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

import UIKit

class FormatLogViewController: UIViewController {

    private var textView: UITextView!
    private var formatButton: UIButton!
    private var doneButton: UIBarButtonItem!
    private var pasteButton: UIBarButtonItem!
    private var resetButton: UIBarButtonItem!
    private var isFormatted = false
    private var rightBarButtonMode: RightBarButtonMode = .paste

    private enum RightBarButtonMode {
        case paste
        case reset
    }

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

    private func setupUI() {
        textView = UITextView()
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.font = UIFont.systemFont(ofSize: 16)
        textView.backgroundColor = .systemBackground
        textView.layer.cornerRadius = 12
        textView.layer.borderWidth = 0.5
        textView.layer.borderColor = UIColor.separator.cgColor
        textView.textContainerInset = UIEdgeInsets(top: 12, left: 12, bottom: 12, right: 12)
        textView.delegate = self
        view.addSubview(textView)

        doneButton = UIBarButtonItem(title: "完成", style: .prominent, 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()

        formatButton = UIButton(type: .system)
        formatButton.translatesAutoresizingMaskIntoConstraints = false
        formatButton.setTitle("格式化", for: .normal)
        formatButton.titleLabel?.font = UIFont.systemFont(ofSize: 18, weight: .semibold)
        formatButton.backgroundColor = .systemBlue
        formatButton.setTitleColor(.white, for: .normal)
        formatButton.layer.cornerRadius = 12
        formatButton.addTarget(self, action: #selector(didTapFormatButton), for: .touchUpInside)
        view.addSubview(formatButton)

        NSLayoutConstraint.activate([
            textView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 16),
            textView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16),
            textView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16),
            textView.bottomAnchor.constraint(equalTo: formatButton.topAnchor, constant: -16),

            formatButton.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16),
            formatButton.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16),
            formatButton.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -16),
            formatButton.heightAnchor.constraint(equalToConstant: 52)
        ])
    }

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

    @objc private func didTapFormatButton() {
        guard !trimmedText().isEmpty else {
            showEmptyAlert()
            return
        }
        if isFormatted {
            saveToFiles()
        } else {
            textView.text = formatLog(textView.text)
            isFormatted = true
            formatButton.setTitle("保存到 iCloud", for: .normal)
            rightBarButtonMode = .reset
            updateRightBarButtonItem()
        }
    }

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

    private func trimmedText() -> String {
        return textView.text?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
    }

    private func showEmptyAlert() {
        let alert = UIAlertController(title: "提示", message: "请输入内容后再进行格式化", preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "确定", style: .default))
        present(alert, animated: true)
    }

    @objc private func didTapResetButton() {
        textView.text = ""
        isFormatted = false
        formatButton.setTitle("格式化", for: .normal)
        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
            }
        }
    }

    private func saveToFiles() {
        let fileName = generateFileName()
        let fileURL = FileManager.default.temporaryDirectory.appendingPathComponent(fileName)

        do {
            try textView.text.write(to: fileURL, atomically: true, encoding: .utf8)
            let documentPicker = UIDocumentPickerViewController(forExporting: [fileURL], asCopy: true)
            documentPicker.delegate = self
            present(documentPicker, animated: true)
        } catch {
            print("Failed to write file: \(error)")
        }
    }

    private func generateFileName() -> String {
        let text = textView.text ?? ""
        let firstLine = text.components(separatedBy: .newlines).first ?? ""
        let trimmed = firstLine.trimmingCharacters(in: .whitespaces)
        let withoutHash = trimmed.replacingOccurrences(of: "^#\\s*", with: "", options: .regularExpression)
        let cleanName = withoutHash.trimmingCharacters(in: .whitespaces)

        if cleanName.isEmpty {
            return "formatted_log_\(Int(Date().timeIntervalSince1970)).md"
        }
        return cleanName + ".md"
    }

    private func formatLog(_ text: String) -> String {
        var content = text

        content = content.replacingOccurrences(of: "# ", with: "")
        content = content.replacingOccurrences(of: "#", with: "")
        content = content.replacingOccurrences(of: ";", with: "。")
        content = content.replacingOccurrences(of: "；", with: "。")
        content = content.replacingOccurrences(of: ".", with: "。")
        content = content.replacingOccurrences(of: "（", with: "(")
        content = content.replacingOccurrences(of: "）", with: ")")
        content = content.replacingOccurrences(of: "?", with: "？")
        content = content.replacingOccurrences(of: ",", with: "，")
        content = content.replacingOccurrences(of: ":", with: "：")
        content = content.replacingOccurrences(of: "日星期", with: "日 星期")
        content = "# " + content
        content = content.replacingOccurrences(of: "一、生活方面", with: "## 一、生活方面")
        content = content.replacingOccurrences(of: "二、交易方面", with: "## 二、交易方面")
        content = content.replacingOccurrences(of: "三、工作方面", with: "## 三、工作方面")

        return content
    }
}

extension FormatLogViewController: UITextViewDelegate {

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

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

extension FormatLogViewController: UIDocumentPickerDelegate {

    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
        // File saved to selected location
    }

    func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
        // User cancelled
    }
}