        let text = orderNumberField.text?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        guard !text.isEmpty else { return }
        appServices.appNavigator.push(.orders(.depositDetail(orderNumber: text)), from: self)
    }

    /// 刷新。
    private func reload(showLoading: Bool) async {
        if showLoading {
            await appServices.globalLoading.withLoading {
                await viewModel.reload(api: appServices.ordersAPI, scenicId: appServices.accountContext.currentScenic?.id, reset: true)
            }
        } else {
            await viewModel.reload(api: appServices.ordersAPI, scenicId: appServices.accountContext.currentScenic?.id, reset: true)
        }
        if let message = viewModel.errorMessage { showToast(message) }
    }

    /// writeOff相关逻辑。
    private func writeOff(_ item: DepositOrderListItem) {
        let alert = UIAlertController(title: "确认核销该押金订单？", message: item.orderNumber, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        alert.addAction(UIAlertAction(title: "确认核销", style: .default) { [weak self] _ in
            Task {
                guard let self else { return }
                let success = await self.viewModel.writeOff(api: self.appServices.ordersAPI, scenicId: self.appServices.accountContext.currentScenic?.id, orderNumber: item.orderNumber)
                if success { self.showToast("核销成功") }
                else if let message = self.viewModel.errorMessage { self.showToast(message) }
            }
        })
        present(alert, animated: true)
    }

    /// refund 业务逻辑。
    private func refund(_ item: DepositOrderListItem) {
        let alert = UIAlertController(title: "申请退款", message: "请填写退款原因", preferredStyle: .alert)
        alert.addTextField { $0.placeholder = "退款原因" }
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        alert.addAction(UIAlertAction(title: "提交", style: .default) { [weak self] _ in
            Task {
                guard let self else { return }
                let reason = alert.textFields?.first?.text ?? ""
                let success = await self.viewModel.refund(api: self.appServices.ordersAPI, scenicId: self.appServices.accountContext.currentScenic?.id, orderNumber: item.orderNumber, reason: reason)
                if success { self.showToast("退款申请已提交") }
                else if let message = self.viewModel.errorMessage { self.showToast(message) }
            }
        })
        present(alert, animated: true)
    }

    /// UITableView 代理：section 标题。
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        "押金订单列表 \(viewModel.orders.count)/\(viewModel.total)"
    }

    /// UITableView 代理：分页加载。
    func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        guard let item = tableDataSource.itemIdentifier(for: indexPath),
              item != DepositListItemID.placeholder,
              item == viewModel.orders.last?.orderNumber,
              viewModel.hasMore else { return }
        Task {
            await viewModel.reload(api: appServices.ordersAPI, scenicId: appServices.accountContext.currentScenic?.id, reset: false)
        }
    }
}

/// DepositOrder列表或网格 Cell，负责单项内容展示。
private final class DepositOrderCell: UITableViewCell {
    static let reuseID = "DepositOrderCell"
    var onDetail: (() -> Void)?
    var onWriteOff: (() -> Void)?
    var onRefund: (() -> Void)?

    private let titleLabel = UILabel()
    private let statusLabel = UILabel()
    private let amountLabel = UILabel()

    /// 初始化实例。
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        selectionStyle = .none
        titleLabel.font = .systemFont(ofSize: AppMetrics.FontSize.subheadline, weight: .semibold)
        statusLabel.font = .systemFont(ofSize: AppMetrics.FontSize.caption)
        amountLabel.font = .systemFont(ofSize: AppMetrics.FontSize.body, weight: .semibold)
        amountLabel.textColor = AppDesignUIKit.primary

        let detailButton = UIButton(type: .system)
        detailButton.setTitle("详情", for: .normal)
        detailButton.addTarget(self, action: #selector(detailTapped), for: .touchUpInside)
        let writeOffButton = UIButton(type: .system)
        writeOffButton.setTitle("核销", for: .normal)
        writeOffButton.addTarget(self, action: #selector(writeOffTapped), for: .touchUpInside)
        let refundButton = UIButton(type: .system)
        refundButton.setTitle("退款", for: .normal)
        refundButton.addTarget(self, action: #selector(refundTapped), for: .touchUpInside)

        let buttonRow = UIStackView(arrangedSubviews: [detailButton, writeOffButton, refundButton])
        buttonRow.axis = .horizontal
        buttonRow.distribution = .fillEqually

        let stack = UIStackView(arrangedSubviews: [titleLabel, amountLabel, buttonRow])
        stack.axis = .vertical
        stack.spacing = 8
        contentView.addSubview(stack)
        contentView.addSubview(statusLabel)
        stack.snp.makeConstraints { make in make.edges.equalToSuperview().inset(12) }
        statusLabel.snp.makeConstraints { make in make.trailing.top.equalToSuperview().inset(12) }
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 配置展示内容。
    func configure(item: DepositOrderListItem, isOperating: Bool) {
        titleLabel.text = item.orderNumber
        statusLabel.text = isOperating ? "处理中" : item.statusName
        amountLabel.text = "¥\(item.amount.isEmpty ? "0.00" : item.amount)"
    }

