//
//  MailboxDetailViewController.swift
//  QuickLocation
//

import UIKit
import RxSwift
import Lottie

final class MailboxDetailViewController: UIViewController {
    private var messages: [MailboxMessage]
    private var currentIndex: Int
    private var currentMessage: MailboxMessage
    private let disposeBag = DisposeBag()
    private let detailView = MailboxDetailView()
    private var isLoading = false

    var onMessageRead: ((MailboxMessage) -> Void)?

    init(messages: [MailboxMessage], initialMessage: MailboxMessage) {
        self.messages = messages
        self.currentMessage = initialMessage
        self.currentIndex = messages.firstIndex(where: { $0.id == initialMessage.id }) ?? 0
        super.init(nibName: nil, bundle: nil)
        modalPresentationStyle = .overFullScreen
        modalTransitionStyle = .crossDissolve
    }

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

    override func loadView() {
        view = detailView
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        detailView.closeButton.addTarget(self, action: #selector(closeAction), for: .touchUpInside)
        detailView.previousButton.addTarget(self, action: #selector(previousAction), for: .touchUpInside)
        detailView.nextButton.addTarget(self, action: #selector(nextAction), for: .touchUpInside)
        renderCurrentMessage()
    }

    private func renderCurrentMessage() {
        detailView.configure(
            message: currentMessage,
            canGoPrevious: currentIndex > 0,
            canGoNext: currentIndex + 1 < messages.count
        )
    }

    private func loadMessage(at index: Int) {
        guard messages.indices.contains(index), !isLoading else { return }
        let cachedMessage = messages[index]
        isLoading = true
        detailView.setControlsEnabled(false)
        DLToast.showLoading()

        UserService.mailboxDetail(id: cachedMessage.id)
            .subscribe(onNext: { [weak self] response in
                guard let self else { return }
                DLToast.dismiss()
                self.isLoading = false
                guard let responseMessage = response.data else {
                    self.detailView.setControlsEnabled(true)
                    DLToast.showError(text: response.message ?? "消息详情加载失败")
                    return
                }
                var detail = self.mergeDetail(responseMessage, fallback: cachedMessage)
                detail.isRead = true
                self.messages[index] = detail
                self.currentIndex = index
                self.currentMessage = detail
                self.onMessageRead?(detail)
                self.renderCurrentMessage()
            }, onError: { [weak self] error in
                DLToast.dismiss()
                self?.isLoading = false
                self?.detailView.setControlsEnabled(true)
                DLToast.showError(error)
            })
            .disposed(by: disposeBag)
    }

    private func mergeDetail(_ detail: MailboxMessage, fallback: MailboxMessage) -> MailboxMessage {
        var merged = detail
        if merged.id == 0 { merged.id = fallback.id }
        if merged.title.isEmpty { merged.title = fallback.title }
        if merged.content.isEmpty { merged.content = fallback.content }
        if merged.senderId.isEmpty { merged.senderId = fallback.senderId }
        if merged.senderIcon.isEmpty { merged.senderIcon = fallback.senderIcon }
        if merged.modifyTime.isEmpty { merged.modifyTime = fallback.modifyTime }
        if MailboxCategory(rawValue: merged.type) == nil { merged.type = fallback.type }
        return merged
    }

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

    @objc private func previousAction() {
        loadMessage(at: currentIndex - 1)
    }

    @objc private func nextAction() {
        loadMessage(at: currentIndex + 1)
    }
}

private final class MailboxDetailView: UIView {
    let previousButton = UIButton(type: .custom)
    let closeButton = UIButton(type: .custom)
    let nextButton = UIButton(type: .custom)

    private let cardView = UIView()
    private let cardBackgroundView = UIImageView()
    private let birdImageView = UIImageView(image: UIImage(named: "Mailbox/detail_bird"))
    private let typeLabel = UILabel()
    private let dividerView = UIView()
    private let titleLabel = UILabel()
    private let scrollView = UIScrollView()
    private let contentContainerView = UIView()
    private let contentLabel = UILabel()
    private let lottieView = LottieAnimationView()
    private let quickMessageLabel = UILabel()
    private var animationName: String?
    private var contentBottomConstraint: NSLayoutConstraint?
    private var cardHeightConstraint: NSLayoutConstraint?

