// AboutViewController.swift
// Emoney Info

import UIKit

class AboutViewController: UIViewController {

    // MARK: - Lifecycle

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = Theme.Color.background
        setupUI()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        navigationController?.setNavigationBarHidden(true, animated: animated)
        (tabBarController as? MainTabBarController)?.setTabBarHidden(true, animated: animated)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        (tabBarController as? MainTabBarController)?.setTabBarHidden(false, animated: animated)
    }

    // MARK: - Setup

    private func setupUI() {
        let scrollView  = UIScrollView()
        let contentView = UIView()
        scrollView.showsVerticalScrollIndicator = false
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        contentView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(scrollView)
        scrollView.addSubview(contentView)

        NSLayoutConstraint.activate([
            scrollView.topAnchor.constraint(equalTo: view.topAnchor),
            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),

            contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
            contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
            contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
            contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
            contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor),
        ])

        // MARK: Back button + nav title
        let backButton = UIButton(type: .system)
        let chevron = UIImage(systemName: "chevron.left",
                              withConfiguration: UIImage.SymbolConfiguration(pointSize: 16, weight: .semibold))
        backButton.setImage(chevron, for: .normal)
        backButton.tintColor = Theme.Color.textPrimary
        backButton.addTarget(self, action: #selector(backTapped), for: .touchUpInside)
        backButton.translatesAutoresizingMaskIntoConstraints = false

        let navTitleLabel = UILabel()
        navTitleLabel.text = L10n.aboutAppTitle
        navTitleLabel.font = Theme.Font.caption(weight: .semibold)
        navTitleLabel.textColor = Theme.Color.textSecondary
        navTitleLabel.translatesAutoresizingMaskIntoConstraints = false

        // MARK: App icon
        let iconView = UIImageView(image: UIImage(named: "AppLogo"))
        iconView.contentMode  = .scaleAspectFit
        iconView.layer.cornerRadius = 24
        iconView.clipsToBounds = true
        iconView.layer.shadowColor   = UIColor.black.cgColor
        iconView.layer.shadowOpacity = 0.12
        iconView.layer.shadowOffset  = CGSize(width: 0, height: 4)
        iconView.layer.shadowRadius  = 12
        iconView.translatesAutoresizingMaskIntoConstraints = false

        // MARK: App name + version
        let appNameLabel = UILabel()
        appNameLabel.text = "Emoney Info"
        appNameLabel.font = .systemFont(ofSize: 28, weight: .bold)
        appNameLabel.textColor = Theme.Color.textPrimary
        appNameLabel.textAlignment = .center
        appNameLabel.translatesAutoresizingMaskIntoConstraints = false

        let appVersion = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String ?? ""
        let versionLabel = UILabel()
        let versionText = "VERSI \(appVersion)"
        let versionAttr = NSAttributedString(string: versionText, attributes: [
            .kern: 1.5,
            .font: Theme.Font.caption(weight: .semibold),
            .foregroundColor: Theme.Color.textSecondary,
        ])
        versionLabel.attributedText = versionAttr
        versionLabel.textAlignment = .center
        versionLabel.translatesAutoresizingMaskIntoConstraints = false

        // MARK: Description
        let descLabel = UILabel()
        descLabel.text = L10n.aboutAppDescription
        descLabel.font = Theme.Font.body(weight: .regular)
        descLabel.textColor = Theme.Color.textSecondary
        descLabel.numberOfLines = 0
        descLabel.textAlignment = .center
        descLabel.translatesAutoresizingMaskIntoConstraints = false

        // MARK: Feature chips
        let chipsStack = UIStackView(arrangedSubviews: [
            makeFeatureChip(L10n.aboutChipNfc),
            makeFeatureChip(L10n.aboutChipRealtime),
            makeFeatureChip(L10n.aboutChipMulti),
        ])
        chipsStack.axis      = .horizontal
        chipsStack.spacing   = 10
        chipsStack.alignment = .center
        chipsStack.translatesAutoresizingMaskIntoConstraints = false

        // MARK: Legal rows card
        let legalCard = makeCard()

        let termsRow = makeLegalRow(icon: "doc.text", title: L10n.aboutTerms)
        termsRow.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(termsTapped)))
        termsRow.isUserInteractionEnabled = true

        let separator = UIView()
        separator.backgroundColor = Theme.Color.background
        separator.translatesAutoresizingMaskIntoConstraints = false
        separator.heightAnchor.constraint(equalToConstant: 1).isActive = true

        let privacyRow = makeLegalRow(icon: "lock.shield", title: L10n.aboutPrivacy)
        privacyRow.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(privacyTapped)))
        privacyRow.isUserInteractionEnabled = true

        let legalStack = UIStackView(arrangedSubviews: [termsRow, separator, privacyRow])
        legalStack.axis    = .vertical
        legalStack.spacing = 0
        legalStack.translatesAutoresizingMaskIntoConstraints = false
        legalCard.addSubview(legalStack)

        // MARK: Connect card (teal gradient)
        let connectCard = UIView()
        connectCard.layer.cornerRadius = 20
        connectCard.clipsToBounds = true
        connectCard.translatesAutoresizingMaskIntoConstraints = false

