class ChatService {
    constructor() {
        this.messages = [];
        this.welcomeMessageShown = false;
        this.pageReady = false;
        this.userId = this.getOrCreateUserId();
        this.init();
    }

    checkAndShowWelcomeMessage() {
        const checkWelcomeMessage = () => {
            if (document.getElementById('chat-messages')) {
                setTimeout(() => {
                    this.showWelcomeMessage();
                }, 500);
            } else {
                setTimeout(checkWelcomeMessage, 100);
            }
        };

        checkWelcomeMessage();
    }

    getOrCreateUserId() {
        let userId = localStorage.getItem('chatUserId');
        if (!userId) {
            userId = 'user_' + Date.now() + '_' + Math.floor(Math.random() * 1000000);
            localStorage.setItem('chatUserId', userId);
        }
        return userId;
    }

    init() {
        if (!this.userId) {
            this.userId = this.getOrCreateUserId();
        }

        this.loadFromLocalStorage();
        this.displayMessages();
        this.setupEventListeners();
        this.pageReady = true;

        window.addEventListener('languageChanged', () => {
            const welcomeMsg = this.messages.find(msg => msg.id.startsWith('welcome_'));
            if (welcomeMsg) {
                let welcomeText = '您好！欢迎访问无穷智能自动售货机官网，有什么可以帮助您的吗？';
                if (window.languageManager && window.languageManager.isLoaded) {
                    const translatedWelcome = window.languageManager.getTranslation('chat_welcome');
                    if (translatedWelcome) {
                        welcomeText = translatedWelcome;
                    }
                }
                welcomeMsg.message = welcomeText;
                this.displayMessages();
            }
        });

        const waitForLanguageManager = async () => {
            if (window.languageManager && window.languageManager.isLoaded) {
                await this.loadMessages();
            } else {
                setTimeout(waitForLanguageManager, 100);
            }
        };

        waitForLanguageManager();
    }

    loadFromLocalStorage() {
        const storedMessages = localStorage.getItem('chatMessages');
        if (storedMessages) {
            try {
                const parsedMessages = JSON.parse(storedMessages);

                this.messages = parsedMessages.filter(msg => {
                    if (msg.userId !== this.userId) {
                        return false;
                    }
                    if (msg.id.startsWith('welcome_')) {
                        return false;
                    }
                    return true;
                });
            } catch (error) {
                this.messages = [];
            }
        } else {
            this.messages = [];
        }
    }

    async loadMessages() {
        const currentNonWelcomeMessages = this.messages.filter(msg => !msg.id.startsWith('welcome_'));

        try {
            const response = await fetch(`/api/chat?userId=${this.userId}`);
            if (response.ok) {
                const data = await response.json();
                if (data.success && data.data) {
                    const serverMessages = data.data.filter(msg => {
                        const msgUserId = msg.userId || msg.sessionId;
                        if (msgUserId !== this.userId) return false;
                        if (msg.id.startsWith('welcome_')) return false;
                        return true;
                    });

                    const mergedMessages = [...currentNonWelcomeMessages, ...serverMessages];
                    const filteredMergedMessages = mergedMessages.filter(msg => {
                        const msgUserId = msg.userId || msg.sessionId;
                        if (msgUserId !== this.userId) return false;
                        if (msg.id.startsWith('welcome_')) return false;
                        return true;
                    });

                    const uniqueMessages = this.removeDuplicateMessages(filteredMergedMessages);

                    if (!this.messagesEqual(currentNonWelcomeMessages, uniqueMessages)) {
                        const welcomeMsg = this.messages.find(msg => msg.id.startsWith('welcome_'));
                        this.messages = uniqueMessages;
                        if (welcomeMsg) {
                            this.messages.unshift(welcomeMsg);
                        }
                        this.saveToLocalStorage();
                        this.displayMessages();
                    }
                    return;
                }
            }
        } catch (error) {
        }

        const storedMessages = localStorage.getItem('chatMessages');
        if (storedMessages) {
            try {
                const parsedMessages = JSON.parse(storedMessages);
                const filteredMessages = parsedMessages.filter(msg => {
                    const msgUserId = msg.userId || msg.sessionId;
                    if (msgUserId !== this.userId) return false;
                    if (msg.id.startsWith('welcome_')) return false;
                    return true;
                });

                const finalMessages = [...currentNonWelcomeMessages, ...filteredMessages];
                const uniqueMessages = this.removeDuplicateMessages(finalMessages);