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupUI()
    }

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

    func configure(message: MailboxMessage, canGoPrevious: Bool, canGoNext: Bool) {
        typeLabel.text = message.category.detailTitle
        titleLabel.text = message.title
        configureContent(message: message)
        previousButton.isEnabled = canGoPrevious
        nextButton.isEnabled = canGoNext
        updateButtonAppearance()
    }

    func setControlsEnabled(_ enabled: Bool) {
        previousButton.isUserInteractionEnabled = enabled
        nextButton.isUserInteractionEnabled = enabled
        closeButton.isUserInteractionEnabled = enabled
        previousButton.alpha = enabled ? (previousButton.isEnabled ? 1 : 0.35) : 0.35
        nextButton.alpha = enabled ? (nextButton.isEnabled ? 1 : 0.35) : 0.35
        closeButton.alpha = enabled ? 1 : 0.55
    }

    private func setupUI() {
        backgroundColor = UIColor.black.withAlphaComponent(0.68)

        cardView.layer.cornerRadius = 31
        cardView.clipsToBounds = true
        cardBackgroundView.image = UIImage(named: "Mailbox/detail_card")?.resizableImage(
            withCapInsets: UIEdgeInsets(top: 70, left: 70, bottom: 70, right: 70),
            resizingMode: .stretch
        )
        cardBackgroundView.contentMode = .scaleToFill

        birdImageView.contentMode = .scaleAspectFit

        typeLabel.font = .systemFont(ofSize: 18, weight: .medium)
        typeLabel.textColor = UIColor(hexStr: "#14324E")
        typeLabel.textAlignment = .center

        dividerView.backgroundColor = UIColor(hexStr: "#80D8FF", alpha: 0.55)

        titleLabel.font = .systemFont(ofSize: 18, weight: .medium)
        titleLabel.textColor = UIColor(hexStr: "#333333")
        titleLabel.textAlignment = .center
        titleLabel.numberOfLines = 0

        scrollView.showsVerticalScrollIndicator = false
        scrollView.alwaysBounceVertical = false

        contentLabel.font = .systemFont(ofSize: 15)
        contentLabel.textColor = UIColor(hexStr: "#858585")
        contentLabel.textAlignment = .center
        contentLabel.numberOfLines = 0

        lottieView.contentMode = .scaleAspectFit
        lottieView.loopMode = .loop
        lottieView.backgroundBehavior = .pauseAndRestore

        quickMessageLabel.font = .systemFont(ofSize: 15)
        quickMessageLabel.textColor = UIColor(hexStr: "#52606D")
        quickMessageLabel.textAlignment = .center
        quickMessageLabel.numberOfLines = 0
        quickMessageLabel.backgroundColor = UIColor(hexStr: "#DFF5FF")
        quickMessageLabel.layer.cornerRadius = 9
        quickMessageLabel.clipsToBounds = true

        configureControlButton(previousButton, title: "上一条")
        configureControlButton(nextButton, title: "下一条")
        closeButton.setImage(UIImage(named: "Mailbox/detail_close"), for: .normal)
        closeButton.accessibilityLabel = "关闭"

        addSubview(cardView)
        cardView.addSubview(cardBackgroundView)
        addSubview(birdImageView)
        cardView.addSubview(typeLabel)
        cardView.addSubview(dividerView)
        cardView.addSubview(titleLabel)
        cardView.addSubview(scrollView)
        scrollView.addSubview(contentContainerView)
        contentContainerView.addSubview(contentLabel)
        contentContainerView.addSubview(lottieView)
        contentContainerView.addSubview(quickMessageLabel)
        addSubview(previousButton)
        addSubview(closeButton)
        addSubview(nextButton)

        [cardView, cardBackgroundView, birdImageView, typeLabel, dividerView, titleLabel, scrollView,
         contentContainerView, contentLabel, lottieView, quickMessageLabel, previousButton, closeButton,
         nextButton].forEach { $0.translatesAutoresizingMaskIntoConstraints = false }