        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [
            Theme.Color.primary.cgColor,
            Theme.Color.secondary.cgColor,
        ]
        gradientLayer.startPoint = CGPoint(x: 0, y: 0)
        gradientLayer.endPoint   = CGPoint(x: 1, y: 1)
        connectCard.layer.insertSublayer(gradientLayer, at: 0)

        let connectIcon = UIImageView(image: UIImage(systemName: "wave.3.right.circle.fill",
            withConfiguration: UIImage.SymbolConfiguration(pointSize: 32, weight: .medium)))
        connectIcon.tintColor = UIColor.white.withAlphaComponent(0.35)
        connectIcon.contentMode = .scaleAspectFit
        connectIcon.translatesAutoresizingMaskIntoConstraints = false

        let connectTitle = UILabel()
        connectTitle.text = L10n.aboutConnectTitle
        connectTitle.font = Theme.Font.subtitle(weight: .bold)
        connectTitle.textColor = .white
        connectTitle.numberOfLines = 0
        connectTitle.translatesAutoresizingMaskIntoConstraints = false

        let connectDesc = UILabel()
        connectDesc.text = L10n.aboutConnectDesc
        connectDesc.font = Theme.Font.caption(weight: .regular)
        connectDesc.textColor = UIColor.white.withAlphaComponent(0.85)
        connectDesc.numberOfLines = 0
        connectDesc.translatesAutoresizingMaskIntoConstraints = false

        [connectIcon, connectTitle, connectDesc].forEach { connectCard.addSubview($0) }

        // MARK: Copyright
        let copyrightLabel = UILabel()
        copyrightLabel.text = L10n.footerCopyright
        copyrightLabel.font = Theme.Font.caption(weight: .regular)
        copyrightLabel.textColor = Theme.Color.textSecondary
        copyrightLabel.textAlignment = .center
        copyrightLabel.translatesAutoresizingMaskIntoConstraints = false

        // MARK: Add to contentView
        [backButton, navTitleLabel, iconView, appNameLabel, versionLabel,
         descLabel, chipsStack, legalCard, connectCard, copyrightLabel]
            .forEach { contentView.addSubview($0) }

        NSLayoutConstraint.activate([
            // Nav row
            backButton.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 56),
            backButton.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 20),
            backButton.widthAnchor.constraint(equalToConstant: 32),
            backButton.heightAnchor.constraint(equalToConstant: 32),

            navTitleLabel.centerYAnchor.constraint(equalTo: backButton.centerYAnchor),
            navTitleLabel.leadingAnchor.constraint(equalTo: backButton.trailingAnchor, constant: 8),

            // Icon
            iconView.topAnchor.constraint(equalTo: backButton.bottomAnchor, constant: 28),
            iconView.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),
            iconView.widthAnchor.constraint(equalToConstant: 96),
            iconView.heightAnchor.constraint(equalToConstant: 96),

            // Name + version
            appNameLabel.topAnchor.constraint(equalTo: iconView.bottomAnchor, constant: 16),
            appNameLabel.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),

            versionLabel.topAnchor.constraint(equalTo: appNameLabel.bottomAnchor, constant: 6),
            versionLabel.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),

            // Desc
            descLabel.topAnchor.constraint(equalTo: versionLabel.bottomAnchor, constant: 16),
            descLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 32),
            descLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -32),

            // Chips
            chipsStack.topAnchor.constraint(equalTo: descLabel.bottomAnchor, constant: 20),
            chipsStack.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),

            // Legal card
            legalCard.topAnchor.constraint(equalTo: chipsStack.bottomAnchor, constant: 28),
            legalCard.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 24),
            legalCard.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -24),

            legalStack.topAnchor.constraint(equalTo: legalCard.topAnchor, constant: 4),
            legalStack.leadingAnchor.constraint(equalTo: legalCard.leadingAnchor),
            legalStack.trailingAnchor.constraint(equalTo: legalCard.trailingAnchor),
            legalStack.bottomAnchor.constraint(equalTo: legalCard.bottomAnchor, constant: -4),

            // Connect card
            connectCard.topAnchor.constraint(equalTo: legalCard.bottomAnchor, constant: 20),
            connectCard.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 24),
            connectCard.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -24),

            connectIcon.topAnchor.constraint(equalTo: connectCard.topAnchor, constant: 20),
            connectIcon.trailingAnchor.constraint(equalTo: connectCard.trailingAnchor, constant: -20),
            connectIcon.widthAnchor.constraint(equalToConstant: 44),
            connectIcon.heightAnchor.constraint(equalToConstant: 44),

            connectTitle.topAnchor.constraint(equalTo: connectCard.topAnchor, constant: 24),
            connectTitle.leadingAnchor.constraint(equalTo: connectCard.leadingAnchor, constant: 20),
            connectTitle.trailingAnchor.constraint(equalTo: connectIcon.leadingAnchor, constant: -12),

            connectDesc.topAnchor.constraint(equalTo: connectTitle.bottomAnchor, constant: 10),
            connectDesc.leadingAnchor.constraint(equalTo: connectCard.leadingAnchor, constant: 20),
            connectDesc.trailingAnchor.constraint(equalTo: connectCard.trailingAnchor, constant: -20),
            connectDesc.bottomAnchor.constraint(equalTo: connectCard.bottomAnchor, constant: -24),

