import UIKit

public final class RDEPUBReaderTopToolView: RDEPUBReaderToolView, RDEPUBReaderTopToolViewProtocol {

    public var onBack: (() -> Void)?

    public var onToggleBookmark: (() -> Void)?

    public var onSearch: (() -> Void)?

    private let backButton = RDEPUBReaderTintButton(type: .system)
    private let searchButton = RDEPUBReaderTintButton(type: .system)
    private let bookmarkButton = RDEPUBReaderTintButton(type: .system)
    private let titleLabel: UILabel = {
        let label = UILabel()
        label.textAlignment = .center
        label.font = UIFont.systemFont(ofSize: 16, weight: .semibold)
        label.numberOfLines = 1
        return label
    }()
    private var isBookmarked = false

    override init(frame: CGRect) {
        super.init(frame: frame)
        accessibilityIdentifier = "epub.reader.topToolbar"
        self.backgroundColor = .white
        addSubview(backButton)
        addSubview(searchButton)
        addSubview(bookmarkButton)
        addSubview(titleLabel)

        backButton.translatesAutoresizingMaskIntoConstraints = false
        searchButton.translatesAutoresizingMaskIntoConstraints = false
        bookmarkButton.translatesAutoresizingMaskIntoConstraints = false
        titleLabel.translatesAutoresizingMaskIntoConstraints = false

        backButton.addTarget(self, action: #selector(backAction), for: .touchUpInside)
        searchButton.addTarget(self, action: #selector(searchAction), for: .touchUpInside)
        bookmarkButton.addTarget(self, action: #selector(bookmarkAction), for: .touchUpInside)

        NSLayoutConstraint.activate([
            backButton.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 8),
            backButton.topAnchor.constraint(equalTo: safeAreaLayoutGuide.topAnchor, constant: 4),
            backButton.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -4),
            backButton.widthAnchor.constraint(equalToConstant: 44),
            backButton.heightAnchor.constraint(equalToConstant: 44),

            bookmarkButton.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -8),
            bookmarkButton.topAnchor.constraint(equalTo: safeAreaLayoutGuide.topAnchor, constant: 4),
            bookmarkButton.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -4),
            bookmarkButton.widthAnchor.constraint(equalToConstant: 44),
            bookmarkButton.heightAnchor.constraint(equalToConstant: 44),

            searchButton.trailingAnchor.constraint(equalTo: bookmarkButton.leadingAnchor, constant: -4),
            searchButton.topAnchor.constraint(equalTo: safeAreaLayoutGuide.topAnchor, constant: 4),
            searchButton.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -4),
            searchButton.widthAnchor.constraint(equalToConstant: 44),
            searchButton.heightAnchor.constraint(equalToConstant: 44),

            titleLabel.leadingAnchor.constraint(equalTo: backButton.trailingAnchor, constant: 8),
            titleLabel.trailingAnchor.constraint(equalTo: searchButton.leadingAnchor, constant: -8),
            titleLabel.centerYAnchor.constraint(equalTo: backButton.centerYAnchor)
        ])

        if #available(iOS 13.0, *) {
            backButton.setImage(UIImage(systemName: "chevron.left")?.withRenderingMode(.alwaysTemplate), for: .normal)
            searchButton.setImage(UIImage(systemName: "magnifyingglass")?.withRenderingMode(.alwaysTemplate), for: .normal)
        } else {
            backButton.setTitle("返回", for: .normal)
            searchButton.setTitle("搜索", for: .normal)
        }
        backButton.accessibilityIdentifier = "epub.reader.back"
        searchButton.accessibilityIdentifier = "epub.reader.search"
        bookmarkButton.accessibilityIdentifier = "epub.reader.bookmark"
        titleLabel.accessibilityIdentifier = "epub.reader.title"
        updateBookmarkButtonAppearance()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override public func lineFrame(in bounds: CGRect) -> CGRect {
        CGRect(x: 0, y: bounds.height - 0.5, width: bounds.width, height: 0.5)
    }

    override public func apply(theme: RDEPUBReaderTheme) {
        super.apply(theme: theme)
        titleLabel.textColor = theme.toolControlTextColor
        backButton.tintColor = theme.toolControlTextColor
        searchButton.tintColor = theme.toolControlTextColor
        bookmarkButton.tintColor = theme.toolControlTextColor
        if #unavailable(iOS 13.0) {
            backButton.setTitleColor(theme.toolControlTextColor, for: .normal)
            searchButton.setTitleColor(theme.toolControlTextColor, for: .normal)
            bookmarkButton.setTitleColor(theme.toolControlTextColor, for: .normal)
        }
        updateBookmarkButtonAppearance()
    }

    public func setTitle(_ title: String?) {
        titleLabel.text = title
    }

    public func setBookmarkSelected(_ isSelected: Bool) {
        isBookmarked = isSelected
        updateBookmarkButtonAppearance()
    }

    public func setBookmarkEnabled(_ isEnabled: Bool) {
        bookmarkButton.isEnabled = isEnabled
        bookmarkButton.alpha = isEnabled ? 1 : 0.45
    }

    @objc private func backAction() {
        onBack?()
    }

    @objc private func searchAction() {
        onSearch?()
    }

    @objc private func bookmarkAction() {
        onToggleBookmark?()
    }

    private func updateBookmarkButtonAppearance() {
        if #available(iOS 13.0, *) {
            let imageName = isBookmarked ? "bookmark.fill" : "bookmark"
            bookmarkButton.setImage(UIImage(systemName: imageName)?.withRenderingMode(.alwaysTemplate), for: .normal)
        } else {
            bookmarkButton.setTitle(isBookmarked ? "已签" : "书签", for: .normal)
        }
        bookmarkButton.accessibilityValue = isBookmarked ? "selected" : "unselected"
    }
}