        let cardWidth = min(kScreenWidth - 48, 360)
        let cardHeightConstraint = cardView.heightAnchor.constraint(equalToConstant: 245)
        self.cardHeightConstraint = cardHeightConstraint
        NSLayoutConstraint.activate([
            cardView.centerXAnchor.constraint(equalTo: centerXAnchor),
            cardView.centerYAnchor.constraint(equalTo: centerYAnchor, constant: -32),
            cardView.widthAnchor.constraint(equalToConstant: cardWidth),
            cardHeightConstraint,
            cardBackgroundView.topAnchor.constraint(equalTo: cardView.topAnchor),
            cardBackgroundView.leadingAnchor.constraint(equalTo: cardView.leadingAnchor),
            cardBackgroundView.trailingAnchor.constraint(equalTo: cardView.trailingAnchor),
            cardBackgroundView.bottomAnchor.constraint(equalTo: cardView.bottomAnchor),
            birdImageView.leadingAnchor.constraint(equalTo: cardView.leadingAnchor, constant: 36),
            birdImageView.bottomAnchor.constraint(equalTo: cardView.topAnchor, constant: 35),
            birdImageView.widthAnchor.constraint(equalToConstant: 100),
            birdImageView.heightAnchor.constraint(equalToConstant: 74),
            typeLabel.topAnchor.constraint(equalTo: cardView.topAnchor, constant: 49),
            typeLabel.leadingAnchor.constraint(equalTo: cardView.leadingAnchor, constant: 26),
            typeLabel.trailingAnchor.constraint(equalTo: cardView.trailingAnchor, constant: -26),
            dividerView.topAnchor.constraint(equalTo: typeLabel.bottomAnchor, constant: 15),
            dividerView.leadingAnchor.constraint(equalTo: cardView.leadingAnchor, constant: 23),
            dividerView.trailingAnchor.constraint(equalTo: cardView.trailingAnchor, constant: -23),
            dividerView.heightAnchor.constraint(equalToConstant: 0.5),
            titleLabel.topAnchor.constraint(equalTo: dividerView.bottomAnchor, constant: 20),
            titleLabel.leadingAnchor.constraint(equalTo: cardView.leadingAnchor, constant: 30),
            titleLabel.trailingAnchor.constraint(equalTo: cardView.trailingAnchor, constant: -30),
            scrollView.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 13),
            scrollView.leadingAnchor.constraint(equalTo: cardView.leadingAnchor, constant: 28),
            scrollView.trailingAnchor.constraint(equalTo: cardView.trailingAnchor, constant: -28),
            scrollView.bottomAnchor.constraint(equalTo: cardView.bottomAnchor, constant: -25),
            contentContainerView.topAnchor.constraint(equalTo: scrollView.contentLayoutGuide.topAnchor),
            contentContainerView.leadingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.leadingAnchor),
            contentContainerView.trailingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.trailingAnchor),
            contentContainerView.bottomAnchor.constraint(equalTo: scrollView.contentLayoutGuide.bottomAnchor),
            contentContainerView.widthAnchor.constraint(equalTo: scrollView.frameLayoutGuide.widthAnchor),
            contentLabel.topAnchor.constraint(equalTo: contentContainerView.topAnchor),
            contentLabel.leadingAnchor.constraint(equalTo: contentContainerView.leadingAnchor),
            contentLabel.trailingAnchor.constraint(equalTo: contentContainerView.trailingAnchor),
            lottieView.topAnchor.constraint(equalTo: contentLabel.bottomAnchor, constant: 10),
            lottieView.centerXAnchor.constraint(equalTo: contentContainerView.centerXAnchor),
            lottieView.widthAnchor.constraint(equalToConstant: 116),
            lottieView.heightAnchor.constraint(equalToConstant: 116),
            quickMessageLabel.topAnchor.constraint(equalTo: contentLabel.bottomAnchor, constant: 14),
            quickMessageLabel.centerXAnchor.constraint(equalTo: contentContainerView.centerXAnchor),
            quickMessageLabel.leadingAnchor.constraint(greaterThanOrEqualTo: contentContainerView.leadingAnchor, constant: 20),
            quickMessageLabel.trailingAnchor.constraint(lessThanOrEqualTo: contentContainerView.trailingAnchor, constant: -20),
            quickMessageLabel.heightAnchor.constraint(greaterThanOrEqualToConstant: 40),
            previousButton.topAnchor.constraint(equalTo: cardView.bottomAnchor, constant: 20),
            previousButton.leadingAnchor.constraint(equalTo: cardView.leadingAnchor, constant: 34),
            previousButton.heightAnchor.constraint(equalToConstant: 40),
            nextButton.topAnchor.constraint(equalTo: previousButton.topAnchor),
            nextButton.trailingAnchor.constraint(equalTo: cardView.trailingAnchor, constant: -34),
            nextButton.heightAnchor.constraint(equalTo: previousButton.heightAnchor),
            closeButton.centerXAnchor.constraint(equalTo: centerXAnchor),
            closeButton.centerYAnchor.constraint(equalTo: previousButton.centerYAnchor),
            closeButton.widthAnchor.constraint(equalToConstant: 24),
            closeButton.heightAnchor.constraint(equalToConstant: 24)
        ])
    }

