//
//  PermissionApplyViewController.swift
//  suixinkan
//

import SnapKit
import UIKit

/// 权限申请页，对齐 Android `PermissionApplyScreen`。
final class PermissionApplyViewController: BaseViewController {

    private let viewModel: PermissionApplyViewModel
    private let homeAPI: HomeAPI
    private let pendingData: RoleApplyPendingResponse?

    private let scrollView = UIScrollView()
    private let contentStack = UIStackView()
    private let bannerView = PermissionApplyBannerView()
    private let roleSelector = PermissionFormSelectorRow(title: "角色信息", subtitle: "单选 · 请选择您需要申请权限的角色", placeholder: "请选择角色")
    private let existingScenicTags = PermissionSelectedTagsView()
    private let scenicSelector = PermissionFormSelectorRow(title: "新增景区", subtitle: "多选 · 请选择需要新增权限的景区", placeholder: "请选择景区")
    private let selectedScenicTags = PermissionSelectedTagsView()
    private let submitButton = PermissionSubmitButton()

    init(
        pendingData: RoleApplyPendingResponse? = nil,
        viewModel: PermissionApplyViewModel = PermissionApplyViewModel(),
        homeAPI: HomeAPI = NetworkServices.shared.homeAPI
    ) {
        self.pendingData = pendingData
        self.viewModel = viewModel
        self.homeAPI = homeAPI
        super.init(nibName: nil, bundle: nil)
    }

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

    override func setupNavigationBar() {
        title = "申请权限"
    }

    override func setupUI() {
        contentStack.axis = .vertical
        contentStack.spacing = 16

        let card = UIView()
        card.backgroundColor = .white
        card.layer.cornerRadius = 8
        let cardStack = UIStackView(arrangedSubviews: [roleSelector, existingScenicTags, scenicSelector, selectedScenicTags])
        cardStack.axis = .vertical
        cardStack.spacing = 20
        card.addSubview(cardStack)
        cardStack.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(16)
        }

        contentStack.addArrangedSubview(bannerView)
        contentStack.addArrangedSubview(card)
        scrollView.addSubview(contentStack)
        view.addSubview(scrollView)
        view.addSubview(submitButton)

        contentStack.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(UIEdgeInsets(top: 0, left: 16, bottom: 16, right: 16))
            make.width.equalTo(scrollView).offset(-32)
        }
        scrollView.snp.makeConstraints { make in
            make.top.leading.trailing.equalTo(view.safeAreaLayoutGuide)
            make.bottom.equalTo(submitButton.snp.top).offset(-12)
        }
        submitButton.snp.makeConstraints { make in
            make.leading.trailing.equalToSuperview().inset(16)
            make.bottom.equalTo(view.safeAreaLayoutGuide).offset(-12)
        }
    }

    override func bindActions() {
        viewModel.onStateChange = { [weak self] in
            Task { @MainActor in self?.applyViewModel() }
        }
        viewModel.onShowMessage = { [weak self] message in
            Task { @MainActor in self?.showToast(message) }
        }
        viewModel.onSubmitSuccess = { [weak self] applyCode in
            Task { @MainActor in self?.handleSubmitSuccess(applyCode: applyCode) }
        }

        bannerView.onApplyNewScenic = { [weak self] in
            self?.showToast("功能开发中")
        }
        roleSelector.onTap = { [weak self] in self?.presentRolePicker() }
        scenicSelector.onTap = { [weak self] in
            guard let self else { return }
            self.viewModel.showScenicPickerSheet()
            if self.viewModel.availableScenics.isEmpty {
                Task { await self.viewModel.loadAvailableScenics(api: self.homeAPI) }
            }
            self.presentScenicPickerIfNeeded()
        }
        submitButton.addTarget(self, action: #selector(submitTapped), for: .touchUpInside)

        if let pendingData {
            viewModel.initWithPendingData(pendingData)
            Task { await viewModel.loadAvailableScenics(api: homeAPI) }
        }
        applyViewModel()
    }

    private func applyViewModel() {
        if viewModel.selectedRoleName.isEmpty {
            roleSelector.setValue("请选择角色", isPlaceholder: true)
            existingScenicTags.isHidden = true
        } else {
            roleSelector.setValue(viewModel.selectedRoleName, isPlaceholder: false)
            if let roleId = viewModel.selectedRoleId {
                let names = viewModel.existingScenics(for: roleId).map(\.name)
                existingScenicTags.apply(title: "已开通景区", names: names, onRemove: nil)
            }
        }

        if viewModel.selectedScenicNames.isEmpty {
            scenicSelector.setValue("请选择景区", isPlaceholder: true)
            selectedScenicTags.isHidden = true
        } else {
            scenicSelector.setValue("已选 \(viewModel.selectedScenicNames.count) 个景区", isPlaceholder: false)
            selectedScenicTags.apply(
                title: "待申请景区",
                names: viewModel.selectedScenicNames
            ) { [weak self] index in
                guard let self else { return }
                let id = self.viewModel.selectedScenicIds[index]
                let name = self.viewModel.selectedScenicNames[index]
                self.viewModel.removeSelectedScenic(id: id, name: name)
            }
        }

        submitButton.setSubmitting(viewModel.isSubmitting)
        presentScenicPickerIfNeeded()
        presentRolePickerIfNeeded()
    }

    private func presentRolePickerIfNeeded() {
        guard viewModel.showRolePicker else { return }
        viewModel.hideRolePickerSheet()
        presentRolePicker()
    }

    private func presentRolePicker() {
        let alert = UIAlertController(title: "选择角色", message: nil, preferredStyle: .actionSheet)
        viewModel.availableRoles.forEach { role in
            alert.addAction(UIAlertAction(title: role.name, style: .default) { [weak self] _ in
                self?.viewModel.selectRole(role)
                Task { await self?.viewModel.loadAvailableScenics(api: self?.homeAPI) }
            })
        }
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        present(alert, animated: true)
    }

    private func presentScenicPickerIfNeeded() {
        guard viewModel.showScenicPicker else { return }
        viewModel.hideScenicPickerSheet()
        presentScenicPicker()
    }

    private func presentScenicPicker() {
        guard viewModel.selectedRoleId != nil else {
            showToast("请先选择角色")
            return
        }
        if viewModel.availableScenics.isEmpty {
            Task {
                await viewModel.loadAvailableScenics(api: homeAPI)
                await MainActor.run { self.presentScenicPicker() }
            }
            return
        }

        let alert = UIAlertController(title: "选择景区", message: nil, preferredStyle: .actionSheet)
        viewModel.availableScenics.filter { !$0.isDisabled }.forEach { scenic in
            let prefix = scenic.isSelected ? "✓ " : ""
            alert.addAction(UIAlertAction(title: "\(prefix)\(scenic.name)", style: .default) { [weak self] _ in
                self?.viewModel.toggleScenic(scenic)
            })
        }
        alert.addAction(UIAlertAction(title: "完成", style: .cancel))
        present(alert, animated: true)
    }

    @objc private func submitTapped() {
        Task { await viewModel.submit(api: homeAPI) }
    }

    private func handleSubmitSuccess(applyCode: String) {
        guard !applyCode.isEmpty else {
            navigationController?.popViewController(animated: true)
            return
        }
        var controllers = navigationController?.viewControllers ?? []
        controllers.removeAll { $0 === self }
        let statusVC = PermissionApplyStatusViewController(applyCode: applyCode)
        controllers.append(statusVC)
        navigationController?.setViewControllers(controllers, animated: true)
    }
}