                if (!this.messagesEqual(currentNonWelcomeMessages, uniqueMessages)) {
                    const welcomeMsg = this.messages.find(msg => msg.id.startsWith('welcome_'));
                    this.messages = uniqueMessages;
                    if (welcomeMsg) {
                        this.messages.unshift(welcomeMsg);
                    }
                    this.displayMessages();
                }
            } catch (error) {
                this.displayMessages();
            }
        }
    }

    removeDuplicateMessages(messages) {
        const uniqueMessages = [];
        const seenMessages = new Map();
        const welcomeMessages = [];

        const sortedMessages = messages.sort((a, b) => {
            return new Date(b.timestamp) - new Date(a.timestamp);
        });

        for (const message of sortedMessages) {
            if (message.id.startsWith('welcome_')) {
                if (welcomeMessages.length === 0) {
                    welcomeMessages.push(message);
                }
            } else {
                const messageKey = `${message.message}-${message.userType}-${message.timestamp}-${message.userId || message.sessionId}`;

                if (!seenMessages.has(messageKey)) {
                    seenMessages.set(messageKey, true);
                    uniqueMessages.push(message);
                }
            }
        }

        return [...welcomeMessages, ...uniqueMessages].sort((a, b) => {
            return new Date(a.timestamp) - new Date(b.timestamp);
        });
    }

    messagesEqual(arr1, arr2) {
        if (arr1.length !== arr2.length) return false;
        for (let i = 0; i < arr1.length; i++) {
            if (arr1[i].id !== arr2[i].id ||
                arr1[i].message !== arr2[i].message ||
                arr1[i].userType !== arr2[i].userType ||
                arr1[i].timestamp !== arr2[i].timestamp ||
                arr1[i].status !== arr2[i].status ||
                arr1[i].userId !== arr2[i].userId) {
                return false;
            }
        }
        return true;
    }

    saveToLocalStorage() {
        const filteredMessages = this.messages.filter(msg => {
            if (msg.id.startsWith('welcome_')) {
                return false;
            }
            return true;
        });
        localStorage.setItem('chatMessages', JSON.stringify(filteredMessages));
    }

    setupEventListeners() {
        const setupListeners = () => {
            const chatSend = document.getElementById('chat-send');
            const chatInput = document.getElementById('chat-input');

            if (chatSend) {
                chatSend.addEventListener('click', () => {
                    const message = chatInput.value.trim();
                    if (message) {
                        this.sendMessage(message);
                        chatInput.value = '';
                    }
                });
            }

            if (chatInput) {
                chatInput.addEventListener('keypress', (e) => {
                    if (e.key === 'Enter') {
                        const message = chatInput.value.trim();
                        if (message) {
                            this.sendMessage(message);
                            chatInput.value = '';
                        }
                    }
                });
            }

            const chatButton = document.getElementById('chat-button');
            const chatBox = document.getElementById('chat-box');
            const chatClose = document.getElementById('chat-close');

            if (chatButton && chatBox) {
                chatButton.addEventListener('click', () => {
                    chatBox.classList.add('open');
                    chatButton.style.display = 'none';
                    this.showWelcomeMessage();
                });
            }

            if (chatClose && chatBox) {
                chatClose.addEventListener('click', () => {
                    chatBox.classList.remove('open');
                    const chatButton = document.getElementById('chat-button');
                    if (chatButton) {
                        chatButton.style.display = 'flex';
                    }
                });
            }
        };

        if (document.readyState === 'loading') {
            document.addEventListener('DOMContentLoaded', setupListeners);
        } else {
            setupListeners();
        }
    }

    getCurrentDate() {
        const now = new Date();
        return now.toISOString().split('T')[0];
    }

    isTodayMessage(message) {
        if (!message.timestamp) return false;
        const messageDate = new Date(message.timestamp).toISOString().split('T')[0];
        const currentDate = this.getCurrentDate();
        return messageDate === currentDate;
    }

    showWelcomeMessage() {
        const chatMessages = document.getElementById('chat-messages');
        if (!chatMessages) return;

        let welcomeText = '您好！欢迎访问无穷智能自动售货机官网，有什么可以帮助您的吗？';

        if (window.languageManager && window.languageManager.isLoaded) {
            const translatedWelcome = window.languageManager.getTranslation('chat_welcome');
            if (translatedWelcome) {
                welcomeText = translatedWelcome;
            }
        }

        this.messages = this.messages.filter(msg => !msg.id.startsWith('welcome_'));

        const welcomeMessage = {
            id: 'welcome_' + Date.now(),
            message: welcomeText,
            userType: 'bot',
            timestamp: new Date().toISOString(),
            status: 'sent',
            userId: this.userId
        };

