//
//  PigeonMessageHistoryVC.swift
//  QuickLocation
//

import UIKit
import AVFoundation
import RxSwift

final class PigeonMessageHistoryVC: BaseViewController {

    private let groupKey: String
    private var items: [PigeonHistoryItem] = []
    private var rootView: PigeonMessageHistoryView!

    private var playingItemId: String?
    private var isVoicePlaying = false
    private var voiceElapsed: TimeInterval = 0
    private var voiceDuration: TimeInterval = 0
    private var voiceTimer: Timer?
    private var audioPlayer: AVAudioPlayer?

    init(groupKey: String) {
        self.groupKey = groupKey
        super.init(nibName: nil, bundle: nil)
    }

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

    override func loadView() {
        rootView = PigeonMessageHistoryView(frame: UIScreen.main.bounds)
        view = rootView
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        rootView.tableView.dataSource = self
        rootView.tableView.delegate = self
        rootView.tableView.register(PigeonHistoryCell.self, forCellReuseIdentifier: PigeonHistoryCell.reuseId)
        loadHistory()
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        stopVoicePlayback(reset: true)
    }

    @objc private func goBack() {
        navigationController?.popViewController(animated: true)
    }

    private func loadHistory() {
        DLToast.showLoading()
        PigeonService.sent(groupKey: groupKey)
            .subscribe(onNext: { [weak self] response in
                DLToast.dismiss()
                guard let self else { return }
                self.items = response.list.map { $0.toHistoryItem() }
                self.rootView.tableView.reloadData()
            }, onError: { _ in
                DLToast.dismiss()
            })
            .disposed(by: disposeBag)
    }

    private func togglePlayback(for item: PigeonHistoryItem) {
        guard item.kind == .voice else { return }
        guard item.localAudioData != nil || item.mediaURL != nil else {
            DLToast.show(text: "无法播放")
            return
        }
        if playingItemId == item.id {
            if isVoicePlaying {
                pauseVoicePlayback()
            } else {
                startVoicePlayback(item: item)
            }
            return
        }

        stopVoicePlayback(reset: true)
        startVoicePlayback(item: item)
    }

    private func startVoicePlayback(item: PigeonHistoryItem) {
        playingItemId = item.id
        if audioPlayer == nil || playingItemId != item.id {
            preparePlayer(for: item)
            return
        }
        audioPlayer?.play()
        isVoicePlaying = true
        startTimer()
        refreshVisiblePlayback()
    }

    private func preparePlayer(for item: PigeonHistoryItem) {
        if let data = item.localAudioData {
            startPlayer(data: data, item: item)
            return
        }
        guard let url = item.mediaURL else {
            DLToast.show(text: "无法播放")
            playingItemId = nil
            return
        }
        DLToast.showLoading()
        URLSession.shared.dataTask(with: url) { [weak self] data, _, error in
            DispatchQueue.main.async {
                DLToast.dismiss()
                guard let self, self.playingItemId == item.id else { return }
                guard let data, error == nil else {
                    DLToast.show(text: "无法播放")
                    self.playingItemId = nil
                    return
                }
                self.startPlayer(data: data, item: item)
            }
        }.resume()
    }

    private func startPlayer(data: Data, item: PigeonHistoryItem) {
        guard playingItemId == item.id else { return }
        do {
            let player = try AVAudioPlayer(data: data)
            player.prepareToPlay()
            audioPlayer = player
            voiceDuration = max(0.01, player.duration)
            voiceElapsed = 0
            player.play()
            isVoicePlaying = true
            startTimer()
            refreshVisiblePlayback()
        } catch {
            DLToast.show(text: "无法播放")
            playingItemId = nil
            refreshVisiblePlayback()
        }
    }

    private func startTimer() {
        voiceTimer?.invalidate()
        let timer = Timer(timeInterval: 0.05, repeats: true) { [weak self] _ in
            self?.tickVoicePlayback()
        }
        RunLoop.main.add(timer, forMode: .common)
        voiceTimer = timer
    }

    private func pauseVoicePlayback() {
        isVoicePlaying = false
        audioPlayer?.pause()
        voiceTimer?.invalidate()
        voiceTimer = nil
        refreshVisiblePlayback()
    }

    private func stopVoicePlayback(reset: Bool) {
        isVoicePlaying = false
        voiceTimer?.invalidate()
        voiceTimer = nil
        audioPlayer?.stop()
        audioPlayer = nil
        if reset {
            voiceElapsed = 0
            playingItemId = nil
        }
        refreshVisiblePlayback()
    }

    private func tickVoicePlayback() {
        if let player = audioPlayer {
            voiceElapsed = player.currentTime
            voiceDuration = max(player.duration, voiceElapsed)
        } else {
            voiceElapsed = min(voiceDuration, voiceElapsed + 0.05)
        }
        refreshVisiblePlayback()
        guard voiceElapsed >= voiceDuration, voiceDuration > 0 else { return }
        stopVoicePlayback(reset: true)
    }

    private func refreshVisiblePlayback() {
        for cell in rootView.tableView.visibleCells {
            guard let historyCell = cell as? PigeonHistoryCell,
                  let indexPath = rootView.tableView.indexPath(for: historyCell) else {
                continue
            }
            let item = items[indexPath.row]
            let isCurrent = item.id == playingItemId
            let duration = isCurrent && voiceDuration > 0 ? voiceDuration : item.duration
            historyCell.applyPlayback(
                isPlaying: isCurrent && isVoicePlaying,
                elapsed: isCurrent ? voiceElapsed : 0,
                duration: duration
            )
        }
    }
}

extension PigeonMessageHistoryVC: UITableViewDataSource, UITableViewDelegate {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        items.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(
            withIdentifier: PigeonHistoryCell.reuseId,
            for: indexPath
        ) as! PigeonHistoryCell
        let item = items[indexPath.row]
        let isCurrent = item.id == playingItemId
        cell.configure(
            item: item,
            isPlaying: isCurrent && isVoicePlaying,
            elapsed: isCurrent ? voiceElapsed : 0
        )
        cell.onTogglePlay = { [weak self] in
            self?.togglePlayback(for: item)
        }
        return cell
    }

    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
        guard isVoicePlaying else { return }
        stopVoicePlayback(reset: true)
    }
}