    private func configureControlButton(_ button: UIButton, title: String) {
        button.setTitle(title, for: .normal)
        button.setTitleColor(.white, for: .normal)
        button.setTitleColor(UIColor.white.withAlphaComponent(0.45), for: .disabled)
        button.titleLabel?.font = .systemFont(ofSize: 16)
    }

    private func configureContent(message: MailboxMessage) {
        animationName = nil
        lottieView.stop()
        lottieView.animation = nil
        lottieView.isHidden = true
        quickMessageLabel.isHidden = true
        contentLabel.text = message.content
        cardHeightConstraint?.constant = message.content.count > 80 ? 300 : 245

        guard message.category == .interaction,
              let payload = parsePayload(message.content) else {
            updateContentBottomAnchor(visibleView: contentLabel)
            return
        }

        contentLabel.text = payload.prefix
        switch payload.kind {
        case let .animation(name):
            cardHeightConstraint?.constant = 330
            animationName = name
            lottieView.isHidden = false
            updateContentBottomAnchor(visibleView: lottieView)
            EmojiPanelCell.loadAnimation(for: name) { [weak self] animation in
                guard let self, self.animationName == name else { return }
                guard let animation else {
                    self.showFallbackContent(message.content)
                    return
                }
                self.lottieView.animation = animation
                self.lottieView.currentProgress = 0
                self.lottieView.play()
            }
        case let .quickMessage(text):
            cardHeightConstraint?.constant = 265
            quickMessageLabel.text = "  \(text)  "
            quickMessageLabel.isHidden = false
            updateContentBottomAnchor(visibleView: quickMessageLabel)
        }
    }

    private func updateContentBottomAnchor(visibleView: UIView) {
        contentBottomConstraint?.isActive = false
        contentBottomConstraint = visibleView.bottomAnchor.constraint(equalTo: contentContainerView.bottomAnchor)
        contentBottomConstraint?.isActive = true
    }

    private func showFallbackContent(_ content: String) {
        animationName = nil
        lottieView.stop()
        lottieView.animation = nil
        lottieView.isHidden = true
        quickMessageLabel.isHidden = true
        contentLabel.text = content
        updateContentBottomAnchor(visibleView: contentLabel)
    }

    private func parsePayload(_ content: String) -> MailboxPayload? {
        guard let opening = content.firstIndex(of: "["),
              let closing = content[opening...].firstIndex(of: "]"),
              let lastOpening = content.lastIndex(of: "[") else {
            return nil
        }
        let codeStart = content.index(after: opening)
        let code = String(content[codeStart..<closing])
        guard code.count > 1, let prefixCode = code.first else { return nil }
        let value = String(code.dropFirst())
        let prefix = String(content[..<lastOpening]).trimmingCharacters(in: .whitespacesAndNewlines)

        switch prefixCode {
        case "1":
            guard Int(value) != nil else { return nil }
            return MailboxPayload(prefix: prefix, kind: .animation(name: "normal_\(value)"))
        case "2":
            guard Int(value) != nil else { return nil }
            return MailboxPayload(prefix: prefix, kind: .animation(name: "fun_\(value)"))
        case "3":
            guard let index = Int(value), QuickMessageView.messageList.indices.contains(index) else { return nil }
            return MailboxPayload(prefix: prefix, kind: .quickMessage(QuickMessageView.messageList[index]))
        default:
            return nil
        }
    }

    private func updateButtonAppearance() {
        previousButton.alpha = previousButton.isEnabled ? 1 : 0.35
        nextButton.alpha = nextButton.isEnabled ? 1 : 0.35
        closeButton.alpha = 1
        setControlsEnabled(true)
    }
}

private struct MailboxPayload {
    enum Kind {
        case animation(name: String)
        case quickMessage(String)
    }

    let prefix: String
    let kind: Kind
}