        this.messages.unshift(welcomeMessage);
        this.displayMessages();
        this.welcomeMessageShown = true;
    }

    updateWelcomeMessage(welcomeText) {
        const welcomeMsg = this.messages.find(msg => msg.id.startsWith('welcome_'));
        if (welcomeMsg) {
            welcomeMsg.message = welcomeText;
            this.saveToLocalStorage();
            this.displayMessages();
        }
    }

    async sendMessage(message) {
        const newMessage = {
            id: 'msg_' + Date.now() + '_' + Math.floor(Math.random() * 1000),
            message: message,
            userType: 'user',
            timestamp: new Date().toISOString(),
            status: 'sending',
            userId: this.userId
        };

        this.messages.push(newMessage);
        this.saveToLocalStorage();
        this.displayMessage(newMessage);

        try {
            const response = await fetch('/api/chat', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    message: message,
                    userType: 'user',
                    timestamp: newMessage.timestamp,
                    userId: this.userId
                })
            });

            if (response.ok) {
                const data = await response.json();
                if (data.success) {
                    newMessage.status = 'sent';
                    this.saveToLocalStorage();
                    this.updateMessageDisplay(newMessage);
                    await this.loadMessages();
                }
            }
        } catch (error) {
            newMessage.status = 'failed';
            this.saveToLocalStorage();
            this.updateMessageDisplay(newMessage);
        }
    }

    escapeHtml(text) {
        const div = document.createElement('div');
        div.textContent = text;
        return div.innerHTML;
    }

    displayMessage(message) {
        const chatMessages = document.getElementById('chat-messages');
        if (!chatMessages) return;

        const messageElement = document.createElement('div');
        messageElement.id = 'msg_' + message.id;
        messageElement.className = `chat-message ${message.userType === 'user' ? 'user' : 'bot'}`;

        let statusIndicator = '';
        if (message.userType === 'user') {
            if (message.status === 'sending') {
                statusIndicator = '<span class="message-status sending">发送中...</span>';
            } else if (message.status === 'failed') {
                statusIndicator = '<span class="message-status failed">发送失败</span>';
            }
        }

        messageElement.innerHTML = `
            <div class="chat-message-content">
                <p>${this.escapeHtml(message.message)}</p>
                <div class="chat-message-footer">
                    <span class="chat-message-time">${this.formatTime(message.timestamp)}</span>
                    ${statusIndicator}
                </div>
            </div>
        `;

        chatMessages.appendChild(messageElement);
        chatMessages.scrollTop = chatMessages.scrollHeight;
    }

    updateMessageDisplay(message) {
        const messageElement = document.getElementById('msg_' + message.id);
        if (!messageElement) return;

        let statusIndicator = '';
        if (message.userType === 'user') {
            if (message.status === 'sent') {
                statusIndicator = '<span class="message-status sent">已发送</span>';
            } else if (message.status === 'failed') {
                statusIndicator = '<span class="message-status failed">发送失败</span>';
            }
        }

        const footerElement = messageElement.querySelector('.chat-message-footer');
        if (footerElement) {
            footerElement.innerHTML = `
                <span class="chat-message-time">${this.formatTime(message.timestamp)}</span>
                ${statusIndicator}
            `;
        }
    }

    displayMessages() {
        const chatMessages = document.getElementById('chat-messages');
        if (!chatMessages) return;

        chatMessages.innerHTML = '';

        this.messages.forEach(message => {
            this.displayMessage(message);
        });

        if (this.messages.length === 0) {
            this.welcomeMessageShown = false;
        }
    }

    formatTime(timestamp) {
        const date = new Date(timestamp);
        return date.toLocaleTimeString('zh-CN', {
            hour: '2-digit',
            minute: '2-digit'
        });
    }

    clearMessages() {
        this.messages = this.messages.filter(msg => !msg.id.startsWith('welcome_'));
        this.welcomeMessageShown = false;
        this.saveToLocalStorage();
        this.displayMessages();
    }

    startPolling() {
        this.pollingInterval = setInterval(() => {
            this.loadMessages();
        }, 5000);
    }

    stopPolling() {
        if (this.pollingInterval) {
            clearInterval(this.pollingInterval);
        }
    }
}

if (typeof window !== 'undefined') {
    const initChatService = () => {
        const waitForLanguageManager = () => {
            if (window.languageManager) {
                window.chatService = new ChatService();
                window.chatService.startPolling();
            } else {
                setTimeout(waitForLanguageManager, 100);
            }
        };
        waitForLanguageManager();
    };

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', initChatService);
    } else {
        initChatService();
    }
}