//
//  CreateTravelAlbumSheetViewController.swift
//  suixinkan
//

import SnapKit
import UIKit

/// 新建相册任务底部 Sheet，对齐 Android `CreateTravelAlbumModal`。
final class CreateTravelAlbumSheetViewController: BaseViewController {
    var onDismissed: (() -> Void)?

    private let viewModel: TravelAlbumEntryViewModel
    private let api: any TravelAlbumServing
    private let mode: TravelAlbumEntryViewModel.CreateMode = .preShoot

    private let scrollView = UIScrollView()
    private let contentView = UIView()
    private let titleLabel = UILabel()
    private let preShootCard = TravelAlbumModeOptionView()
    private let fieldsStack = UIStackView()
    private let freeCountField = UITextField()
    private let singlePriceField = UITextField()
    private let packagePriceField = UITextField()
    private let cancelButton = UIButton(type: .system)
    private let confirmButton = UIButton(type: .system)

    init(viewModel: TravelAlbumEntryViewModel, api: any TravelAlbumServing) {
        self.viewModel = viewModel
        self.api = api
        super.init(nibName: nil, bundle: nil)
        modalPresentationStyle = .pageSheet
        if let sheetPresentationController {
            sheetPresentationController.detents = [.medium(), .large()]
            sheetPresentationController.prefersGrabberVisible = false
        }
    }

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

    override func setupNavigationBar() {}

    override func setupUI() {
        view.backgroundColor = .white
        titleLabel.text = "新建相册任务"
        titleLabel.font = .systemFont(ofSize: 18, weight: .semibold)
        titleLabel.textColor = AppColor.textPrimary
        titleLabel.textAlignment = .center

        preShootCard.apply(
            title: "先拍再买",
            desc: "拍完后分享给用户，用户在小程序上选择性购买",
            selected: true
        )

        fieldsStack.axis = .vertical
        fieldsStack.spacing = 14

        configureTextField(freeCountField, placeholder: "请输入免费张数", keyboardType: .numberPad)
        configureTextField(singlePriceField, placeholder: "请输入单张照片价格", keyboardType: .decimalPad)
        configureTextField(packagePriceField, placeholder: "请输入打包价格", keyboardType: .decimalPad)

        configureActionButton(cancelButton, title: "取消", backgroundColor: UIColor(hex: 0xF4F4F4), titleColor: AppColor.textSecondary)
        configureActionButton(confirmButton, title: "确定", backgroundColor: AppColor.primary, titleColor: .white)

        view.addSubview(scrollView)
        scrollView.addSubview(contentView)
        [titleLabel, preShootCard, fieldsStack, cancelButton, confirmButton].forEach(contentView.addSubview)
        rebuildFields()
    }

    override func setupConstraints() {
        scrollView.snp.makeConstraints { make in
            make.edges.equalTo(view.safeAreaLayoutGuide)
        }
        contentView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
            make.width.equalToSuperview()
        }
        titleLabel.snp.makeConstraints { make in
            make.top.equalToSuperview().offset(18)
            make.leading.trailing.equalToSuperview().inset(20)
        }
        preShootCard.snp.makeConstraints { make in
            make.top.equalTo(titleLabel.snp.bottom).offset(18)
            make.leading.trailing.equalToSuperview().inset(16)
        }
        fieldsStack.snp.makeConstraints { make in
            make.top.equalTo(preShootCard.snp.bottom).offset(18)
            make.leading.trailing.equalTo(preShootCard)
        }
        cancelButton.snp.makeConstraints { make in
            make.top.equalTo(fieldsStack.snp.bottom).offset(22)
            make.leading.equalToSuperview().offset(16)
            make.height.equalTo(48)
            make.width.equalTo(confirmButton)
            make.bottom.equalToSuperview().offset(-16)
        }
        confirmButton.snp.makeConstraints { make in
            make.top.height.width.equalTo(cancelButton)
            make.leading.equalTo(cancelButton.snp.trailing).offset(12)
            make.trailing.equalToSuperview().offset(-16)
        }
    }

    override func bindActions() {
        cancelButton.addTarget(self, action: #selector(cancelTapped), for: .touchUpInside)
        confirmButton.addTarget(self, action: #selector(confirmTapped), for: .touchUpInside)
        [freeCountField, singlePriceField, packagePriceField].forEach {
            $0.addTarget(self, action: #selector(textFieldEditingChanged(_:)), for: .editingChanged)
        }
    }

    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)
        if isBeingDismissed {
            onDismissed?()
        }
    }

    private func configureTextField(_ field: UITextField, placeholder: String, keyboardType: UIKeyboardType) {
        field.placeholder = placeholder
        field.keyboardType = keyboardType
        field.font = .systemFont(ofSize: 14)
        field.layer.cornerRadius = 8
        field.layer.borderWidth = 1
        field.layer.borderColor = AppColor.border.cgColor
        field.leftView = UIView(frame: CGRect(x: 0, y: 0, width: 12, height: 1))
        field.leftViewMode = .always
        field.snp.makeConstraints { make in
            make.height.equalTo(44)
        }
    }

    private func configureActionButton(_ button: UIButton, title: String, backgroundColor: UIColor, titleColor: UIColor) {
        button.setTitle(title, for: .normal)
        button.setTitleColor(titleColor, for: .normal)
        button.titleLabel?.font = .systemFont(ofSize: 16, weight: .medium)
        button.backgroundColor = backgroundColor
        button.layer.cornerRadius = 10
    }