            // Copyright
            copyrightLabel.topAnchor.constraint(equalTo: connectCard.bottomAnchor, constant: 24),
            copyrightLabel.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),
            copyrightLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -32),
        ])

        // Gradient frame — set after layout
        DispatchQueue.main.async {
            gradientLayer.frame = connectCard.bounds
        }
    }

    // MARK: - Helpers

    private func makeCard() -> UIView {
        let v = UIView()
        v.backgroundColor     = Theme.Color.card
        v.layer.cornerRadius  = 16
        v.layer.shadowColor   = UIColor.black.cgColor
        v.layer.shadowOpacity = 0.06
        v.layer.shadowOffset  = CGSize(width: 0, height: 2)
        v.layer.shadowRadius  = 8
        v.translatesAutoresizingMaskIntoConstraints = false
        return v
    }

    private func makeFeatureChip(_ title: String) -> UIView {
        let container = UIView()
        container.backgroundColor    = Theme.Color.primary.withAlphaComponent(0.12)
        container.layer.cornerRadius = 12
        container.translatesAutoresizingMaskIntoConstraints = false

        let label = UILabel()
        label.text      = title
        label.font      = Theme.Font.caption(weight: .semibold)
        label.textColor = Theme.Color.secondary
        label.translatesAutoresizingMaskIntoConstraints = false
        container.addSubview(label)

        NSLayoutConstraint.activate([
            label.topAnchor.constraint(equalTo: container.topAnchor, constant: 6),
            label.leadingAnchor.constraint(equalTo: container.leadingAnchor, constant: 12),
            label.trailingAnchor.constraint(equalTo: container.trailingAnchor, constant: -12),
            label.bottomAnchor.constraint(equalTo: container.bottomAnchor, constant: -6),
        ])
        return container
    }

    private func makeLegalRow(icon: String, title: String) -> UIView {
        let row = UIView()
        row.translatesAutoresizingMaskIntoConstraints = false

        let iconContainer = UIView()
        iconContainer.backgroundColor    = Theme.Color.background
        iconContainer.layer.cornerRadius = 10
        iconContainer.translatesAutoresizingMaskIntoConstraints = false

        let iconView = UIImageView(image: UIImage(systemName: icon,
            withConfiguration: UIImage.SymbolConfiguration(pointSize: 14, weight: .medium)))
        iconView.tintColor    = Theme.Color.secondary
        iconView.contentMode  = .scaleAspectFit
        iconView.translatesAutoresizingMaskIntoConstraints = false
        iconContainer.addSubview(iconView)

        let titleLabel = UILabel()
        titleLabel.text      = title
        titleLabel.font      = Theme.Font.body(weight: .medium)
        titleLabel.textColor = Theme.Color.textPrimary
        titleLabel.translatesAutoresizingMaskIntoConstraints = false

        let chevronImg = UIImage(systemName: "chevron.right",
            withConfiguration: UIImage.SymbolConfiguration(pointSize: 12, weight: .semibold))
        let chevron = UIImageView(image: chevronImg)
        chevron.tintColor   = Theme.Color.textSecondary
        chevron.translatesAutoresizingMaskIntoConstraints = false

        [iconContainer, titleLabel, chevron].forEach { row.addSubview($0) }

        NSLayoutConstraint.activate([
            iconContainer.widthAnchor.constraint(equalToConstant: 36),
            iconContainer.heightAnchor.constraint(equalToConstant: 36),
            iconView.centerXAnchor.constraint(equalTo: iconContainer.centerXAnchor),
            iconView.centerYAnchor.constraint(equalTo: iconContainer.centerYAnchor),
            iconView.widthAnchor.constraint(equalToConstant: 18),
            iconView.heightAnchor.constraint(equalToConstant: 18),

            iconContainer.leadingAnchor.constraint(equalTo: row.leadingAnchor, constant: 16),
            iconContainer.centerYAnchor.constraint(equalTo: row.centerYAnchor),

            titleLabel.leadingAnchor.constraint(equalTo: iconContainer.trailingAnchor, constant: 14),
            titleLabel.centerYAnchor.constraint(equalTo: row.centerYAnchor),
            titleLabel.trailingAnchor.constraint(lessThanOrEqualTo: chevron.leadingAnchor, constant: -8),

            chevron.trailingAnchor.constraint(equalTo: row.trailingAnchor, constant: -16),
            chevron.centerYAnchor.constraint(equalTo: row.centerYAnchor),

            row.heightAnchor.constraint(equalToConstant: 60),
        ])
        return row
    }

    // MARK: - Actions

    @objc private func backTapped() {
        navigationController?.popViewController(animated: true)
    }

    @objc private func termsTapped() {
        let vc = TermsViewController()
        navigationController?.pushViewController(vc, animated: true)
    }

    @objc private func privacyTapped() {
        let vc = PrivacyPolicyViewController()
        navigationController?.pushViewController(vc, animated: true)
    }
}