    /// 点击detail的处理逻辑。
    @objc private func detailTapped() { onDetail?() }
    /// 点击writeOff的处理逻辑。
    @objc private func writeOffTapped() { onWriteOff?() }
    /// 点击refund的处理逻辑。
    @objc private func refundTapped() { onRefund?() }
}

/// 押金订单详情页。
final class DepositOrderDetailViewController: UIViewController {

    private let orderNumber: String
    private let viewModel = DepositOrderDetailViewModel()

    private lazy var tableView: UITableView = {
        let table = UITableView(frame: .zero, style: .insetGrouped)
        table.backgroundColor = AppDesignUIKit.pageBackground
        return table
    }()

    /// Diffable 数据源，驱动详情字段展示。
    private var tableDataSource: UITableViewDiffableDataSource<DepositDetailSection, DepositDetailRow>!

    /// 初始化实例。
    init(orderNumber: String) {
        self.orderNumber = orderNumber
        super.init(nibName: nil, bundle: nil)
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 视图加载完成后的 UI 初始化与数据绑定。
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "押金订单详情"
        configureTableDataSource()
        view.addSubview(tableView)
        tableView.snp.makeConstraints { make in make.edges.equalToSuperview() }
        Task { await loadDetail() }
    }

    /// 配置 Diffable 数据源。
    private func configureTableDataSource() {
        tableDataSource = UITableViewDiffableDataSource<DepositDetailSection, DepositDetailRow>(
            tableView: tableView
        ) { [weak self] (_: UITableView, _: IndexPath, row: DepositDetailRow) -> UITableViewCell? in
            guard let self else { return UITableViewCell() }
            let cell = UITableViewCell(style: .value1, reuseIdentifier: nil)
            cell.selectionStyle = .none
            guard let detail = self.viewModel.detail else {
                cell.textLabel?.text = self.viewModel.errorMessage ?? (self.viewModel.loading ? "加载中..." : "暂无详情")
                return cell
            }
            let rows: [(String, String)] = [
                ("订单号", detail.orderNumber),
                ("状态", detail.orderStatusName),
                ("类型", detail.orderTypeLabel),
                ("付款金额", detail.actualPayAmount),
                ("手机号", detail.phone),
                ("项目", detail.projectName),
                ("创建时间", detail.createdAt),
                ("备注", detail.remark)
            ]
            let index = Int(row.split(separator: ":").last ?? "") ?? 0
            if index < rows.count {
                cell.textLabel?.text = rows[index].0
                cell.detailTextLabel?.text = rows[index].1
            }
            return cell
        }
        applyTableSnapshot(animated: false)
    }

    /// 构建 Diffable snapshot。
    private func buildTableSnapshot() -> NSDiffableDataSourceSnapshot<DepositDetailSection, DepositDetailRow> {
        var snapshot = NSDiffableDataSourceSnapshot<DepositDetailSection, DepositDetailRow>()
        snapshot.appendSections([0])
        if viewModel.detail == nil {
            snapshot.appendItems([DepositDetailRowID.placeholder], toSection: 0)
        } else {
            snapshot.appendItems((0..<8).map { DepositDetailRowID.field($0) }, toSection: 0)
        }
        return snapshot
    }

    /// 应用 snapshot 刷新列表。
    private func applyTableSnapshot(animated: Bool = true) {
        tableDataSource.apply(buildTableSnapshot(), animatingDifferences: animated)
    }

    /// 加载Detail数据。
    private func loadDetail() async {
        await appServices.globalLoading.withLoading {
            await viewModel.load(
                api: appServices.ordersAPI,
                storeId: appServices.accountContext.currentStore?.id,
                orderNumber: orderNumber
            )
        }
        applyTableSnapshot()
        if let message = viewModel.errorMessage { showToast(message) }
    }
}

/// 押金拍摄信息页。
final class DepositOrderShootingInfoViewController: UIViewController, UITableViewDelegate {

    private let orderNumber: String
    private let scenicSpotId: Int
    private let photogUid: Int
    private let viewModel = DepositOrderShootingInfoViewModel()

    private lazy var tableView: UITableView = {
        let table = UITableView(frame: .zero, style: .insetGrouped)
        table.delegate = self
        return table
    }()

    /// Diffable 数据源，驱动拍摄摘要与素材列表刷新。
    private var tableDataSource: UITableViewDiffableDataSource<DepositShootingSection, DepositShootingRow>!