    private func rebuildFields() {
        fieldsStack.arrangedSubviews.forEach { $0.removeFromSuperview() }
        fieldsStack.addArrangedSubview(makeFieldGroup(title: "免费张数", required: false, field: freeCountField))
        fieldsStack.addArrangedSubview(makeFieldGroup(title: "单张照片价格（元）", required: true, field: singlePriceField))
        fieldsStack.addArrangedSubview(makeFieldGroup(title: "打包价格（元）", required: false, field: packagePriceField))
    }

    private func makeFieldGroup(title: String, required: Bool, field: UITextField) -> UIView {
        let container = UIView()
        let label = UILabel()
        label.attributedText = fieldTitle(title, required: required)
        container.addSubview(label)
        container.addSubview(field)
        label.snp.makeConstraints { make in
            make.top.leading.trailing.equalToSuperview()
        }
        field.snp.makeConstraints { make in
            make.top.equalTo(label.snp.bottom).offset(8)
            make.leading.trailing.bottom.equalToSuperview()
        }
        return container
    }

    private func fieldTitle(_ text: String, required: Bool) -> NSAttributedString {
        let result = NSMutableAttributedString(
            string: text,
            attributes: [.font: UIFont.systemFont(ofSize: 14, weight: .medium), .foregroundColor: AppColor.textPrimary]
        )
        if required {
            result.append(NSAttributedString(string: " *", attributes: [.foregroundColor: UIColor.red]))
        }
        return result
    }

    @objc private func cancelTapped() {
        dismiss(animated: true)
    }

    @objc private func confirmTapped() {
        Task {
            await viewModel.confirmCreate(
                mode: mode,
                freeCount: freeCountField.text ?? "",
                singlePrice: singlePriceField.text ?? "",
                packagePrice: packagePriceField.text ?? "",
                order: nil,
                api: api
            )
            await MainActor.run {
                if !viewModel.isCreateSheetVisible {
                    dismiss(animated: true)
                }
            }
        }
    }

    @objc private func textFieldEditingChanged(_ field: UITextField) {
        let text = field.text ?? ""
        if field === freeCountField {
            field.text = text.filter(\.isNumber)
        } else {
            field.text = sanitizeMoneyInput(text)
        }
    }

    private func sanitizeMoneyInput(_ value: String) -> String {
        var result = ""
        var hasDot = false
        for char in value {
            if char.isNumber {
                result.append(char)
            } else if char == ".", !hasDot {
                result.append(char)
                hasDot = true
            }
        }
        guard !result.isEmpty else { return "" }
        if result.hasPrefix(".") {
            result = "0" + result
        }
        guard let dotIndex = result.firstIndex(of: ".") else {
            let trimmed = result.drop { $0 == "0" }
            return trimmed.isEmpty ? "0" : String(trimmed)
        }
        let integerPart = result[..<dotIndex].drop { $0 == "0" }
        let decimalStart = result.index(after: dotIndex)
        let decimal = result[decimalStart...].prefix(2)
        return "\(integerPart.isEmpty ? "0" : String(integerPart)).\(decimal)"
    }
}

/// 新建相册模式选择卡片。
private final class TravelAlbumModeOptionView: UIControl {
    private let dotView = UIView()
    private let innerDotView = UIView()
    private let titleLabel = UILabel()
    private let descLabel = UILabel()

    override init(frame: CGRect) {
        super.init(frame: frame)
        layer.cornerRadius = 10
        layer.borderWidth = 1
        dotView.layer.cornerRadius = 10
        innerDotView.backgroundColor = .white
        innerDotView.layer.cornerRadius = 3.5
        titleLabel.font = .systemFont(ofSize: 15, weight: .semibold)
        descLabel.font = .systemFont(ofSize: 12)
        descLabel.textColor = AppColor.textSecondary
        descLabel.numberOfLines = 0

        addSubview(dotView)
        dotView.addSubview(innerDotView)
        addSubview(titleLabel)
        addSubview(descLabel)
        dotView.snp.makeConstraints { make in
            make.leading.top.equalToSuperview().offset(14)
            make.size.equalTo(20)
        }
        innerDotView.snp.makeConstraints { make in
            make.center.equalToSuperview()
            make.size.equalTo(7)
        }
        titleLabel.snp.makeConstraints { make in
            make.top.equalToSuperview().offset(14)
            make.leading.equalTo(dotView.snp.trailing).offset(10)
            make.trailing.equalToSuperview().offset(-14)
        }
        descLabel.snp.makeConstraints { make in
            make.top.equalTo(titleLabel.snp.bottom).offset(4)
            make.leading.trailing.equalTo(titleLabel)
            make.bottom.equalToSuperview().offset(-14)
        }
    }

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

    func apply(title: String, desc: String, selected: Bool) {
        titleLabel.text = title
        descLabel.text = desc
        backgroundColor = selected ? AppColor.primary.withAlphaComponent(0.06) : .white
        layer.borderColor = (selected ? AppColor.primary : AppColor.border).cgColor
        titleLabel.textColor = selected ? AppColor.primary : AppColor.textPrimary
        dotView.backgroundColor = selected ? AppColor.primary : .clear
        dotView.layer.borderWidth = selected ? 0 : 2
        dotView.layer.borderColor = AppColor.border.cgColor
        innerDotView.isHidden = !selected
    }
}