import UIKit

final class RDEPUBAnnotationEditorViewController: UIViewController, UITextViewDelegate {

    private let quote: String
    private let initialNote: String?
    private let onSave: (String?) -> Void
    private let textView = UITextView()
    private let countLabel = UILabel()

    init(quote: String, initialNote: String?, onSave: @escaping (String?) -> Void) {
        self.quote = quote
        self.initialNote = initialNote
        self.onSave = onSave
        super.init(nibName: nil, bundle: nil)
        title = "写注释"
    }

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

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor(red: 0.975, green: 0.965, blue: 0.935, alpha: 1)
        configureNavigation()
        configureContent()
        updateCount()
        DispatchQueue.main.async { [weak self] in self?.textView.becomeFirstResponder() }
    }

    private func configureNavigation() {
        navigationItem.leftBarButtonItem = UIBarButtonItem(
            title: "取消", style: .plain, target: self, action: #selector(cancelAction)
        )
        navigationItem.rightBarButtonItem = UIBarButtonItem(
            title: "保存", style: .done, target: self, action: #selector(saveAction)
        )
        navigationController?.navigationBar.tintColor = UIColor(red: 0.10, green: 0.34, blue: 0.78, alpha: 1)
        navigationController?.navigationBar.titleTextAttributes = [
            .foregroundColor: UIColor(red: 0.08, green: 0.10, blue: 0.14, alpha: 1),
            .font: UIFont.systemFont(ofSize: 17, weight: .semibold)
        ]
    }

    private func configureContent() {
        let quoteCard = UIView()
        let rail = UIView()
        let quoteLabel = UILabel()
        let inputCard = UIView()

        [quoteCard, rail, quoteLabel, inputCard, textView, countLabel].forEach {
            $0.translatesAutoresizingMaskIntoConstraints = false
        }
        view.addSubview(quoteCard)
        quoteCard.addSubview(rail)
        quoteCard.addSubview(quoteLabel)
        view.addSubview(inputCard)
        inputCard.addSubview(textView)
        inputCard.addSubview(countLabel)

        quoteCard.backgroundColor = UIColor.white.withAlphaComponent(0.78)
        quoteCard.layer.cornerRadius = 16
        rail.backgroundColor = UIColor(red: 0.94, green: 0.63, blue: 0.18, alpha: 1)
        rail.layer.cornerRadius = 2
        quoteLabel.text = quote
        quoteLabel.numberOfLines = 5
        quoteLabel.font = UIFont.systemFont(ofSize: 16)
        quoteLabel.textColor = UIColor(red: 0.19, green: 0.20, blue: 0.23, alpha: 1)

        inputCard.backgroundColor = .white
        inputCard.layer.cornerRadius = 18
        inputCard.layer.shadowColor = UIColor.black.cgColor
        inputCard.layer.shadowOpacity = 0.06
        inputCard.layer.shadowRadius = 18
        inputCard.layer.shadowOffset = CGSize(width: 0, height: 6)
        textView.text = initialNote
        textView.delegate = self
        textView.font = UIFont.systemFont(ofSize: 17)
        textView.textColor = UIColor(red: 0.08, green: 0.10, blue: 0.14, alpha: 1)
        textView.backgroundColor = .clear
        textView.accessibilityIdentifier = "epub.reader.annotation.editor"
        countLabel.font = UIFont.monospacedDigitSystemFont(ofSize: 12, weight: .regular)
        countLabel.textColor = .secondaryLabel
        countLabel.textAlignment = .right

        NSLayoutConstraint.activate([
            quoteCard.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20),
            quoteCard.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
            quoteCard.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20),
            rail.leadingAnchor.constraint(equalTo: quoteCard.leadingAnchor, constant: 16),
            rail.topAnchor.constraint(equalTo: quoteCard.topAnchor, constant: 16),
            rail.bottomAnchor.constraint(equalTo: quoteCard.bottomAnchor, constant: -16),
            rail.widthAnchor.constraint(equalToConstant: 4),
            quoteLabel.leadingAnchor.constraint(equalTo: rail.trailingAnchor, constant: 14),
            quoteLabel.trailingAnchor.constraint(equalTo: quoteCard.trailingAnchor, constant: -18),
            quoteLabel.topAnchor.constraint(equalTo: quoteCard.topAnchor, constant: 16),
            quoteLabel.bottomAnchor.constraint(equalTo: quoteCard.bottomAnchor, constant: -16),

            inputCard.topAnchor.constraint(equalTo: quoteCard.bottomAnchor, constant: 18),
            inputCard.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
            inputCard.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20),
            inputCard.bottomAnchor.constraint(equalTo: view.keyboardLayoutGuide.topAnchor, constant: -16),
            inputCard.heightAnchor.constraint(greaterThanOrEqualToConstant: 210),
            textView.topAnchor.constraint(equalTo: inputCard.topAnchor, constant: 14),
            textView.leadingAnchor.constraint(equalTo: inputCard.leadingAnchor, constant: 14),
            textView.trailingAnchor.constraint(equalTo: inputCard.trailingAnchor, constant: -14),
            textView.bottomAnchor.constraint(equalTo: countLabel.topAnchor, constant: -8),
            countLabel.leadingAnchor.constraint(equalTo: inputCard.leadingAnchor, constant: 16),
            countLabel.trailingAnchor.constraint(equalTo: inputCard.trailingAnchor, constant: -16),
            countLabel.bottomAnchor.constraint(equalTo: inputCard.bottomAnchor, constant: -12)
        ])
    }

    func textViewDidChange(_ textView: UITextView) {
        if textView.text.count > 1000 {
            textView.text = String(textView.text.prefix(1000))
        }
        updateCount()
    }

    private func updateCount() {
        countLabel.text = "\(textView.text.count)/1000"
    }

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

    @objc private func saveAction() {
        let note = textView.text.trimmingCharacters(in: .whitespacesAndNewlines)
        onSave(note.isEmpty ? nil : note)
        dismiss(animated: true)
    }
}