    /// 初始化实例。
    init(orderNumber: String, scenicSpotId: Int, photogUid: Int) {
        self.orderNumber = orderNumber
        self.scenicSpotId = scenicSpotId
        self.photogUid = photogUid
        super.init(nibName: nil, bundle: nil)
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 视图加载完成后的 UI 初始化与数据绑定。
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "押金拍摄信息"
        configureTableDataSource()
        view.addSubview(tableView)
        tableView.snp.makeConstraints { make in make.edges.equalToSuperview() }
        Task { await loadDetail() }
    }

    /// 配置 Diffable 数据源。
    private func configureTableDataSource() {
        tableDataSource = UITableViewDiffableDataSource<DepositShootingSection, DepositShootingRow>(
            tableView: tableView
        ) { [weak self] (_: UITableView, indexPath: IndexPath, row: DepositShootingRow) -> UITableViewCell? in
            guard let self else { return UITableViewCell() }
            guard let detail = self.viewModel.detail else {
                let cell = UITableViewCell()
                cell.textLabel?.text = self.viewModel.errorMessage ?? "加载中..."
                return cell
            }
            if row == DepositShootingRowID.scenicSpot || row == DepositShootingRowID.rating {
                let cell = UITableViewCell(style: .value1, reuseIdentifier: nil)
                if row == DepositShootingRowID.scenicSpot {
                    cell.textLabel?.text = "打卡点"
                    cell.detailTextLabel?.text = detail.scenicSpotName
                } else {
                    cell.textLabel?.text = "拍摄评分"
                    cell.detailTextLabel?.text = detail.orderComment.map { "\($0.starShooting) 星" } ?? "--"
                }
                return cell
            }
            let files: [OrderMediaFile]
            if row.hasPrefix("depositShooting:material:") {
                files = detail.materialList
            } else {
                files = detail.completeList
            }
            let index = Int(row.split(separator: ":").last ?? "") ?? 0
            let media = files[index]
            let cell = UITableViewCell(style: .subtitle, reuseIdentifier: nil)
            cell.textLabel?.text = media.fileName
            cell.detailTextLabel?.text = media.fileUrl
            return cell
        }
        applyTableSnapshot(animated: false)
    }

    /// 构建 Diffable snapshot。
    private func buildTableSnapshot() -> NSDiffableDataSourceSnapshot<DepositShootingSection, DepositShootingRow> {
        var snapshot = NSDiffableDataSourceSnapshot<DepositShootingSection, DepositShootingRow>()
        guard let detail = viewModel.detail else {
            snapshot.appendSections([0])
            snapshot.appendItems([DepositShootingRowID.placeholder], toSection: 0)
            return snapshot
        }
        snapshot.appendSections([DepositShootingSectionID.summary, DepositShootingSectionID.material, DepositShootingSectionID.complete])
        snapshot.appendItems([DepositShootingRowID.scenicSpot, DepositShootingRowID.rating], toSection: DepositShootingSectionID.summary)
        snapshot.appendItems(detail.materialList.indices.map { DepositShootingRowID.material($0) }, toSection: DepositShootingSectionID.material)
        snapshot.appendItems(detail.completeList.indices.map { DepositShootingRowID.complete($0) }, toSection: DepositShootingSectionID.complete)
        return snapshot
    }

    /// 应用 snapshot 刷新列表。
    private func applyTableSnapshot(animated: Bool = true) {
        tableDataSource.apply(buildTableSnapshot(), animatingDifferences: animated)
    }

    /// 加载Detail数据。
    private func loadDetail() async {
        await appServices.globalLoading.withLoading {
            await viewModel.load(
                api: appServices.ordersAPI,
                storeId: appServices.accountContext.currentStore?.id,
                orderNumber: orderNumber,
                scenicSpotId: scenicSpotId,
                photogUid: photogUid
            )
        }
        applyTableSnapshot()
        if let message = viewModel.errorMessage { showToast(message) }
    }

    /// UITableView 代理：section 标题。
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        guard viewModel.detail != nil,
              let sectionID = tableDataSource.snapshot().sectionIdentifiers[safe: section] else { return nil }
        switch sectionID {
        case DepositShootingSectionID.material: return "素材"
        case DepositShootingSectionID.complete: return "成片"
        default: return nil
        }
    }
}

/// 安全下标，避免 section 越界。
private extension Array {
    subscript(safe index: Int) -> Element? {
        indices.contains(index) ? self[index] : nil
    }
}