//
//  FormatNoteViewController.swift
//  Note
//
//  Created by fish on 2026/7/12.
//

import UIKit

class FormatNoteViewController: UIViewController {

    private var textView: UITextView!
    private var iCloudButton: UIButton!
    private var noteButton: UIButton!
    private var doneButton: UIBarButtonItem!
    private var pasteButton: UIBarButtonItem!
    private var resetButton: UIBarButtonItem!
    private var rightBarButtonMode: RightBarButtonMode = .paste

    private enum RightBarButtonMode {
        case paste
        case reset
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        title = "格式化笔记"
        navigationItem.largeTitleDisplayMode = .never
        view.backgroundColor = .systemGroupedBackground
        setupUI()
    }

    private func setupUI() {
        textView = UITextView()
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.backgroundColor = .systemBackground
        textView.layer.cornerRadius = 12
        textView.layer.masksToBounds = true
        textView.font = UIFont.preferredFont(forTextStyle: .body)
        textView.textContainerInset = UIEdgeInsets(top: 12, left: 12, bottom: 12, right: 12)
        textView.isEditable = true
        textView.delegate = self
        view.addSubview(textView)

        doneButton = UIBarButtonItem(title: "完成", style: .plain, target: self, action: #selector(didTapDoneButton))
        pasteButton = UIBarButtonItem(title: "粘贴文案", style: .plain, target: self, action: #selector(didTapPasteButton))
        resetButton = UIBarButtonItem(title: "重置", style: .plain, target: self, action: #selector(didTapResetButton))
        updateRightBarButtonItem()

        iCloudButton = createBottomButton(title: "iCloud 格式化", color: .systemBlue)
        iCloudButton.addTarget(self, action: #selector(didTapiCloudButton), for: .touchUpInside)
        view.addSubview(iCloudButton)

        noteButton = createBottomButton(title: "Note 格式化", color: .systemGreen)
        noteButton.addTarget(self, action: #selector(didTapNoteButton), for: .touchUpInside)
        view.addSubview(noteButton)

        let safeArea = view.safeAreaLayoutGuide
        let buttonHeight: CGFloat = 52
        let spacing: CGFloat = 16

        NSLayoutConstraint.activate([
            textView.topAnchor.constraint(equalTo: safeArea.topAnchor, constant: spacing),
            textView.leadingAnchor.constraint(equalTo: safeArea.leadingAnchor, constant: spacing),
            textView.trailingAnchor.constraint(equalTo: safeArea.trailingAnchor, constant: -spacing),

            iCloudButton.topAnchor.constraint(equalTo: textView.bottomAnchor, constant: spacing),
            iCloudButton.leadingAnchor.constraint(equalTo: safeArea.leadingAnchor, constant: spacing),
            iCloudButton.trailingAnchor.constraint(equalTo: safeArea.centerXAnchor, constant: -spacing / 2),
            iCloudButton.heightAnchor.constraint(equalToConstant: buttonHeight),
            iCloudButton.bottomAnchor.constraint(equalTo: safeArea.bottomAnchor, constant: -spacing),

            noteButton.topAnchor.constraint(equalTo: textView.bottomAnchor, constant: spacing),
            noteButton.leadingAnchor.constraint(equalTo: safeArea.centerXAnchor, constant: spacing / 2),
            noteButton.trailingAnchor.constraint(equalTo: safeArea.trailingAnchor, constant: -spacing),
            noteButton.heightAnchor.constraint(equalToConstant: buttonHeight),
            noteButton.bottomAnchor.constraint(equalTo: safeArea.bottomAnchor, constant: -spacing)
        ])
    }

    private func createBottomButton(title: String, color: UIColor) -> UIButton {
        var config = UIButton.Configuration.filled()
        config.title = title
        config.baseBackgroundColor = color
        config.baseForegroundColor = .white
        config.cornerStyle = .medium
        config.contentInsets = NSDirectionalEdgeInsets(top: 0, leading: 16, bottom: 0, trailing: 16)

        let button = UIButton(configuration: config)
        button.translatesAutoresizingMaskIntoConstraints = false
        return button
    }

    @objc private func didTapDoneButton() {
        textView.resignFirstResponder()
    }

    @objc private func didTapPasteButton() {
        if let string = UIPasteboard.general.string {
            textView.text = string
        }
    }

    @objc private func didTapResetButton() {
        textView.text = ""
        rightBarButtonMode = .paste
        updateRightBarButtonItem()
    }

    private func updateRightBarButtonItem() {
        if textView.isFirstResponder {
            navigationItem.rightBarButtonItem = doneButton
        } else {
            switch rightBarButtonMode {
            case .paste:
                navigationItem.rightBarButtonItem = pasteButton
            case .reset:
                navigationItem.rightBarButtonItem = resetButton
            }
        }
    }

    @objc private func didTapiCloudButton() {
        rightBarButtonMode = .reset
        updateRightBarButtonItem()
    }

    @objc private func didTapNoteButton() {
        rightBarButtonMode = .reset
        updateRightBarButtonItem()
    }
}

extension FormatNoteViewController: UITextViewDelegate {

    func textViewDidBeginEditing(_ textView: UITextView) {
        updateRightBarButtonItem()
    }

    func textViewDidEndEditing(_ textView: UITextView) {
        updateRightBarButtonItem()
    }
}