//
//  ChatRoomViewModel.swift
//  SodaLive
//
//  Created by klaus on 9/2/25.
//

import Foundation
import Combine
import Moya

final class ChatRoomViewModel: ObservableObject {
    // MARK: - Published State
    @Published var isLoading: Bool = false
    @Published var errorMessage: String = ""
    @Published var isShowPopup = false
    
    @Published private(set) var characterProfileUrl: String = ""
    @Published private(set) var characterName: String = "Character Name"
    @Published private(set) var characterType: CharacterType = .Character
    @Published private(set) var chatRoomBgImageUrl: String? = nil
    @Published private(set) var roomId: Int = 0
    
    @Published private(set) var countdownText: String = "00:00:00"
    @Published private(set) var showQuotaNoticeView: Bool = false
    
    @Published private(set) var showSendingMessage: Bool = false
    
    // MARK: - Message State
    @Published var messageText: String = ""
    @Published private(set) var messages: [ServerChatMessage] = []
    
    @Published var selectedMessage: ServerChatMessage? = nil
    @Published var selectedMessageIndex: Int = -1
    
    // MARK: - Private
    private let userRepository = UserRepository()
    private let repository = ChatRoomRepository()
    private var subscription = Set<AnyCancellable>()
    
    private var hasMoreMessages: Bool = true
    private var nextCursor: Int64? = nil
    
    private var timer: Timer?
    
    // MARK: - Actions
    @MainActor
    func sendMessage() {
        guard !messageText.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
            return
        }
        
        let message = messageText.trimmingCharacters(in: .whitespacesAndNewlines)
        messageText = ""
        
        let nowMs = Int64(Date().timeIntervalSince1970 * 1000)
        
        messages.append(
            ServerChatMessage(
                messageId: 0 - nowMs,
                message: message,
                profileImageUrl: "",
                mine: true,
                createdAt: nowMs,
                messageType: "TEXT",
                imageUrl: nil,
                price: nil,
                hasAccess: true
            )
        )
        
        showSendingMessage = true
        repository.sendMessage(roomId: roomId, message: message)
            .sink { result in
                switch result {
                case .finished:
                    DEBUG_LOG("finish")
                case .failure(let error):
                    ERROR_LOG(error.localizedDescription)
                }
            } receiveValue: { [weak self] response in
                let responseData = response.data
                
                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponse<SendChatMessageResponse>.self, from: responseData)
                    
                    if let data = decoded.data, decoded.success {
                        self?.messages.append(contentsOf: data.messages)
                        self?.updateQuota(totalRemaining: data.totalRemaining, nextRechargeAtEpoch: data.nextRechargeAtEpoch)
                    } else {
                        if let message = decoded.message {
                            self?.errorMessage = message
                        } else {
                            self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                        }
                        
                        self?.isShowPopup = true
                    }
                    
                    self?.showSendingMessage = false
                } catch {
                    self?.showSendingMessage = false
                    self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                    self?.isShowPopup = true
                }
            }
            .store(in: &subscription)
    }
    
    @MainActor
    func enterRoom(roomId: Int) {
        isLoading = true
        self.roomId = roomId
        
        repository.enterChatRoom(
            roomId: roomId,
            characterImageId: getSavedBackgroundImageId()
        )
        .sink { result in
            switch result {
            case .finished:
                DEBUG_LOG("finish")
            case .failure(let error):
                ERROR_LOG(error.localizedDescription)
            }
        } receiveValue: { [weak self] response in
            let responseData = response.data
            
            do {
                let jsonDecoder = JSONDecoder()
                let decoded = try jsonDecoder.decode(ApiResponse<ChatRoomEnterResponse>.self, from: responseData)
                
                if let data = decoded.data, decoded.success {
                    self?.characterName = data.character.name
                    self?.characterType = data.character.characterType
                    self?.characterProfileUrl = data.character.profileImageUrl
                    
                    self?.chatRoomBgImageUrl = data.bgImageUrl ?? data.character.profileImageUrl
                    self?.messages.insert(contentsOf: data.messages.sorted(), at: 0)
                    
                    self?.hasMoreMessages = data.hasMoreMessages
                    self?.nextCursor = data.messages.last?.messageId
                    
                    self?.updateQuota(totalRemaining: data.totalRemaining, nextRechargeAtEpoch: data.nextRechargeAtEpoch)
                } else {
                    if let message = decoded.message {
                        self?.errorMessage = message
                    } else {
                        self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                    }
                    
                    self?.isShowPopup = true
                }
                
                self?.isLoading = false
            } catch {
                self?.isLoading = false
                self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                self?.isShowPopup = true
            }
        }
        .store(in: &subscription)
    }
    
    func purchaseChatMessage() {
        guard let selectedMessage = selectedMessage else {
            return
        }
        
        isLoading = true
        
        repository.purchaseMessage(roomId: roomId, messageId: selectedMessage.messageId)
            .sink { result in
                switch result {
                case .finished:
                    DEBUG_LOG("finish")
                case .failure(let error):
                    ERROR_LOG(error.localizedDescription)
                }
            } receiveValue: { [weak self] response in
                let responseData = response.data
                
                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponse<ServerChatMessage>.self, from: responseData)
                    
                    if let data = decoded.data, decoded.success {
                        self?.messages.insert(data, at: self?.selectedMessageIndex ?? 0)
                        self?.messages.remove(at: (self?.selectedMessageIndex ?? 0) + 1)
                        
                        self?.selectedMessage = nil
                        self?.selectedMessageIndex = -1
                    } else {
                        if let message = decoded.message {
                            self?.errorMessage = message
                        } else {
                            self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                        }
                        
                        self?.isShowPopup = true
                    }
                    
                    self?.isLoading = false
                } catch {
                    self?.isLoading = false
                    self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                    self?.isShowPopup = true
                }
            }
            .store(in: &subscription)
    }
    
    func purchaseChatQuota() {
        
    }
    
    private func checkQuotaStatus() {
        isLoading = true
        
        repository.getChatQuotaStatus()
            .sink { result in
                switch result {
                case .finished:
                    DEBUG_LOG("finish")
                case .failure(let error):
                    ERROR_LOG(error.localizedDescription)
                }
            } receiveValue: { [weak self] response in
                let responseData = response.data
                
                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponse<ChatQuotaStatusResponse>.self, from: responseData)
                    
                    if let data = decoded.data, decoded.success {
                        self?.updateQuota(totalRemaining: data.totalRemaining, nextRechargeAtEpoch: data.nextRechargeAtEpoch)
                    } else {
                        if let message = decoded.message {
                            self?.errorMessage = message
                        } else {
                            self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                        }
                        
                        self?.isShowPopup = true
                    }
                    
                    self?.isLoading = false
                } catch {
                    self?.isLoading = false
                    self?.errorMessage = "다시 시도해 주세요.\n계속 같은 문제가 발생할 경우 고객센터로 문의 주시기 바랍니다."
                    self?.isShowPopup = true
                }
            }
            .store(in: &subscription)
    }
    
    private func updateQuota(totalRemaining: Int, nextRechargeAtEpoch: Int64?) {
        isLoading = true
        stopTimer()
        
        // epoch 없음 → 카운트다운 비표시
        guard let nextRechargeAtEpoch else {
            countdownText = "00:00:00"
            showQuotaNoticeView = false
            isLoading = false
            return
        }
        
        // 즉시 1회 갱신
        let remainMs = remainingMs(to: nextRechargeAtEpoch)
        updateCountdownText(remainMs)
        
        // 이미 0이면 종료 처리
        guard remainMs > 0 else {
            checkQuotaStatus()
            return
        }
        
        isLoading = false
        showQuotaNoticeView = true
        
        // 타이머 시작 (1초마다 갱신)
        startTimer(targetEpoch: nextRechargeAtEpoch)
    }
    
    private func updateCountdownText(_ remainMs: Int64) {
        countdownText = remainMs > 0 ? formatMillisToHms(remainMs) : "00:00:00"
    }
    
    private func startTimer(targetEpoch: Int64) {
        stopTimer()
        timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { [weak self] _ in
            guard let self else { return }
            let remain = self.remainingMs(to: targetEpoch)
            self.updateCountdownText(remain)
            if remain == 0 {
                self.stopTimer()
                self.checkQuotaStatus()
            }
        }
        if let t = timer { RunLoop.main.add(t, forMode: .common) }
    }
    
    func stopTimer() {
        timer?.invalidate()
        timer = nil
    }
    
    private func remainingMs(to epoch: Int64) -> Int64 {
        let ms = normalizeToMs(epoch)
        let nowMs = Int64(Date().timeIntervalSince1970 * 1000)
        let fudgeMs: Int64 = 5000
        
        // Kotlin 로직과 동일하게 표시 보정 적용
        return max(ms - nowMs + fudgeMs, 0)
    }
    
    /// 초 단위/밀리초 단위 혼용 대비
    private func normalizeToMs(_ epoch: Int64) -> Int64 {
        epoch < 1_000_000_000_000 ? epoch * 1000 : epoch
    }
    
    private func formatMillisToHms(_ ms: Int64) -> String {
        let total = ms / 1000
        let h = total / 3600
        let m = (total % 3600) / 60
        let s = total % 60
        return String(format: "%02d:%02d:%02d", h, m, s)
    }
    
    private func getSavedBackgroundImageId() -> Int? {
        let imageId = UserDefaults.standard.integer(forKey: bgImageIdKey())
        return imageId > 0 ? imageId : nil
    }
    
    private func bgImageIdKey() -> String {
        return "chat_bg_image_id_room_\(roomId)"
    }
}